Tanglin Trust School Carbon Audit Report

Tanglin Trust School

Tanglin Trust School Carbon Audit

Copyright © 2024 Helios Renewable Energy Limited.

www.metanoia-eco.com

8/F, Cheung Hing Industrial Building, Smithfield, Kennedy Town Hong Kong

Tanglin Trust School

Carbon and Energy Audit

2024

“Education for sustainability is more than just a new curriculum. It is about how the content and process of education can be interwoven with real-life contexts to create opportunities for young people to take the lead in building sustainable communities and societies.”

– Peter Senge

“Hope is a verb with its sleeves rolled up.”

– David Orr

“What gets measured, gets managed.”

– Peter Drucker

Introduction

Executive Summary

1. Context

1.1 Global Context

1.2 Singapore Context

1.3 Singapore's Adaptation to Climate Change

2. Tanglin's Carbon Footprint

2.1 Overview

2.2 Hotspot Analysis

3. Roadmap to Net Zero

3.1 Reducing emissions from electricity

3.2 Reducing supply chain emissions

3.3 Reducing travel emissions

3.4 Reducing emissions from other sources

3.5 Carbon offsetting and climate action beyond Tanglin’s footprint

4. Tanglin's Other Environmental Impacts

4.1 Water Use

4.2 Food and Food Waste Audit

4.3 General Waste Audit

4.4 Uniform Audit

4.5 Feedback from the Travel Survey

Appendices

Endnotes

Metanoia: A Path to Sustainable Learning

As we navigate an increasingly interconnected and complex world, the urgency of addressing climate change becomes more apparent. The Tanglin Trust School community recognizes the critical role education plays in fostering a generation of environmentally conscious and responsible citizens.

This report, a collaborative effort between Tanglin Trust School and Metanoia, offers a comprehensive assessment of our energy consumption and carbon footprint. By understanding our current baseline, we can identify areas for improvement and develop targeted strategies to reduce our environmental impact.

The insights gained from this audit will inform our curriculum and co-curricular programs, ensuring that

our students are equipped with the knowledge and skills to make informed decisions about their personal and collective actions to mitigate climate change. Through experiential learning, community engagement, and sustainable initiatives, we aim to cultivate a culture of environmental stewardship within our school.

I am confident that this report will serve as a catalyst for positive change and inspire our students to become active participants in building a more sustainable future. Together, we can create a legacy of environmental responsibility that will benefit generations to come.

Craig Considine Chief Executive Officer

Introduction

On a Friday afternoon in August 2018, a thenunknown high school student sat down in front of the Swedish parliament with a hand drawn sign that read “school strike for climate.” Within a few months Greta Thunberg’s solo protest had inspired hundreds of thousands of young people around the world to join her in calling for more urgent action on climate change. At the time, the concentration of CO₂ in the atmosphere was 407 ppm. “Our house is on fire and no one is acting” she said to a meeting of the World Economic Forum.

Six years later, CO₂ levels are 419 ppm and climate anxiety and dissatisfaction with government responses are widespread. A study published in Lancet Planetary Health in 2021 reported that 59% of young people aged 16-25 were very or extremely worried about climate change, 45% said their feelings about climate change negatively affected their daily life and functioning, and more than 50% reported feeling sad, anxious, angry,

powerless, helpless and guilty. Distress was correlated with perceived inadequate government response.

I established Metanoia to offer schools a way to respond to students on this issue, recognizing that action is one of the best antidotes to eco-anxiety and that schools are a more immediate sphere of influence for students than the halls of government. By supporting students to identify meaningful opportunities to make their campuses more sustainable and working with them to implement the changes, schools can help “make hope possible, rather than despair convincing,” in the words of the British social critic, Raymond Williams.

In fact, the campus where students spend eight hours a day for half the year is a vastly under-utilised reservoir of possibilities for learning and impact. How much solar could you put on the school roof? What progress is the school making with handling waste? How many million kilometres did the school community fly on overseas school trips last year? What can we do about these impacts?

Creating a sustainable school in this deep sense is no easy task. It’s no easy task because there is a lot to be done. Consider the hardware – typical school campuses are short on greenery, cooled year-round, with energy-inefficient designs, limited use of solar energy, millions of commuting kilometres in school buses using fossil fuel, unsustainably produced food, and tonnes of waste sent to landfill. And who has the time to manage even one meaningful course correction here? Facilities managers have their hands full ensuring the smooth and continuing operations on which classes depend, teachers’ timetables are inflexible and full, and students’ afternoons are overflowing with extracurricular activities.

It’s not an easy task because it also requires upgrading the “software” - hearts and minds.

How is sustainability relevant to the mission of the school? If a hardware upgrade can’t be commercially justified by the savings it will produce, might we nevertheless agree there are other ways to measure its value? Will a department be content with the restrictions of a sustainable procurement policy when their favorite product happens to be made on the other side of the world? Will parents settle for reference letters issued on less than pure white recycled paper? What of the contentious issue of mandatory busing? How many students will choose to forego meat in the cafeteria even one day a week, or walk or bus to school when driving is more convenient or comfortable?

It’s not an easy task because even if hearts and minds are willing, many people simply don’t know what actions matter, what really moves the needle, or what’s technically feasible. I once heard a group of students give a polished presentation about an environmental strategy for the school they had worked on for months under the guidance of an external consultant. Their vision was laudable but their recommendations very high level. When I asked them what one thing they would change to really impact the school’s environmental footprint, it became clear that they had gathered no data and so had no idea which were the most important levers to pull.

Creating a sustainable school may not be an easy task, but it’s clear the impact of the endeavour extends far beyond the campus boundary and the current cohort of students.

This is true, first of all, because schools are microcosms of the city. They share the same challenges of waste, air quality, energy inefficient buildings, infrastructure lock-in, and carbon emissions, combined with the constraints of space, time, money and expertise and a range of competing interests. But in schools, these problems show up at a more addressable scale and in a culture where the pedagogical paradigms of risk-taking, collaboration and experiential learning are more commonplace than they are in government, and solutions (and by this I don’t just mean technological ones) can be prototyped and innovations demonstrated to the wider community.

And second, because the roughly 1 million school students who will graduate from high school in Singapore in the next 25 years will represent around 25% of the workforce in 2050. So the degree to which Singapore will be a sustainable city will be determined at least as much, I would argue, by educating for sustainability as it will by formulating policy and adopting new technology.

Metanoia's mission is to help schools unlock the sustainability learning that is embedded in the campus and the school’s daily life and to develop the capacity of students and schools to do the practical as well as intellectual work of becoming a truly sustainable community. We are pleased to have had the opportunity to work with Tanglin students and staff on this review and trust that it will provide a foundation for schoolwide action and future progress on sustainability.

Anthony Dixon Founder of Metanoia

Executive summary

Metanoia conducted a carbon and energy audit of Tanglin Trust School operations during the period March - July 2024. The audit was conducted according to the greenhouse gas accounting and reporting standards of the GHG Protocol. The key objectives of the audit were to quantify the school’s total carbon footprint in 2023, identify hotspots and reduction opportunities, and develop a carbon reduction roadmap.

In 2023 Tanglin’s carbon footprint was 9,573 tonnes of carbon dioxide equivalent emissions (tCO₂e). The major contributors to this were electricity use (31%), purchased goods and services (22%), school trips (17%), capital goods (11%), and commuting (9%).

We have developed a decarbonisation roadmap for Tanglin based on the Science Based Target initiatives (SBTi) Corporate Net-Zero Target standards, and our understanding of what is feasible for the school following our audit.

We recommend that Tanglin set a target to become net-zero emissions by 2050, with a near-term target of a 63% reduction by 2035, from a 2023 baseline. These targets are aligned with SBTi’s ambitious ‘1.5C pathway’. A less ambitious option would be SBTi’s ‘well below 2°C’ pathway which would require a 63% reduction in Scope 1 and 2 emissions (mostly electricity) and a 37.5% reduction in Scope 3 (indirect emissions such as supply chain emissions, and school trips) by 2035. Alignment with SBTi is not mandatory but is considered best practice.

We are confident that it is feasible for Tanglin to achieve net zero emissions by 2050, with a 63% reduction in emissions by 2035, despite the forecasted increase in student population (15% in 2030 and 41% in 2040 from today’s levels). That said, the decarbonisation pathway depends heavily on several factors that are outside the school’s control, including the decarbonisation of Singapore’s electricity grid, low carbon options becoming available in the school’s supply chains, system-wide improvements in the energy efficiency and carbon intensity of buildings materials, equipment

(such as ACs) and transportation (such as electric vehicles). There is therefore a high degree of uncertainty in the pathway, particularly beyond the near-term target of 2035. The most difficult areas to decarbonise are expected to be school trips (flights) and procurement of goods and services.

Electricity

The school consumed 7.2 million kWh of electricity in 2023, resulting in emissions of 3,000 tCO₂e. This is a 19% increase over 2022 owing largely to the completion of the Centenary building. Tanglin’s energy use intensity (EUI) is 88 kWh/m² which is low compared to other schools Metanoia has audited or has direct knowledge of. Among Singapore schools, the lowest EUI we are aware of is UWCSEA Dover’s at 55 kWh/m².

Cooling, ventilation, lighting, and appliances are the biggest consumers of electricity at Tanglin. In the case of the Centenary building, cooling accounts for about 40% of electricity use, the pool accounts for 18%, ventilation 12%, and lighting 11%. Similar data isn’t available for the other buildings but without the swimming pool heating, cooling may be as high as 60%.

Most of the buildings at Tanglin are cooled by efficient ACs systems, either split-type VRV units or (in the case of Nixon) a chiller system. However, some of the AC units, particularly those in the infant school, are old and in need of replacement. Many other units will reach their end of life in the next 5 years. Older ACs are much less efficient. When they are replaced, the school should choose the most efficient units available.

Tanglin can substantially reduce its emissions from electricity by a combination of measures including technical upgrades of equipment, operational and behaviour changes, ensuring new buildings are designed to the highest energy efficiency standards, maximising solar PV on campus, and purchasing renewable energy certificates (RECs). The Singaporean government has set a target for the electricity grid to decarbonise by 2050 so emissions from electricity

use will also continue to decrease over time, but nevertheless Tanglin should do all it can to become more efficient and reduce its emissions from electricity in the ways mentioned above.

Tanglin has installed two small rooftop solar PV arrays, one on the West Wing (69 kWp), and one on the Centenary building (28 kWp). Although they only contribute less than 1% of the school’s electricity consumption, there is significant potential for further rooftop solar installations on campus. Our modelling indicates that 20% of the school’s electricity could be met by rooftop solar and even more is possible if carpark shade, building façades, and cantilevered structures are utilised. In addition, any new buildings must seek to maximise the deployment of solar PV from the design stage. The Greenhouse at Dulwich College, Singapore is an excellent and innovative example of best practise in this area.

We recommend that Tanglin explore using energy efficiency technologies such as hybrid cooling (adding ceiling fans to reduce AC usage), green walls and roofs, and smart lighting management. All new buildings should be designed to be highly energy efficient, and ideally net-zero energy.

We note that over 40% of the school’s electricity consumption occurs during non-operating hours (overnight and during weekends and holidays). Clearly there is potential for significant energy and carbon savings by addressing this.

Travel

In 2023 Tanglin students and staff took 120 international school-related trips, which generated 1,623 tonnes of CO₂. Nearly all these trips were by plane – only four trips to Kuala Lumpur were by road. Just eight trips (7%) accounted for 53% of all trip emissions. The trips which had the highest emissions per person were to Switzerland (4.2 tCO₂e/person), New Zealand (3.3) and Australia (2.5). There were also many domestic trips by bus which gave rise to a further 22 tCO₂e.

Emissions from school-related trips can be mitigated by reducing the number of flights, particularly long-haul flights to distant places, travelling by bus and train to locations in Malaysia, and by choosing economy over business class where possibles (for reference a round-trip business class trip to London emits 12.5 tCO₂e/person).

The introduction of the Tanglin Highlands Programme in Gippsland poses a challenge to the goal of reducing emissions from flying. We estimate that one year group travelling return to Melbourne will emit 460 tonnes of CO₂e, 28% to the school’s current emissions from flying. We recommend the school purchase offsets to address this, but caution that offsetting cannot be used to claim emissions reductions, only to contribute to global climate action.

In its daily commute to and from school, the Tanglin community travelled over 13 million passengerkilometres in 2023 resulting in 848 tonnes of CO₂e emissions. Encouragingly, three-quarters of the school community already travels to school in an environmentally friendly way - almost half take the school bus, 19% take public transport and 9% cycle or walk. But there is room for improvement.

The most significant actions Tanglin can take to reduce emissions from commuting are electrifying the school buses, increase the number of people that take the school bus, or use other green modes and implementing a green transport policy.

Electrifying the school bus could reduce emissions from the service by almost 80% right away and thereafter emissions will continue to fall to zero by 2050 as the grid decarbonises. Public and private vehicles in Singapore are expected to be all electric by 2040 adding significant momentum to Tanglin’s decarbonisation efforts.

Supply chain

Emissions from Tanglin’s supply chain - purchased goods and services (2,107 tCO₂e) and capital goods (1,069 tCO₂e) - accounted for a third of the school’s carbon footprint in 2023. This does not include items teachers purchase using their class or subject budgets since data on this was not readily available.

The four largest categories contributing to supply chain emissions were building construction and related services, building and renovation work services, and electrical lighting products and services.

We believe that Tanglin’s supply chain emissions in 2023 may have been higher than a typical year owing to procurement related to the completion of the Centenary building, but we were not able to quantify this. We recommend the school recalculate its supply chain emissions next year to get a better indication of their level in a year without new building activity.

Reducing supply chain emissions is challenging as there is limited transparency and suppliers often lack adequate data to reliably quantify their own emissions. However, there are policies Tanglin can adopt to achieve its targets such as buying less, buying local, and avoiding air shipping where possible. The school should also ensure that its contracts with suppliers contain strong sustainability provisions, that it takes sustainability into account when choosing suppliers and service providers (e.g. compliance with ISO 14001 for Environmental Management Systems), and that it chooses products and services with low embodied carbon.

The school should also consider developing a sustainable procurement policy and a strategy aligned with ISO 20400: 2017 Sustainable Procurement.

Minor components of Tanglin’s carbon footprint

10% of the school’s carbon footprint is composed of multiple minor components: upstream emissions from fossil fuels and electricityi (6%), refrigerant leaks (2%), the transportation of purchased goods and services (1%) and of the school’s waste (0.003%), emissions from gas used in the kitchen (0.1%) and science labs (0.002%), and emissions from fuel used in the school’s vehicles (0.05%).

i These emissions are from the extraction, processing, and transportation of fossil fuels consumed by the school in the forms of gas, petrol, diesel, and electricity, and transmission and distribution losses.

Figure 1

Tanglin’s annual emissions according to the roadmap. The remaining emissions in 2050 can be neutralised by purchasing carbon offsets (Annual emissions, tCO₂e)

10,000 8,000 9,000

7,000

6,000 5,000 4,000 3,000 2,000 1,000 0 Electricity

Capital goods

Commuting

Transport of goods and services

Fuel use on campus

Purchased goods and services

Upstream emissions from energy

School-related trips

Refrigerant emissions

Fuel use in school vehicles Waste

Fuel use in canteens operated by Chartwells

SBTi Target

Table 1

Modelled reduction opportunities for key hotspots by 2035

Hotspot

Electricity use Solar PV 2025-2028 20% in emissions from electricity use

Electricity use Asset replacement - lighting and ACs Ongoing ~ 7.5% in emissions from electricity use by 2035

Electricity use Out of hours energy use (overnight, weekend, holiday)

By 2030 Up to 35% in emissions from electricity use

Electricity use Hybrid cooling By 2030 Up to 20% of emissions from electricity use

Electricity use Occupancy and lighting control of lights (and possibly ACs)

Supply chain Reduction in purchasing and emissions from supply chain

School trips Reduce school flights (passenger kilometres)

By 2030 Up to 4% of emissions from electricity use

1,437,000 kWh, 20% of current electricity use

More potential possible with shaded walkways, carparks, cantilevered roof structures, facade and with the new buildings

10-20% of replaced units. Replacement to occur at end of life, or earlier for lighting. High uncertainty beyond 2030 due to unknown future efficiency and the emergence of new technologies

Up to 35% of total energy use

Up to one third of AC and ventilation energy use

Up to 30% energy use reduction from lighting

Ongoing to 2035 6% per year -

Ongoing 10% per year -

Commuting Electric school bus by 2030 83% in emissions compared to diesel school buses in 2030. 60% reduction if the switched in 2024.

DALi lighting control can be integrated into the ITM system

Reduction from buying less, careful selection of suppliers and necessary items

Reduction from flying less and flying to closer distance. 10% per year is a 50% reduction by 2035 and 90% reduction by 2050

- Potential increase in energy use (scope 2) dependent on location of charging

Commuting Introduce mandatory busing by 2030 ~10-15% in total commuting emissions - Much greater impact when combined with bus electrification

Tanglin’s other environmental impacts

A carbon audit is a good place to start when quantifying the environmental footprint of a school. However, carbon emissions don’t tell the whole story. During our audit we took a deeper dive into some of the largest contributors to the school’s environmental footprint that don’t necessarily contribute significantly to the school’s carbon footprint.

Water

Tanglin’s water consumption in 2023 was 36,900 m³, an increase of 39% over 2022. Half of this increase is due to the opening of the Centenary, the rest is due to significantly higher water use in the West Wing, Senior Reception, Berrick, and 6th Form College. We don’t know the reason for the substantial increase in water use in these buildings.

The school uses recycled water, (NEWater supplied by PUB, Singapore’s national water agency) for some non-potable uses such as in the chiller system in Nixon building, but there is no rainwater collection, or onsite water reuse (greywater).

The main water users at Tanglin are expected to be toilet flushing, followed by faucets, kitchens, and irrigation. Tanglin does not measure water use by use type (e.g. irrigation or flushing) so these are estimates only. The artificial playing field significantly reduces the amount of water used for irrigation. Tanglin’s water use is relatively low compared to other schools we have audited. The only schools with lower water use intensity and water use intensity per student are two schools in Hong Kong that use salt water for toilet flushing.

Food

Using data provided by Chartwells, we estimated the carbon emissions associated with the food served in the canteen in 2023 to be 520 tCO₂e. Beef products accounted for 26% of this. Reducing the consumption of meat and dairy products is the most effective ways the school can reduce these emissions Tanglin can also work with Chartwells on menu planning and portion sizing. During the food waste audit, we noticed a lot

of starches being discarded because the portions were too large.

Metanoia and Tanglin students conducted a weeklong food waste audit in the junior canteen and the Nixon canteen in May. We estimate Tanglin produces 50kg of food waste per day or close to nine tonnes per year. We recommend Tanglin consider purchasing an industrial composter and setting up some compost boxes so that all the food waste it produces can be composted on campus.

General waste

There are two waste streams at Tanglin: general waste and recyclable waste. In 2023, Tanglin generated over 77 tonnes of general waste. Paper, metal (aluminium cans and food tins), plastic (PET and HDPE) and bottled glass are recycled at Tanglin, but no data was available on the quantity.

Uniforms

Tanglin purchases school uniforms from a supplier called Children Party Dress Shop (CPD) and resells them to parents through the school shop. In 2023, Tanglin bought 7,209 school uniform items which we estimate produced 61 tonnes of CO₂e.

The school has no system in place to encourage environmentally friendly end-of life disposal of its uniforms. Consequently, most old uniforms end up in landfill or the incinerator – as many as 7,000 items every year just from Tanglin alone. This is a significant and largely unseen environmental problem.

Two better options are re-sale of second-hand uniforms or recycling. The primary fabrics in the uniform are cotton, polyester and other synthetics. Cotton and polyester items can be recycled if there is a system in place to collect them.

When surveyed, two-thirds of parents said they never purchase second-hand uniforms and always buy new ones. Many parents noted that second-hand uniforms were difficult to find in the school shop and not advertised as much as they should be.

1.1 Global Context

For the past 12,000 years, the Earth has existed in a geological epoch known as the Holocene. The Holocene began after the last major ice age and is characterised by relatively stable and warm climatic conditions compared to the Pleistocene epoch which preceded it. It is within these climatic conditions that human civilisation has developed, and these conditions are the only state of the Earth system that we know for certain can support modern human societies.1

But many scientists agree that we may have entered a new geological epoch – the Anthropocene – in which human pressures have pushed the Earth system onto a trajectory moving rapidly away from the stability of the Holocene.2

The ability of the Earth system to regulate itself, to remain in a stable, “Holocene-like” state, depends on nine biophysical and biochemical processes.3 These include the global biogeochemical cycles of nitrogen, phosphorus, carbon, and water; the major physical circulation systems of the climate, stratosphere, and ocean systems; the biophysical features of Earth that contribute to the underlying resilience of its capacity to self-regulate (marine and terrestrial biodiversity, land systems); and two critical features associated the

anthropogenic global change – aerosol loading and chemical pollution.4

All these processes are currently heavily perturbed by human activities.

The planetary boundaries framework identifies levels of anthropogenic perturbations below which the risk of destabilising the Earth system remains low (see Figure 1.1).5 These so-called ‘safe operating spaces’ allow for society to continue to develop, without disrupting the environmental functions and life-supporting conditions we have experienced over the past 12,000 years.

However, rapid changes to the Earth system, driven largely by unsustainable resource extraction and consumption, and the resulting waste, are pushing the Earth system beyond its safe operating spaces. In September 2023, scientists announced that six of the nine boundaries have been transgressed.6 Crossing just one boundary increases the risk of generating largescale abrupt and irreversible environmental changes. But the boundaries are interrelated processes within a complex system, so breaching one boundary may have unforeseen impacts on the other boundaries, pushing them closer towards tipping points.

Figure 1.1

The evolution of the planetary boundaries framework.7

7 boundaries assessed, 3 crossed

7 boundaries assessed, 4 crossed

9 boundaries assessed, 6 crossed

Climate change

Climate change is by far the most widely discussed planetary boundary. However, while it may receive the most media attention, it is not the only important boundary. The nine boundaries are interconnected and feedback from any of the nine processes may impact the others.

The climate change boundary defines a threshold beyond which abrupt and irreversible changes in the Earth system would lead to the disruption of regional climates, the collapse of major patterns of climate dynamics such as the thermohaline circulation (deep ocean currents which are controlled by the temperature and salinity), and other negative impacts such as sea level rise.8 The global-scale parameters used to define this boundary are atmospheric CO₂ concentration and radiative forcing.

The increasing concentrations of atmospheric CO₂

Carbon dioxide (CO₂) is a greenhouse gas. Greenhouse gases absorb heat from the sun and heat that is radiating from the Earth’s surface that would otherwise escape into space, a phenomenon known as the greenhouse effect. The greenhouse effect keeps the Earth’s surface at a liveable temperature; without it, the average temperature would be around -18°C.9 Other naturally occurring greenhouse gases include methane (CH₄), nitrous oxide (N₂O), ozone (O3) and water vapour (H₂O).

In the natural carbon cycle, which occurs over timescales from days to millennia, carbon dioxide is continually absorbed and released into the atmosphere, the ocean, the soil, vegetation and geological formations. This process has maintained the concentration of CO₂ in the atmosphere below 280 parts per million for 800,000 years and has contributed to the stable climate of the last 12,000 years.

But since the Industrial Revolution, human activities have resulted in the concentration of atmospheric CO₂ increasing faster than the carbon cycle can remove it. By the end of the 1950s, the level was around

313 ppm.10 By 2000, CO₂ levels had risen to 365 ppm, and at the end of 2023 they were almost 420 ppm (see Figure 1.2) – about 50% higher than it was before the Industrial Revolution.11

Even more important is the fact that the rate of increase in the last 60 years has been about 100 times faster than previous natural increases, such as at the end of the last ice age. The rate of increase makes it harder for ecosystems to adjust to the higher levels.12

Most of the increase is due to the extraction and burning of fossil fuels and land-use change. Fossil fuels (coal, oil, and gas) contain carbon that plants sequestered from the atmosphere millions of years ago, which is released back into the atmosphere as CO₂ when the fuels are burnt. Since the of the 1950s emissions from burning fossil fuels have increased every decade – from almost 11 billion tonnes of CO₂ per year in the 1960s, to around 36.8 billion tonnes in 2023.13

This is supercharging the greenhouse effect and leading to an imbalance in the natural carbon cycle which is causing global warming and climate change. As the IPCC’s Climate Change 2023 Synthesis Report clearly states: “Human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming, with global surface temperature reaching 1.1°C above 1850-1900 levels in 2011-2020.”14

Figure 1.2

Atmospheric carbon dioxide levels (ppm) have fluctuated over the last 800,000 years, but increased sharply following the industrial revolution.15

Figure 1.3

Annual surface temperature (°C) from 1880-2023 compared to the 20th century average (1901-2000). The bars in blue indicate cooler-than-average years, while the red bars indicate warmer than average. The ten warmest years on record have all occurred in the past decade (2014-2023), and 2023 was the warmest year since global records began in 1850 by a wide margin.16

The impacts of climate change

Climate change comes with a myriad of impacts: hotter temperatures, more severe storms, increased drought, rising sea levels, food and water insecurity, health risks, and the displacement of vulnerable communities.

In recent years, extreme floods in Pakistan, South Korea, China, and Italy, prolonged drought and famine across the horn of Africa, wildfires in Greece and Canada, and unprecedented heatwaves across North America, Europe, and Asia have all been linked to or exacerbated by climate change.

But greenhouse gas emissions from human activities are continuing to increase. The Global Carbon Budget announced record high fossil carbon emissions of 36.8 billion tonnes in 2023, a 1.1% increase from 2022.17 And as humanity continues to push further out of the safe operating zone of the climate change boundary, other planetary boundaries are being perturbed.

Climate change is impacting the biodiversity boundary, as plants and animals struggle to adapt to their

changing environments, over a million species are at risk of extinction within the next few decades.18

The increasing concentration of atmospheric CO₂ is causing the ocean to acidify. One of the world’s largest carbon sinks, the ocean absorbs about 30% of the CO₂ released from burning fossil fuels. Carbon dioxide becomes carbonic acid in the marine environment, driving down the ocean’s pH.19 Since the start of the Industrial Revolution, the ocean’s pH has dropped from 8.21 to 8.10.20

The IPCC’s latest Summary for Policymakers states that in the near term, every region in the world is projected to face further increases in climate hazards, increasing multiple risks to ecosystems and humans.21 These risks include an increase in heat-related deaths, an increase in food, water, and vector-borne diseases, flooding in coastal and low lying areas, biodiversity loss, and a decrease in food production in some regions.22 See Figure 1.4.

With each incremental increase in warming, the risks become increasingly more complex and difficult to manage.23

Figure 1.4

The impacts of different degrees of warming according to the IPPC Summary for Policymakers24

The Global Response to Climate Change

Scientists first began noticing that the Earth’s surface temperature was increasing in the early part of the 20th century, but it was only towards the end of the century that the matter became a political one.

In 1988, the Intergovernmental Panel on Climate Change (IPCC) was established by the UN to assess the science and impacts of climate change and the options for responding.25 The IPCC has since produced six comprehensive assessment reports, along with numerous guiding documents and summaries.

In 1992, the UN Framework Convention on Climate Change (UNFCC) was adopted and signed by 197 Parties. Its objective is to “stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.”26 Every year since then, at a Conference of the Parties (COP) countries have met to review the Convention and assess global efforts to reduce global warming, and negotiate new measures to support mitigation and adaptation.

At COP21 (held in Paris in 2015), 195 countries agreed to take steps to limit global warming to 1.5 or 2 degrees Celsius above pre-industrial levels. To achieve this goal, fossil fuels will need to be phased out, and the global economy must become “net zero” by 2050.

Among other things, the Paris Agreement requires each country to commit to reducing greenhouse gas emissions in line with the global target of keeping warming below 1.5 degrees. Countries are required to produce a climate action plan called the Nationally Determined Contribution (NDC) which contains their emission reduction targets, strategies to reach those targets, and how they will monitor and verify their progress. NDCs are required to be updated to more ambitious levels every five years.

Although there are now more policies and laws aimed at limiting greenhouse gas emissions, the commitments in the latest NDCs are still insufficient to reach to the target of the Paris Agreement. It is likely that 1.5 degrees of warming will be exceeded within the next few years.27

1.2 Singapore Context

Singapore is a highly developed and densely populated small island city-state in Southeast Asia, off the southern tip of the Malay Peninsula. It is located 137 km north of the equator.

Singapore has a tropical rainforest climate (Koppen classification: Af) with no distinct seasons throughout the year. It is typically hot and humid, with high rainfall all year round. Despite the lack of distinct seasons, there are variations throughout the year - February to May is generally hotter and drier, while November to January is wetter. Singapore's climate is also characterized by abundant sunshine, with an average of 5-7 hours per day.28

As a small island with a total land area of only 734 km², Singapore has significant space constraints which pose a challenge for its ability to become self- sufficient and sustainable. There is limited space for solar energy, average wind speeds are insufficient for developing meaningful wind energy and there is no potential for hydroelectric power.

Despite the lack of space, Singapore has a very good solar resource with an annual average solar irradiance of 1580 kWh/m². As of December 2023, Singapore has 1.2 GW of installed solar capacity (which supplies about 1.5% of total electricity demand). Solar deployment has increased rapidly in recent years resulting in a doubling of installed capacity in only 2 years.29

At present Singapore continues to rely heavily on imported natural gas and other fossil fuels to meet its energy needs.30 Importing renewable energy (solar, wind, and hydro) from its neighbours is key to reducing its use of fossil fuels by 2050.

Singapore's carbon footprint

Although Singapore's cumulative contribution to global greenhouse gasses is tiny (only 0.12% since 1750), its per capita emissions (9.4 tCO₂e per person in 2021) are twice the global average and significantly higher than Hong Kong (4.4) and the UK (5.2). See Figure 1.7.31 32

When the country was developing rapidly during the period 1965-1995, its greenhouse gas emissions rose to a peak of 60 million tons. In the last 30 years they have stayed below that peak but there has not been a noticeable downward trend. (See Figure 1.5).33

The largest share of emissions comes from the industrial sector at 44.4%, closely followed by the power sector at 39.2%, and then transport at 14.2%. See Figure 1.6.34 Singapore’s industrial sector includes energy intensive oil refining and petrochemicals causing significant emissions. Natural gas power plants generate 92% of the city’s electricity.

Consumption emissions

The emissions numbers quoted above only account for the emissions generated within the country. These are what’s known as production-based or territorial emissions. They don’t include the emissions embodied in the imports of goods and services produced elsewhere and so they tend to understate the impact of countries like Singapore and Hong Kong that import a lot of things. Consumption-based emissionsii are a way of adjusting 'production-based' emissions for trade and provide a more realistic comparison.

In 2021, Singapore’s consumption-based emissions were the highest in the world at 27.7 tCO₂e/person, 1.6 times more than the US (16.5 tCO₂e/person) and 3.6 times more than the UK at (7.6 tCO₂e/person). See Figure 1.7.35 It is important to note that less than 1% of Singapore’s land is available for food production so over 90% of food in the city is imported.

ii Consumption-based emissions = production-based emissions – (emissions embedded in exports + emissions embedded in imports)

1.5

Singapore's annual CO₂ emissions from 1960-2022, excluding land use change36 (million tonnes)

1.6

Singapore’s emissions profile: 53.7 MtCO₂e, 202137

1.7

Per capita emissions of selected countries and regions, 202138 (tonnes CO₂e/person)

Figure

Figure

Figure

Mitigation

Singapore's small size poses a significant challenge to reducing GHG emissions. The government has set a long-term target of reaching net-zero emissions by 2050 with a near-term target of 60 million tonnes of CO₂e by 2030.39

To attempt to reduce its emissions, the country has implemented measures such as a carbon tax, energy efficiency programs, and a plan to import renewable electricity from neighbouring countries such as Australia, Thailand, and Laos.

The carbon tax was implemented in 2019. In 2024 the tax was raised from a low S$5/tCO₂e to S$25/tCO₂e and is expected to be raised to S$50-80/tCO₂e by 2030.40

Electricity generation is responsible for approximately 40% of Singapore’s emissions. Solar is considered the most promising renewable energy source within Singapore and the government has a target for installed capacity by 2030 of at least 2 GW. This is roughly double the current installed capacity and enough to supply 3% of expected electricity requirements in 2030. Energy storage systems to deal with solar intermittency are also under development. Due to the lack of space, most solar is, and will be, installed on rooftops.

To deal with Singapore’s space constraints and lack of renewable resource locally, the city has signed agreements with neighbouring countries to import renewable energy via regional power grids. The government plans for regionally supplied renewable electricity to make up at least a third of electricity by 2035.41

Singapore has also signed an agreement and is already importing up to 100MW of renewable energy from hydroelectric dams in Laos. The city is also trialling two other small-scale imports with Malaysia and Indonesia.

Singapore has granted conditional approvals for 1 GW from Cambodia, 2 GW from Indonesia, 1.2 GW from Vietnam. If all three go ahead it would allow the city to meet it’s target of at least a third of electricity to be regionally supplied renewable electricity by 2035. 42

SunCable has an ambitious project to generate renewable electricity in Australia’s Northern Territory and transmit it via undersea cable to Singapore. The company has recently renewed discussions with Singapore to obtain conditional approval. The project expects to be able to deliver 1.75 GW to the city by early the 2030s.43

Singapore is also planning to study and develop nascent alternatives such as carbon capture, utilization, and storage (CCUS) and green hydrogen.44

Industry is the largest source of emissions in Singapore. Energy efficiency improvements and industrial transformation are the key levers for decarbonisation in this sector.

Buildings are another major source of emissions, predominantly from operational electricity use, but also embodied carbon in building materials such as concrete and steel. Singapore’s Green Building Masterplan, established in 2021, sets energy efficiency and embodied carbon targets for 2030 including:45

• 80% of all buildings to be ‘green’

• 80% of new developments to qualify for Super Low Energy (SLE) certification

• 80% improvement in the energy efficiency of its buildings compared to 2005 levels for best-in-class buildings

Since 2005 the Building Council Authority (The BCA) has run Green Mark, a green building certification scheme. The scheme provides a sustainability rating system for new and existing buildings. The BCA also sets minimum energy performance requirements for new buildings and provides benchmarking for different building types.

More than 4,200 buildings in Singapore have been certified under the Green Mark Scheme. 288 of schools (including tertiary) have been certified, of which 10 have achieved Super Low Energy or Positive Energy certification.46

Transport accounts for over 15% of Singapore’s carbon emissions, the majority of this is from petrol and diesel

consumption in cars, vans, and trucks. To address this, the government aims to shift people from cars towards walking, cycling, and public transport modes. The Land Transport Masterplan targets 75% of journeys to be by public transport during peak commuting times by 2030. Key drivers for this are the expansion of the MRT as well as developing walking and cycling networks.47 Additionally, all vehicles are expected to run on cleaner energy (e.g. electric, hybrid, or hydrogen) by 2040 and public buses are gradually being replaced with electric buses, further reducing emissions.48

Climate action tracker

The Climate Action Tracker (CAT) is a scientific programme that tracks government climate action and rates it against the goals of the Paris Agreement.

Overall, CAT rates Singapore’s climate action as ‘critically insufficient’, and states that it is not at all consistent with the Paris Agreement’s 1.5°C temperature limit.

According to CAT, Singapore’s current policies and action, as well as its official Paris Agreement target (its nationally determined contribution or NDC) are ‘highly insufficient’ – meaning they are consistent with more than 3°C of warming.

CAT also calculates “fair share” NDC targets which take into account historic emissions and current levels of development. The fair share approach places an expectation on highly developed countries like Singapore to do better than the world average. Therefore, Singapore is classified as ‘critically insufficient’ or consistent with more than 4°C of warming.

CAT highlights Singapore’s weak near-term target which they estimate is 87% higher than required based on their fair share methodology.49

Based on CAT’s rating, more ambition, policy, and action is required in Singapore.

Figure 1.8

Climate Action Tracker - Singapore

1.3 Singapore's adaptation to climate change

The National Climate Change Secretariat (NCCS) is Singapore's main government body responsible for implementing the city's policies and strategies on climate change on a domestic and international scale.

NCCS’s subgroup, Singapore’s Resilience Working Group (RWG), established a resilience framework

Figure 1.9

Singapore’s Resilience Framework50

to support Singapore’s climate adaptation for the next 50 to 100 years. It is comprised of two pillars: risk assessment and adaptation planning. The former identifies climate change risk and any advances in climate science. The latter provides options that address those risks. See Figure 1.9.

Coastal Protection

Singapore's climate adaptation efforts are focused on the risks it faces by its natural topography As a low-lying nation and high-density city, it is vulnerable to rising sea levels, increased rainfall intensity and stronger winds. The city is within 15 meters above sea level and 30% of the land is less than 5 meters above sea level.51 This makes any rise in sea levels caused by climate change a serious risk. See Figure 1.10.

As a result, Singapore has focused on protecting its coastline and improving drainage. In 2011, the minimum land reclamation level was raised from 3 meters to 4 meters above the Singapore Height Datumiii to cope with sea level rise in the long term. Stone barriers and walls cover 70-80% of Singapore’s coastlines, which is over 300km. Mangroves have also been used as a natural tool against coastal erosion and flooding. They are also a source of carbon sequestration - it is estimated the Singapore's mangroves store 450,570 tonnes of carbon.52

iii A height datum is a reference system that defines a surface, which serves as the "zero point" for measuring elevations and depths.

* Averaged over six locations in Singapore

Chart: STRAITS TIMES GRAPHICS - Source: CENTRE FOR CLIMATE RESEARCH SINGAPORE

Figure 1.10

Stormwater Management

Since 2014 it is a requirement for developers of new and redeveloped sites to implement on-site water detention tanks, green roofs, rain gardens and water retention ponds, to slow the flow of stormwater collected on-site into the public drainage system.

Singapore’s stormwater drainage system consists of two catchment-level detention tanks (total capacity of 53,000 cubic meters), rain gardens, over 8,000 km of drains, rivers and canals54, and green roofs. A third detention tank is expected to be completed by 2025 with a holding capacity of 9,300 cubic meters.

In 2023, PUB, Singapore’s national water agency, installed 400 additional water level sensors to its

1.11

existing network of 1,000 water level sensors. These sensors are in drains and canals and provide realtime data so early warnings of flood can be made to the public and responses, like traffic management, can be made.55

Singapore’s stormwater management approach is known as the “Source-Pathway-Receptor” was created to identify areas in its drainage system where mitigation measures can be implemented. Sources, such as detention tanks, play a key role in retaining water. Pathways like drains and canals can reduce stormwater flow by widening and deepening. Receptors - where floods occur - are used as buffers and flood barriers to protect critical infrastructure and minimise flood damage. See Figure 1.11.

Projections of average relative* sea-level rise in Singapore in 2100 and 215056

Figure

Water Resources

Singapore is one of the most water-stressed countries in the world as its natural water resources are limited. The island has no lakes, natural aquifers or groundwater and imports 40% of its water from Malaysia through an import agreement that lasts until 2061.57 Climate change is expected to increase the frequency of droughts and irregular rainfall patterns, which is why water security is one of the key factors in Singapore’s climate adaptation plan.

Singapore has focused on diversifying its water resources through four “national taps”: rainfall collection in reservoirs, imported water, recycled water (NEWater), and desalinating water.

Roughly two-thirds of Singapore is covered with water catchment areas, like reservoirs and drainage systems. Rainwater collected within these areas is channelled through a network of over 8,000 kilometres of drains and canals, eventually reaching 17 reservoirs for storage before being treated for drinking purposes.58

Recycled water, or NEWater meets 40% of Singapore’s current water demand is expected to meet up to 55% by 2060.59

Another 30% of the island's water is met through desalinated water, which converts seawater into potable water through technology. Singapore currently has five desalination plants.

Desalination can be an energy-intensive process depending on the technology used and emissionsintensive depending on the energy source used to power the process. This will be an important consideration if the city plans to expand on desalinated water production.

Food security

Singapore imports more than 90% of its food, which is a significant contributor to its consumption emissions. It also makes the city vulnerable to disruptions in global supply chains and reduced agricultural productivity caused by extreme weather events in other parts of the world.

To increase food security, the government has considered diversifying food sources by importing from different countries, increasing local food production so that 30% of its nutritional needs are met locally by 2030 (30 by 30), and continuing to support R&D efforts in Agri-tech and food science.60

2 Tanglin's Carbon Footprint

2.1 Overview

Metanoia conducted a carbon and energy audit of the Tanglin’s operations during the period MarchJuly 2024.

The school’s activities gave rise to 9,573 tonnes of carbon dioxide equivalent emissions (tCO₂e) in 2023. These are summarised in Table 2.1 and Figure 2.1

The audit was conducted in accordance with standards developed by the GHG Protocol, which are the world’s most widely- used standards for greenhouse gas accounting and reporting.

The standards classify emissions into three categories defined as follows:

Scope 1 – direct emissions. These are emissions from sources owned or controlled by Tanglin such as the use of gas in the science labs, or the use of diesel or petrol in vehicles the school owns, or leaks of refrigerant gas from the chillers and air conditioners that provide cooling to the buildings on campus. Scope 1 emissions are relatively minor, accounting for only 2% of the school’s total emissions.

Scope 2 – indirect emissions. These are emissions from generating the electricity the school consumes. Scope 2 emissions account for 31% of Tanglin’s total emissions.

Scope 3 – indirect emissions. These are emissions that occur as a consequence of the school’s activities, but from sources that are not owned or controlled by the school. Examples include emissions from daily commuting and school trips, and emissions associated with goods and services the school purchases. Scope 3 is divided into 15 categories – see Appendix A.

Scope 3 emissions account for 66% of the school’s total emissions. They are the hardest to measure and to mitigate because the school doesn’t have direct control over them.

The emissions are expressed in terms of a standardised unit - tonnes of carbon dioxide equivalent (tCO₂e)because different greenhouse gases have different

global warming effects. For example, methane warms the atmosphere 80 times more than carbon dioxide over a 20-year period, but only 24 times as much over a 100-year period because it breaks down faster. So, to add up the cumulative effect of all the greenhouse gases on an apples-to-apples basis, we convert the amount of each gas emitted to an amount of carbon dioxide that would have the same warming impact over a 100-year time period. This is called the 100year global warming potential or 100-year GWP. On this basis, 1 tonne of methane emissions is equivalent to 24 tonnes of CO₂, and we re-express the 1 tonne of methane emissions as 24 tonnes of CO₂ - equivalent (24 tCO₂e).

Table 2.1

Summary of Tanglin’s greenhouse gas emissions by source, 2023

*These emissions are from the extraction, processing, and transportation of fossil fuels consumed by the school in the forms of gas, petrol, diesel, and electricity transmission and distribution losses

Sources of Tanglin’s greenhouse gas emissions, 2023

*Other includes emissions from transport of purchased goods and services, transport of waste, gas used in the kitchen and science labs, and fuels used in the school truck, motorbike, and generator.

Figure 2.1

2.2 Hotspot Analysis

2.2.1 Electricity consumption

The largest contributor to Tanglin’s carbon footprint is electricity use. The school consumed 7.2 million kWh of electricity in 2023 – the same as about 1,450 average Singaporean homes. This was 19% higher than 2022 due to the opening of the Centenary building. See Figure 2.2.

Cooling, lighting and appliances are the biggest consumers of electricity. In the case of the Centenary building, cooling accounts for about 40% of electricity use, heating the pool accounts for 18% and lighting 11%. Similar data isn’t available for the other buildings but without the swimming pool heating, cooling may be as high as 60%. See Figure 2.4.

Most of the buildings at Tanglin are cooled by split-type AC units which consist of a single outdoor unit (the compressor) connected to one or more indoor units. The AC units are so-called VRVs or variable refrigerant volume units. VRVs are more efficient because they control the amount of refrigerant flowing to each indoor unit (room) based on the cooling demand of each room.

The Nixon building is the only building that is cooled by a chiller system. It is centralised water-cooled chiller that delivers cool air to each room via ducts. The chiller has an efficiency of 0.62 kW/RT, which is considered highly efficient; best-in-class efficiency is 0.5-0.6 kW/RT and the threshold to achieve the Green Mark Platinum rating is below 0.65 kW/RT. An inefficient cooling system would be 1 kW/RT or more.

The cooling system is centrally controlled by a Daikin building management system. The temperature is set to 23°C and cannot be lowered by individual room occupants. Cooling runs from 6 am to 7 pm Monday to Friday and 7 am to 2pm on Saturday.

Lighting accounts for about 10-15% of the school's electricity use. 80% of the lights at Tanglin are LEDs which are more energy efficient than conventional lights. The remaining 20% are lights that are not regularly used but are expected to be upgraded in the near future.

There are two small rooftop solar PV arrays, one on the West Wing (69 kWp), and one on the Centenary building (28 kWp). In 2023 the Centenary array generated 8,500 kWh which was only equal to 0.6 % of the school’s electricity consumption.

Figure 2.2

Figure 2.3

Proportion of total annual consumption of each building in 2023 (kWh)

Senior Reception, 1%

Figure 2.4

Breakdown of electricity use in the Centenary Building, 2023

Patterns of electricity use

Tanglin’s facilities team provided us with monthly electricity consumption data from September 2021 - January 2024 for the whole campus as well as monthly data for each building for 2022 and 2023.

In addition, we obtained energy consumption data from the school’s En-trak account. En-trak is a real-time energy management platform with meters installed throughout the campus enabling students, teachers, and facility managers to view and understand energy use patterns and help drive energy saving. All buildings have at least one Entrak meter measuring total consumption, although as of July 2024, many of them are offline and need reconnecting. The Centenary building has multiple En-trak meters that allow electricity consumption of different services (AC, lighting, plug loads etc.) to be monitored floor by floor. See Figures 2.3 and 2.4.

Monthly electricity use

Singapore’s relatively steady climate means that Tanglin’s monthly electricity use is relatively stable with a small peak in May and a minimum in July during the summer holiday.

Consumption in July is lower than in June but only by about a third. We would have expected the difference

Figure 2.5

Monthly electricity consumption per building in 2023 (kWh)

to be greater considering there are almost no teachers and students on campus in July. The same goes for other holiday periods and weekends.

For example, during the 2023/2024 Christmas break, air conditioning units in the Centenary Building were still used every day, and more energy was used on weekdays than weekends despite there being a limited number of people on campus. This suggests potential for significant energy and carbon savings.

Daily electricity use

Figure 2.6 shows the school’s daily energy use profile. Usage is low (but not zero) overnight from 8 pm until 6 am. It increases rapidly from 6 to 8 am, peaks between 8 am and 4pm, then tapers off until 8 pm and reaches its minimum around midnight.

The data indicates that about 30% of the school’s electricity is consumed during non-operating hours (outside of 7am – 5pm). This is even higher in the Centenary and Nixon buildings. See Figure 2.7.

A similar analysis of weekends indicates that daily energy use on the weekend is around 40% of daily energy use on a school day.

2.6

Average hourly energy use during an average school day at Tanglin (kWh)

01:0002:0003:0004:0005:0006:0007:0008:0009:0010:0011:0012:0013:0014:0015:0016:0017:0018:0019:0020:0021:0022:0023:0024:00

2.7

30% of Tanglin’s energy use occurs during non-operating hours energy use (kWh)

Figure

Figure

Energy use intensity

Figure 2.3 shows that Centenary and Nixon use the most energy and the West Wing and Senior Reception use the least energy. However, electricity use depends partly on the floor area of the building: other things being equal, bigger buildings will consume more electricity. So, to remove the effect of floor area on comparisons, we look at electricity use per unit area (kWh/m²). We call this electricity use intensity or energy use intensity (EUI).

The West Wingiv, Infant, Junior buildings have the lowest EUI. This is probably due to shorter school hours and lower appliance usage. The two newest buildings, Nixon and Centenary, have the highest EUI. This may be explained by their different use patterns – higher occupancy and longer hours with office staff and events after school. See Figure 2.8.

iv The data for West Wing building is slightly incorrect as a faulty meter meant there was a negative reading for April. The meter was replaced after this. In 2022, and for every other month of 2023, the building was still one of the most energy efficient buildings.

How does

Tanglin’s electricity

use compare to other schools?

We compared Tanglin’s energy use intensity (88 kWh/ m²) to other international schools Metanoia has audited or has direct knowledge of in similar climate zones. The only schools with lower energy use per square meter are UWCSEA Dover and UWCSEA East. UWCSEA Dover’s EUI is the lowest in our sample at an impressive 55 kWh/m².

Tanglin’s EUI is also below the average of a sample of private schools (98 kWh/m²) compiled by Singapore’s Building Construction Authority (BCA) in 2022.

The BCA’s green building certification scheme, Green Mark, has a certification for low energy building called Super Low Energy (SLE). Private school buildings need an EUI below 80 kWh/m² to achieve SLE Platinum. This is only 10% lower than Tanglin’s average 2023 EUI, with many of the school’s individual buildings already below this threshold. See Figure 2.9.

2005 building code for private schools (200)

average of a sample of private schools (98)

Figure 2.8

Figure 2.9

Singapore

BCA

Green Mark Super Low Energy Platinum benchmark for private schools (80)

2.2.2 Travel-related emissions

Emissions from travel accounted for 26% of Tanglin’s carbon footprint.

Commuting

The Tanglin community commuted 13,125,500 passenger-kilometres to and from school in 2023 resulting in 848 tonnes of CO₂e emissions. See Table 2.2.

This is the finding of an on-line and in-class survey of staff and students we conducted in June 2024. 383 senior students and 322 staff responded – an overall response rate of 35%. All junior and infant students completed an in class survey.

How does Tanglin commute?

Three-quarters of the school community travel to school in an environmentally friendly way. Almost half (1,580 students and 50 staff) take the school bus, 19% take public transport and 9% cycle or walk. See Figure 2.10.

70% of the infant and junior students use the school bus, compared to only 36% of senior students and 7% of staff. The school buses make 171 trips, travelling about 3,000 kilometres each day.

Around a third of staff and senior students use the MRT, and staff walk and cycle more than students. See Figure 2.11.

Table 2.2

Commuting at Tanglin

2.10

How Tanglin staff and students commute to school

2.11

Figure

Private car - hybrid, 0.04%

- electric, 1.5%

Figure

Emissions from commuting

We estimated the annual passenger kilometres and CO₂ emissions for each transport mode. (see Figure 2.12).

To calculate emissions we used the commuting mode and distance data from the surveys and applied the distance-based method (see Appendix C – Distancebased method (survey)). We used a fuel efficiency, distance-based approach to calculate emissions from the school buses. See Appendix C for the formulae.

About 70% of commuting trips are by school bus or private car and these are also responsible for 70% of commuting emissions (645 and 230 tCO₂e respectively). The third highest emissions source is motorbikes (47 tCO₂e), but these are only used by a small number of staff, typically people commuting long distances from locations that are not well served by public transport such as over the border in Johor Bahru. See Table 2.2.

How does Tanglin’s commuting emissions compare to other schools

We estimate Tanglin’s overall emissions per passenger km (p-km) from commuting to be 65.8 gCO₂e/p-km. This is close to the average of other schools we have audited in Hong Kong and Dubai, which ranged from 50 – 110 gCO₂e/p-km. However, given Singapore’s high public transport connectivity, and the efficient school bus system the school already in place, we think there is room for Tanglin to do better by encouraging more people to choose green commuting options. See Figure 2.12.

For reference, the emissions from walking and cycling is 0 gCO₂e/p-km, the MRT is 13 gCO₂e/p-km, Tanglin’s school bus service is 45 gCO₂e/p-km and a petrol car with a single occupant ranges from 120250 gCO₂e/p-km.

Emissions per p-km is a common metric for making comparisons, however it doesn’t account for how far away people live. For example, two schools could have the same emissions per p-km but if people at one school live twice as far from campus then their emissions will be twice as high.

Commuting

comparison with other schools (kg CO₂/p-km/year)

Figure 2.12

School trips

In 2023 1,860 Tanglin students, faculty and other staff took 120 international trips, which generated 1,623 tonnes of CO₂. Nearly all of these trips were by plane – only four trips (to Kuala Lumpur) were by road.

There were also a number of domestic trips by bus which gave rise to a further 22 tCO₂e.

The above are school-related trips only and do not include holiday travel or relocation.

97% of the journeys were student-related and they gave rise to 89% of the emissions. Long-haul flights were only 20% of the journeys but accounted for more than half the total emissions.

8 of the 120 trips accounted for over half of the total emissions, and 35% of the total journeys.

Over half of the journeys were to four nearby locations: Bangkok, Chiang Mai, Khao Yai (fly to Bangkok), and Sarawak. All four locations had one or more large student groups travelling to it. See Table 2.4

Tanglin’s travel emissions per student is 600 kg CO₂/pkm which is in the middle of the range of other schools

Table 2.3

Emissions from school trips

Metanoia has audited (Figure 2.14) – although there is high variance.

A few people flew business class , resulting in 36 tCO₂e. The emissions from flying business class are two to three times higher than flying economy class.

Calculating emissions from school travel

To calculate emissions from school trips we used a distance-based method (see Appendix C for formula). It’s worth noting that estimates of emissions from flying can vary significantly because of differing assumptions about the so-called radiative forcing factor which is used to explain the impact of contrails. The factor used may range from 1 (no additional impact) to around 3 (triple the impact).

For domestic travel, Tanglin’s bus department provided us with data on domestic travel for November 2023. We assumed this was representative of other months in the school year and used a distancebased method and the bus fleet’s fuel efficiency (see Appendix C for formula).

Table 2.4

Figure 2.14

2.2.3 Supply chain emissions

Emissions from Tanglin’s purchased goods and services (2,107 tCO₂e) and capital goods (1,069 tCO₂e) accounted for a third of the school’s carbon footprint in 2023. See Appendix E for assumptions made during the quantification of supply chain emissions.

Purchased goods and services and capital goods includes any items procured through the procurement department. This does not include items teachers purchase using their class or subject budgets. We used the procurement department’s classification to distinguish between purchased goods and services and capital goods.

Examples of purchased goods include uniforms, electronic hardware like MacBooks, iPads, and computers, sports equipment, musical instruments, as well as goods needed for building construction, renovation, or refurbishment like ceiling fans, window handles, and paint. Services include things like software subscriptions and licenses, gardening services, security services, and maintenance and repair services.

Examples of capital goods include building construction, AV equipment, photocopiers, and coffee machines.

The four largest contributors to supply chain emissions were emissions arising from building construction services, building and renovation work services, building construction, and electrical lighting products and services. These were all classified as capital goods and collectively contributed 683 tCO₂e. See Table 2.5.

The next five largest categories were all purchased goods and services and included building and renovation work services, IT products, security services, building construction services, and AC maintenance work services. See Table 2.5.

The Centenary building was under construction in 2022 and opened in January 2023. The data we received from the procurement department was for the 202223 academic year, which we used as an approximation for 2023 calendar year (see Appendix E). As a result, the supply chain emissions include emissions related to the outfitting of the Centenary building, which may have inflated the total supply chain emissions.

It would be worthwhile for the school to recalculate its supply chain emissions during a year when there are no new builds to better estimate the school's annual supply chain emissions.

Roadmap to Net Zero

3. Overview of Tanglin’s roadmap to Net-Zero

The IPPC has concluded that in order to limit global warming below 1.5 °C above pre-industrial levels, global net anthropogenic emissions need to reach net-zero by around 2050.

With this ambitious target in mind, we have proposed a decarbonisation roadmap for Tanglin based on the Science Based Target initiatives (SBTi) Corporate NetZero Target standards.

SBTi requires organisations to set a near-term target (to be achieved within 10 years) and a net-zero target (to be achieved by 2050, at the latest). SBTi’s target setting tool provides a simple method of aligning organisational targets with the latest climate science. Based on the tool, we recommend that Tanglin set a target of achieving netzero emissions by 2050, with a near-term target of a 63% reduction in emissions by 2035.

The 63% reduction by 2035 applies to Scopes 1, 2, and 3 emissions. However, if the school wishes to choose a less ambitious target (SBTI's "well below 2 degrees pathway") then the required reduction in its Scope 3 emissions would only be 37.5% by 2035. We have modelled the more ambitious 1.5C aligned pathway.

SBTi defines "net-zero" as a minimum 90% absolute reduction in emissions from the baseline year (2023 for Tanglin), combined with carbon removals for any remaining, un-abatable emissions.61

We propose that Tanglin’s Scope 2 target (emissions associated with electricity) be a market-based target. Under SBTi, organisations have the choice of setting location-based or market-based Scope 2 reduction targets. For Tanglin, a location-based target uses the average emissions intensity of grid supplied electricity in Singapore. In contrast, a market-based target allows for the use of locally sourced renewable energy credits (RECs).v

v A REC is a market-based instrument that represents rights to the environmental attributes of 1 MWh of renewable electricity generated and delivered to the grid.

Therefore, market-based targets allow Tanglin to have greater flexibility in its decarbonisation pathway.

Tanglin will need to review, adjust if necessary, and approve our proposed near-term and long-term targets. Although schools are not eligible to submit their targets to the SBTi for validation, alignment with SBTi is considered best practice.

The targets and a summary of the roadmap are shown in Table 3.1 and Figure 3.1.

In the roadmap, Scope 1 targets (reducing emissions from sources owned and controlled by Tanglin e.g., refrigerant leaks) are met primarily by phasing out refrigerants with high Global Warming Potential ("GWP") used in the existing ACs on campus. ACs with lower GWPs are becoming available in Singapore and ultra-low GWP will be available in future. AC asset replacement at the end of life is expected to be sufficient to meet the Scope 1 target. Phasing out fossil fuel powered equipment, including vehicles and gas use in labs will also be needed.

Scope 2 targets (reducing emissions from electricity) are met by a combination of energy efficiency improvements in existing buildings through technical upgrades, as well as operational and behaviour changes, building highly energy efficient new buildings, maximising solar PV on campus, and purchasing renewable energy certificates (RECs) or equivalent. The Singaporean government has set a target for the electricity grid to decarbonise by 2050 so emissions from electricity use will decrease over time.

Scope 3 targets (mostly emissions associated with travel and the school's supply chain) can be met by a variety of measures across all relevant emissions categories. Scope 3 is the most difficult to decarbonise and will require a range of approaches. These include buying less, buying local, considering GHG emissions in purchasing decisions, using sustainability criteria when selecting suppliers, being more selective with school travel, as well as encouraging green commuting.

Although there are uncertainties in our projections, particularly after 2035, we are confident that the emissions reductions in the proposed roadmap are feasible.

Each section ends with several ‘enabling recommendations’ that, if implemented, will not only help Tanglin decarbonise but will also help the school reduce its environmental footprint and build a culture of sustainability. The implementation of many of these enabling recommendations can be led by students in classrooms, clubs, projects, and other initiatives.

3.1

Tanglin's annual emissions (tCO₂e) according to the roadmap. The residual emissions in 2050 can be neutralised by purchasing carbon offsets (Annual emissions, tCO₂e)

10,000 8,000 9,000

6,000 7,000 5,000 4,000 3,000 2,000 1,000 0

Figure

Table 3.1

Summary of Tanglin’s near-term target and net-zero target

*Remaining 10% can be neutralised by purchasing carbon offsets.

Modelled reduction opportunities for key hotspots

Electricity use Replacing lighting and AC units with more efficient models Ongoing 7.5% in emissions from electricity use by 2035

10-20% of replaced units.

Electricity use Out of hours energy use (overnight, weekend, holiday) By 2030 Up to 35% in emissions from electricity use Up to 35% of total energy use

Electricity use Hybrid cooling By 2030 Up to 20% of emissions from electricity use Up to one third of AC and ventilation energy use

Electricity use Occupancy and lighting control of lights (and possibly ACs) By 2030 Up to 4% of emissions from electricity use Up to 30% energy use reduction from lighting

More potential possible with shaded walkways, carparks, cantilevered roof structures, facade and with the new buildings

Replacement to occur at end of life, or earlier for lighting. High uncertainty beyond 2030 due to unknown future efficiency and the emergence of new technologies

DALi lighting control can be integrated into the ITM system

Supply chain Reduction in purchasing and emissions from supply chain Ongoing to 2035 6% per year - Reduction achieved by buying less and through careful selection of suppliers and products

School trips Reduce school flights (passenger kilometres) Ongoing 10% per year - Reduction from flying less and flying to closer destinations. 10% per year is a 50% reduction by 2035 and 90% reduction by 2050

Commuting Electric school bus by 2030 83% in emissions compared to diesel school buses in 2030. 60% reduction if switched in 2024. -

Commuting Introduce mandatory busing by 2030 10-15% in total commuting emissions -

Potential increase in energy use (scope 2) depending on charging location

Much greater impact when combined with bus electrification

Table 3.2

3.1 Reducing emissions from electricity

Emissions from electricity use can be mitigated in multiple ways:

• Reducing energy consumption,

• Generating clean energy,

• Building energy efficient or net-zero energy new buildings

• Purchasing renewable energy certificates (RECs)

• System-wide decrease as Singapore’s grid decarbonises.

Table 3.3

Decarbonisation

of Singapore's grid

We have modelled the decarbonisation of Singapore’s grid based on the government’s targets for 2035 and 2050. It is shown in Table 3.3. Singapore’s 2035 target states that 50% of the electricity supply will come from will be natural gas, 30% will be renewable energy from regional grids and 3-5% will be locally generated solar. The source of the remaining 18-20% is not specified, but we have assumed it will be a zero carbon source. This assumption should be reviewed and updated in future as more information is available.

Decarbonisation of Singapore’s grid, based on government targets

* Some natural gas with carbon capture utilisation and storage (CCUS) may be present in the grid

EUI targets and metrics

To model energy use we have set a reduction in energy use intensity (EUI) of 2% per year from now to 2050. By 2050 this equates to a campus EUI of 51 kWh/m², a 45% decrease from 2023. The target is based on current best practice for private schools in Singapore and we used percentage reductions from 2005 codes as a guide.

There are three private schools and colleges (16%) in Singapore's Building and Construction Authority's (BCA) 2022 benchmark report that have already achieved EUI’s below 50 kWh/m².62 Additionally, new and refurbished educational buildings in Singapore are achieving EUIs around this value today.63

The BCA conducted a technology feasibility roadmap for buildings to 2030. They concluded that a 60% reduction in the energy use of new buildings from

Table 3.4

Proposed near-term and long term target EUIs for Tanglin

2005 levels is feasible today (equates to a final EUI of 80 kWh/m² for private schools), and that an 80% reduction (final EUI of 40 kWh/m²) is technically feasible by 2030, assuming technological development is sufficient.64

In the roadmap we assumed the two planned new school buildings will be highly energy efficient and have EUI’s of 50 kWh/m² (first building in 2030) and 40 kWh/m² (second building in 2040). Building the two new buildings to be highly energy efficient will account for around 35% of the EUI reduction required by 2050.

We believe that there may be scope for more ambition in energy reduction than we have modelled by implementing operational and behavioural changes as well as retrofitting the existing buildings with energy efficient technologies. Specific energy reduction opportunities are discussed below.

Table 3.5

Reference EUIs and EUI targets

EUI reduction opportunities

Several initiatives have already been implemented to reduce energy use and improve energy efficiency at Tanglin, but many opportunities remain. Quantifying the individual energy reduction potential from each action is difficult due to the interplay between different actions. For example, if occupancy sensors already turn off AC and ventilation equipment when it is not in use, then the impact of installing demand-controlled ventilation may not be as significant. Nevertheless we have made what we consider to be reasonable assumptions in our model.

Operational changes

We identified and modelled several operational changes Tanglin can make to reduce the EUI of the campus.

Around 30% of the school’s electricity is consumed out-of-hours (outside 7am-5pm). To reduce this, Tanglin can implement a shutdown policy that ensures all unused equipment is switched off between 4-5pm. Students and the FM team should investigate the reasons for energy use in the evenings, overnight, and at weekends to pinpoint and reduce unnecessary consumption. We believe it is feasible to reduce out-ofhours consumption by about a third. This equates to a 10% reduction in total energy use.

We modelled a 42% reduction in weekend energy consumption by 2027 compared to 2023. This would reduce daily consumption at weekends to 25% of a regular school day. Some buildings are already achieving this, but other buildings like the Berrick, Centenary, and Nixon are all used frequently during weekends. A complete shutdown policy for buildings that are not in use, and careful scheduling to concentrate weekend building usage to one part of a single building will reduce the overall energy demand. The school can also consider a user turn on only policy for AC and lights during the weekends, with automatic shut offs beginning at 2pm.

Operational changes can also reduce the amount of energy consumed during school holidays. We modelled an ambitious 64% reduction in holiday energy consumption. This is achievable by reducing holiday consumption to 25% of a regular school day, as is already happening in some buildings over the weekend. It will require completely shutting down all buildings that are not under renovation or in use, and a reduction in holiday operating hours for other buildings. Introducing a user-turn-on policy for AC and lights, and an early automatic switch off (e.g., at 2pm) will also help achieve this target.

The current temperature set point throughout the school is between 23-24°C. Set points have a big impact on energy consumption, with research indicating that changing the set point from 23 to 24°C can reduce energy consumption by as much as 10%.65

Table 3.6

Operational energy reduction opportunities

Classroom behaviour

Ensuring that all lights, ACs, and appliances are turned off when rooms are not in use and in particular overnight and at weekends and holidays will lower the school’s electricity consumption.

Visual prompts have been shown to be a cost-effective measure to positively affect occupants’ behaviour. Signage to remind occupants to turn everything off when they leave can be developed by students.

Students can also lead regular classroom audits and designate energy monitors to be responsible for the energy consumption in their classrooms.

The classroom energy audits should review:

• Lighting conditions – Is there sufficient natural light for learning so the lights can be switched off?

• Air conditioning, ventilation and thermal comfort – what are the temperature set points, are people hot/cold? Could the AC be switched off?

• Appliances – are appliances left on or in standby when not in use? Are there power strips so that all appliances can easily be turned off?

• Building envelope and air tightness – is energy being wasted by outside hot air entering into the building via open doors and windows?

• Occupancy – is equipment on when people are not in the room/ not using it?

Technological upgrades

Singapore’s Building Construction Authority (BCA) has identified four broad areas in which key-actions can be taken to cut consumption and achieve super low energy buildings:66

• Passive strategies

• Active strategies

• Smart energy management

• Renewable energy

Passive strategies

Passive design strategies include sunlight shading and daylighting, natural ventilation, and dynamic façades.

Retrofitting passive design elements to existing buildings is difficult. The main opportunities without major retrofitting of the building envelope are installing external shading fins around windows that receive significant direct sun, applying reflective paint on roofs (cool roofs), installing green walls and roofs, and enhancing air tightness of the building to reduce heat transfer from outside.

We recommend that any non-white roofs at Tanglin be retrofitted with a green roof or a cool roof to reduce solar heat gain and internal temperatures. Studies indicate that green roofs can reduce energy consumption by about 20-45%, compared to insulated black roofs, in tropical climates like Singapore.67 Similarly, research shows that cool roofs can reduce energy consumption by 35% in tropical climates.68 Rooftop solar will also mitigate solar heat gain so an expensive roofing system is not necessary if solar will be maximised on rooftops. Solar panels can be combined with a green roof to further reduce indoor and outdoor temperatures, lowering energy demand and enhancing the efficiency of the PV panels.

In addition to the classroom energy audits, students can investigate the air tightness of all windows and doors around the school. When gaps and leaks are discovered, the window/door should be replaced with a better fit. Double doors and/or air curtains can be added to high traffic entrances such as the Nixon canteen.

During our audit we observed that most windows appear to be double-glazed. However we did not access every part of the campus. Any single glazed windows should be replaced with double glazing.

Active strategies

Active strategies include improvements to the energy efficiency of air-conditioning, mechanical ventilation, and lighting technologies.

Air conditioning and ventilation

AC and ventilation use approximately half of all electricity on campus. Replacing old AC units with the most efficient models available will result in significant energy savings. We recommend that Tanglin continue to replace ACs according to their existing asset management practice and ensure the most efficient Daikin model is selected as a replacement. Other brands can be considered, but since almost all units are Daikin, we recommend continuing with the brand for ease of maintenance and integration with the automation system.

The FM team provided us with an inventory of all AC units in each building. The available information differed for each building but generally included make and model, cooling capacity, and sometimes refrigerant type and installation date.

80% of the VRV AC units on campus are older and less efficient than Daikin's latest models available in Singapore. The newest and most efficient Daikin model is VRV 4X, followed by VRV 4A which is smaller in physical size and is therefore ideal in certain scenarios. 33 (16% of VRVs) model VRV 4A are already installed on campus, primarily in the Centenary building.

VRV 4A, which is installed in the Centenary building, and a few other locations, is 14% more efficient than VRV 4, the most common AC type at Tanglin (53% of VRVs). A further 23% of VRVs are VRV 3 type, of which most were installed in 2009. We don’t have exact figures, but we expect VRV 3 to be 20% less efficient than the latest VRV 4A and VRV 4X models. The remaining few VRVs (8%) are all smaller units and

are a range of new and old models. One third of these smaller units are due for replacement

Over 80% of single the split ACs are very old and in need of replacement. Almost all these old units are in the infant school and were installed in 2011. They could either be replaced by the latest single split AC or more efficient VRVs, depending on available space for the VRV compressor units. If they are replaced by single split ACs then energy savings of at least 10% can be expected. An estimate of the energy saving by switching to VRV type units can be provided by the vendor, Daikin.

Based on best practice in Singapore and abroad, we recommend both hybrid cooling and demandcontrolled ventilation (DCV) be explored further and trialled at Tanglin. The two strategies can be combined for additional benefit.

Hybrid cooling is a term used to describe combining multiple systems of multiple systems to provide cooling. In buildings it refers to the use of mechanical cooling (ACs) combined with fans to increase air flow. The use of fans significantly reduces the energy required for cooling as the temperature set point can be raised without it feeling too warm. One hybrid cooling trial at an office in Singapore achieved an impressive onethird reduction in energy use. The office space was fitted out with ceiling and desk fans which enabled the temperature setpoint to be raised to 26.5 °C with no reduction in thermal comfort.69

Demand Controlled Ventilation (DCV) optimizes indoor air quality and energy efficiency by automatically adjusting the amount of outdoor air supplied to a space based on real-time occupancy and pollutant levels. Carbon dioxide (CO₂) levels are measured in each room. As occupancy in a room increases, CO₂ levels rise, prompting the DCV system to increase the ventilation rate to ensure adequate fresh air. Conversely, when the room is unoccupied or has fewer occupants, the system reduces the airflow, thus conserving energy. Energy saving potential of DCV systems range significantly based on occupancy, building type, and ventilation type. Studies in schools and universities show energy savings in heating, cooling, and ventilation of up to 40%.70

We are not aware of DCV being implemented on campus, however some of the newer buildings (Nixon and Centenary) may already have a DCV system as CO₂ sensors in the ducts where they are hidden.

Novel cooling technologies, such as Ecoline Solar’s hybrid solar-thermal air conditioners which can reduce energy use by up to 55% are commercially available in Singapore. A technology such as this could be trialled on campus and would bring significant energy savings.71

If occupancy sensors are installed for lighting, they should be explored to turn on/off AC systems too.

Lighting

The lighting system at Tanglin is relatively efficient. Based on the FM team’s lighting schedule we calculated a lighting power density (W/m²) for each building, as well as the entire school. The overall value was 4.9 W/m², below Green Mark’s Super Low Energy target of 5 W/m² for classrooms, offices, and meeting rooms.72 Berrick, 6th Form, and Senior are all above this value. See Table 3.7.

83% of lights on campus are already energy efficient LED models. We estimate that if LEDs replace all lights on campus, a 10% reduction in energy consumption of the lighting system can be achieved. Most florescent lights are in the 6th Form and Berrick buildings so replacement should begin there.

*Field not included

Table 3.7

Lighting at Tanglin

We note that many remaining fluorescent lights are in infrequently used areas such as storerooms. As such, classrooms that still have fluorescent lights (such as in 6th Form College) should be prioritised.

Lights in the Senior school have already been replaced with LEDs, but the building still has high lighting power density. Illuminance should be reviewed to ensure that areas aren’t overlit. If this is not the case, retrofitting strategies to bring more natural light (window shelves, more windows and skylights) should be explored.

Metal Halide lights are used on the school field, the sky quad in the Junior school and the Berrick gym. LED field lighting is a commercially available alternative and can reduce power consumption by 70%.73

We recommend a smart lighting management ‘Dali’ system be trialled in one building and eventually be rolled out across the campus. Lighting management systems install light and occupancy sensors in rooms so that lights automatically turn off when not needed or dim when natural light is sufficient. They are commercially available in Singapore and can be integrated with the existing Daikin ITM system that controls the schools ACs. One supplier in Singapore claims energy savings of up to 66%, although 20-30% is more reasonable.74

Smart energy management

Smart energy management includes building automation, smart buildings, and plug load management.

A building management system (BMS) is a control system which can monitor and manage the mechanical, electrical, and electromechanical equipment in a building. This includes air-conditioning, lighting, ventilation, building access control, pumps, elevators, and other appliances.

Smart technologies have shown the potential to reduce a building’s total energy consumption by 8-18%.75

The Nixon building has a BMS system which can switch the cooling system on and off, and reset the temperature set points. The rest of the school runs on an ITM system which can also switch ACs on and off and reset temperature set points.

We recommend that the new buildings maximise the use of smart technologies to aid in achieving their low EUIs, as well as provide educational opportunities.

Plug loads (appliances) can account for as much as a quarter of a buildings electricity consumption.76 Responsible user behaviour is essential in reducing this consumption, however technologies such as BMSlinked power sockets, timers, and smart power strips can also be used. More energy efficient equipment (printers, computers, audio-visual equipment, gym equipment, etc.) will consume less when on standby or idle modes, while eliminating redundant equipment is another strategy to reduce plug loads.

Renewable energy

Solar energy is currently the most feasible renewable energy source for buildings in Singapore.77

Onsite solar energy generation

We developed a preliminary solar model using Helioscope, a modelling software. The model shows that if all available roof space is used, approximately 20% of Tanglin’s energy use could be provided by solar panels. Even more solar energy generation could be achieved if panels are installed over carparks, play areas, and walkways, as well as on some east and west-facing walls. In the roadmap we have assumed a phased installation of rooftop solar to 2028 (25% per year), followed by additional solar on the new buildings in 2030 and 2040 to make them net zero energy. Solar panels have a lifespan of 20 years so many are expected to be replaced before 2050. See Figure 3.2 and Table 3.8.

Table 3.8

Figure 3.2

Proposed layout of solar panels based on Helioscope model

Offsite renewable energy generation and renewable energy credits (RECs)

A renewable energy certificate (REC) is proof that 1 MWh of electricity was generated from renewable energy (e.g., solar). By purchasing RECs, Tanglin can claim the environmental benefits of the renewable energy associated with the certificate.

It should be noted that if Tanglin decides to pursue the Green Mark Super Low Energy (SLE) certification program, RECs must be generated by companies within Singapore. To achieve the Green Mark requirements beyond SLE (Zero Energy and Positive Energy), RECs can only be used once the first 60% energy savings have been achieved through energy efficiency improvements and onsite renewable energy production.78

We have not modelled any REC procurement in the roadmap as we modelled the location-based emissions from electricity use. If Tanglin were to purchase RECs to account for their entire electricity generation, Tanglin’s market-based Scope 2 emissions would be zero. RECs must be purchased every year to continue to claim zero market-based Scope 2 emissions. The current cost to purchase RECs from Genco, Tanglin's electricty supplier, is approximately S$11/MWh. Therefore, the cost to purchase RECs to compensate to Tanglin's 2023 emissions from electricty is approximately S$80,000.

We recommend that Tanglin explore purchasing RECs directly from the school’s electricity supplier, Geneco.

New buildings

Our proposed roadmap assumes that the two new buildings, to be built in 2030 and 2040, will be highly energy efficient, with EUIs of 50 kWh/m² and 40 kWh/m² respectively. Achieving these low EUIs will require intelligent green-building design, efficient technologies, and responsible building management.79

The roadmap also assumes that both new buildings will be net zero energy, achieved by the extensive deployment of solar.

During the design phase, the buildings’ orientation should be considered to optimise natural lighting and ventilation, as well as minimise solar heat gain on east and west facing walls, which will receive intense morning and afternoon sun year-round. A northsouth orientation for the longer axis of the building is generally preferred for buildings near the equator. The orientation should also consider the prevailing wind directions to maximise natural ventilation.

Other design features that the school should consider include natural ventilation in all ancillary spaces (e.g., corridors, toilets, staircases), shading devices such as overhangs, louvers, and vegetation, and green roofs and walls.

The buildings’ envelopes should use materials with high thermal mass and be well insulated and airtight. BCA defines a Zero Energy Building (ZEB) as “the best-in-class energy performing Green Mark building with all of its energy consumption, including plug load, supplied from renewable sources (both on-site and off-site”, while a positive energy building (PEB) is a “super low energy building with 115% of all energy consumption, including plug, supplied from onsite renewable energy sources.”80,81

BCA has conducted a feasibility study to show that a medium rise building (similar to the Nixon or Centenary) could achieve ZEB status with technologies currently available, and that with further technological developments, it would be viable for such a building to achieve PEB by 2030. 82

Summary

Reducing electricity consumption on campus can be achieved through behavioural changes, operational changes, and technological upgrades. By producing green energy on campus and buying RECs, the school can further reduce its emissions from electricity.

Incorporating green building design and passive design features into new builds will play an important role in helping the school decarbonise.

Finally, emissions from electricity consumption will naturally reduce as Singapore’s grid decarbonises in accordance with government targets.

Recommendations

Switch off all unused equipment earlier (e.g. 4pm or 5pm).

Investigate reasons for energy use in evenings and overnight to pinpoint and reduce unnecessary consumption.

Reduce weekend energy consumption by implementing a complete shutdown policy for buildings not in use and concentrating building use as much as possible.

Consider a user turn on policy for AC and lights during weekends and holidays, with an automatic switch off time of 2pm.

Completely shut down all buildings not under renovation during holidays.

Consider increasing campus set point by 1 degree.

Ensure all lights, ACs, and appliances are switched off when classrooms are empty.

Encourage students to develop visual prompts to remind occupants to turn off everything when leaving a room.

Have students lead regular classroom audits to identify energy saving opportunities.

Replace all non-LED lights with LED equivalent, including the outdoor pitch lights.

Designate an energy monitor in each class who is responsible for reducing their class’s energy consumption.

Responsibly eliminate redundant equipment to reduce plug loads.

Consider passive design retrofits such as shading fins, reflective paint on roofs, installing green roofs and walls, and enhancing air tightness of building envelope.

Replace electronic equipment with best available energy efficient options at end-of-life.

Consider installing double doors and/or air curtains in high traffic entrances.

Increase solar energy generation on campus by adding panels to all available roof space and consider installing additional shade and façade solar.

Investigate whether there are any single glazed windows on campus and replace with double glazed.

Consider purchasing RECs from Genco.

Trial hybrid cooling and/or demand-controlled ventilation in one building.

Develop a green building policy that ensures all new buildings are designed to meet best practice green building standards and maximise the deployment of solar from the design stage.

3.2 Reducing supply chain emissions

Reducing supply chain emissions is challenging as supply chains are notoriously murky and suppliers often lack adequate data to reliably quantify their own emissions. However, there are policies Tanglin can adopt to achieve its targets.

The first step in reducing emissions from the supply chain is simply to buy less. The school can develop a sustainable procurement policy that defines what is considered a 'necessary' purchase. This policy could be used to guide all procurement decisions and could be aligned with ISO 20400: 2017 Sustainable Procurement.

The next step is choosing service providers, suppliers, and products based on sustainability criteria. Examples of this include prioritizing suppliers who comply with ISO 14001 Environmental Management Systems, or suppliers that have declared emission reduction targets.

Another example is choosing products that have lower embodied carbon. This information is not always available at the moment. However, it will become more readily available as the world moves towards decarbonization the coming years. The school should incorporate the practice of considering products' embodied carbon during procurement decisions and continue to refine these decisions as more information becomes available.

Tanglin can also encourage suppliers to disclose their own carbon emissions and products' embodied carbon.

Another way Tanglin can reduce emissions from its supply chain is by including sustainability provisions in contracts and tender criteria. Requiring contractors to use recycled materials for renovation and construction projects, or to source materials from within a [500]km radius are examples of clauses that could be included.

In general, Tanglin should try to first source goods and service providers locally or regionally. The school should also avoid shipping goods by air freight whenever possible.

The largest emission sources from the supply chain are building construction services, building and renovation work services, and building construction. Tanglin should prioritize reducing emissions from these categories first.

We were unable to obtain any primary emissions data from the school's suppliers, partly because many suppliers don't track and report their own emissions. Instead, we used standard emissions factors from relevant secondary sources to arrive at our estimates. The Singapore Emission Factors Registry (SEFR) is a national database for Singapore-specific emission factors currently being developed. It will be released in phases with the first phase expected to be ready by the end of 2024.

Tanglin should use emission factors from the SEFR to recalculate its supply chain emissions once the database is complete. This will give the school a more accurate picture of its supply chain emissions and can inform procurement decisions.

Another way to improve the accuracy of estimating the school's supply chain emissions is to develop operational systems within the procurement department that track the data required to quantify these emissions. Useful data to track from each procurement order is:

• The category of good or service (as categorised by the PO current system)

• Whether the good is a capital good or not

• Supplier’s name

• Supplier’s address

• A brief summary of what was ordered

• Total cost of order (SGD)

• Shipping cost (SGD)

• Shipping mode

This data could be recorded in an excel and would make quantifying supply chain emissions easier and more accurate.

Emissions from water consumption are quantified as purchased goods and services (GHG Scope 3, category 1). From a carbon standpoint, Tanglin’s water consumption is insignificant, contributing less than one percent to the school’s carbon footprint. However, water use intensity and water efficiency have other environmental impacts beyond carbon emissions. See Chapter 4 - Tanglin's Other Environmental Impacts for more information.

In the roadmap, we used a goal seek approach to find the percentage reduction in emissions from Tanglin’s supply chain required to achieve the near-term and long-term targets, while accounting for population increases in 2030 and 2040. The result that the school needs to achieve is a 6% annual reduction until 2035, followed by a 2% reduction until 2050.

Recommendations

Develop sustainable procurement policy that aligns with ISO 20400:2017 Sustainable Procurement.

Prioritize suppliers that have declared emission reduction targets.

Choose suppliers and contractors that comply with ISO 14001 for Environmental Management Systems, when possible.

Encourage suppliers to disclose their carbon emissions and products' embodied carbon.

Choose suppliers and service providers based on sustainability criteria.

Include sustainability provisions in contracts and tender criteria.

Prioritize products and materials with low embodied carbon when possible.

Review top emissions categories within the school's supply chain and prioritise reducing these emission sources first.

Avoid air shipping wherever possible.

Develop an operational management system that records the data needed from procurement orders to enable more accurate estimates to be made of supply chain emissions.

3.3 Reducing travel emissions

Commuting to and from school

To reduce emissions from commuting, increasing the number of people that use green modes (walking, cycling, public transport, and the school bus), electrifying the school buses, and implementing a green transport policy are the most significant actions Tanglin can take.

In the roadmap, the school bus fleet is electrified in 2030. This will reduce emissions from the service by almost 80% and continue to reduce emissions to zero by 2050 as the grid decarbonises.

We assumed a strong shift in student commuting practices, driven by a green transport policy and expansion of the school bus service. The roadmap assumes that students are not allowed to come by car to school by 2030, and that this policy is phased in from 2025. All green transport modes increase to replace the car use. Staff see a less significant shift from private car use to green transport.

Actions to achieve this include improving walking and cycling entrances at school, improving bike facilities (racks and changing areas), expanding the availability of buses for staff, and offering shuttle buses to/from the MRT.

Some schools we have worked with have implemented mandatory busing, busing for all, or green transport policies, to great effect. Some schools include the cost of the bus service in every student's school fees, enabling them to drastically increase bus use and overall efficiency of the service.

All actions the school takes to green its commuting will happen in tandem with the electrification of cars in Singapore and worldwide. We assumed that the adoption of electric vehicles by the Tanglin community will be in line with Singapore’s targets of 50% by 2030, 100% by 2040.

Public transport, both buses and the MRT will decarbonise as the grid decarbonises and the buses are replaced by electric buses.

Recommendations

Electrify school buses.

Consider ways to improve the walking and cycling entrances to the school.

Improve bike storage facilities on campus.

Expand the availability of buses for staff.

Consider offering shuttle buses to/from the MRT.

Consider implementing a mandatory busing for all policy.

School trips

Flying is the most environmentally damaging type of travel per kilometre. Although the airline industry is responsible for only 2% of global CO₂ emissions, emissions from air travel are the fastest-growing source of emissions.

Flying less and choosing closer locations are the most important actions to reduce emissions from school travel. To model this, we reduced staff kilometres travelled by 5% per year, and student kilometres travelled by 3% per year. We also assumed no business class flights. The airline industry is working to reduce emissions, so we also modelled conservative assumptions for sustainable aviation fuel (SAF) uptake in Singapore, and aeroplane efficiency improvements.

We recommend that staff travel for professional development and other business purposes be reviewed and alternatives such as equivalent local opportunities and/or teleconferencing be explored.

Staff travel is only 12% of total emissions, with the rest being student trips for outdoor education, sports and other cultural events, and educational trips. At present, many of these flights are short-haul flights to destinations in Southeast Asia, however most of the emissions from school trips were generated by just eight trips. The trips with the highest emissions per person were to Switzerland, Australia and New Zealand. To reduce emissions some of these trips should be reviewed and reduced.

Student travel is going to be harder to reduce with the introduction of the Tanglin Highlands Programme in Gippsland. We estimate that one year group travelling return to Melbourne will emit 460 tonnes of CO₂e, or 28% of the current total emissions from flying.

For contrast, if 25% of current student trips were changed to bus trips to KL, emissions would decrease by 353 tCO₂e, 22% of the total emissions from school travel.

The school community will have to decide when and where to travel but we offer some potential suggestions below:

• Develop and participate in more sports, arts, and other competitions based in Singapore. The city already has many competitions among schools reducing the need to fly elsewhere for these competitions. Tanglin could also look to host competitions more often.

• Review all overseas trips to determine their necessity considering emissions as well as educational benefits and alternative options.

• Offer more trips and opportunities in Peninsula Malaysia that are reachable by bus (and hopefully eventually train) as well as other nearby locations that only require short haul flights.

• Continue to offer trips as close to Singapore as possible.

Although the airline industry is also working to reduce emissions from flying, there is limited progress to date and future potential is uncertain.

Singapore has a nascent SAF industry with targets for 1% and 3-5% blend by 2026 and 2030 respectively. These short-term targets will have a limited impact on flight emissions. Singapore does not have any longterm SAF mandates and projections vary widely for the expected percentage of SAF in future. We assumed a SAF blend in 2050 of 65%, a projection from the World Economic Forum (WEF).83 This is less than the EU’s mandate of 70% SAF by 2050.

There is also significant uncertainty in the emission reduction potential of SAF. Depending on feedstock and production method, this could range from 2% to 100% reduction. However, all the very high reduction technologies are in development or lack sufficient feedstock to be scaled globally (waste cooking oil).

Therefore, we modelled a relatively conservative view of SAF’s potential for emissions reduction of 14%. This is based on available technologies and global feedstock and should be updated if technologies become proven and widely implemented.

We also modelled energy efficiency improvements of best-in-class planes and plane engines.84

Domestic travel

Domestic travel for sports and educational trips were also modelled. They are assumed to increase by 5% in 2030 and 2040 to account for increased domestic trips. This is on top of the increase due to population growth from the new buildings in the same two years. Electric school buses introduced in 2030 decreases emissions from domestic trips by 80%.

Even if the school dramatically increases local travel, it will have a minimal impact on emissions, especially once the bus fleet is converted to electric. For example, in 2023 there were about 1,200 domestic trips that travelled a combined 27,000km, equivalent to travelling the width of Singapore 540 times. If the number of domestic trips where to double, replacing the total number of overseas trips 10 times over, emissions from domestic travel would double to 44 tonnes, the equivalent of 18 people flying to Melbourne.

Recommendations

Avoid business class travel.

Develop a policy that defines what is and is not necessary travel taking emissions into account as well as other considerations.

Only fly when necessary and consider alternatives such as teleconferencing and travelling by road, rail, or boat.

Reduce long haul flights by choosing destinations close to Singapore.

3.4 Reducing emissions from other sources

Refrigerant leakage

Refrigerants are potent greenhouse gases some of which have global warming potentials (GWP) thousands of times larger than CO₂. Although refrigerant leaks during operations can be minimised by good maintenance practices, they cannot be eliminated entirely. It is therefore important to choose refrigerants with low GWPs.

Alternatives to the high GWP refrigerants used at Tanglin (R410a, R134a, etc.) are already available and as of 2022 are mandated for certain applications in Singapore. In fact, Tanglin already has a few ACs with a relatively low GWP refrigerant, R32. R32 reduces the potential global warming impact from refrigerant leaks by 71% compared to an equivalent AC unit with R410a, due to its much lower GWP (677 compared to

Table 3.9

Summary

1,924) and less total refrigerant required per unit. The roadmap assumes that all room ACs (single- and multisplit) will be replaced with ACs using R32 at their end of life (10-15 years).

Most of Tanglin’s cooling is provided by VRV type ACs. While VRVs are energy efficient, their long refrigerant lines are more prone to refrigerant leaks than chiller systems. All VRVs on campus are Daikin brand. The brand has recently introduced a new model, VRV 5, which is their first model to use R32, although it is not yet available in Singapore. The roadmap assumes that the VRV 5 model will be available from 2026 and that all VRVs will be progressively replaced with a VRV 5 at the end of their life until 2035. Beyond then it is assumed that HFO refrigerants (hydrofluoroolefins) or natural refrigerants will dominate the market – both of which have very low global warming potentials of 0-10.

Montreal- production to be phased out by 2020. However, it is still available in Singapore.

Potential drop-in replacement for R410A

Kigali – production to be phased out by 2030.

When we asked Daikin about the introduction of VRV 5 to the Singapore market, they stated that regulatory changes are needed before the product will be available. Given that Singapore has agreed to phase down HFCs such as R410a, and the US and EU will ban the sale of VRV systems with R410a in the next few years, we believe low GWP VRV options will become available in the next few years in Singapore.85 86

In the roadmap, refrigerant leakage from the watercooled chillers in the Nixon building is assumed to be constant until replacement in 2036 (20 years life span). When replaced, it is assumed that the new model will be a low GWP chiller. Low GWP chillers are already available in Singapore and are mandated for new large, water-cooled chiller installations (>1,055kW).87

We also assumed that any new buildings will have water cooled chillers instead of VRVs. If VRVs are selected, low GWP refrigerants will be necessary to prevent a significant spike in emissions from refrigerant leaks.

Reviewing refrigerant management practices to ensure leaks are minimised is an important operational action to reduce emissions from refrigerant leakage. In certain cases, refrigerants can be replaced in existing AC units, referred to as a ‘drop-in’. This can be explored in future, particularly from VRVs, provided that the replacement does not cause any significant reduction in performance.

Mobile emissions

In the roadmap, mobile emissions from the school’s van and motorbike are assumed to be steady until 2030 when they are replaced by electric vehicles. The direct emissions from these vehicles are therefore zero from this point and are accounted for in Scope 2, electricity use. The exact date of replacement is up to the school and based on the vehicle’s lifespan. However, any new vehicles purchased by the school should be electric vehicles.

Stationary emissions

Stationary emissions at the school are minimal. There is some gas use in science classes as well as some diesel use to test and maintain the backup diesel generator. We have assumed that both sources are constant until 2040 when alternatives are put in place. Alternatives to the diesel use in the generator could be biodiesel and/ or batteries for power storage. Gas use in the science lab could be replaced with electric based heating, or burning green hydrogen if it is readily available. To keep stationary emissions low, no new equipment requiring fossil fuels should be procured.

Upstream emissions from fueland-energy related activities

These emissions are from the extraction and processing of fossil fuels used by the school (in the form of gas, diesel, petrol, etc.) and emissions associated with transmission and distribution losses of electricity consumed by Tanglin. They represent about 6% of the school's total emissions.

In the roadmap, upstream emissions from fuels consumed by the school remain steady until 2030, when it is assumed that the school will replace fossil powered vehicles with electric ones. There are still residual upstream emissions from fuel consumed by the school which is due to the gas used in the science labs. This gas use could be replaced with electric based heating or green hydrogen (if available).

Reducing electricity consumption will reduce upstream energy emissions in a meaningful way. The roadmap shows a reduction in emissions from upstream electricity and T&D losses that correlates to the modelled reduction in electricity consumption.

Finally, as Singapore’s grid decabonises, Tanglin’s upstream energy emissions will also decrease. However, even when Singapore’s grid is 100% renewable, the school will still have some upstream energy emissions associated with the production and installation of the renewable energy infrastructure.

Emissions from waste transportation

Tanglin’s waste is incinerated in waste-to-energy plants where the resultant heat is used to generate electricity. This means that the emissions from incinerating waste are built into the grid factor and are thus accounted for in electricity emissions.

To avoid double counting, we did not quantify emissions from Tanglin’s waste incineration. However, we did quantify the emissions produced in the transportation of Tanglin’s waste, which is modelled in the roadmap.

Sembcorp transports Tanglin’s waste via electric vehicles, so the emissions from waste transportation are insignificant in the scheme of Tanglin’s entire footprint –they account for just 0.005% of Scope 3 emissions.

We modelled a reduction in these emissions that aligns with the reduction in emissions from the supply chain, under the assumption that as the school begins to buy less, it will produce less waste.

Emissions from gas used in the kitchens

The kitchen at Tanglin is is owned by the school and leased to, and operated by Chartwells, the school’s food service provider. The stoves in the kitchen use gas and the emissions associated with this gas consumption form part of Tanglin’s carbon footprint.

Emissions from gas use in the kitchen are insignificant, accounting for just 0.2% of all Scope 3 emissions. However, the school should still consider retiring the gas-powered stoves at the end of life and replacing them with electric ones. The roadmap assumes this will happen in 2030, the same year the school’s vehicles are replaced with electric ones.

Assuming the gas in the science labs is also replaced, Tanglin could have a fossil free campus in the future, a unique talking point for the school.

Recommendations

Replace AC units according to the school’s existing asset replacement policy. When replacing AC units, select best in class energy efficiency, low GWP refrigerant options. Low GWP options in the near term are expected to be R32. Low GWP options in the longer term are expected to be HFOs and natural refrigerants.

Replace the school van and motorbike with electric alternatives at their end of life.

When replacing the school’s chillers, ensure it is a low GWP chiller.

Consider replacing gas used in science labs with electric alternatives or green hydrogen if available.

Review refrigerant management practices to minimise leaks.

Replace the school’s generator at end-of-life with a battery or other non-carbon emitting backup power option.

Explore using biodiesel (a blend such as B20 (20%) or B100 (100%)) in the existing generator.

Create a policy to prevent the purchase of any new, direct fossil fuel consuming equipment.

3.5 Carbon offsetting and climate action beyond Tanglin’s

footprint

Offsetting is the act of compensating for GHG emissions produced in one place (Tanglin’s footprint) by investing in projects that reduce or avoid or remove emissions from the atmosphere in another place. Examples include planting trees, reducing deforestation, developing renewable energy, and implementing energy efficiency projects. Companies can purchase offsets to supplement their efforts to reduce their own emissions and to contribute to global decarbonisation beyond their own carbon footprint.

Offsets are controversial for a few reasons. First, they can be used by companies to delay taking other actions to reduce their emissions; this is seen as a form of greenwashing. Offsets on their own are not a solution to the climate crisis, they are merely one tool to accelerate global climate action and to neutralise those emissions that cannot easily be mitigated in other ways. Second, in recent months, it has come to light that some high profile offset programs have failed to deliver their promised climate benefit and, in some cases, the projects were alleged to have been fraudulent. This has been covered widely in the media and academic papers .88 89 90 91

In short, offsets are far from a perfect tool. Used carelessly, they could slow global progress on climate change. But used responsibly, they can accelerate progress beyond the slow pace that has so far been set.

Due to the controversies surrounding offsets, major net-zero standards, such as ISO and SBTi, do not allow offsetting to be used to meet interim net-zero targets. To claim net-zero, the standards require a minimum of 90% emissions reduction before removals-based offsets can be used to neutralise the residual emissions remaining.92 93

This is not to say that offsetting should not be pursued as a climate action prior to the 90% threshold. Offsetting can be undertaken at any time and is recommended as a method of contributing to global

climate action. However, it should not be used to make the claim of being net-zero until an organisation has made significant progress (90% reduction) with reducing its own emissions. And where offsetting is used in parallel, organisations should be able to show that they are making serious efforts internally to reduce their emissions in other ways.

In Tanglin’s case we recommend the establishment of an offsetting program that contributes to climate action outside of the school. We recommend that the level of contribution is at least equivalent to the emissions of the school’s annual emissions from flying, if not the school’s total emissions (emissions from electricity could be excluded as they can be covered by RECs).

Any investment in emissions reduction projects must be done in parallel with a reduction to Tanglin’s own carbon footprint. For the example of flights, a review of how the school can reduce the number of flights, particularly long-haul flights would need to happen in parallel.

In the case of emissions from flights, there are two ways the school could implement such a program:

The first is to purchase offsets online at the time of booking each trip. Many airlines provide this option, but it while it is convenient from an administrative point of view, it has limited educational value for the school and is likely to be more expensive than buying offsets directly from a registry or project developer.

Alternatively, Tanglin could charge a carbon tax on all flights throughout the year and establish a fund that can be used to invest in offset projects of its own choosing or carbon reduction projects on campus. The tax could either be a fixed percentage of the cost of the flight or a standard rate (in $/tonne CO₂e) could be applied to the emissions generated.

The latter approach provides an opportunity for the school to be more selective in its choice of projects and offers the potential to develop relationships with specific projects and developers that could bring important educational benefits for Tanglin students.

If Tanglin continues to calculate its’ carbon footprint annually, the school can easily identify the level of contribution required, whether that be for emission from flights or total emissions.

We estimate the cost to implement an offsetting project for Tanglin would be ~S$20,000 – S$40,000 if it covered flights, and ~S$80,000 - S$160,000 for Tanglin’s total footprint, except for electricity.

Recommendation

Develop an offset program to contribute to climate action outside of the school to at least the level of the school’s emissions from flights.

Tanglin's Other Environmental Impacts

4. Tanglin's other environmental impacts

A carbon audit is a good place to start when quantifying the environmental footprint of a school. However, carbon emissions don’t tell the whole story.

In this section, we look at some of the other contributors to the school’s environmental footprint.

4.1 Water use

Water consumption in 2023 was 36,900 m³, up 39% from 2022. Half of this increase is due to the opening of the Centenary, the rest is due to significantly higher water use in the West Wing, Senior Reception, Berrick, and 6th Form College. We don’t know the reason for the large increase in water use in these buildings.

Water use intensity (water use per square metre) is very high in West Wing, and high in the Infant and Senior Reception buildings. Conversely, Berrick and Centenary have low water use intensity.

Consumption peaks in April, but in 2023 is relatively consistent each month. In 2022 there was more variance, February and March had low water use.

Tanglin does not measure water use per major water user (irrigation, toilet flushing, kitchen etc.) so it is unknown where and how this water is used on campus. From our knowledge of other schools, we expect toilet flushing to be the largest use of water on campus, especially considering that Tanglin's playing field does not require irrigation.

The school uses some recycled water, (NEWater supplied by PUB, Singapore’s national water agency) for non-potable uses such as in the chiller system in Nixon building.

There is no rainwater collection, or onsite water reuse (greywater) systems at Tanglin.

Tanglin’s water use is relatively low compared to our sample of international schools in Asia. The only schools with lower water use intensity and water use

intensity per student are two schools in Hong Kong that use salt water for toilet flushing, one of the major water users at a school. The schools with very highwater use in our sample have large grass playing fields that require watering multiple times a day.

Recommendations

Install submeters to obtain more granular data about the major sources of water consumption on campus (toilets, swimming pool, irrigation, kitchen etc). Ultrasonic, clamp-on flowmeters are a simple and non-invasive method of submetering.

Expand the use of NEWater on campus.

Explore rainwater collection and/or greywater reuse for irrigation and toilet flushing to reduce freshwater use.

Investigate high water consumption in the West Wing, Infant, and Senior Reception buildings.

Tanglin’s water consumption per building in 2022 and 2023 (m³) 4,500 5,000 4,000 3,500

Tanglin’s monthly water consumption, 2022-2023 (m³) 4,500 4,000 3,500 3,000 2,500 2,000 1,500 1,000 500

Figure 4.2

Figure 4.1

Infant

West Wing Junior

Snr. Reception

Senior

6th Form Nixon Centenary

Berrick

Figure

Figure 4.4

Tanglin’s

Infant West Wing Junior Snr. Reception

Senior 6th Form Nixon Centenary Berrick

4.2 Food and food waste audit

Chartwells is Tanglin’s food service provider. Chartwells rents the kitchen space from the school, and is responsible for all food procurement, preparation, serving, and food-related waste management.

This being the case, food technically falls outside the operational boundary of Tanglin. For this reason, food and food waste were not included in the greenhouse gas inventory. However, the school can assert a reasonable amount of control over the food service provider through requests and contract clauses.

Food procurement

Nearly half of the food Chartwells procured for Tanglin in 2023 came from Malaysia, based on dollar value. 11% came from Brazil and 8% from France (see Figure 4.5).

Only 6% of food procured by dollar value came from Singapore. This is unsurprising; as a nation Singapore imports 90% of its food, with only around 10% being produced locally.94

While travel miles are not the largest contributor to a food’s carbon footprint, usually accounting for less than 10%, sourcing locally does reduce these emissions, as well as distribution emissions - emissions from refrigeration.95

Sourcing locally also supports local farmers and encourages eating seasonal produce. Seasonal produce generally requires fewer resources to produce than out-of-season produce, thus making it more environmentally friendly.

Carbon emissions from food

Food and agriculture are responsible for more than a quarter of global greenhouse gas emissions. Every step along the food supply chain from farm to fork produces greenhouse gases - methane from agriculture, nitrous oxide from fertilisers, CO₂ from transporting and manufacturing, and hydrofluorocarbons from refrigeration (see Figure 4.5).

Where Chartwells procures food from, by dollar value. Countries that contributed <1% of produce were excluded from the figure.

Indonesia, India, Korea (all 1% respectively)

Belgium, 2% New Zealand, 2%

Denmark, 2%

2%

Figure 4.5

Figure 4.5

Greenhouse gas emissions across the food supply chain (kg CO₂e per kg of product)96

Methane production from cows and other GHG emissions from land conversion for grazing and animal feed production means beef from dedicated beef herds has a very high carbon footprint.

Dairy co-products mean beef from dairy herds has a lower carbon footprint per kg of product than dedicated beef herds.

Pigs and poultry are non-ruminant livestock, so they do not produce methane and have lower emissions than beef and lamb.

Flooded rice paddies produce methane, which is the main source of emissions for rice.

In general, emissions from transport, retail and packaging are much less than emissions from producing the food.

Methane production from cows means dairy milk has significantly higher emissions than plant-based milks like soy milk, and oat milk.

CO₂ emissions from most plant foods are as much as 10-50 times lower than most animal-based products. Nuts have a negative land use figure because tree nuts are currently replacing crop lands and carbon is stored in the trees.

To estimate the carbon footprint of food at Tanglin, we used an average-data approach (see Appendix C for methodology).

Emission factors (EFs) were found from one of the six following scientific publications or databases: Ecosperity, OurWorldinData, Pignagnoli et al. 2023, My Emissions, Carbon Calculator, and Climatiq.

Where possible, preference was given to Ecosperity, as the data was Singapore specific.

Overall, we found suitable emission factors for 92% of the food groups by weight and 59% of the food groups by volume. The food groups that we were unable to find appropriate EFs for were mostly processed foods which contained many ingredients and have yet to be quantified by the EF sources we used.

The total quantified carbon emissions from Tanglin’s food in 2023 is 452 tCO₂e. When this is adjusted to include the food groups we were unable to find emission factors for, the total is 520 tCO₂e.

Beef products were by far the largest contributor to Tanglin’s food carbon footprint, accounting for 26% of the quantified emissions (see Figure 4.7 and Table 4.1.).

Globally, meat and dairy products have a disproportionately large environmental impact - they provide only 18% of the calories and 37% of the protein humans consume, but they use 84% of all the farmland and are responsible for 60% of the greenhouse gases emitted by the agricultural sector. Even the most sustainably produced meat and dairy products have a bigger environmental footprint that most other foods, especially plant based foods.97

Meat and dairy products combined accounted for a third of Tanglin’s quantified food emissions.

One of the most effective ways the school can manage the environmental impact of its canteens is to reduce the consumption of meat and dairy products (see Figure 4.6).

Reducing meat and dairy consumption not only reduces the carbon footprint of school food, but also reduces the water pollution, air pollution, freshwater use, land use change, and deforestation that is generally associated with livestock production.98

4.6

The environmental impacts of dietary change

4.7

Estimated emissions from food groups purchased by Chartwells in 2023. Any food group contributing less than 2% is grouped in "other"

Figure

Figure

Beef Dairy

Baked goods

Chicken

Other Fish

Other vegetables

Popcorn Rice, 2%

Tofu, 2% Bread, 2%

Muesli bar, 2%

Fruits, 2%

Table 4.1

Estimated emissions of the different food groups purchased by Chartwells in 2023

Table 4.1 (continued)

Estimated emissions of the different food groups purchased by Chartwells in 2023

The food waste audit

Over one week in September 2023, Metanoia, with the help of Tanglin students, conducted a food waste audit in the junior canteen and the Nixon canteen.

The audit aimed to determine the amount of plate waste generated daily in the two canteens. Plate waste is food that has been served to diners but not eaten. During the audit, we asked diners to separate out their plate waste from general waste, and place it in a specific bin, which was then weighed at the end of the lunch period.

In the junior canteen we weighed the food waste at the end of Year 7 lunch. We requested Chartwells to ensure that all Year groups who ate before the Year 7s sorted their food waste into the appropriate bin, but we’re unsure how well this was monitored.

In the Nixon canteen we weighed the waste at the end of the senior lunch period. Many students who purchase food from the Nixon canteen take it away and eat it elsewhere. Thus, the audit did not account for potential food waste from these diners.

We did not measure any food waste produced in the Infant School, M Café, the Banyan Café, and in any food tech classrooms.

The average daily plate waste from diners in the junior canteen and the Nixon canteen was 30kg/day.

Chartwells uses the LeanPath platform to track three categories of food waste: presented but not sold (items that were cooked and displayed but not sold); timed or temp’d out (food that goes beyond holding time); and trimmings and by products (back-of-house prep waste).

Using the data from the LeanPath Report (March 2024) we were able to estimate a daily average of food waste from these sources – an average of 20kg/day.

Combining this data with the data from the food waste audit, we were able to determine the average daily food waste at Tanglin per person, as well as the food waste over the year.

Tanglin produces close to nine tonnes of food waste each year, or 18kg/person/year. This equates to 99g/ person/day, close to the weight of an average cupcake.

Tanglin’s food waste per person is close to the average of other schools Metanoia has audited (see Figure 4.8).

Note, to normalise the data, we used the number of meals Chartwells prepares each day as the average number of diners – 500. This number may be a slight underestimation, as it does not include diners who brought packed lunches and discarded their food waste in the canteen food waste bins. However, during the audit we observed that very few diners who brought packed lunch did this.

4.8 Tanglin’s food waste per person per year is close to the average of the schools Metanoia has audited (kg/person/year)

Figure

Downstream handling of food waste

Chartwells places all canteen waste in three bins outside the waste room, where Sembcorp collects them daily. Almost all the waste collected by Sembcorp is incinerated in a waste-to-energy plant.

Transporting and incinerating food waste is not the most efficient method of handing the waste, even if the heat is recovered for energy. Food waste has a very high-water content (between 70-80%) which decreases the efficiency of the incinerator, and means the food waste may require pretreatment or mixing with other materials to overcome this.99

An alternative way of handling food waste is to compost it. Compost is the decayed organic matter made up of greens (e.g., plant-based food waste or grass clippings) and browns (e.g., dried leaves or paper) that improves soil structure and promotes fertility when added to a garden. Composting food waste speeds up the natural decomposition process and offers an excellent experiential learning activity for students.

While most backyard compost systems can only take plant-based food waste, industrial composter are able to handle all food waste, including bio-based plastics.

How to reduce the environmental impact of food at Tanglin

There are several ways Tanglin can reduce the environmental impact of its food and food waste.

Reducing the environmental impact of food begins with the choice of suppliers. Tanglin should request that Chartwells endeavours to source local, in season produce as much as possible. All meat, dairy, and eggs should come from free-range, hormone-free farms. Seafood should be certified by the Marine Stewardship Council (MSC), and wherever possible, only suppliers that are certified Fairtrade and certified by the Rainforest Alliance should be selected.

To reduce the carbon footprint of its food, Tanglin can work with Chartwells to serve less red meat (particularly beef) and dairy products. Red meat can be replaced with chicken, but the school could also consider having ‘meat-free’ days. Another way to reduce meat consumption is to offer a broader variety of plant-based options.

Tanglin can also work with Chartwells on menu planning and portion sizing. During the food waste audit, we noticed a lot of starches being discarded because the portions were too large. Preparing food that students want to eat and listening to diners’ requests regarding portion sizes will reduce the amount of plate waste at the end of the meal.

Another approach to reducing plate waste is to continue separating it from waste streams and regularly weigh and report on the amount of food waste produced thereby drawing attention to how much food waste the school produces every day.

Finally, the school should consider purchasing an industrial composter and setting up some compost boxes to handle the food waste produced on campus and use the compost on the school gardens.

Recommendations

Request Chartwells to improve the sustainability of their supply chain.

Work with Chartwells to serve less meat and dairy.

Consider having a ‘meat free’ day once a week.

Request Chartwells serves more plant-based options.

Reinstate the food waste separation system and conduct regular food waste audits. Report food waste data to the school community.

Include specific sustainability criteria in future tenders for food service providers.

Consider purchasing an industrial composter and setting up a compost system.

Work with Chartwells to improve menu planning.

Require Chartwells staff to pay greater attention to students’ portion requests.

4.3 General waste audit

There are two waste streams at Tanglin: general waste and recyclable waste. Sembcorp, Tanglin’s waste management provider, collects general waste once a day, and recyclables are collected every Friday. At Tanglin, all general waste is compacted in a waste room before collection.

General waste

In 2023, Tanglin generated over 77 tonnes of general waste equivalent to 468 kg per school day.vi We normalized data according to the student population and found 167g of general waste was generated per student per dayvii. When compared to other schools, Tanglin’s waste generation per student per day is midrange. None of the comparison schools are in Singapore.

Recyclables

Paper, metal (aluminium cans and food tins), plastic (PET and HDPE) and bottled glass are recycled at Tanglin. All recyclables are placed in a mixed recycling skip bin, except for the corrugated cardboard which was kept in a separate skip bin. Table 4.2 outlines what recyclable materials are accepted and rejected by Sembcorp.

Data on recycling was not recorded in 2023, however it began in 2024. For this reason, it is excluded in the GHG inventory as the reporting year is 2023.

Waste audit

In September 2023, Metanoia and Tanglin students conducted a waste audit for one week. General waste bin bags were collected and weighted outside the waste room.

Based on our waste audit results, the average daily waste generated was 224 kg per day. It is worth noting that weightings were conducted at 2pm to cater to student schedules. Because waste was not weighed at

vi Excludes January. Total waste is from February –December 2023. General waste does not include food waste.

vii Based on 165 days

the end of the day, it is not representative of all the waste generated on campus.

However, observations from the audit provide valuable insight into the current waste sorting practices on campus and common sources of contamination in the recycling bins.

When we looked inside the general waste bins, we noticed a lot of recyclables, such as plastic drink bottles, plastic wrappings, paper drink cartoons and food waste. In the recycling bins, we observed zero cases of contamination. Approximately 75% of the mixed recycling bins contained paper, plastic containers (mostly cleaning products and chemicals), a handful of cans and plastic bottles. Two to three recycling bins were filled with flatted cardboard.

Carbon emissions from waste and recycling

Majority of municipal waste in Singapore is incinerated at its four Waste-to-Energy (WTE) plants, which generate electricity from the heat produced during combustion. This process helps conserve landfill space and reduces the volume of waste sent to landfills. To avoid double counting emissions, emissions from general waste combustion is not included in the GHG inventory as it is already included in the grid emissions factor of Singapore.

Recyclables in Singapore are collected and sent to Materials Recovery Facility (MRF). The recyclables are sorted into different waste streams, baled and sent to local and overseas recycling plants. We recommend Tanglin investigate the end-of-life treatment of their recyclables to estimate emissions from recycling.

Collect monthly data from Sembcorp on recyclables and begin monitoring

Work with Sembcorp to investigate end-of-life treatment of recyclables

Collect supplier-specific data from Sembcorp on recycling emissions, if possible.

Figure 4.9

Create signage to increase the visibility of recycling guidelines to reduce recyclables going into the general waste bin

Tanglin’s waste compared to select schools Metanoia has audited (g/student/day)

Recycling guidelines by

Accepted

Paper Cardboard boxes-Paper drink cartons-Office paperNewspapers-Phone books-Used envelopes-Files-Pamphlets/ brochures-Posters-Magazines-Junk mail

Ferrous and non-ferrous metals (steel cans, containers, metal objects, aluminium cans and containers, tin cans, etc.

Plastic Plastic drink bottles, detergent bottles, plastic bags, plastic wrappings, shrink wrap, etc.

Glass Clear, brown, green etc. coloured bottles / containers / jars

Rejected (source of contamination)

Tissue paper-Styrofoam and foodstained items

Any reusable items such as backpacks, clothes, or sneakers

Bulky items like blankets or pillows

Table 4.2

Sembcorp

4.4 Uniform audit

Tanglin purchases school uniforms from a supplier called Children Party Dress Shop (CPD), which is displayed in a uniform shop on campus. Students are required to wear a uniform throughout all stages of school, from infant year to the 6th form. In 2023, Tanglin purchased 7,209 school uniform items. Most of the school uniforms are a polyester blend with cotton or rayon, or both. See Figure 4.10.

Tanglin also purchases sports uniforms from Kukri Sports Asia. Each student is required to purchase a swim kit, PE kit and house team kit. Sports teams have their own kits, which students are required to purchase if they are in the team. In 2023, Tanglin purchased 3,294 sports uniform items. Almost all Tanglin sports uniforms are a blend of Polyester and Elastane.

We calculated the total quantity of individual uniform items purchased in 2023 to calculate the emissions of uniforms purchased. We assumed an average weight for each uniform item – for example, a pair of pants weigh 0.56 kg. Based on this, we assumed infant pants

weighed 50% less and junior pants weighed 30% less because of their smaller size. See Table 4.3.a. Using on the fabric composition provided from the uniform suppliers; the weight of a uniform item was divided by the material. Cradle-to-gate emission factors by material type was used to calculate emissions and summed for each uniform item. See Table 4.3.b. Industry cradle-togate emissions were used as we were unable to obtain supply chain details from suppliers, such as where they source their fabrics.

Based on the number of uniforms purchased in 2023, Tanglin’s school uniforms resulted in 37 tonnes CO₂eq and sports uniforms with 24 tonnes CO₂eq. Total emissions from the purchase of uniforms account for less than 5% of the total Category 1, Scope 3 emissions. While this is relatively low, it reflects just half of the total emissions with cradle-to-gate and does not account for end-of-life disposal emissions and the lasting environmental impact of textile waste. There was no information on the end-of life treatment of Tanglin’s uniforms so students created a 5-minute survey that was sent to Tanglin parents.

4.10

Fabric composition of school uniforms at Tanglin from Children Party Dress shop (CPD)

6thFormgirlpants6thFormblouse 6thForm trousers6thFormshirtSeniorboyshirtSeniorboytrousers JuniorboyshortsJuniorboyshirtJuniorgirlskirtJuniorgirlblouseInfantculottes Infantgirlblouse/dressInfantPETshirt(red)InfantboyshirtInfantboyshorts Infant/JuniorPE/Houseshorts SeniorPEshortsSeniorgirlblouseSeniorcapJuniorgirlculottes

Table 4.3a

Estimated clothing mass by garment type100

Table 4.3b

Cradle-to-gate emissions factors by textile101

Figure

Polyester Cotton Rayon Vicose

Elastane/spandex

Student uniform survey findings

Out of the 255 responses received, 46% of parents reported that each child has a minimum of three uniform sets and one-third of parents reported having four or more uniform sets for each child. Roughly 50% of parents reported that they needed to replace their uniforms due to wear and tear at least once a year.

When a uniform item no longer fits, most parents hand it down to a younger sibling or another child or give it back to the School Shop for second-hand sale. However, two-thirds of parents said they never purchase secondhand uniforms and always buy new ones. See Figures 4.10 and 4.11. Many parents noted that second-hand uniforms were difficult to find in the School Shop and not advertised as much as they should be.

Feedback from the uniform survey

At the end of the survey, we asked for suggestions and general feedback about sustainable uniform practices at Tanglin. This is summarised in Table 4.4.

Tanglin parents strongly suggest increasing the visibility and accessibility of second-hand uniforms in the school shop to encourage more sustainable practices. Many were unaware of the availability of second-hand uniforms and believed better promotion and dedicated spaces for these items would significantly improve their usage.

Parents also felt strongly about the need to replace white junior school shirts with darker colours or patterns. Parents find these shirts impractical due to frequent staining, which leads to higher replacement rates and is not environmentally sustainable. They suggest using more sustainable, natural fabrics that are better suited to Singapore’s climate.

Finally, many parents feel the current number of uniforms required for various activities is excessive, not sustainable and costly. Simplifying uniform requirements could reduce waste and costs.

Recommendations

Work with uniform suppliers to investigate where fabric materials are sourced from and gain a better understanding of the supply chain.

Promote second-hand uniform sales, recycling, upcycling and donation initiatives.

Reduce the number of different uniforms required throughout all stages of school

Investigate sustainable and durable uniform materials suited to Singapore’s climate for potential uniform replacement.

Figure 4.11

Response to the survey question: When your child's uniform no longer fits, what do you typically do with it?

Repurpose the fabric for another sale, 2%

Throw it away

Hand it down to another sibling or another child

Give it back to the School Shop for second-hand sale

4.12

Response to the survey question: Do you purchase any second-hand uniforms for your child? 15%

Yes, frequently

Yes, occasionally Donate it to charity

Figure

Table 4.4

Feedback or suggestions by parents regarding sustainable uniform practices at Tanglin

Theme Common feedback/ suggestions

Promoting second-hand uniform sales

Changing white junior shirts

More advertisements on it throughout the campus

Make it more easily available at the school shop

Should be advertised to new parents

White shirts often get stained

White shirts are highmaintenance

They need to get replaced often

Reducing the number of different uniforms

Having multiple types of uniforms is excessive and not environmentally friendly

Simplifying uniform requirements could reduce waste and costs

Using sustainable and practical fabrics

Advocate for more sustainable, natural fabrics better suited for Singapore’s climate, easier to maintain and more durable

Example responses:

“I didn’t actually realise that there was a second hand school uniform shop. Maybe this can be better promoted?"

“There should be a MUCH bigger emphasis on second-hand uniform. You have to HUNT for it in the school shop, it's like they don't want you to find it. There should be a dedicated space for it…”

"Currently stock is kept in the cupboards and is not advertised to parents, particularly new parents. It used to be very visible in see through boxes and very easy to access."

“White shirts in junior school + lunchtime butter chicken = unavoidable and lasting stains! Is it not possible to have another colour?"

“Replace the white shirt for boys in junior school to dark blue or same checks as in infant - they will need less rigorous washing and water saving.”

“They stay white for 5 minutes and end up looking so dirty and have to be replaced often."

“Older students have a ridiculous number of different sports kits for each sport, each event, etc. So bad for the environment."

"Reduce the number of different types of uniform the children have to wear and the parents have to buy multiple sets for - PE kit, house kit, school uniform, sports kit (separate to PE kit).”

“Use natural fabrics which are easy to wash. White junior shirts are from thick fabric and easily get marks. Because of lots of stains we need to buy again and again. And stained white shirts are hardly reusable for another child."

“Better quality using sustainable materials like cotton for the shirts. Coloured polyester shirts especially for senior school fades fast and looks worn out after just a few months of use."

“More humid friendly / eco friendly fabrics - all uniforms are some sort of polyester that is not good for the environment or heat."

“Please relook at the material of the school uniform. Given the climate of Singapore, it's extremely uncomfortable for children in Infant school. The material of the PE kit and House T-shirts are much more suitable."

4.5 Feedback from the travel survey

In the travel survey (completed by staff and secondary students) we asked for suggestions as well as general feedback in relation to commuting a Tanglin, this is summarised in Table 4.5 below.

The most common feedback theme was suggestions to improve the school bus by actions such as optimising routes, expanding route coverage, making the service cheaper, and using electric buses to reduce impact.

Many staff and students mentioned that the distance from the nearest MRT and bus stations is a major barrier to higher public transport use. Similarly, the safety of walking and cycling near Tanglin, and the lack of covered walkways for when it rains was highlighted. Many suggestions to increasing walking and cycling, as well as connectivity to the nearby public transport stops included providing shuttles for staff and senior students, developing a bike share scheme, working with authorities to build closer bus stops and create covered walkways, as well as reviewing and improving walking and cycling access around Tanglin.

Others requested more bike storage and some staff also suggested better showering and changing facilities for those that do walk/cycle. Incentivising green modes of travel was another common suggestion. Some provided specific suggestions including awarding school/year group/house points system and having a school-wide public transport day.

Others complained about excessive traffic around Gate C in the morning.

The suggestions can be taken as recommendations from the community towards reducing the impact of commuting at Tanglin.

Table 4.5

Common feedback from commuting survey

Theme

Common feedback/suggestions

Make school buses cheaper and more accessible

Increase coverage area and routes for school buses

Use electric or more eco-friendly buses

School Bus Improvements

Shuttle Services

Adjust bus timings to be more convenient

Allow students to use staff shuttle buses

Add a 6 pm bus for after-school activities

Provide shuttle services from nearby MRT stations (e.g., One North, Commonwealth)

Offer staff shuttles from different parts of Singapore

Introduce bicycle sharing and provide shuttle to nearest MRT for cyclists

Allow staff to travel on student buses for a fee

Create covered walkways and better protection from elements

Make school entrances and the area around the school more pedestrian/ cyclist friendly

Example responses:

"Make the cost of school buses cheaper so more people use it rather than other vehicles. The buses usually have a lot of empty space."

"Increase the number of school buses going to certain places in Singapore"

"start using electric buses"

"Bus routes are often inefficient. The building in front of me gets a different school bus"

"Make the bus morning pickup later so it doesn't wait for 20 mins outside school campus stationary with the engine on"

"Offer a shuttle bus to/from One-North MRT"

"School Staff bus from more locations-MRT stations"

"It would be great to have those public bicycle lots around TTS to allow use of bicycle sharing companies like Hello Ride and Anywheel."

Improved Infrastructure

Provide more bicycle racks, lanes, and locker space

Improve shower and changing facilities for staff who walk/cycle

Work with authorities to provide bus stops closer to school gates

"Liaise with local governing bodies to offer better protection from the elements when walking to the campus. Also, the main entrances are not pedestrian friendly"

"Improve the staff showering/changing facilities to incentivise staff to walk/run/bike in. I'd cycle in if there were more convenient bike racks at school entrances and better showering/locker options."

"Authorities could help provide additional bus stops nearer to the gates around Tanglin Trust School to help ease ingress/exit to/from the campus and improve convenience. Provision of covered linkways to/from bus stops to school gates are also preferred."

Table 4.5 (continued)

Common feedback from commuting survey

Theme Common feedback/suggestions

Promote and encourage usage of MRT

Incentivise rail/bus travel

Encourage Public Transport

Carpooling and Ride Sharing

Make public transport more convenient and accessible

Have a public transport day for the whole school community

Create forums and systems to facilitate carpooling among staff and students

Collate data on who lives near each other to enable ride sharing

Encourage ride sharing to reduce traffic

Adjust school start times

Provide higher housing/transport allowances for staff

Example responses:

"Encourage students to use MRT - too easy not to use"

"Incentivise rail/bus travel"

"Have a public transport day, when all members of the community are encouraged to use public transport to travel to/from school, if possible."

"Create a forum for promoting car sharing"

"I'd be very happy to carpool or drive other staff a few days a week to reduce my carbon footprint as I commute alone."

"Encourage ride sharing/easier access to public bicycles"

Other

Hybrid and flexible working arrangements

Address fast driving and lack of care around school

Reduce idling buses and cars

Appendix A - Consolidation approach

Tanglin is a private, not-for-profit, British-based international school for students aged 3-18 years old. It is situated at 95 Portsdown Road, Singapore.

Under the Corporate Accounting and Reporting Standard of the GHG Protocol there are two approaches to consolidating emissions: the equity share approach and the financial or operational control approach. We used the operational control consolidation approach to account for emissions because Tanglin owns and has operational control over all the buildings on campus. The organisation boundary for the audit is the Portsdown Road campus.

The reporting period covered in this report is January – December 2023. Our audit has estimated emissions arising from all operations relating to the life of the school, including all operations at Portsdown Road Campus. We did not include emissions from food services in the school’s carbon footprint, as these emissions fall outside the operational boundary because they arise from the activities of an independent company, Chartwells.

Emissions (expressed in tonnes of carbon dioxide equivalent (tCO₂e) were classified according to the following categories:

Scope 1 – direct emissions: emissions from sources owned or controlled by TTS.

Scope 2 – indirect emissions: emissions from the generation of purchase electricity, heat, and steam consumed by the school.

Scope 3 – indirect emissions: emissions occurring as a consequence of the school’s activities, but not from sources directly owned or controlled by the school.

Scope 3 has 15 distinct emission categories. See Table 1 and 2 for a summary of categories included in Tanglin’s Scope 3 and a summary of categories excluded, including justifications for their exclusion.

Scope

categories

Category 1 Purchased goods and services

Category 2 Capital goods

Category 3 Fuel- and energy-related activities (not included in scope 1 and 2)

Category 4 Upstream transportation and distribution

Category 5 Waste generated in operations

Category 6 Business travel

Category 7 Employee commuting

Category 13 Downstream leased assets

All goods and services purchased through Tanglin’s procurement department

All capital goods procured by Tanglin

Emissions from the extraction, processing, and transportation of fossil fuels consumed by the school, and emissions associated with transmission and distribution losses of electricity consumed by the school

Emissions from the transport of procured goods and services (including capital goods)

Emissions from the transportation of Tanglin’s waste

All school related trips and business travel

Staff and students commuting to and from school

Emissions from gas use in the school’s kitchens

Table a.1

Tanglin

Scope 3 categories in which Tanglin has zero emission sources

Excluded Scope 3 categories

Category 5 Waste generated in operations

Category 8 Leased Assets

Category 9 Downstream transportation and distribution

Category 10 Processing of sold products

Category 11 Use of sold products

Category 12 End-of-life treatment of sold products

Category 14 Franchises

Category 15 Investments

Justification

Singapore incinerates waste in waste-to-energy plants, so emissions from waste incineration are included in the electricity grid factor. To avoid double counting, emissions from incineration weren’t quantified.

TTS leases the land from the government but has operational control of all buildings so emissions are included in Scope 1 and 2.

TTS does not transport and/or distribute any products

TTS does not sell any intermediate products that require processing.

TTS does not sell any products that produce direct use-phase emissions

Singapore incinerates waste in waste-to-energy plants, so emissions from waste incineration are included in electricity grid factor.

TTS has no franchises.

TTS has no relevant investments.

Appendix B: Summary of Tanglin’s carbon emissions across the GHG scopes and categories

Appendix C: Methodologies used to quantify Tanglin’s emissions

a. Average-data method where

E = emissions in tCO₂e

S = emissions source (in the same unit, e.g. kg or m³)

EF = relevant emissions factor

b. Spend-based method

E = emissions in tCO₂e

EF = relevant emissions factor (kgCO₂e/$)

c. Refrigerant purchase method

where,

E = emissions in tCO₂e

RS = remaining stock (kg)

PS = purchased stock (kg)

EF = relevant emissions factor (kgCO₂e/kg)

d. Refrigerant leakage rate method

where,

E = emissions in tCO₂e

LR = annual leakage rate

EF = relevant emissions factor (kgCO₂e/kg)

e. Distance-based method where

E = emissions in tCO₂e

d = distance travelled (km)

EF = relevant emissions factor (kgCO₂e/km)

f. Distance-based method (air travel)

E = emissions in tCO₂e

Pd = passenger distance travelled (distance x number of passengers)

EF = relevant emissions factor (kgCO₂e/km)

g. Distance-based method (fuel efficiency)

E = emissions in tCO₂e

Td = trip distance (km)

f c = fuel efficiency (l/100km)

EF = relevant emissions factor (gCO₂e/km)

h. Distance-based method (survey)

E = emissions in tCO₂e

D = number of school days in a year = 180

j = the cohorts of staff, senior, and junior and infant students, respectively, in the sample

nkj = the number of survey respondents in cohort j, commuting with vehicle type k

wj = the ratio of the sample size of each cohort to the total population of the cohort

Appendix D: Description of data used to quantify Tanglin’s carbon footprint

Source

Gas in science labs

Diesel in generator

Fuel in school truck and school motorbike

Refrigerant leaks

Scope 1

Scope 1

Scope 1

Scope 2

Electricity

Purchased goods and services

Capital goods

Upstream emissions from fossil fuel extraction and transportation, and electricity transmission and distribution losses

Transportation of purchased goods and services

Scope 2

Scope 3, category 1

Quantity of gas burnt obtained from science department (primary)

Quantity of diesel used obtained from facilities department

Fuel consumption obtained from facilities department

Refrigerant purchase records obtained from facilities department (primary data)

Theoretical leakage rates of chillers obtained from manufacturer (Daikin) (secondary data)

Electricity consumption data from facilities department

Purchase orders for 2022-23 from TTS procurement department (primary data).

Utility bills for 2023 from TTS facilities department (primary data).

Emissions factors from academic papers and Climatiq database (secondary data).

Waste transportation

Scope 3, category 2

Scope 3, category 3

School travel

Commuting

Gas use in the kitchen

Scope 3, category 4

Purchase orders for 2022-23 from TTS procurement department (primary data).

Emissions factors from academic papers and Climatiq database (secondary data).

Fuel and energy consumption records obtained from TTS facilities department (primary data).

Emission factors sourced from IEA (2023) and UK Government –DESNZ and BEIS (secondary data).

Purchase orders for 2022-23 from TTS procurement department (primary source).

Transportation distance calculated using Google maps or https://www. climatiq.io/data.

Spend-based emission factors from Climatiq database (secondary data).

Distance-based emissions quantified using the GHG Protocol

Transport Tool (secondary data).

Scope 3, category 5

Scope 3, category 6

Scope 3, category 7

Scope 3, category 13

Distance route listed on waste vendor company website. Sembcorp, 2024

Fuel efficiency of heavy-duty EV dump truck - International Council on Clean Transportation, 2023

Travel data from TTS transport department (primary data).

Travel data from TTS transport department and Kal – school bus service provider (primary data).

Gas procurement data from Chartwells

Appendix D: Description of data used to quantify

Tanglin’s carbon footprint

Appendix E: Assumptions made in GHG inventory calculations

Emissions Source

Purchased goods and services

Scope 3, Category 1

Transportation of purchased goods and services

Scope 3, Category 4

• Emissions from 72% of purchase orders for 2022-2023 were calculated. This total was then grossed-up to estimate 100% of emissions.

• Assumed data from the 2022-23 school year is representative of one calendar year (2023).

Uniforms

• Sports Uniforms - Anything from the Kukri Core range is assumed to be 90% polyester and 10% Elastane

• Sports Uniforms - All tee's and jerseys are 87% polyester and 13% Elastane

• For swimwear, one of the most common fabric compositions were chosen - a blend between Elastane and Polyester

• The weight of individual uniform items was unknown, so the average industry weight of typical garment items (i.e. Dress) was used.

• Infant uniforms weigh 50% less and Junior uniforms weigh 30% less because of their smaller size.

• Google maps was used to determine the distance between vendors/ suppliers and TTS. Assumed the most direct route was taken.

• Assumed all goods transported via light goods diesel truck.

• Assumed all consultants travelled via petrol car.

• Transportation emissions for 72% of purchased goods and services were calculated, then adjusted to represent 100%. 100% of transportation emissions for capital goods calculated.

Transportation of waste

Scope 3, Category 5

School travel

Scope 3, category 6

• Sembcorp collects waste from Tanglin with an EV vehicle as the school is in between EV operating routes from Clementi to Bukit Merah.

• Sembcorp's electric vehicles are heavy duty electric dump trucks. Energy consumption of these vehicles is 117.5 kWh/100km.

• Sembcorp electric vehicles that pick up general waste from Tanglin’s campus do not make any other stops along the way. A one-way trip is 23km.

• Trip data for one month (November 2023) was extrapolated (prorated means distributed or divided) to the whole year based on the number of school days

Appendix F. What other schools are doing

School and Location

Dulwich College, Singapore

207 Generates 529,037 kWh/year

The Greenhouse is certified Green Mark Platinum Zero Energy

Singapore American School, Singapore

UWCSEA Dover, Singapore

UWCSEA East, Singapore

1,122 Solar 10% of school's energy needs, generating 1 million kWh/ year

598 ~700,000 kWh/ year, saving >S$110,000 a year in electricity

390 Generates ~420,000 kWh/yr saving >S$84,000 a year in electricity

Reawarded Green Mark Platinum Super Low Energy Campus, 2023EUI =56.7 kWh/m²)

Reawarded Green Mark Platinum Super Low Energy Campus, 2023 (EUI = 62.4 kWh/m²)

• Data from the Greenhouse is integrated into the senior school curriculum

• Students conduct a carbon audit of school's footprint (Scope 1 and 2).

• Food waste composting

• Recycling bins on every floor and in every class

• Aiming to achieve net zero energy and Green Mark Platinum standard and WELL standard for new construction in campus upgrade project (2021-2026)

• 100% hot water source generated by heat pump

• Hybrid cooling system (ceiling fans and ACs) resulted in 70% reduction in electricity consumption

• 100% solar thermal system for hot water (including boarding house)

• Hybrid cooling system (ceiling fans and ACs) resulted in 70% reduction in electricity consumption

Appendix F. What other schools are doing

School and Location

The Grange Institution, Singapore

Dulwich College, Puxi, China

International School Beijing, China 500 kWp (estimate) (1,323 panels) 1,323 panels generates 10% of the school's electricity

Chinese International School, Hong Kong

30 Generates ~ 20,450 kWh/year

Voted Sustainable International School of the Year at the Singapore Educational Awards 2023

• Eco-farm and urban garden integrated into outdoor play area "Grow with The Grange" initiative plants a tree named after each student

• Calculates carbon footprint of all staff flights and coverts to monetary value. The costs are collected and donated to projects that mitigate climate risks.

• Publishes annual sustainability report

• 70% bus fleet electric

13,624 (emissions from supply chain not quantified)

• Mandatory busing policy for Y2-11

• Committed to becoming carbon neutral by 2030

• Committed to becoming zero-waste by 2030

• Installing 500 kWp solar facade

3,684 (emissions from supply chain not quantified)

Endnotes

Endnotes

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