Greening our buildingsn

GREENING OUR BUILDINGS

BUILT ENVIRONMENT RENEWABLES ARE ESSENTIAL TO MITIGATE CLIMATE COLLAPSE.

We have heard a lot about climate change in recent years, and can now see the evidence of it in our day-to-day lives. Floods, fires, storms, hurricanes and heatwaves are all more prevalent than ever before, and the ten years to the end of 2019 have been confirmed as the warmest decade on record. The Intergovernmental Panel on Climate Change Special Report on Global Warming of 1.5ºC paints

FEATURE

Finnbar Howell,

Technical Director, KRA Renewables

a bleak picture, but provides a vital wake-up call to those among us who still don’t understand the severity of the situation we are now in. Unfortunately, the current business-as-usual approach won’t bring us to merely 1.5º of warming, but rather to 4º, 5º, or more. What will

that look like? The ice will melt, the oceans will acidify, the fish will die, there will be massive collapse in all the ecosystems of the world, and we will continue to see an increase in fires, floods, hurricanes, heatwaves and desertification. There will be a slew of new diseases, we will be unable to grow food to sustain our population, there will be mass migration, wars over resources, and the global economy will completely collapse. Many of us will die, and the survivors will struggle to survive in this new, harsh, unforgiving world.

“THERE WILL BE MASS MIGRATION,

WARS OVER RESOURCES AND THE GLOBAL ECONOMY WILL COMPLETELY COLLAPSE. MANY OF US WILL DIE, AND THE SURVIVORS WILL STRUGGLE TO SURVIVE IN THIS NEW, HARSH, UNFORGIVING WORLD.

Let’s talk about buildings Climate change is being driven by greenhouse gases (GHGs), which we urgently need to stop emitting. Renewable energy technologies are key to reducing our GHG emissions, but what does that mean in practice? When we think of renewable energy, we usually envision large-scale wind farms, huge parks of solar arrays and hydroelectric dams. In most of our minds, the built environment is strictly a consumer of energy, and the energy used is generated, drilled for, mined, fracked, or otherwise produced somewhere else. The built environment uses a lot of energy, and globally is responsible for an incredible 39% of all GHG emissions (World Green Building Council, 2017). Some 11% of that is the embodied emissions of construction and manufacturing, which still leaves 28% of total global GHGs from the operation of buildings. It’s this 28% that we should be talking about. So we see the challenge: we need to reduce the fossil-fuelled operational energy use of buildings to zero, and we need to do it now. Some of this reduction can come from efficiencies, and the natural starting point is the low-hanging fruit: LED lighting and light controls, insulation, replacement of inefficient fixtures, etc. Another aspect is behaviour: thinking about our usage and having plans and policies in place to increase efficiency and minimise waste. But this can only bring us so far, and at that point we must stop thinking about reduction and start thinking about generation. Built environment energy use is split between demand for electricity, heating and cooling (not so much of this last one in Ireland). There’s also the interplay with transport, as a lot of us still drive from one building to another.

Electricity Let’s start with electricity. Grid electricity is still very dirty, with around 70% on average still coming from fossil fuels. This fluctuates throughout the day and year, and if you’re curious as to what it is right now, check out www.electricitymap.org/zone/IE. For many buildings, electricity is the largest source of emissions and the easiest to green. Solar photovoltaics (PV), or solar panels as they’re usually called, are a proven clean technology. They’ve become incredibly cheap (dropping 80% in price within ten years), and are durable, long lasting, predictable in output, and safe. How much of a building’s electricity they can produce depends on a lot of factors (building demand, orientation, tilt, shading, and roof type to name just a few), but new technologies such as higher efficiency modules, solar facades and the solar brise soleil are now increasing that generation potential during daylight hours, and the rapid advances in battery storage are fast making electricity storage more viable economically and environmentally. Heat Heating is a much bigger challenge. In Ireland, despite the abovementioned 70% fossil-fuelled grid power, we congratulate ourselves on having gotten that far. When it comes to heating, we’re not even close to that. We’re well above 90% reliance on fossil fuels, and even our target, which we will miss, was only to reduce this to 88% by 2020. We typically need heating for two things: space and water. For space heating, the best solution is the use of a heat pump, which works like the compressor in your fridge, pumping the heat from the air, water or ground into (or out of, when cooling is required) buildings. Whether air source, water source or ground source is the right choice depends a lot on the building and its surroundings. Ground source heat pumps are more expensive to install, but also much more efficient in winter when you need heat the most. For water heating, you can also use a heat pump, or solar thermal modules, which have much higher efficiency than PV modules, but can only produce hot water. Thinking holistically Heat pumps should strictly be classed as a high-efficiency device, since they require a source of electricity, and only become a true renewable device when combined with renewable electricity. This is true of much of the built environment renewables suite. A combined heat and power (CHP) system burns natural gas at very high efficiency to produce both electricity and heat, and offers huge GHG reductions, but is not truly renewable unless supplied with biomethane. Electric cars tie into the built environment through electric vehicle (EV) charge points, and offer a way to green transport, but in truth only offer lower emissions, ”WE DON’T CHOOSE OUR FUTURES. WE CHOOSE OUR ACTIONS, AND THOSE DECIDE OUR FUTURES. not zero, unless fed with green electricity. This highlights the need to think holistically and see the bigger picture of a building’s energy demand. There are plenty of reasons why built environment renewables are a smart choice: they reduce grid losses by producing close to demand, add value to properties, cut costs significantly, protect against increasing energy prices, increase air quality and thermal comfort, offer good PR, and raise awareness. But for me, the most important thing about them is that they offer the only pathway to bring the operational emissions of the built environment to zero, an urgent and necessary change to preserve this beautiful, fragile ball on which we all dwell. We don’t choose our futures. We choose our actions, and those decide our futures.