OCTOBER 2021
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BAKER PACIFIC CLIMATE CHANGE & BISCUIT BAKING UK £4.95 CAN $7.95 USA $7.95 EUR €5.95 SA ZAR 69.00
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In past issues of Endeavour, we have featured biscuit oven and baking company, Baker Pacific, on several occasions. We’re always keen to hear what Iain Davidson, company ROLE, is up to, whether it’s releasing a latest book or revolutionising biscuit oven design. Lately, Iain has been looking into the relationship between biscuit baking and climate change, and how to improve matters for a greener future. Below is an article and report penned by Iain that further explores the issue, breaks down the science, and looks at what can be done.
Written by Alice Instone-Brewer
1. Combustion Data: Natural Gas Gas has been and continues to be the predominant fuel for biscuit baking ovens. The development and availability of natural gas supplies have made gas the main fuel for the baking industry throughout the world. Countries where electricity was the main energy source, for example China and countries where diesel oil was used for example India and the Middle East now use gas as the lowest cost energy source. The combustion of natural gas is a major source of greenhouse gases which are causing climate change. This has become a major concern throughout the world. This situation makes it essential that we seek ways to reduce the carbon footprint of the biscuit baking industry. 1.1 Combustion Process The combustion process is a reaction of rapid oxidisation started by the correct mixture of fuel, oxygen and an ignition source. In order for complete combustion of natural gas, excess air is supplied.
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The chemical reaction for natural gas combustion with 20% excess air is:
is an important indication of the combustion efficiency. The content of carbon dioxide after combustion with CH4 + 1.20 x 2(O2 + 3.76 N2) -> CO2 + 2 H2O + 0.5 O2 + 9.4 N2 excess air is approximately Ref. Engineering Toolbox 10.5% for natural gas and Air is composed of 20.9% of oxygen, approximately 13% for light fuel oils. 78% of nitrogen and 1% of other gases. For most applications, every 1 m3 of natural gas, approximately 10 m3 of air is required to provide complete combustion of natural gas. To ensure complete combustion of the fuel, excess air is drawn in by the burners. The combustion efficiency will increase with increased excess air, until the heat loss in the excess air is larger than the heat provided by more efficient combustion. When fuel and oxygen in the air are in perfectly balance and the fuel is burned completely, the combustion is said to be stoichiometric. Typical excess air to achieve the best efficiency for combustion is 10-20%. FIG.1 Stoichiometric combustion Carbon dioxide is a product of the Ref. engineeringtoolbox.com/ /stoichiometriccombustion and the content in the flue gas combustion-d_399.html
CLIMATE CHANGE: ENERGY FOR BISCUIT BAKING
1.2 Carbon Dioxide Emission from Burning Natural Gas To calculate the Carbon Dioxide (CO2) emission from a fuel, the carbon content of the fuel must be multiplied with the ratio of molecular weight of CO2 (44) to the molecular weight of Carbon (12) -> 44 / 12 = 3.7 Carbon Dioxide emission from burning a fuel can be calculated as qCO2 = cf / hf MCO2 /Mm where:
particularly fossil fuel use and distribution and agriculture. Work on reducing air pollution is valuable and can lead to lasting cuts in methane emissions. Water vapour is also a potent greenhouse gas, but it has a short lifetime and is an amplifier, not a driver of climate change. Human activities currently emit an estimated 10 billion tonnes of carbon each year, mostly by burning fossil fuels. Ref. The Royal Society www.royalsociety.org
qCO2 = specific CO2 emission [kgCO2/kWh] cf = specific carbon content in the fuel [kgC/kgfuel] hf = specific energy content in the fuel [kWh/kgfuel] MC = Molecular weight Carbon [kg/kmol Carbon] MCO2 = Molecular weight Carbon Dioxide [kg/kmol CO2] Emission of CO2 from methane, natural gas is given below: Specific carbon content: kgc / kg fuel
0.75
Specific energy content:
kWh / kg fuel
15.4
Specific CO2 emission (amount of fuel basis)
kgco2 / kg fuel
2.75
Specific CO2 emission (amount of energy basis)
kgco2 / kWh
0.18
Note Heat loss - 55-75% - in power generation is not included in the numbers. Ref. Engineering Toolbox – carbon dioxide emissions
2. The Biscuit Industry Carbon Footprint 2.1 Climate Change and Green House Gases Greenhouse gases in the atmosphere absorb heat energy from the sun and emit it, keeping the earth’s surface and lower atmosphere warm. Greenhouse gases include carbon dioxide, water vapour, methane and nitrous oxide. The biggest contributor to the warming of the climate is carbon dioxide, CO2. Since preindustrial times the atmospheric concentration of CO2 has increased by over 40% and methane by over 150%. More than half of this increase has occurred since 1970. Methane is an important greenhouse gas which leaks during industrial processes,
The biscuit industry now uses gas as the fuel for baking in almost every country. Natural gas is now widely available and economic. However this gives our industry a large carbon footprint. It will attract pressure in many countries to reduce the use of gas, by using electricity from renewable sources and improving efficiency.
Efficiency can be improved by: • Effective insulation of the baking chambers and return band • Burner specification and adjustment for low CO2 emission • Baking chambers of minimum cross section to increase radiation from the surfaces • Heat recovery systems for Indirect Fired ovens • Using the extraction from the flues for heating factory services such as heating water • Using hot flue gases to pre-heat combustion air
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2.2 Energy Usage For Baking The table below indicates some typical values for energy usage for baking. Product type
Energy for baking kWh/kg (excluding oven losses)
Energy for baking kWh/kg (including est. losses)
Short dough biscuits
0.2121
0.404
Semi-sweet biscuits
0.2502
0.477
Crackers
0.3402
0.646
Note: 1 From actual installation Note: 2 From calculations see Chapter 20
2.3 Consumption Of Gas For Baking Density:
0.68 kg/m3
Density at baking temperature
0.4 kg/m3
Heat value of burning natural gas (methane):
42 - 55 MJ/kg (11.6 – 15.3 kWh/kg )
Average energy per kg of gas:
13.45 kWh/kg
www.world.nuclear.org
The calorific value, density and energy for natural gas vary with the source, process and delivery. The values above are from the sources listed under references.
Energy usage
kWh/kg
Natural gas consumption for baking one tonne of biscuits
Short dough biscuits
0.404 kWh/kg
30.0kg of gas
Semi-sweet biscuits
0.477 kWh/kg
35.5kg of gas
Crackers
0. 646 kWh/kg
48.0kg of gas
Average power requirement per tonne of product range 509 kWh CO2 emissions: 104 kg per tonne of product Average gas consumption per tonne 37.8 kg range A bakery with three production lines 2.4 The Carbon Footprint producing a total of 50 tonnes per 8 hour shift The combustion of 1.0kg of natural gas and 20 shifts a week will produce approximately produces 2.75kg of CO2 and 0.18 kWh of energy. 1000 tonnes of biscuits per week. www.engineeringtoolbox.com
The average production of CO2 for one tonne of product range (short dough / semisweet, cracker) is: 37.8 x 2.75 = 104 kg
The CO2 emissions will be approximately 104,000 T per week and over 5,200,000 T per year.
CLIMATE CHANGE: ENERGY FOR BISCUIT BAKING
Biscuit consumption and CO2 emissions in several countries
In these countries the total population of 2327 million produce 960500 T of CO2 emissions each year from biscuit production. Per capita emissions: 0.413 kg/year The total global CO2 emissions in 2016: 35,753,305,000 T. The world population is 7.46 billion. Per capita CO2 emissions: 4.79 T
led to rapid development of renewable energy sources, solar, hydropower, wind and biomass. In addition nuclear power is an important source for the generation of electricity. The methods of the generation of electricity have changed during the last 10 years and now energy from some renewables is less costly than energy from new fossil fuel sources.
www.worldometers.info/co2-emissions
LCOE (Levelised costs of energy): based on 2.5 Energy Sources For Biscuit Baking the cost of building the power plant and the The current energy source for biscuit costs of fuel and operation during the plants baking world-wide is gas. The option in some lifetime. countries is fuel oil. However oil has a higher CO2 emission rate than gas, 3.15 kgco2/kg fuel USD/MWh 2009 2019 compared to 2.75 kgco2/kgfuel for gas. 359 40 Electricity has substantial advantages for Solar photovoltaic baking, but currently is expensive and the main Solar thermal tower 168 141 generation systems involve substantial CO2 Nuclear 123 155 emissions. Fossil fuels have been the cheapest 135 41 source of power for generating electricity. Onshore wind However, burning fossil fuels for generating Coal 111 109 electricity and heat is the largest source of Gas peaker 275 175 greenhouse gases, causing 30% of global Gas 83 56 emissions. www.ourworldindata.org
3. Generating Electricity from Renewable Energy Sources The concern over climate change and the urgent need to reduce carbon emissions has
Electricity costs from solar fell 13% yearon-year reaching USD 0.068 / kWh in 2019. Onshore and offshore wind costs fell about 9%
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year on year to USD 0.053 / kWh and USD 0.115 / kWh respectively for newly commissioned projects. Renewables made up 26.2% of global electricity generation in 2018. It is expected to rise to 45% by 2040. Over half of all utility scale renewable capacity additions in 2019 achieved lower costs than the cheapest equivalent new coal plant. www.c2es.org
www.energypost.eu
3.1 Power Generation Costs For Renewable Energy USD/MWh
2010
2021
Solar photovoltaic
0.37
0.05
Solar thermal tower
0.35
0.07
Offshore wind
0.16
0.13
Onshore wind
0.08
0.05
www.energypost.eu
The price of generation from onshore wind and solar PV-generated power have both fallen below USD 0.05 / kWh. Fossil fuel powered generation usually costs between USD 0.05/ kWh and 0.18/kWh. These developments will continue based on concerns over climate change and the need to reduce carbon emissions. This will affect the options for energy for biscuit baking.
in 2020 reaching 38% of the total electricity generated. For several individual countries it is now the main source of electricity, including United Kingdom, Germany and Spain. In United Kingdom 54% of electricity came from low carbon sources. In 2020 renewable energy sources accounted for 12% of the total energy consumption and 20% of electricity generation in the USA. Japan’s government has pledged to increase renewable sources, solar and wind, for electricity generation from 10% in 2018 to 2224% by 2030. The Renewable Energy Master Plan (REMP) for Nigeria seeks to increase the supply of renewable electricity from 13% of total electricity generation in 2015 to 23% in 2025 and 36% by 2030. Renewable electricity would then account for 10% of Nigerian total energy consumption by 2025. REMP targets higher electrification rates, from 42% in 2005 to 60% in 2015 and 75% by 2025. In a number of countries in Asia Pacific, Latin America and Africa energy from biomass contributes a significant source of energy with low carbon dioxide emissions. The most common biomass materials used for energy are plants, such as corn and soy and wood. The energy from these materials can be burned to create heat or converted into electricity. Some coal fired power stations are now being converted to burn biomass.
FIG 3 Increase in energy from renewables 2019 - 2025 From International Energy Agency. www.iea.org FIG 2
After Lazard
3.2 Development Of Electricity Generation From Renewables Renewable energy became the biggest source of electricity in the European Union
Renewables will become the largest source of energy by 2025, surpassing coal.
CLIMATE CHANGE: ENERGY FOR BISCUIT BAKING
DSM International Ltd Hong Kong
Quality, Professional, Expertise
Tel: +852-2545-6122 Fax: +852-2541-9643 Email: sales@dsm-intl.com
www.dsm-mc.com
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3.3 Future Developments For Biscuit Baking It is predicted that electricity will in the future be a preferred energy for many industries, based on competitive costs with current gas supplies and the need to reduce reliance on fossil fuels. In addition electricity is a clean and easily controlled energy source. Electric baking ovens have the following features: • Radiant heat transfer which is penetrative and achieves optimum volume and texture of the products • Clean energy that does not contaminate the products or the baking environment. There are no products of combustion. • Dry heat which is efficient in reducing moisture content. Steam application and turbulence systems provide humidity as required by the baking process • Electric heaters are easily and accurately controlled • Minimum oven maintenance is required.
Solar panels Photo by MICHAEL WILSON on Unsplash
4.2 Solar energy for a new bakery A bakery roof of 4,500m2 could support 2000 solar panels of 96cells and 350W capacity for each panel. The panel size is 1.90m x 1.0m. Energy = solar panel watts x average hours of sunlight per year x 0.75 0.75 typical efficiency factor. Hours based on mid Europe: 2000 hours per year
4. Solar Energy Calculation: 4.1 New Biscuit Bakeries
350 W x 2000 hrs x 0.75 = 525,000W per year per panel 525 kWh/panel x 2000 panels = 1,050,000kWh per year Vivint Solar www.vivintsolar.com
FIG 4 New PT Mayora Indah bakery in Indonesia with solar panels
Modern biscuit bakeries have long flat roofed production areas. The image above is an example of modern bakery design. New bakeries now often have production areas of around 150m x 30m, 4,500m2. This area could be used for solar panels.
Power Requirement For A Production Line: Average power requirement for producing 1000kg of cracker, semi-sweet and short dough biscuits: 509kWh Our 2000 solar panels would power the production line for approximately 2000 hours. Average hours of sunlight per year: • • • • • • •
Europe: Paris 1660, Rome 2500 USA: Chicago 2508 Brazil: Sao Paolo 1948 Asia: Bombay 2680, Jakarta 2975 Africa: Lagos 1885, Johannesburg 3182 China: Shanghai 1874 Australia: Sydney 2426
CLIMATE CHANGE: ENERGY FOR BISCUIT BAKING
So there you have it! A bit dense? For more information and a bigger break-down on this and other biscuit over matters, you can check out Iain’s various books, as well as his contributions on www.biscuitpeople.com Iain Davidson graduated from the School of Industrial Design (Engineering) at RCA in London in 1965 and joined Baker Perkins Ltd as an Industrial Design Engineer. He worked in the Technical Department on the design of new biscuit and bakery processing machines until 1975, gaining a thorough technical knowledge of the machines and processes. He rose through the ranks at Baker Perkins, until he was appointed leadership roles such as Managing Director of Baker Perkins (Hong Kong) Ltd and Director of Baker Perkins Japan KK. Iain established PT Baker Pacific Mandiri in Indonesia in 2000, and in Hong Kong in 2004. Baker Pacific Ltd is now a UK registered company.
REFERENCES CEIC Data www.ceicdata.com 2021 Center for Climate and Energy Solutions www.c2es.org 2021 Energy Post.eu www.energypost.eu 2021 Global Solar Atlas www.globalsolaratlas.info/map 2021 International Energy Agency www.iea.org 2021 INHABITAT 909 N. Pacific Coast Highway, 11th Floor, El Segundo, CA 90245, USA https://inhabitat.com 2021 IPCC. Intergovernmental Panel on Climate Change www.unfoundation.org/climate/panel 2021 Lazard www.lazard.com 2021 NFPA Committee Input No.48 – NFPA 87-2012 www.nfpa.org 2021 Nuclear Energy Agency www.oecd-nea.org/lcoe 2021 Our World in Data www.ourworldindata.org 2021 Photovoltaic Software www.photovoltaic-software.com 2021 Photonic Universe www.photonicuniverse.com 2021 Statista www.statista.com 2021 Testo Inc. Applications Guide Rev. 1.0. 2006 www.testo-international.com 2021 Thermowatt DhE www.thermowatt.com www.dhesrl.com 2021 The Engineering ToolBox www.engineeringtoolbox.com 2021 UK Power www.ukpower.com 2021 Vivint Solar www.vivint.com 2021 Watlow www.watlow .com 2021 World Bakers www.worldbakers.com 2021
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