Table A2.3 Summary of energy and emission intensities of transport modes used in GHG-Calc
Table A2.4 Emission factors for electricity purchased/used/delivered per kWh
Table A2.5 Global Warming Potential (GWP) for 8 categories of foods
Table A2.6 Methane yield from selected landfilled solid waste components
Table A2.7 Embodied energy of waste materials in MSW
Table A2.8 Embodied energy and emissions per square metre of floor area, free standing residential house (Derived from figures for a ‘standard 94 m2 house’.
Table A2.9 Annual embodied energy and emissions attributable to possessions (other than car and house)
Acknowledgements I wish to acknowledge the invaluable contribution made by Steve Grabham, who programmed the current Delphi calculator from the original Excel version.
1. INTRODUCTION Burning of fossil fuels to supply the energy and produce the goods used in today’s Western economies is increasing the greenhouse gases in our atmosphere at a rate greater than the capacity of the oceans and forest to absorb them. The resulting global warming is the greatest threat in human history to the world’s environment and the biological systems that support human life. Its effects – increasing incidence of extreme weather, rising sea levels, melting of ice-caps, coral bleaching and extinction of climate sensitive species – are already being observed.
Oil depletion is the other major threat faced by modern civilisation heavily dependent on this commodity for transport and industry. With the ‘oil rollover’ currently occurring as production fails to meet demand, prices have risen and will continue to do so. No renewable fuels will ever be as cheap as fossil fuels, which can be simply extracted from the ground. The days of cheap fossil fuels will soon be over.
Overcoming these two issues will be a huge challenge. However it is achievable because they are phenomena that are caused directly by the inefficient and excessive consumption habits of Western developed nations. Over half of the energy use and pollution is caused either directly or indirectly domestic households (i.e. us) and there are many ways we can change or lifestyles to become more energy efficient and less polluting.
This paper describes a greenhouse gas emissions calculator (GHG-Calc) and an energy calculator (Energy-Calc) for use by individuals and businesses to conduct their own energy and emissions audits easily and quickly. GHG-Calc is available for the public to use, on the Warren Districts Renewable Energy Group website www.wdreg.org.au. Other energy-related calculators and information, such the ‘Be Energy Wise’ booklets and brochures, can also be found on the website. These resources are intended to help people minimize their greenhouse gas emissions and maximise their utilization of ‘clean’ energy, products and services.
1.1 Australian domestic greenhouse gas emissions In Australia, greenhouse gas emissions from all sources amount to 28 tonnes per person per year. The sustainable level of GHG emissions has been estimated at 3.5 tonnes per head of world population (Lenzen, 1997). “In the previous years, global greenhouse gas emissions totalled about 42 Gigatonnes of CO2 equivalent (Gt CO2-e; 1 Gt = 109 t) per year, while the global population was almost 6 billion, both figures rising steadily. Applying the concept of international equity in greenhouse gas emissions on a per capita basis means that a sustainable situation is reached if everyone on the planet caused an amount of emissions of not more than 50% of the present world average, given the results of climate models mentioned at the end of the first section. Hence, apportioning the same amount of pollution to everybody on the planet and at the same time reducing emissions by 50% leaves about 3.5 t CO2-e emissions per year and per capita to be released.” Recent statements by senior scientists, including the Australian Governments Chief Scientist, support the proposition that emissions must be reduced by 50% or more.
Australian Bureau of Statistic figures show that about 56% of Australia’s energy related greenhouse gases were emitted in the production and consumption of goods and services, for the purpose of household final consumption. A further 23% of energy related emissions were generated in the production of goods and services for export. Other final use categories (general government final consumption and gross fixed capital formation) were responsible for the remaining emissions (AusStats, 2002).
GHG-Calc clearly shows where saving can be made. Table 1 shows the results of budgets using typical energy and consumption figures. The results show that a typical household of three generates about 40–45 tonnes CO2e of GHG emissions – about 14 tonnes per person:
Direct energy use – electricity and fuels – in the home and for transport
Indirect energy/emissions from the consumption of food and goods by the household.
That is about 50% of the 28 tonne average total emissions, which is in accordance with the ABS figure, given that GHG-Calc does not include emissions from services.
Household energy consumption varies greatly. For example, a Swedish study of 6 households (Carlsson-Kanyama et al) showed that energy consumption varied from 80 to 691 GJ, with the Swedish average being 263 GJ. Australians can have a direct influence – through their energy, consumption, and transport and waste disposal decisions – on about 50% of the nation’s GHG emissions. A GHG-Calc audit using energy efficiency measures in the home and for transport (Table 1) shows that emissions reductions of more than 50% are easily achievable for the average Australian household. If all Australian households adopted such energy efficiency measures this may result in a reduction of 25% or more in Australia’s emissions. No new technology would be required and no loss of quality of life need be incurred to achieve these results.
Table 1.1 Potential emission reductions by changing consumer habits – as estimated using GHG-Calc (family of three) (Rose, B., 2004)
Emissions – typical Aust. Family
Energy Wise household
Emissions savings, tonnes
Overseas holiday – air travel, 20,000 passenger km
Holiday in home State; travel by car or bus.
Car travel, 20,000 km in large car
Change to a light car,
Reduce driver-only car mileage by using bus/train more, sharing transport
Electricity and domestic fuels
Purchase 50% ‘Natural Power’.
Reduce from 5000 units to 2,500 by converting all heating appliances to gas or solar. Low volume shower-head, energy efficient appliances eg. One smaller fridge, reduce air conditioner.
Food and water
Eat less processed/ imported/ packaged foods, red meats and dairy and more local fresh produce.
Buy less packaged and disposable products. Recycle and compost
Housing and possessions
Buy less new things that you don’t use often – hire or borrow instead. Live in a smaller house, occupied to capacity
24 tonnes CO2e ( 8 tonnes per person)
If we are serious about global warming and energy resource depletion issues, we need to change many of our consumer habits, focussing first on the big emissions items. For example:
Holidaying locally instead of taking a trip to Europe or the US will save over 14 tonnes of emissions
Having only one small car and minimizing driver-only commuting car can save 5 or more tonnes CO2e of emissions per year.
Changing our diet to minimise containerised food/drinks, meat and dairy products can save up to 3 tonnes of emissions year.
Changing to compact fluorescent light bulbs can save about 0.4 tonnes.
All such actions are worthwhile, but GHG-Calc quantifies the emissions impacts, giving a realistic picture as to which changes will have the most impact.
We don’t have to go without holidays and cars altogether, but by carefully considering how we travel and what goods we consume, we can reduce emissions by 50% and suffer no loss of quality of life.
2. The Calculators GHG-Calc is a ‘stand alone’ calculator that can be downloaded from the Internet site www.wdreg.org.au and used without any supporting software. The current version is written in the Delphi program and can be downloaded from the WDREG website. It is designed to run simple audits and budgets of greenhouse gas emissions for households and small businesses, from the direct consumption of fuel, electricity, food and goods but not services. GHG-Calc is not intended to provide the accurate, detailed audit outputs that may be required, for example by corporations or industry. However it is useful for the purpose of domestic energy and emissions budgeting, or for ‘first cut’ estimates preliminary to more detailed audits. The accuracy is sufficient to give a good indication of where emissions reductions could be achieved, but is dependent on:
Accuracy of the consumption data entered by the user
Error ranges of the energy input algorithms (see Sections 3-9)
Error ranges of the emission factor algorithms (Table 2.1).
The design of GHG-Calc will be periodically improved and updated. Emissions factors will change as electricity generation technology becomes more efficient and the energy sources shift from predominantly coal to gas and ‘renewables’. More accurate embodied emissions data will become available as the life cycle analysis (LCA) databases currently under development are published. It is hoped that in 10 years time, GHG-Calc will give more accurate results and that improved technology will be reflected in lower emissions.
A new, more convenient version is planned, which will integrate GHG-Calc and Energy-Calc in the one web-based calculator. It will be written in Java Script or similar program that can be used directly from the website. Both energy and emissions results will be obtainable at the click of the mouse for any or all of the six categories of energy/goods consumption. Users will only have to fill in their data once to see both energy and emissions results.
Fig. 2.1 GHG-Calc (2004 version written in Delphi) showing figures for a typical Australian family of three.