The Climate Wise Carbon Calculator

Technical Overview – Version 2.0

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The Climate Wise calculator was developed using the most recent scientific information regarding climate change, GHG emission and carbon neutrality.

The calculator is based on data from the following sources:

Household Emissions:

• GHG-Energy Calc – a Tool for Self-audit of Domestic Greenhouse Gas Emissions, B. Rose, 2006
• Australian Greenhouse Office, Factors and Methods Workbook, 2003. Houck et al, 1998

Road Transport

• Fuel Emissions Factors by the AGO Factors and Methods Workbook, 2003. Houck et al, 1998
• Vehicle fuel efficiency is partly based on data from US Environmental Protection Agency (EPA) Guide 2001

Flight Emissions: The Greenhouse Gas Protocol (GHG Protocol) by the WBCSD

TUFTS Climate Initiative: Radiative Forcing

IPCC, 1999

Flights

Data for our flight calculations has been gathered from the following sources.

1. The Greenhouse Gas Protocol (GHG Protocol) by the WBCSD
2. TUFTS Climate Initiative: Radiative Forcing

By using the most current data in both of these documents the following metrics are used to calculate GHG emissions in the calculator.

The following is a detailed overview of the approach taken.

• The calculations are based on “The Greenhouse Gas Protocol” (GHG Protocol) by the World Business Council on Sustainable Development (WBCSD). This publication is the most widely used international accounting tool for government and business leaders to understand, quantify, and manage greenhouse gas emissions. The GHG Protocol Initiative, a decade-long partnership between the World Resources Institute and the World Business Council for Sustainable Development, is working with businesses, governments, and environmental groups around the world to build a new generation of credible and effective programs for tackling climate change.
• Aircraft emissions are exceptional in that most of the global warming potential is caused by emissions other than CO2. Aircraft travel at altitudes of 9 to 13 kilometres (approximately 5.6 to 8 miles). At these altitudes, the effect of the emitted gases is considerably different than on the ground level and in many cases still incompletely understood. Aircraft also emit water vapour during flight. When emitted in the stratosphere, H2O can cause the formation of ice clouds, called contrails. Where contrails persist, cirrus clouds begin to form which have an additional impact on global warming. Clouds can have a double effect on radiation: they warm the earth by reducing the amount of radiation from the earth that escapes into space but also cool the earth by reflecting the sun’s rays back into space. However, contrails lead to a net warming (William, Noland and Toumi, 2002; IPCC, 1999). Nitrous oxides (NOx), water vapor contrails and soot from the jet exhausts are involved in complex chemical and physical phenomena in the upper troposphere and stratosphere. Jet aircraft emissions have 2-4 times the global warming potential of the CO2 alone. However, the impact of NOx, water, and hydrocarbons at high altitude are poorly understood. It is possible that the forcing of water vapour is being underestimated by as much as a factor of 10 (see: Workshop on the Impacts of Aviation on Climate Change June 7-9, 2006, Boston, MA)

• In the fuel-based approach, fuel consumption is multiplied by the CO2 emission factor for each fuel type. This emission factor is developed based on the fuel’s heat content, the fraction of carbon in the fuel that is oxidized (generally approximately 99% but assumed to be 100% in this tool), and the carbon content coefficient. Since this approach uses previously aggregated fuel consumption data, it is considered “fuel-based.”
• Additionally, a Radiative Forcing factor of 2.7 has been applied, as argued by the TUFTS Climate Initiative (http://www.tufts.edu/tie/tci/carbonoffsets/aircalculator.htm) :
• Calculating the CO2 emissions from jet fuel burned on flights is relatively simple but the overall warming impacts of air travel are much more complex and difficult to calculate. Therefore, and to allow comparisons of varying types of emissions, the concept of radiative forcing is used. Radiative forcing measures the rate at which a given atmospheric gas alters radiation that is entering the atmosphere. A positive value denotes warming; a negative number signifies cooling (IPCC, 1999).
• Aviation is a fast growing source of GHG emissions, estimated to be 4 -9% of the world’s total (EFTE, 2006). Unless the growth of the air travel industry is slowed, it is estimated that by 2050 air travel will be contributing at least 6% of the total radiative forcing from human activities (RCEP, 2003; Bows, 2005).

Notes:

1. We have used three standard flight distances. Extended long flight calculations have not been made.
2. All data is based on economy class. If a traveller is flying business or first class their emissions would be up to 4 times higher.

Household:

Data for our flight calculations has been gathered from the following sources.

• Source: GHG-Energy Calc , B. Rose 2006; Factors and Methods Workbook, Australian Greenhouse Office, 2005.

The following is a detailed overview of the approach taken.

Electricity

• Why do you have to chose the state you live in to calculate emissions from electricity consumption? The emissions from electricity are dependent on the fuel source that has been used to generate it. Because each state has a specific electricity infrastructure, the emissions from electricity generation  are different in each state. The Australian Greenhouse Office has calculated emission factors for each State in Australia, taking into account the efficiency of the power stations and energy sources used.
• Over all, electricity supplied in Australia is about 80% sourced from coal. Some states use more natural gas (NT >90 % natural gas), while Tasmania has mainly hydropower. Electricity generation in Victoria, which is mainly dependent on dirty brown coal, has an emission factor more than twice as high as Northern Territory.
• Total emission factors for power generation, including embodied energy of the plant are known as Greenhouse gas costs (GGCs). Emission factors Australian grid power average about 1.2 kg CO2e/kWhr (AGO, 2000), depending on the State power grid.
• Electricity from Renewable sources is not entirely free of emissions, since emission occurred from building the devices (wind mills, solar panels) and constructing the sites. Emission factor estimate for all ‘renewable electricity’ = 0.1 kg/kWh.

Natural Gas

• Natural Gas, the most common heating fuel, is assumed to have an emissions factor of 0.25 kg/kWh (AGO, Factors and Methods Workbook, 2003. Houck et al, 1998)

Waste

• Municipal Solid Waste (MSW) – domestic, local council, commercial and food waste – amounts to about 680 kg per capita per year and is composed of:
•  80% Organic – garden 30%, food 26%, paper/cardboard 24%.
• 20% metals, plastic and glass plus some inert waste. (12 % is potentially recyclables)

• MSW contributes to greenhouse gas emissions in two ways:
• Embodied energy of the waste material.
• Methane generation from anaerobic decomposition of organic materials (food scraps and paper waste) in landfill.

• The average embodied emissions per kg of MSW was calculated by multiplying the embodied energy by the Embodied Energy factor of 0.158 kg CO2e/kg of manufactured goods = (0.158* 15.45) = 2.45 kg CO2e/ kg MSW.
• Methane emissions from the organic landfill waste streams were estimated to be 0.24 kg CO2e/ kg MSW. The estimated total embodied emissions (including methane) from MSW = 2.7 kg CO2e/ kg MSW.
• Average MSW per person bin = 474 kg per year collections (Note: without commercial, council, etc)
• In total, without recycling, this equals emissions of 1280 kg CO2e per year.

Road Travel

Our calculator estimates fuel emissions for a selection of vehicles by multiplying the average fuel efficiency (measured in litres of fuel per km) by an emission factor for the specific fuel type.

• Vehicle fuel efficiency is partly based on data from US Environmental Protection Agency (EPA) Guide 2001
• Emissions factors of fuels based on data from the Australian Greenhouse Office AGO (AGO, Factors and Methods Workbook, 2003. Houck et al, 1998)

NOTE: We do not calculate the embodied emissions of the vehicle, because both the average lifespan and the distance travelled by vehicles in their lifetimes varies widely and make it difficult to obtain reliable data.