Methodologies

Methodologies already exist for measuring CO₂ emissions from energy related projects. Methodologies for these activities within the UK Emissions Trading Scheme (ETS) are annexed to the DEFRA Guidelines for the Measuring and Reporting of Emissions in the UK Emissions Trading Scheme. Read the full paper.

For energy related emissions the protocol is based on the product of energy consumption and CO₂ emission factors. This approach can be used for determination of the project baseline and the forecast of annual emissions. The calculation of CO₂ emissions is simply:

CO2 emissions (tonnes) = Energy consumption
(kWh) x Fuel emission factor (kg CO2/kWh) x 0.001

The emission factors for a range of different fuels are given in Table 1. In the case of electricity consumption it is in most cases impossible to identify with any certainty the source of generation that has been reduced or displaced. For this reason the Climate Change Levy Negotiated Agreements and the ETS are using an average carbon intensity factor for the estimation of carbon dioxide emissions from the consumption of electricity. This has been fixed at 0.43 kgCO₂/kWh.

Fuel can be purchased in a variety of units. Conversion factors for the most commonly used units are given in Table 2. Where fuels are purchased or measured by volume or weight the calorific value of the fuel is needed to convert to energy units. This should be specified by the fuel supplier, but where this data is not available default factors should be used. Default calorific values for selected fuels are given in Table 3.