To ask the hon. Member for North Devon, representing the House of Commons Commission what estimate the House authorities have made of the volume of (a) carbon dioxide, (b) methane, (c) perfluorocarbons, (d) nitrous oxide and (e) carbon equivalent released by the incineration of waste from the House of Commons estate when calculating the estate's carbon footprint.
Only residual waste after recycling has taken place is sent for incineration with energy recovery. In 2006 residual waste collected from the parliamentary estate amounted to 1,299 tonnes. This material was combusted at an energy recovery facility regulated by the Environment Agency, generating 725,000 kilowatt hours of electricity. The recovered energy is classed as renewable energy by the UK Government, in line with Directive 2001/77/EC on the promotion of electricity produced from renewable energy sources in the internal electricity market.
Recovering energy from waste is acknowledged in the Stern review as an effective weapon in combating climate change, displacing carbon dioxide emissions from fossil fuel power generation sources.
The carbon footprint associated with the combustion of this waste is made up of a number of components:
(1) Direct emissions of greenhouse gases (GHG), expressed as carbon equivalents
(2) "Avoided" emissions of GHG (that is, emissions displaced from an equivalent amount of fossil fuel power generating capacity)
(3) GHG emissions (additional or saved) from waste transportation
(4) Net GHG emissions, taking account of direct, avoided and transport-related emissions.
Direct emissions of GHG
GHG emissions from waste combustion are calculated in two steps. First, an estimate is made of the percentage of fossil and non-fossil carbon in the waste. Second, the emissions from the combustion of the fossil carbon within the waste are calculated. Emissions of non-fossil carbon do not contribute to global warming and are therefore not taken into account.
Methane is not produced in combustion plants. The remaining greenhouse gases are released in trace quantities relative to emissions of carbon dioxide. Because their concentrations in the emission gases vary according to the composition of the waste, the total GHG effect expressed in tonnes of carbon dioxide equivalents (Teq) is estimated using emission factors developed by DEFRA, based on measured emissions averaged across UK energy recovery facilities.
Direct GHG emissions following the combustion of residual waste from parliamentary estates amounts to 415 Teq, of which 295 Teq is carbon dioxide.
GHG emissions from waste transportation
A saving in GHG emissions is realised when residual waste from the parliamentary estates is combusted, since the energy recovery facility is just 12 miles from the House. Previously the waste was being transported to landfill further away from the estate.
The GHG emission factor developed by DEFRA for waste transportation varies between 0.37 and 0.49 kg carbon dioxide equivalents per tonne of waste transported, depending on distance travelled. For transportation of 1,299 tonnes of parliamentary estates waste, this amounts to a GHG emission of between 0.48-0.65 Teq. Since this is less than 1 per cent. of the emissions of direct or avoided emissions, the GHG saving in transporting the waste a shorter distance will be omitted when presenting net emissions.
Net GHG emissions
The carbon footprint associated with the combustion of waste from the parliamentary estates is obtained by subtracting avoided emissions from direct emissions.
This equates to a net GHG saving of 20 Teq. Therefore 20 Teq should be subtracted when determining the total carbon footprint of parliamentary estates.