Decarbonising buildings by indirect use of gas and biomass

Abstract

Current efforts to reduce carbon dioxide emissions associated with energy services in buildings have focused on efficiency and a ‘distributed energy’ approach, using renewables and small-scale combined heat and power plants fuelled by natural gas or biomass. The same fuels can, however, give similar results if used in centralised plants to generate electricity that can then power heat pumps. A greater emphasis on the use of heat pumps would also facilitate the use of non-fossil electricity and the future application of carbon capture and storage to reduce emissions from any centralised fossil fuel use. Carbon capture and storage and electricity can give cuts in carbon dioxide emissions of 75% or more compared with local direct use of gas and overall negative emissions with biomass. Centralised hydrogen production with carbon capture and storage can also be combined with distributed combined heat and power. Given the potential effectiveness of these combined centralised/distributed approaches for emissions reductions, it is important that further work is undertaken so that they can be accurately evaluated as additional policy options. Infrastructure developments should also take into account the likely importance of decarbonised electricity and/or hydrogen in the future and not be locked into direct use of natural gas with its minimum emission limit of approximately 0·2 kgCO2/kWh.