CO₂ Emissions: Biomass

Current emissions

The table below shows the CO₂ emissions associated with the gas and electricity that would be replaced by the CHP system.

	Tonnes CO2
CO2 saving from reduced industrial gas use	6228
CO2 saving from reduced industrial electricity imported from the national grid	9513
CO2 saving from reduced domestic electricity imported from the national grid	2148
Total CO2 annual saving from energy offset	17890

Table 1: CO₂ saving from energy

The payback period for the embodied CO₂ is estimated as 1 year, which is equivalent to 17890 tonnes CO₂ .  Over the 20 year life cycle this works out as 894 tonnes of CO₂ per year.  The emissions associated with both the production and transport of the wood chips are based on estimates from the Royal Commission on Environmental Pollution and are expected to be 138 tonnes of CO₂ per year. 

	Tonnes CO2
Embodied carbon of system installation (over 20 years)	894
Embodied carbon of wood chips	120
Emissions from transport of wood chips	18
Total annual CO2 emissions of CHP system	1033

Table 2: Embodied CO₂ of the system

Total CO₂ saving

The total annual saving CO₂ associated with this scheme is 20583 tonnes, which represents a saving of 29%  on the original CO₂ emissions of the community.

	Tonnes CO2
Total CO2 annual saving from energy offset	17890
Total annual CO2 emissions from CHP system	1033
Total annual CO2 saving from installation of system	16857

Table 3: Annual CO₂ saving

Cost per tonne CO₂ saved

Capital cost per tonne CO2 saved over 20 years	£525
Annual saving per tonne CO2 saved excluding ROCs	£8
Annual saving per tonne CO2 saved including ROCs	£59

Table 4: Cost per tonne of CO₂ saved