Defra's green office: better than BREEAM excellent? | Archive Titles

Renewables: the payback (as estimated during project design)
	Predicted energy output	Predicted CO2 emissions cut	Estimated payback
Three 15kW wind turbines	63,000kWh/yr	35,784kg CO2/yr	15.4 years*
120m² photovoltaics	11,908kWh/yr	6764kg CO2/yr	24.3 years*
50kW biomass boiler	32,000kWh/yr	5409kg CO2/yr	No payback*
Solar thermal panels	1840kWh/yr	77kg CO2/yr	12.4 years*
*including for maintenance and energy savings, allowing for fuel inflation
%3Cb%3EPredicted operational carbon emissions:%3C/b%3E
As-built Part L assessment (regulated CO2 emissions only) %3D -7.3kgCO2/m²/yr
Total operational carbon emissions (both regulated and non-regulated CO2 emissions calculated according to BREEAM true zero carbon method) %3D -6094.89kg CO2/yr