Can this be right?

BREEAM (1993) stipulated an electricity conversion factor of 0.72 for CO2/Kg/kWh. I have written to the Office of the Deputy Prime Minister for confirmation of the new figure (0.42), but to date have had no reply. This new figure has a huge impact on CO2 emission calculation results – the lower the figure, the lower the CO2 emission.

I believe the only way this conversion factor change could be made is by increased efficiency of power stations/national grid. The only way this can happen is by increasing installations of natural resources supporting the grid.

I would agree the conversion factor is now lower than specified in BREEAM (1993) but surely not as low as 0.42. If the installation of natural resources continues to reduce this conversion factor then soon it will be more feasible to utilise electricity than gas! The conversion factor for gas is 0.194, which is only fractionally lower than BREEAM (1993) at 0.21.

Any comments would be appreciated.

Edward Jolly BEng (Hons)

Ted King from the ODPM replies: I am advised that the carbon intensity is indeed falling very swiftly. The value of 0.72 kgCO2/kWh was for 1991 – probably the latest available when BREEAM 5/97 was published – while 0.42 is the projected average emission factor for 2005–2010, produced by the DTI energy modelling team. We are using this value as relevant to the anticipated life of the new editions of the Approved Documents.