Green meaning

Congratulations on an excellent first edition of the Sustainability in Practice series

Congratulations on an excellent first edition of the Sustainability in Practice series (). It captured the challenges and opportunities inherent in addressing sustainability issues.

One of the priority challenges is to make sense of the definition of 'zero carbon'. To clarify: HM Treasury defined zero carbon for the purposes of its Stamp-Duty relief, and in doing so excluded the use of off-site renewables. This sweetener has had a perverse effect. The Building Regulations will be tightened against the energy criteria set out in the Code for Sustainable Homes, with 2016 being the zero-carbon end point. But here's the rub – the Code's definition of zero carbon was belatedly amended to exclude off-site renewables, to remain consistent with the Treasury's definition.

Whatever the future holds for the Treasury definition, it's critical we get the Code definition right. The UK Green Building Council task group will report on this in early 2008, under the leadership of Mark Clare (head of housebuilder Barratt).

John Alker, public affairs manager, UK Green Building Council