Greens welcome Britain's "zero carbon" homes goal

LONDON, Dec 14 (Reuters) Environmentalists praised plans laid out by Britain on Wednesday to tackle global warming by making all new housing ''zero carbon'' in a decade, but questioned what the term would mean in practice.

''We really like this idea. It is a big step in the right direction. Our only problem with it is the lack of urgency,'' a Friends of the Earth spokeswoman told Reuters yesterday.

''Zero carbon homes could be built now, so why wait 10 years before insisting that builders construct them?'' she added.

Definitions of ''zero carbon'' range from using renewable building materials and transport fuel to sharply reducing emissions from occupation.

Environmental architect Steve Piltz said that in practice the definition did not include construction carbon.

''If you assume a house has a life of 60 years before redevelopment, then the embedded carbon is less than one percent of the total,'' he told Reuters.

''Zero carbon means in practice striking a balance between consumption and production of carbon -- using design technology to make sure you need less energy and renewables and microgeneration to generate what you do need,'' he added.

A spokesman for local government minister Ruth Kelly said the definition used in the government plans included all emissions from power generation after construction but not the ''embodied'' carbon in building materials or transport to the site.

There are only a handful of such developments in Britain to date -- the largest being the Beddington Zero Energy Development in south London, which was completed in 2002 and describes itself as ''carbon neutral'' -- but there are plans for more.

One is the planned Gallions Park development in east London which says its ''zero carbon'' homes will have to be 40 percent more carbon efficient than existing building regulations require, and get all their energy from local or renewable sources.

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