Industry calls for flexibility on definition of zero carbon

The government must relax the definition of zero carbon to include offsite and near-site energy if the industry is to achieve zero carbon by 2016, experts have warned.

There is unease that developers will be unable to build zero-carbon homes on urban infill sites as the sole use of onsite renewables will be prohibitively costly and problematic.

Last year, the definition of Code for Sustainable Homes level six was altered to discount the use of offsite energy amid fears that it was too difficult to verify the energy source. But industry experts believe the door should have been left open to offsite use while the finer details were worked through.

John Tebbit, industry affairs director at the Construction Products Association, said: "The government is concerned that someone will build 1,000 houses and put £10m in a pot for renewables without truly knowing what it will be invested in. We all need to sit down and work out the parameters.

"The concern is that some developers won't want to build any new homes on sites under 500 units."

A zero-carbon task group is currently examining the options for meeting the energy needs of very efficient homes and is expected to push the government to relax its stance.

Julian Brooks, a sustainable development consultant and member of the task force, said: "If the government is serious and any subsequent government recommits [to zero carbon by 2016] then a developer needs to have as many tools and methods available as possible."

Chris Twinn, another zero-carbon task group member and a director at Arup, commented: "The idea should always be to incentivise building efficiency, then maximise on-site renewable potential, followed by near-site before going to remote offsite."

The group is due to make its recommendations in April, when it is likely to suggest accreditation methods for offsite energy and promote resource mapping, whereby smaller sites can make use of energy generated by nearby developments.