Housebuilders could be allowed to avoid reaching the highest environmental standards by paying a levy to offset carbon savings under plans to be unveiled next week, writes Joey Gardiner.

Building understands that the Zero Carbon Task Group, headed by Barratt chief executive Mark Clare, will recommend that small or difficult sites be exempted from the highest levels of the Code for Sustainable Homes by paying a charge.

This charge would be used to pay for equivalent carbon savings in other areas, such as improving the existing housing stock.

The government has said that all homes must meet level six of the code – zero carbon – by 2016.

Sources close to the task group said it would report that the challenges of reaching zero carbon are different for large, medium and small sites.

It will argue that small sites will find it impossible to reach level six as they are not large enough to make combined heat and power systems work and do not have scope for other forms of renewable energy generation.

This is a sensible approach as to how we meet the zero-carbon.

Task Group Source

Developers of these sites would then be able to pay a levy rather than have them rendered unviable. The findings will feed into a government consultation on the definition of zero carbon, scheduled for the summer.

A source close to the group said: “This is a sensible and pragmatic approach as to how we meet the zero-carbon obligation.”

However, the group is said to be undecided on how the levy might work. A separate source said: “They’ve got to be careful they don’t find that most homes, which are built on small sites, are able to escape reaching zero carbon.”

Speaking on the sidelines of the Think 08 conference, Paul King, chief executive of the UK Green Building Council, refused to confirm the details of the group’s recommendations. He said: “The aim is to come up with a mechanism that does not dumb down the commitment to zero carbon, but does provide equity between large and small sites.”

The task group, which was set up by the government and the UK Green Building Council to define zero-carbon housing, will present their findings to ministers on Tuesday.