The government’s drive for zero-carbon new homes by 2016 is in danger of failing unless it allows the purchase of off-site renewable energy.

The warning comes in a report from the UK Green Building Council, titled The Definition of Zero Carbon.

Currently, all energy has to be generated on-site for a home to be zero carbon. The report, however, includes new modelling that suggests this is not achievable for up to 80% of new housing.

According to the council, zero carbon status should include the ability to buy energy from off-site renewable energy sources.

The report recommends a revised definition of zero carbon to include:

• all new buildings to meet strict energy efficiency standards for both the building and the household appliances

• new buildings should seek to mitigate carbon emissions from energy use on or near the development.

Above this threshold, off-site solutions should be allowed provided they have been built specifically to deliver the energy needs of the development. Alternatively, a developer would be allowed to pay into a community energy fund, although at a premium price to discourage this option.

Paul King, chief executive of the Green Building Council, said: “This is about allowing developers more flexibility to deliver zero carbon homes in the numbers required.”

The council’s report will feed in to a government consultation on the definition of zero carbon due in the summer. It is available at www.ukgbc.org.