Further to Bill Watts’ Open mike column on schools (24 August, page 32), it must be made clear that the government’s plan for schools is not to “generate 60% of their energy from on-site renewables”, but to reduce carbon emissions by 60% from 2002 levels.

A building’s carbon burden can of course be cut by reducing demand as well as by using renewables.

The primary answer is that we need more efficient school buildings. This can be done by passive measures such as controlled use of daylight, natural ventilation, better U-values, thermal mass and more efficient services.

Is biomass an on-site renewable? Watts says it isn’t if the fuel is grown elsewhere, but the Department for Children, Schools and Families (DCSF) will classify biomass as on-site. Most of schools’ heating needs can be met using heat-generating renewables such as biomass or ground source heat pumps.

Biomass has been incredibly popular, mopping up much of the local supply of fuel in some areas. This has led to a need for fuel from further afield. However, at Faithful + Gould – the DCSF’s technical adviser on the project – we think instruments are being put in place to encourage biomass to be sourced locally and to come from waste products.

While we concur that carbon could be offset more cheaply at a wind farm, the choice to always do the cheapest thing would lead us to catastrophe. What we need is balance.

If we begin manufacturing, specifying and installing the whole range of renewables (and micro-combined heat and power), the technologies will develop and prices will fall.

Off-site wind is no silver bullet – if we relied on wind every time, our Countryside would be covered in wind turbines.

Guidance on achieving zero carbon in schools and the extra funding should be published in late October.

Sean Lockie, director, Faithful + Gould