The policy, agreed at a cabinet meeting last Wednesday (23 November), means the authority must ensure renewable energy accounts for 30 per cent of a building's consumption by 2011.
According to Green Party councillor Andrew Cooper, who championed the proposed guidelines for almost two years, the policy would apply to all new council-funded building projects.
He said: 'We had a lot of one-off green initiatives but we wanted to make that mainstream. We thought a standard of 30 per cent of energy from renewable sources in new public buildings was achievable.
'So we asked our architects section about this and commissioned a report by Faber Maunsell to look into various technologies and into whole-life costing.
'They agreed that 30 per cent was absolutely OK.'
It is understood the policy will be viewed as the council's 'own Part L' and will be applied wherever there is a capital investment.
Cooper believes the move will have a national impact and could spark interest from the private sector which, he hopes, will follow suit.
He said: 'Our approach may open doors for other councils to follow and I think the market will have to respond. This could be the beginning of a large-scale upturn in renewable energy across the board.'