Council bosses believe 100pc of the energy needed to power their buildings will be from renewable energy sources within weeks.

Norwich City Council says it has already achieved this target for City Hall, with biomass, wind and hydroelectricity among the sources.

And officials say a small number of changes are needed before its neighbourhood offices, car parks and other sites reach this target. These are expected to be completed by October.

But the opposition Green Party said people living in the authority's 15,900 houses have to source their own electricity and they were also interested to see more information to support the council's claims.

A Norwich City Council spokeswoman said: 'We purchase our energy via a company called Eastern Shires Purchasing Organisation (ESPO).

'They broker energy rather than provide it directly themselves. Our contract is for them to provide us with 100 per cent renewable energy, which will include provision from a range of sources including biomass, wind and hydro.

'We spend around �700,000 a year on energy for all our buildings, including a cost of ensuring it is from renewable sources of approximately �10,000.'

The council estimates it has saved �500,000 from its energy bills in the last four years.

Claire Stephenson, opposition Green Party leader, said: 'To say it's all coming from renewable energy makes it sound like they have got solar panels and wind turbines on or near their buildings. There's a difference between that and getting it through a renewable energy supplier.'

Mark Crutchley, chairman of the Norwich Carbon Reduction Trust, said: 'My immediate thought is it's certainly a good thing. It's a positive aspiration to be utilising entirely renewable energy. I know the council has done work optimising the energy use in the buildings, which is very good at reducing energy use if not more important than where you are sourcing it from.'

Do you have a council-related story for the Norwich Evening News? Contact Richard Wheeler on 01603 772474 or email richard.wheeler@archant.co.uk