Supporters of a controversial new incinerator in West Norfolk insist the project will save Norfolk council taxpayers �200m in the long run, as opponents challenge the annual costs of the scheme.

Norfolk County Council has selected Anglo-US firm Cory Wheelabrator as its preferred bidder to construct an incinerator at the Saddlebow Industrial Estate at King's Lynn.

The council has secured �169m of PFI credits from the government to help pay for the project, which if approved is expected to process 170,000 tonnes of household waste and a further 90,000 tonnes of commercial waste.

But council figures show the likely projected costs to council taxpayers over the life of the 25-year scheme is around �500m, or around an average of �20m a year.

Currently the county council pays �18.4m a year to dispose of its residual waste and this will rise to �23.7m in 2015/16 after the cabinet agreed an interim deal this week for five new contracts including transporting waste to an incinerator in Kent.

But the authority says that if the incinerator is built that �500m cost could well fall, while it will also receive income from generating electricity and selling the recyclable materials produced in the process.

However, opponents point to council papers putting the costs closer to �600m, and the savings of any landfill alternative would be of the same order without any associated risks to the health or the environment.

Ann Steward, Cabinet member for Sustainable Development said that doing nothing would cost �800m, and with the help of the PFI credits the authority was effectively saving �200m, or around �8m a year.

'Where costs are concerned, I am very clear that Norfolk can't afford the continued costs or environmental consequences of continuing to dump waste into the ground,' Mrs Steward said. 'If this project does go ahead, Norfolk taxpayers will be saved at least �8 million a year from 2015 onward which would help pay for a lot of frontline service. On top of that, the council would receive extra income from energy generated and extra materials recycled.

'The precise costs of the proposed new facility are to be pinned down now we have a preferred bidder and will be finalised when and if a contract is finally awarded. The good news is that the Government is convinced enough about the Norfolk case to have awarded the council a grant in the form of PFI credits worth �169m to help pay the costs.

'This means that the early, original estimates of costs (between �525m and �668m) are now able to be revised substantially downwards and the latest estimate is now below �500m.

'The proposals are of course still subject to the facility being granted planning permission, an Environmental Permit from the Environment Agency and further assessment by Defra that it meets its requirements under the PFI diverting waste from landfill scheme.'

Mike Knights, co-ordinator of the farmers' campaign against the incinerator, said the council's figures were based on the false assumption of a 'standstill situation'.

'I am not advocating landfill, and nobody else is either,' he said. 'Any altnernative to landfill is going to save that amount money they are talking about,' he said. 'It's just that this is potentially the most expensive solution and most definitely the one that poses the greatest threat, not just to our health, but also to our agriculture as well.'