The Cornwall Energy Recovery Centre is proposed for a site at Rostowrack Farm, near to the village of St Dennis, near St Austell.
The combined heat and power facility will generate 16.6 megawatts of electricity and divert 90% of the county’s residual waste away from landfill.
Developer Sita Cornwall said the scheme will provide electricity for 21,000 homes in the region.
French-owned Sita UK was awarded a 30-year, waste management contract by the county council in 2006. But long delays in the planning process saw a new PFI deal signed this month for £1.1m.
Now the firm has signed an engineering and construction contract with Vinci who beat rival bidders including Kier.
SITA project director David Buckle said: “Although Cornwall is recycling more waste than ever, it is anticipated that there will still be more than 200,000 tonnes of residual household waste, and at least the same tonnage of commercial and industrial waste, to dispose of each year. This is a problem that won’t go away.
“Landfill sites in Cornwall could be full by 2014, which means that within five years the county would have to start exporting waste by lorry to landfill sites in other parts of the country.”