An eco village, planned for the site of a former cement works in Weardale, could attract almost 230,000 visitors a year, experts have predicted.
The project, on the site of the former Lafarge works in Eastgate, will feature a hot spring spa, alternative energy resources and a leisure complex.
The Eastgate Renewable Energy Village is hoping to attract £20m in lottery funding and create 350 jobs.
A task force has predicted 227,000 visitors a year could visit the site.
The Lafarge Blue Circle cement plant closed in 2002, with the loss of 140 jobs.
Weardale Task Force says research suggests a huge potential for tourists, predicting 180,000 day trippers and another 47,000 staying at least one night in local accommodation.
Ambitious plans could also see part of the River Wear diverted through an underground pipeline to turbines which would generate electricity.
A wind farm and biomass plant fuelled by forest waste would also be used to produce power.
John Hamilton, chairman of the Weardale Task Force, said: "Work is ongoing, but current estimates suggest that approximately 227,000 visitors would come to Eastgate each year.
"About 65,000 are predicted to come by rail, which reflects the emphasis being given to public transport."
John Topliss, Eastgate project manager, added: "Work is ongoing and a revised master plan will be the subject of a further round of community consultation around October 2007.
"This continues our commitment to keeping local people informed and involved in the pre-planning application process."
A formal planning application is likely to be submitted towards the end of 2007, with planning permission hoped for during 2008.