Hopes are being pinned on a renewable energy site and model village fuelled partly by a rarely-used source of natural power. Bessie Robinson looks at the history of hot rocks and how water would be harnessed.

ROCKS are hot news in a rural corner of County Durham where hopes are high that a solution to economic ills could lie deep underground.

Drilling experts currently boring 1,000m down into Weardale granite are optimistic that they will find natural hot water which can be pumped upwards to heat buildings on the surface.

The hot rocks energy idea would be a key element in a model village fuelled entirely by renewable sources and likely to attract thousands of visitors a year.

The idea came from a task force set up before the closure of the Eastgate cement works by Lafarge cement in 2002.

The force, which includes Wear Valley and Durham county councils and regeneration agency One NorthEast, discovered that Eastgate is unique in the country in combining five natural energy sources - hot rocks, wind, hydro-electric and solar power as well as electricity produced from burning woodland waste.

But because Weardale is one of only two sites where hot granite is close enough to the surface to be easily reached, it is the geothermal element which is the most exciting as well as the most controversial.

Using energy from hot rocks is a simple concept that has been employed for thousands of years.

For centuries, the Romans heated the water in their bathhouses and homes with geothermally heated water, which they also used to treat eye and skin diseases.

As far back as 10,000 years ago, Native Americans used hot springs water for cooking and medicine.

The Maoris of New Zealand have cooked geothermally for centuries while since the sixties, 200,000 Parisians have been keeping their homes warm with geothermal water.

The first scheme in the UK was launched in 1986 in Southampton where it heats homes, businesses and public buildings.

In modern-day direct systems, a well is drilled into a geothermal reservoir to provide a steady stream of hot water to the surface.

At Eastgate, current plans are to extract the water through the same boreholes being drilled on the cement works site.

A pump, which could either be placed at the base of the borehole or higher, would then pipe the water to the surface and send it through a holding tank directly into the buildings it will heat.

A loop system could then feed the water, which is salty, back into the ground, replenishing the supply.

Underground warm water was found near Eastgate at Cambokeels Mine in the 1980s.

Daniel Dufton, of drilling project managers PB Power, said: "We know the rock is hot. It is a question of how close the water is to the surface."