Pilot drilling using new technology has revealed awesome potential for geothermal power in East Africa's Great Rift Valley, the UN talks on climate change heard here on Tuesday.

Engineers using new seismic tools to locate hot spots hit powerful veins of steam, warmed by heat from Earth's core, near the Kenyan capital of Nairobi, according to a press conference hosted by the UN Environment Programme (UNEP) and the Global Environment Facility (GEF).

Several wells have been identified, most of them generating four to five megawatts of electricity, while one has a "bumper" capacity of eight megawatts, they said.

"The energy doesn't come from an oil tanker," GEF Chief Executive Officer Monique Barbut said.

"This is a story that has been frankly under-reported... it's a nice change of pace from all the doom and gloom stories you have been hearing about."

The geothermal potential from the Rift Valley is "at least 7,000 megawatts," providing a mighty contribution to the energy needs of 12 countries in East Africa, she said.

Under geothermal, superheated water from underground reservoir is drawn to the surface, where it can be harnessed for several uses according to the temperature.

In Kenya's case, the water, heated at a depth of two or three kilometres (one or two miles), emerges as steam, which can be used to drive turbines.

The Valley is a gouge that extends from the Red Sea to Madagascar where massive tectonic energies are ripping crustal plates apart.

Kenya already has a geothermal plant, dating back a quarter of a century, that delivers around 115 megawatts, or just over a tenth of the country's electricity capacity.

However, more power is urgently need to meet the needs of the country's fast-growing population, and electricity cuts are common, UNEP experts said.

Kenya's other main power sources are hydro, which has been affected by low rainfall patterns, and oil, whose costs have only recently fallen after a long surge.

The pilot drills, some of which took place near the existing plant operated by power company KenGen at Olkaria, aimed at proving a new technology called micro-seismic and magneto-telluric surveying.

GEF provided 900,000 dollars (700,000 euros) for the experiment.

By pinpointing promising sites, the scheme has slashed the risk for corporations which are keen to invest in geothermal but remain leery about drilling into locations where they fear the heat source is absent or poor, UNEP Executive Director Achim Steiner said.

The success of the pilot project could mean savings of as much as 75 million dollars for a new heat-capturing installation, he said.

Steiner spoke enthusiastically of geothermal as clean and "indigenous," a code word that usually means free from geopolitical risk and immune to market fluctuations.

He believed that geothermal was "probably" competitive against oil that was priced at 49 dollars a barrel, but pointed out that the oil market had been swinging wildly and that most analysts predict the cost of crude will rise in the medium term.

"The oil price is one variable in determining a nation's energy matrix and energy security and that is why we believe that this is the most rational pathway for a country, to proceed to invest in its long-term infrastructure for energy supplies," said Steiner.

The December 1-12 talks, taking place under the flag of the UN Framework Convention on Climate Change (UNFCCC), are tasked with advancing a negotiation blueprint for a new treaty to tackle global warming beyond 2012.