With their recent agreement to extract methane gas from under Lake Kivu, one of Africa's Great Lakes, DR Congo and Rwanda hope not only to produce power but also to defuse a massive timebomb.
"The reserves are currently estimated at around 55 billion cubic metres (two trillion cubic feet)," said Celestin Kasereka, researcher at nearby Goma's volcanic observatory.
"The danger with the gas is that it is explosive when in a very strong concentration."
Around two million people live around the lake. If the methane exploded, carbon dioxide — denser than air — would be released, killing tens of thousands of people, Kasereka believes.
There is four times as much carbon dioxide under the lake as methane.
Lake Kivu sits in an area of high volcanic activity, and a large flow of lava into its waters could cause an explosion, prompting a catastrophe, Kasereka said.
When Mount Nyiragongo last erupted in 2002, the volcano spewed out 38 million cubic metres of lava, engulfing parts of the nearby city of Goma.
"If a similar amount went directly into the lake, at high velocity, that could reach the deep waters and cause a gas explosion," Kasereka said.
The resulting disaster would be even worse than when gas escaped from Lake Nyos in Cameroon in August 1986, Kasereka said, when carbon dioxide seeped out of the lake after an explosion and suffocated 1,800 people.
Taking out the gas would reduce the risk, although the joint Kigali-Kinshasa project, signed on March 28, is not scheduled to be operational before 2009.
The project could provide 500 megawatts of energy, supplying electricity to all those living around the 50-by-90-kilometre lake, said DRC's hydrocarbons minister Lambert Mende.
