KIGALI, Rwanda — An innovative plan to extract methane gas from the depths of Lake Kivu here in central Africa might save millions from a deadly natural catastrophe and help solve this country's severe energy shortage.
In March the New York-based energy company ContourGlobal signed a $325 million deal to develop a power station using natural gas extracted from Lake Kivu. It promises to produce 100 megawatts of power per day by 2012, enough to satisfy Rwanda’s needs and export power to other energy-starved countries in the region such as the Democratic Republic of Congo, Uganda and Burundi.
Lake Kivu is one of a series of large lakes nestled in Africa's Great Rift Valley, an immense tectonic gash that is still pulling Africa apart. In the depths of Lake Kivu, an estimated 65 billion cubic meters of methane gas are dissolved, as well as three times that amount of carbon dioxide.
Combined with the region’s almost constant volcanic activity, these gases are a volatile and potentially deadly combination for the 2 million people who live around Lake Kivu.
The heavy upper water keeps the gas in place, much like a lid on a bottle of beer, but experts warn that a sudden increase in heat could ignite the methane and break that seal in a phenomenon known as "lake turnover," releasing a toxic cloud of suffocating carbon dioxide.
Not only is the lake’s bed — 1,240 feet below the surface — itself volcanic, but an active volcano overlooks the Congolese city of Goma just a few miles from the lake's northern shore. Nyiragongo last erupted seven years ago. Fractures yards wide opened up in the ground and rivers of lava poured out, running through the city destroying everything in their path and killing 150 people.
The fractures have been moving closer to the town and the lake with each eruption. “We expect the next eruption will be a fracture opening up in the town. If that happens Goma is finished,” says Honore Ciraba, a scientist at the Goma volcano observatory.
“Right now the carbon dioxide and methane below the surface of the lake do not pose much of a danger,” he says. “But if the lava flow from Nyiragongo reaches the lake, it could force the gases out. The poisonous cloud could spread for miles in every direction killing all people, animals and plants. It would be a biological extinction.”
This is not idle doomsday speculation. In 1986, seismic activity caused Lake Nyos in Cameroon to release a massive toxic cloud that killed 1,700 people in an 18-mile area around the lake. Eyewitnesses described a terrifying scene: Victims lay dead where they had fallen seemingly untouched; there was an eerie silence.
Scientists have called the methane in Lake Kivu a potential detonator for an explosion that could release a thousand times more gas than Lake Nyos. Removing the methane from the lake is something that Ciraba believes “may be the solution.”
ContourGlobal plans to do just that. The company will build a floating gas extraction platform that will be moored off the Rwanda coast and suck methane out from 1,150 feet below the surface. The natural gas will then be piped to the lakeside town of Kibuye where a power plant will be built to produce 25 megawatts by 2010 and a full 100 megawatts by 2012.
This would be a significant boost to Rwanda’s paltry power supply. Rwanda currently generates 55 megawatts, enough to supply electricity to only 5 percent of the country’s 10 million people. While the capital Kigali and large regional towns have electricity, the majority of rural folk live in the dark and burn wood for fuel. This in turn contributes to deforestation and degradation of the land on which Rwandans rely for food.
The lack of power also hinders the country’s economic development.
“Lake Kivu’s gas will provide a clean source of power generation for a region suffering from extreme shortages of reliable and affordable electricity,” says Joseph Brandt, ContourGlobal’s chief executive. “[It] will also serve to reduce the risk of an uncontrolled release of the Lake’s gas.”
The government aims to provide electricity to a third of the population by 2020 and sees the natural gas in Lake Kivu as key to hitting this target.
Officials say the lake could eventually produce up to 350 megawatts, which would enable Rwanda to become a net exporter of power. It would be a much-needed boost to the country’s tiny economy, which is based on tea, coffee and high-end mountain gorilla tourism.
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Editor's Note: This story was updated to correct dates.