Rwanda Plant Powered by 'Killer Lake'
Finnish turbine maker Wartsila on May 17 announced the inauguration by Rwanda's President Paul Kigame on May 16 of a 25 MW KivuWatt power plant at Kibuye powered by methane gas lifted from the depths of Lake Kivu. The event was hosted by the power plant’s owner, ContourGlobal.
Lake Kivu has been known as the “killer lake” due to the large amounts of methane gas trapped under a layer of heavy water washed out of the nearby volcanoes. When the gas concentration gets too high, or an earthquake occurs, the gas can be set free, posing a deadly threat to local people.
In west Africa on August 21 1986, carbon dioxide (CO2) saturated in Cameroon’s Lake Nyos erupted as clouds, drifted onshore, and suffocated some 1,700 people. So in east Africa, any attempt to mitigate Lake Kivu’s methane risk is worthwhile, especially as it will improve Rwanda's access to electricity. World Bank/IEA data for 2013 show that only 21% of Rwandans had access to electricity.
The KivuWatt plant has been operational and running on the extracted methane since December 2015. The methane is lifted from a depth of 300 metres by a special barge anchored 13km offshore, purified on the barge, and transported to the shore through an underwater pipeline.
“By tapping into these gas resources, the project makes Lake Kivu a safer place, while supplying much-needed electricity to the national grid,” said Wartsila. The company has previously delivered two other power projects to ContourGlobal in Africa: a 100-MW plant in Togo, and a 53-MW new plant in Senegal that started up in April 2016 and now has a 32-MW extension under construction.
New York-based ContourGlobal said phase 2 of KivuWatt will add two or three barges to this configuration on the lake to generate an additional 75 MW, reaching 100 MW by 2019. The project has benefited from debt financing from the African Development Bank, and similar Dutch and Belgian institutions.
Kivu contains a thousand times more gas than Nyos, wrote MIT Technology Review a year ago: "If even part of it escaped this way, more than two million people living near its shores would be at risk." It acknowledged the risks of processing the methane out of the water, but said those of doing nothing are much greater.
In December 2015, another US company Symbion Power committed to develop a similar 50 MW project on the opposite side of Lake Kivu, also powered by the lake's submerged methane. Symbion said then: "Lake Kivu contains an estimated 55bn m3 of naturally occurring methane gas. The total power generation potential of this resource has been conservatively estimated at more than 500 MW over 40 years."
Wartsila’s installed capacity in Rwanda is now 46 MW, 50% of the country’s available power generation capacity. Across Africa, its installed base is 6500 MW in 46 countries.
Mark Smedley