Lake Kivu is one of the African Great Lakes. It lies on the border between the Democratic Republic of the Congo and Rwanda. It covers a total surface area of some 2,700 sq km and its maximum depth of 485 m makes it the fifteenth deepest lake in the world.
Unlike other lakes in the East African Rift, Lake Kivu exhibits some very peculiar characteristics. Along with Lake Nyos and Lake Monoun in Cameroon, Lake Kivu is one of the three known exploding lakes in the world. It contains 250 cubic kilometres of carbon dioxide and 65 cubic kilometres of methane in its basin.
Carbon dioxide primarily comes from the molten rocks on the lake bed while methane is formed as a result of two simultaneous actions : the fermentation of biogenic sediments and the reduction in magmatic CO2 by bacteria.
Studies have shown that the biogenic process, which apart from producing methane also produces carbon dioxide, is by far the biggest source. Perhaps, this explains why the ratio of carbon dioxide to methane is almost 4 to 1.
These gases pose a huge risk to the millions of people who live in on its shores and on some of its islands. If geological or volcanic events can disturb the lake’s waters and release the gases, the impact would be devastating.
On 21 August 1986, a disturbance of the waters of Lake Nyos in Cameroon, which were saturated with carbon dioxide, resulted in an eruption of carbon dioxide that asphyxiated some 1,800 people. Two years earlier, Lake Monoun also exploded and suffocated 37 people.
In the case of Lake Kivu, some scientists say that the probability of an eruption is slim. They argue that the concentration of carbon dioxide and methane in Lake Kivu is still much lower than Lakes Nyos and Monoun in Cameroon at the time when they erupted.
Nonetheless, the risk in Kivu is much bigger such that it should not be taken for granted. The lake, itself, is much larger than Nyos and Monoun. There are millions of people on its shores; some even live on Idjwi, an island in the lake.
Furthermore, the Nyiragongo and Nyamuragira volcanoes, which together are responsible for 40% of Africa’s historical volcanic eruptions, are located just a few kilometres north of the lake.
In 2002, when Nyiragongo erupted, lava streamed from it into Lake Kivu for several days. On this occasion there was no disturbance of the lake’s deep layers of gas to cause an eruption.
However, according to Rwanda News Agency, Professor George Kling, of the department of ecology and evolutionary biology at Michigan University, warns that in the event of another eruption the region may not be so lucky again.
On the other hand, much as these gases are dangerous, the lake has a huge economic potential. New York Times green blog reports that a study from Eawag, an aquatic research institute based in Switzerland, estimated that 90 percent of the dissolved methane in Lake Kivu was harvestable.
The study further reports that the methane in Lake Kivu could be worth as much as $20 billion. If it can be safely extracted, it will also help to mitigate the risks of dangerous eruptions.
The Rwandans have been extracting the gas on a small scale. But they are now making expansions. Last month, they announced plans to lease the methane gas project on Lake Kivu, which currently contributes 1.8 megawatts to the national grid.
They have also agreed with the Congolese government to establish a joint project that will produce 200 megawatts of power from methane gas.
Rwandan minister of Infrastructure, Vincent Karega says , “the joint project will be in place probably in 36 months and all procedures are going well. The European Union has accepted to fund the project which will operate under CEPGEL (Economic Community of the Great Lakes Region).”
Many companies are exploring gas extraction projects in Lake Kivu. Some of them include South Africa’s Added Value Engineering Consultants, the Danish environmental and engineering consultancy COWI, Rwanda Investment Group, and the American group ContourGlobal.
If all these projects succeed, Rwanda will become entirely self-sufficient in its electricity supply. There will be many job opportunities. There will also be the potential for Rwanda to export energy to her neighbours.