Exploiting a hidden menace

THE breathtaking beauty of the Lake Kivu region, resting between the volcanoes and steep hills of the Democratic Republic of Congo and Rwanda, is exceeded only by its mercurial temperament. A clear sunny day can turn to a tropical downpour in minutes, before the sun beats down again. The lake’s still waters also hide another face: dissolved within are billions of cubic meters of flammable methane and more still of carbon dioxide, the result of volcanic gases seeping in.

Two other lakes, in Cameroon, are filled with deadly carbon dioxide. One of them, Lake Nyos, belched out a huge bubble of it in 1986, asphyxiating about 1,700 people. But Lake Kivu is the only lake anywhere also to contain methane. The mix of gases, held tight by pressure like bubbles in a bottle of fizzy drink, presents both a source of power and a danger to hundreds of thousands of people living around the lake. If it were to froth over, as scientists think it has in the distant past, it could generate huge explosions and smother towns and villages in dense clouds of carbon dioxide.

Now several firms are working to harness the energy and mitigate the dangers by gingerly extracting the methane from the lake. Among them is Contour Global, an American firm with power projects across Africa. In December it started producing power from its KivuWatt project. Below a huge barge is a pipe that sucks up water, from which it extracts and purifies the methane before pumping the less-fizzy water back down.

In time the project will be expanded to produce about 100 megawatts of energy. That is more than half of Rwanda’s current, inadequate, generating capacity. Other firms are racing to catch up. Symbion Power, another American company, recently signed an agreement with the Rwandan government to build a 50MW power plant that will also run off methane tapped from the lake’s waters.

The technology being used to tap the lake’s gas is cutting-edge; but this generation of wildcatters is not the first to see power beneath its placid waters. In 1963 an intrepid businessman sent down a small pipe that he used to power a brewery to produce Primus, a light lager with bubbles altogether more palatable than those used to make it.