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Environment

Rwanda turns dangerous lake into power source

Lake Kivu in East Africa is one of a handful of lakes on Earth with the power to unleash a peculiar and deadly phenomenon. Rwandans are in a race against time to defuse it, and are putting its energy to use.

The shoreline of a lake, with banks leading up to hills.

Lake Kivu: the energy resource Rwanda needs?

As the little motor boat slowly chugs out into the sprawling expanse of Lake Kivu, there is no missing the volcanoes rising above the northern shoreline.

Cloud and smoke hang low above their craters, and their slopes are caked in dried lava, betraying a long history of periodic eruption.

Alex Kabuto leans over the side of his boat and points towards what looks like an oil rig floating on the surface of the water. It is actually a pumping station to which the engineer attaches the boat before climbing aboard.

A large pipe leads into a white building

The methane gas is pumped ashore via a pipeline

From here, scientists are able to retrieve a small amount of the dissolved methane recently discovered hundreds of meters below the water's surface.

Although the find, which scientists believe is the result of nearby volcanic activity, is hugely valuable in energy terms, it also has the potential to be extremely dangerous.

Scientists refer to what is known as the champagne effect, in which a loss of pressure would trigger a massive eruption from inside the lake, as if it were a bottle of over-shaken bubbly.

"The gasses keep on increasing which means there is the potential that maybe after 100,200 or 500 years, the lake will become saturated and at that time it can be very dangerous," Kabuto said.

"This may become like Nyos in Cameroon and kill a lot of people."

Precautionary tale

A scenic picture of a lake surrounded by mountains

Volcanic lake Nyos in Cameroon

In 1986, a similar phenomenon killed an estimated 1,700 people when gas erupted from Lake Nyos in Cameroon, suffocating almost everyone within 25 kilometers of the lake.

Scientists believe a similar process occurs at Lake Kivu roughly every 1000 years, devastating life in the area. If it were to occur today, some two million people living around the lake could be killed.

In order to prevent this, the Rwandan government is trying to pump the methane out of Lake Kivu, and put it to good use.

A straw-like construction leads from the platform into the depths below. It captures the gas as it fizzes to the surface. It is then pumped through a pipeline to three generators in a warehouse on shore.

At the moment, the facility generates 3.6 megawatts of electricity. But Kabuto says that output could easily be increased.

"The gas in the lake has the potential to produce a total of 700 megawatts of electricity," he said, adding that it is much more than Rwanda needs. "It is our aim to generate enough energy to be able to export electricity."

But that is currently far from reality.

As things stand only ten percent of homes are connected to the grid. About 11 megawatts are generated by hydroelectric power, but most of Rwanda's energy comes from diesel generators.

Rwandan energy alternatives

Solar panels

Sun is something there is rarely a shortage of in Africa

As Rwanda has to import every drop of diesel it uses, supply is a costly and environmentally unfriendly business. What the country needs is alternatives.

German environmental technician Anthony Simm is involved in one such project.

He climbs one of the highest mountains in the country to check that everything is running smoothly.

The four thousand solar panels are capable of producing 250 kilowatts. It is not much in the grand scheme of Rwandan power needs, but as Simm explains, it is only the beginning.

The solar field was built by the German utility company Stadtwerke Mainz, as the result of a long-standing close partnership with Rwanda.

Simm recalls how the 2004 drought first gave rise to the idea for the project.

"The rivers and the power station dams were all but empty. There was very little energy, and back then there was only one fossil fuel power station," he said

Solar energy seemed like a safe bet, and long-term the Mainz utility company hopes to generate one megawatt through the solar project.

That will require an investment of three million euros ($3.87 million) on top of the one million already spent. Even then, Simm says, it would not turn a profit. Solar power is too expensive for that. But it is likely the most plentiful of all of Africa's resources.

Reporter: Sabine Schlindwein
Editor: Nathan Witkop

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