Treacherous Waters A Dangerous Treasure in Lake Kivu

There is a wealth of methane trapped in a lake in the heart of Africa. Engineers hope to transform the gas from the depths of the lake into electricity, but if it escapes in an uncontrolled manner, the methane could cause a catastrophe.
Von Simone Schlindwein

Patrick Muhizi sits under an umbrella at the Bikini Tam-Tam Bar, keeping a watchful eye on the perfectly smooth surface of Lake Kivu. The sun is shining, but Muhizi blows his whistle whenever the children wander too far out into the lake. With good reason: The 19-year-old Rwandan is the manager of a beach club on the world's most dangerous lake. Kivu, in central Africa, has already swallowed three people this year, when bubbles apparently sucked the bathers down into the depths. Sometimes dead fish float to the surface.

Lake Kivu, at the foot of the Virunga Volcano Chain, lies in a groove in the earth's crust known as the East African Rift. The Congolese jungle grows rampant along its western shore and Rwanda's coffee plantations stretch along the eastern side. Activity in the tectonic faults throughout the Rift causes periodic earthquakes.

This combination of factors is what attracts curious geophysicists, volcanologists, chemists and biologists to the region, where many congregate at Muhizi's bar, lured by a unique treasure in the 485-meter (1590-foot) deep lake.

At depths below 75 meters (246 feet), massive amounts of gas are dissolved into the water in layers, as in a bottle of carbonated water -- an estimated 65 cubic kilometers of methane and 256 cubic kilometers of carbon dioxide. What makes the lake so dangerous is the so-called champagne effect. When an earthquake, a powerful storm or lava flows from the surrounding volcanoes churn up the upper layers, water from the depths can reach the upper level. Then gas escapes in much the same way as when a bottle of champagne is shaken and then opened.

"This sort of eruption can cause more deaths than a volcanic eruption," says Matthier Yalire, a Congolese geochemist at the Goma Volcano Observatory. Yalire, who develops emergency plans for the Kivu region, is very concerned about the lake.

In February, an earthquake with a magnitude of 6.0 on the Richter scale produced a small tsunami. "We found dead fish and snakes on the shore," says Yalire. He is most concerned about Mt. Nyamuragira, a volcano 32 kilometers (20 miles) away, which he says is "long overdue." All it takes is a glance out the window to recognize Yalire's dilemma when it comes to evacuation plans. "If the volcano erupts, the people will flee from the lava down to the lake," he says, "which is precisely where the dangerous gas will escape."

'Killer Lakes'

Lake Nyos in Cameroon released a similar cloud of gas in 1986. Because carbon dioxide is heavier than air, 1.7 million tons of the gas bubbled out of the water and rolled onto the shore. Within a few minutes, some 1,746 people and more than 2,000 suffocated.

These bodies of water that contain gas are called "killer lakes." There are several in Africa. But Lake Kivu is unique, because, along with carbon dioxide, it contains methane, which is explosive when combined with air. For the past 15,000 years, bacteria have converted dead organic matter and magma-related carbon dioxide into methane. The lake is now 40 percent saturated with the two gases. Recent tests suggest that the gas content has risen dramatically in the last 30 years. The causes have not been studied.

A suspected factor is population growth and the corresponding increase in the level of nutrients from agriculture, as well as the Tanganyika sardine, which was released into Lake Kivu in 1959. But it's clear that the lake's equilibrium has been destroyed. Studies warn that its capacity will be exhausted in the next 100 to 200 years. This leads scientists to conclude that the gas should be removed.

It could prove to be a blessing for the people living on Lake Kivu. Since April, engineers on a research team headed by French physicist Michel Halbwachs have been welding and screwing together a floating platform only a few hundred meters from Muhizi's beach bar. A black tube attached to the platform extends down into the waters of Kivu. The tube is supposed to act like a straw, and gas is expected to begin bubbling out of the lake soon.

The escaping gas will make a hissing noise and shoot up out of the lake, forming a small fountain. Engineers eventually hope to use the combustible gas to drive turbines, but they are under pressure to act. About a kilometer from the shore, a competing mechanism, similar to an oil-drilling platform, already protrudes from the water. Methane production began at this platform a few days ago, but it's not functioning properly yet. "Growing pains," says the Israeli engineer who operates the system on behalf of the Rwandan government. "Shut it down!" he shouts into his telephone.

Electricity production is scheduled to begin in January, when the two pilot projects will feed a total of nine megawatts into the power grid. This will be just a first step for an African country that has almost no energy resources of its own. All power plants in the country produce a total output of only 50 megawatts, derived from hydroelectric power and imported diesel. It's not even enough to keep one light bulb lit in every household in Rwanda.

African Gas and Electric

Bar manager Muhizi is all too familiar with the consequences of scarce electricity. There are power outages almost every evening, silencing the music and darkening the strings of lights in his Bikini Bar. The methane, he hopes, will soon bring more electricity and more customers.

Anyone who wants to understand what the pilot project means for Rwanda should take a drive through the capital Kigali, where computer networks and fiber-optic cables are being installed in new office buildings to convert the economy to e-business. On the sixth floor of the Union Trade Centre, which is equipped with video surveillance cameras, Ivan Twagirashema switches on the air-conditioning and opens the windows. Kigali, brightly lit at night, lies below. But the hill behind it is pitch-black. "My dream is that in 10 years all of the households over there will have electricity and that we will even be able to supply power to our neighboring countries," he says.

The 32-year-old industrial chemist is the managing director of the Rwanda Investment Group. Rwandan oligarchs have invested $6 million (€4.2 million) in the test facility constructed by French physicist Halbwachs. The project is a financial risk, as Twagirashema readily admits, but he is convinced that Rwanda has discovered a new energy source. "We can generate more than 100 megawatts (in capacity) for 400 years," he says enthusiastically.

There is no guarantee that the technology will work, he admits, but he says the country has more to lose by not trying.

Klaus Tietze, a geophysicist from the northern German city of Celle, disagrees. He has a low opinion of tapping the lake as a permanent source of energy. "Only a lake with low concentrations of gas is a good lake," he explains. For this reason, he advocates removing the gas from the water as quickly as possible -- not just the methane, but also the carbon dioxide.

The two existing pilot projects call for pumping the CO2 back into the deep water after separating out the methane, to keep the gas layers stable. But, according to Tietze's calculations, this could destroy the current layering.

Tietze's nickname is "Papa Kivu." As a young doctoral student, 34 years ago, he was the first to submerge specially developed testing instruments into the lake water. He concluded that the lake is a complex, almost unpredictable system, and that no one can foresee how it will react to disruption. "If you weaken the stable layers, the risk of an eruption increases," Tietze warns. He is afraid that Kivu will fall into the hands of "sorcerers' apprentices" who are drawing the wrong conclusions from incorrect data.

To address this concern, Tietze has established a consulting firm for "applied Kivu studies." The German Zarnack Group, as well as American, Indian, South African and two other German investors have shown interest in his services. A South Korean company is negotiating with the Congolese government.

The race to capture the Lake Kivu gas has its risks. In the end, 10 or more drilling platforms will be installed on the lake. But who will supervise them all and monitor water and gas pressure in the lake?

The bloody war between rebels and government troops in eastern Congo also poses a threat. It has deeply shaken Congo's relations with neighboring Rwanda. The government in Kinshasa accuses its much smaller neighbor of supporting the rebels and plundering Congolese minerals, like coltan and gold. Cooperation in methane production seems unlikely.

On the contrary, a Rwandan methane production tower could easily become a target of sabotage. If that happens, it is hard to imagine what powerful fountains could end up shooting out of the lake.

Residents on the Congolese shore of Lake Kivu, plagued by other worries, are relatively unaware of the dangers. In the evening, when techno music blares across the lake from Muhizi's beach bar, the city of Goma, on the Congolese side, seems like a ghost town. A curfew is in effect there after 10 p.m. The war has driven 60,000 refugees to the shore of Lake Kivu -- looking for safety on a killer lake.

Translated from the German by Christopher Sultan
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