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Lake Kivu, located on the border between Rwanda and the Democratic Republic of Congo, hides a deadly secret beneath its calm surface. Its waters contain huge amounts of dissolved carbon dioxide and methane, which could explode at any time, releasing a toxic cloud into the atmosphere. One way to deal with the threat is to extract the methane. However, it is unclear how this will affect the delicate balance of the waters and whether Lake Kivu will explode. Will a safer solution be found?
Geological anomaly with deadly potential
Kivu is one of only three known lakes with similar characteristics, along with the Nyos and Monoun reservoirs, which have exploded in the last 50 years, with all the resulting devastating consequences. The depths of Lake Kivu are saturated with carbon dioxide and methane – gases that can erupt spontaneously and suffocate millions of people living around its shores. The catastrophic eruption of Nyos in 1986, which claimed nearly 2,000 lives – four villages in Cameroon – serves as a grim warning of what could happen here as well. The fact that Lake Kivu is 50 times longer than it is and more than twice as deep additionally works on the imagination.
Kivu is located in Africa’s Rift Valley, home to hot springs and active volcanoes. The lake itself is characterized by a complex structure of water layers, with nearly 72 mi3 (cubic miles) of carbon dioxide and 14 mi3 of methane with toxic hydrogen sulfide at a depth of 250 meters below the surface, posing a potential threat of spontaneous gas eruption.
Moreover, the geological structure and location mean that gases are constantly reaching the lake, which, if they reach a critical point, could lead to disaster. Currently, the saturation is more than 60 percent, and when it reaches 100 percent, an explosion will occur. In addition, if there were an earthquake or volcanic eruption in the vicinity of the reservoir, the risk of an explosion would increase dramatically.
Lake Kivu – will there be an explosion? Methane extraction is to be prevented
In an innovative attempt to neutralize this ticking time bomb, the Rwandan government has allowed British company KivuWatt to extract methane from the lake and convert it into electricity. Currently, more than 10 percent. of the country’s total energy capacity of 300 MW is produced just by extracting gas from Lake Kivu.
This initiative is intended not only to reduce the risk of a potential lake eruption, but also to provide a sustainable source of energy for the country. However, the process is not without risk. Some scientists fear that methane extraction could destabilize the lake’s delicate stratification, triggering the disaster that everyone wants to prevent. Experts suggest alternative methods, pushing, for example, measures to dilute the methane in the lake, which could minimize the risk, but are more costly and complicated. They are also concerned about the possibility of increasing the scale of mining, as this too could lead to disaster.
How does the methane extraction process currently work? In the first stage, water is taken from a depth of less than 250 meters, because there it is rich in gas. At the surface, carbon dioxide and methane are separated from it to then discharge the degassed water into the upper layers of the lake. As it falls, it forms a plume, which causes vertical mixing of the layers. As experts explain, it is the vertical movement that affects the risk of limnic eruption.
The future of Lake Kivu – innovation or disaster?
The unique geological and chemical composition of Lake Kivu and its location along the unstable Great Rift Valley of Africa, with the added threat of earthquakes or volcanic activity that could disrupt its condition, means that the actions taken by KivuWatt are being watched by the whole world. The challenge is to extract the gases safely without causing a catastrophic eruption that could release gigatons of carbon dioxide into the atmosphere, affecting climate change and causing immediate, deadly danger to local people.
KivuWatt’s current efforts, while commendable for their innovative approach to the use of renewable energy, have come under criticism for increasing the potential risk of eruptions. Experts such as Sergei Katsev and Martin Schmid debate the safety and long-term use of KivuWatt’s chosen methods, stressing the importance of using the right gas extraction technique before scaling up extraction. Experts are concerned that without careful evaluation, the project could reach a point of no return, involving damage to the lake and the entire valley.
So it seems that the biggest challenge is to strike a balance between preserving security and pursuing economic development, while safeguarding the region’s future from potential disaster. The decision on how to proceed is not just a technical or economic issue – it is deeply political, with implications that reach far beyond the shores of Lake Kivu.
Photo source: Wikipedia/ Steve Evans from Citizen of the World – Congo: Lake KivuUploaded by PDTillman, CC BY 2.0
