Don’t Pop the Champagne!

In Rwanda’s version of Russian Roulette there’s no revolver; instead, it just takes a massive 1,042 square-mile lake and some 55 billion cubic meters of volcanic gas!

Photo of Lake Kivu by Jacob Freeze.

Lake Kivu is both one of Africa’s Great Lakes and one of the world’s most dangerous. Mt. Nyamylagria and Mt. Nyiragongo, the active twin volcanoes towering over Kivu, hint at the seismic commotion pumping volatile gases into the frigid waters 300 meters beneath its surface. Carbon dioxide and methane gases hide here, and their idea of peek-a-boo is lethal. And to make matters worse, these gases can be testier than a teenager in the morning. When temperatures fluctuate or this sleeping monster is otherwise disturbed, methane and carbon dioxide gases bubble upward like a deadly, 150-trillion gallon glass of champagne!

In the 1980s, when gases in two of these appropriately dubbed “exploding lakes” in Cameroon rushed to the surface, they suffocated nearly 1,800 people. But Lake Kivu is nearly 2,000 times the size of Lake Nyos, the larger of these two, and has roughly 2 million people living around it. Sounds like a great source of safe, clean energy, right?

If you’re not quite into this living-on-the-edge energy from water, we can look to more conventional hydropower. While hydroelectric power might not be as high-profile as solar and wind, it actually paved the way for these newer clean energy celebs as one of our first! And today, it still leads the way as the top source of green electricity in the United States, producing 6.5% of all US electricity in 2016.

Hydropower just boils down to plopping a turbine ahead of water that has places to be and letting it do all of the heavy lifting! In its haste to get on its way, water will shove the turbine blades and get it spinning. And a spinning turbine, just like an electric current, is the key to electricity!

Turbines in Hoover Dam. Photo by pingnews.com.

Hydropower comes in two different flavors. One is au-natural, where the current of a stream or river turns the blade of a turbine. The less organic variety involves hoarding water in reservoirs (think Hoover dam!) and releasing it when we call for more electricity. But as any of our green energy superstars, hydropower has a good side and a bad side.

For one, hydropower is simple, safe, and dependable. Not only will it churn out electricity 24/7 with no complaint, but it can also adjust based on demand. Plus, it is green and renewable, an enormous upgrade from fossil fuels. But it has environmental impacts that we must not overlook. By altering the flow of a waterway, we also muddle up aquatic habitats, adversely affecting fish and other aquatic species. Dams and turbines also confuse vital fish migrations. Even simply constructing these dams, turbines, and plants together with the accessories to go along with them such as powerlines and roads, disrupts nature and causes pollution.

And although water may seem unlimited, thanks to our handy dandy water cycle, hydropower friendly locations are not! Since it depends on water with road rage, hydropower is picky about where it thrives, being partial to speedy, high traffic sections of large, quick-moving rivers or towering cascades where water crashes down hundreds of feet. Consequently, there are only so many spots for hydropower to take root, and we already have begun to run out! In other words, there is a limited capacity for growth of this renewable energy.

 

Photo by Katie Taylor.

But when it came to Lake Kivu, Rwandan engineers chose to look a bit deeper for energy. Recall those volatile volcanic gases lurking in the depths of Kivu? Well, this is precisely what these engineers went for.

Today a barge floats atop Lake Kivu, drawing water and gases upward, pulling out methane, and then pumping the unused carbon dioxide and water back down. And this methane, the primary component of natural gas, is used to fuel generators on Kivu’s shore.

As of 2010, this plant generated 4% of Rwanda’s power, and schemes were implemented to raise this value to 33% by 2012. Plus, several private firms, both domestic and international, have begun investigating exploiting these gases in the lake. Even a US company, ContourGlobal, has extraction projects on Kivu.

But not only is this methane extraction a “cheap, clean resource that could last [Rwanda] 100 years” according to the Rwandan engineer who leads the plant, but it also helps ease the risk of Kivu “exploding” (or perhaps more accurately “fizzing”) by removing some of the gas that poses this danger. 

But simultaneously, this plant pumps unused carbon dioxide back into Kivu’s depths. And by simply pumping the water up and down, these extractions run the risk of agitating these gas caches and triggering an “explosion.” Seems a bit like playing with fire, no?

Sure, exploding lake energy might not play it safe, but it shows us that maybe we ought to be looking beneath the surface and for quirky, clean energy in the depths of our rivers and lakes! Even though the exploding nature is distinct to Kivu and the Cameroon lakes (thank goodness), who knows: maybe there’s a clean energy gold mine where we least expect it!