A Seabreaking Innovation

Sea Tech’s Lake Kivu Methane extraction project
a seabreaking innovation
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There’s nothing ordinary about Lake Kivu.

On the border of Rwanda and the Democratic Republic of Congo, Lake Kivu one of only three lakes in the world containing naturally occurring methane gas. And with a maximum depth of nearly 1,600 feet and a total surface area of 1,040 square miles, there’s lots of it.

This naturally dissolved gas has accumulated because the lake sits in the northern shadow of two of the world’s most active volcanoes in the world, Mount Nyiragongo and Mount Nyamuragira. Carbon dioxide leaches into the lake from the volcanic rock under the lakebed. The CO2 then converts to methane after reacting with naturally occurring chemical makeup of the lake waters.

So much dissolved gas trapped deep in the lake is subject to release via limnic eruptions – a very rare but very deadly and sudden release of gas. One such eruption happened in 1986 when Lake Nyos in Cameroon unleashed a blast of CO2 that killed more than 1,700 people and 3,500 livestock.

The risk of limnic eruptions like this is mitigated by extracting methane from the lake, which of course can be used to produce electricity for Rwandan residents.

The extraction itself happens deep in the lake where the highest concentrations of methane is located. As lake water is pumped up a long pipe to the surface and pressure reduces, gases separate. Once high levels of CO2 still present in the gas are purified to methane, it’s moved to power generators via a pipeline.

There are currently two methane gas extraction projects underway on the Rwanda side of the lake. One of those is the Kivu56 project led by Shema Power Lake Kivu Limited (SPLK, formally Symbion Energy).

Sea Tech Marine Construction, headquartered in Israel, is handling diving operations for Kivu 56. Underwater caught up with Sea Tech CEO Robbie Hartog in early July to discuss some of the unique challenges associated with working such a unique body of water.

Underwater: What sort of complications have been unique to working in landlocked Rwanda?

Hartog: Well, because Rwanda is a landlocked country, diving operations are virtually nonexistent. Except for the extraction of methane from the lake, there is no diving. These methane extraction processes are the first time that diving operations are actually taking place in the country. And as an international company, we’ve had to bring everything in from elsewhere – equipment, supplies, personnel with various expertise, all of it. And there are no facilities that you find in other, more developed countries that are readily available to meet your needs. So, I would say a far greater level of planning and logistics have been involved here.

Underwater: Can you elaborate on challenges associated with planning and execution?

Hartog: It’s a very challenging project in the sense that this is something that has never been done before, and there are lots of on-thego changes that have to be made. We can’t just say, ‘This is how things are designed to work, so let’s just go and do it.’ This project doesn’t work that way because there are so many unforeseen factors at play. So, it’s a matter of us offering our expertise on the marine work and giving suggestions and solutions to the client as to what can and cannot be done.

Underwater: Are there any specific safety measures you’ve had to put in place?

Hartog: The hospitals here are very basic, and there’s no decompression chamber obviously. It was difficult to get proper insurance working in an area like this. The challenge was originally around figuring out how to keep everyone safe and satisfy the regulation that you have to be within 10 minutes of a decompression chamber if something happens. And that’s not an option here, so we have the decompression chamber on one of the work boats. To maintain a high standard of work and a high standard of safety is definitely a challenge, but it’s happening. So far, so good.

Underwater: Lake Kivu is a very unusual body of water. What kinds of issues has the lake itself presented?

Hartog: The toxicity from the gases in the lake eat away at the ropes and mooring systems and affect their performance in other ways. This is something that we didn’t originally consider. For example, the ropes might not behave as you would expect them to in the water. At one point, we realized that we were unable to put a certain piece of equipment in place because the rope was not holding the way it was anticipated to because of different elongation properties.

Underwater: How long has Sea Tech been there and how many people do you have actively working on this project?

Hartog: We started in 2020, but COVID-19 caused many delays in transport and obviously created many other challenges that delayed the project. So, we’ve basically been there for a year and a half. We have a permanent managerial team of about 15 people, and as far as divers are concerned, the number varies depending on the load, but we have around 15 to 20 active divers and other personnel working with diving operations.

Underwater: What’s the current status of the project?

Hartog: Production is going well. Kivu56 will eventually be four platforms that will extract gas sufficient for generating 56 megawatts of power, hence the name, Kivu 56. We expect to be there for maybe another year, but it’s difficult to say for sure. There is a lot of gas in that lake, and projects are eventually expected to move forward not only in Rwanda but also in neighboring Congo. We obviously want to see this project be a success because of all the challenges that we’ve overcome to enable this power station to get electricity to the people in this area – and of course to continue to do all of this with no safety issues and no incidents.

Underwater: Thanks so much for your time, Robbie. Just to wrap up, what has been your overall impression of Rwanda? I’m told it’s a beautiful country.

Hartog: Contrary to what a lot of people’s first impressions might be, it’s very nice here. It’s a very peaceful, pleasant place and quite beautiful. We hope to stay on and do more work in the future here on Lake Kivu. We’re also looking to Africa in general for other opportunities and locations in other countries. I feel that we’ve established ourselves very well here, and I think we have a great relationship with the local community. We’re here to stay if possible because there will definitely be more development on Lake Kivu.