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Louise Parlons Bentata, cofounder and CEO, Bluemethane
Louise Parlons Bentata, cofounder and CEO, Bluemethane. Image credit: Bluemethane

Bluemethane unveils novel tech to capture methane from water

June 25, 2024

When it comes to methane emissions, most people think of oil, coal, gas and livestock, says Louise Parlons Bentata, co-founder and CEO at UK-based startup Bluemethane. What they often don’t know about, she says, is water.

“Methane emissions from water are an environmental catastrophe but also a waste of valuable resources that can be turned into clean energy. Human sources of methane emissions from water such as rice cultivation, waste streams and reservoirs emit more than three billion tons of CO2e per year from methane emissions, but awareness is really low.”

Founded in 2021 by Parlons Bentata and engineer Nestor Rueda-Vallejo, Bluemethane is part of the fifth cohort of the AgFunder GROW Impact Accelerator [Disclosure: AgFunder is AgFunderNews’ parent company] and is on a mission to remove methane from a variety of water sources, starting with wastewater treatment in the UK, where utility companies have committed to achieve net-zero status by 2030.

AgFunderNews (AFN) caught up with Parlons Bentata (LPB) to discuss how methane is released from water sources, how to monetize methane reduction, and the challenges around raising capital to address a market opportunity that is not yet well understood.

AFN: Give us the origins story of Bluemethane…

LPB: I began my career at L’Oreal [as a brand manager], did an MBA, and then worked at Johnson & Johnson [as a global marketing manager]. I then ran my own strategy company for about 10 years until I started working with an engineering company [a client] that was making very highly valuable things that were ending up in landfill.

I said, ‘Can we do a project [to tackle this problem]?’ And he said ‘No, you’re not qualified.’ I said, ‘Well what do you need to be qualified?’ He said ‘I don’t know, but I can tell you that you’re not qualified to do it.’ So he brought in this lady to take on the project, and I said to her, ‘What makes you qualified?’ And she said, ‘I’ve just got back from Cambridge [University], where I’ve done a postgrad [course] in sustainable business leadership. So I said, ‘All right, I’ll sign up for that then.’

So just as COVID began [in 2020], I signed up for this nine-month course in the evenings while still managing my work [the day job] and three children, and then in 2021, I signed up for a climate technology fellowship program called On Deck, not knowing what I really wanted, but knowing I wanted to do something new.

On the first day [in March 2021], I met my cofounder Nestor, an engineer who was looking at how hydropower reservoirs emitted billion tons of greenhouse gases. By May/June, we gave up the things that paid our mortgages, having never met in person. We met for the first time in September 2021 and joined [the] Carbon13 [climate accelerator].

AFN: Why is there methane in water and when can it cause a problem?  

LPB: Methane is produced through the decomposition of organic matter [by microbes] in water in low oxygen conditions. So think of a sewer, which is an almost entirely anoxic [oxygen-free] environment. Rice cultivation also releases methane because farmers often keep rice paddies flooded, which creates anaerobic conditions that allow microbes to feed on organic matter and produce methane.

There are quite a lot of academic papers on this, but nothing compared to all the stuff written on capturing CO2; but it’s a really big problem. At least 3 billion tons of carbon dioxide equivalent are coming from just the anthropogenic water bodies like reservoirs or rice paddies, and sewage and things like that.

AFN: Why doesn’t the ocean release a bunch of methane gas?

LPB: It’s actually far less of an issue than other water sources because the water is moving [methane released in the deep ocean can be diluted and dispersed by ocean currents over vast areas, making it less likely to reach saturation and escape into the atmosphere], and more oxygen is being circulated [inhibiting the activity of anaerobic microbes that produce methane].

AFN: What determines whether the methane stays in the water or is released into the atmosphere?

LPB: It is released in three different ways. The first is bubbling. You’ll see this in shallow water where methane forms bubbles that rise and burst at the surface as the pressure from overlying water is not sufficient to keep the methane dissolved. In a reservoir with a lot of methane, for example, you’ll see bubbles near the edge, but not in the deep parts.

Then second there’s diffusion, where the molecules transfer at the surface to become gas when the concentration of methane in the water is higher than in the air.

And then there’s degassing where there’s a sudden change of pressure that causes dissolved gases to be released rapidly, so imagine a large volume of water passing through a dam wall. Suddenly there’s no weight in the water above it, it goes through and you see loads of bubbles.

AFN: How easy is it to measure methane emissions from water bodies?

LPB: Methane emissions in the air are easier to measure than methane potential in liquids. To measure methane in the air there are things like satellites and drones that are getting better and better for very large sources of emissions. But that doesn’t help us, as we’re passing liquid through our system and we need to know how much methane is in there at the beginning and at the end so we can see how much we have removed.

There’s very little technology to measure dissolved methane in complex liquids… there’s a lot of things in a sewage stream! But we have recently won a grant to develop our dissolved methane measuring system, which we offer as a paid service, it’s just very hard with the current technology

AFN: What tech is currently deployed to remove methane from water?

LPB: There are several technologies out there including heat, aeration, membrane-based technologies and vacuum towers [by lowering the pressure, the solubility of gases in water decreases, causing them to come out of solution and form bubbles that rise to the surface of the water and are removed]. But they aren’t suitable for every application as they either require large energy inputs or they can’t process water quickly enough.

Membranes are very clever because you can get almost all of the methane out [of a body of water passing through them], but it takes a lot of energy to push through the methane, plus you have to have pretty clean water or they get clogged up.

Vacuum towers are interesting where you have really high methane concentrations, so for example there’s a lake in Rwanda called Lake Kivu where they are capturing methane for energy. [Known as the ‘killer’ or ‘exploding’ lake,’ Lake Kivu contains large amounts of methane and carbon dioxide through thousands of years of volcanic activity and through high levels of organic material from rivers and the surrounding densely populated and agriculturally active regions.]

That approach wouldn’t work in the UK because there isn’t enough methane produced [from concentrated sources such as Lake Kivu] to justify this kind of investment.

AFN: How does Bluemethane’s tech work?

LPB: We’ve always felt that the way we’re going to achieve our mission is removing the most methane using the least amount of energy, which is not the same as the most methane at any cost. We use a physical separation technology without chemicals or membranes and don’t heat up the water.

Think about holding a bottle of sparkling water where you don’t really see the bubbles inside, but when you shake it and open the lid, it fizzes. By shaking it, you speed up that process of the bubbles coming out and by opening it, you suddenly change the pressure. We replicate that process using turbulence to speed up the process of separation driven by gravity, so it’s quite a simple process.

Entering our system is the water stream containing dissolved methane, and we end up with a stream of biogas that contains methane and carbon dioxide. What we do with it is strongly dependent on the customer, but our beach head market is sites where they already have anaerobic digestion facilities and they’re already using biogas.

Bluemethane prototype being tested at Cranfield University UK
Bluemethane “recovers the most methane from water using the least energy,” says the firm. “We achieve this firstly through a methane monitoring system and data platform that identifies when and where methane is present, then secondly through an energy efficient technology recovery solution. The captured biogas can be used to power the system and help support the power requirement of onsite activities.” Pictured: Bluemethane prototype at Cranfield University UK. Image credit: Bluemethane

AFN: What does the tech look like and what partners are you targeting initially?

LPB: Our tech fits inside a 20-foot container for all applications excluding large reservoirs, but for the next few years our focus is on wastewater treatment plants, industrial pretreatment, and anaerobic biomethane sites.

Our partners for municipal wastewater and sewage would be people in charge of the bioresources centers, people who are taking that sludge and creating value from it. For industrial wastewater, our partners would more likely be operating companies who are managing their wastewater equipment. And for biomethane sites, the energy companies would be our partners.

AFN: What’s the business model?

LPB: It really depends on the operating model. In the UK the water company usually wants to own the tech but for industrial wastewater we might own and operate the tech, or we could own it and the management company might maintain it.

The most important first step is that we know how much methane is there, so we begin with a methane measuring service to estimate the biomethane potential and that’s a paid service. And depending on what the cost benefit analysis looks like, we deploy or don’t deploy the technology. There are two ongoing value streams. The first one is from the biogas value itself for energy, and the second one is a clean energy credit.

Bluemethane graphic

AFN: How have you funded the company so far and how do investors see this opportunity?

LPB: We did a pre-seed round two years ago and we were oversubscribed. We have just opened our seed round and the environment is a bit different now. I think one challenge is that we’re doing something people are less familiar with. They get the technology, but it’s an unfamiliar market without clear benchmarks.

AFN: What IP do you have and how and where have you validated the technology?

LPB: We have filed patents that we hope will be granted in the next 12 months.

We have a prototype called Bluey at Cranfield University, but we’re now building our TRL6 technology called Harvey, who is going to remove our first ton of carbon dioxide equivalent at a customer site this year. We’re also planning next year, Stephanie, who is going to remove 100 tons of CO2 equivalent, and that will take us to the point of being ready to commercialize.

 AFN: Why the initial focus on the UK?

LPB: We’re starting in the UK because we’re based here and we understand the market. We were going to have a project in Rwanda, which was amazing until we realized that no customer would say it’s comparable for them, and no investor would go and visit it…

AFN: What are the biggest challenges you face?

LPB: The biggest challenge we see isn’t technology development, it’s financial innovation. In a market where there’s very little regulation for methane mitigation from any of these sources and where there’s no carbon markets for methane credits from this, the question is: why should people do it?

For example, hydropower reservoirs are exciting because while they have fairly low methane concentrations, they handle massive volumes of water. But they don’t have the infrastructure on site to upgrade it [the methane] into anything, whether it’s biogas or a feedstock for hydrogen or ammonia production or something else.

We needed to find a mechanism that would enable hydropower operators to adopt the tech without incurring the risks associated with new technology outside their business scope, so we worked with The Global Innovation Lab for Climate Finance to develop a financial instrument for hydropower reservoirs that would separate the ownership of the tech from the benefits.

The instrument—for piloting in Brazil—involves a special purpose vehicle [managed by a firm called Open Hydro] which would own both the methane capture and biogas plants [to handle the captured methane]. Bluemethane would develop the methane capture plant, a local developer would be responsible for the biogas plant, and the hydropower plant operator would provide water usage rights.

The benefit of this ‘methane capture as a service’ approach is that the technology is owned by a third party investor, even though the tech is on site at the hydropower dam.

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