Bar graph of the relative net carbon usage per kWh of power output energy storage

Carbon-negative renewable gas is a Climate Changer

Is Africa’s Lake Kivu also a huge complex energy storage device?

Adjacent to this lake, Lake Victoria is like a gigantic hydro-power battery. But Kivu’s not just a hydro battery, it contains the world’s biggest bio-digester. It’s doing a double storage job with water and renewable gas. The combination enables 40 megatons of carbon emission reductions every year, while Kivu can also generate 1.2 GW of power on demand.

So how does hydro with carbon negative renewable natural gas (RNG) become a real big climate changer? Has nature provided the potential to get the countries around the lake to beyond carbon neutral? Is it in the “really-good-for-the-planet” category of climate solutions? How can it also help this gorilla’s habitat survive and thrive?

We illustrate this as a leading example of how “Carbon negative” projects can be the super-achievers in the great climate challenge of our times.

The renewable natural gas contribution

Even methane from cattle can become part of the solution. Let’s break this argument down further. RNG is known for providing carbon-neutral energy. Take biogas from agricultural waste, where the USA is targeting 40 megatons of carbon reduction by 2030. This one project on Lake Kivu in Rwanda and DRC achieves the USA’s RNG target by itself.

So how does gas recovery prevent gigatons of natural background carbon emissions? What if we can add a side benefit of reversing destruction of vast equatorial forests to keep that carbon sink viable? In reality these benefits are a step-up, adding to being carbon negative. So “RNG Neg” can be a vital, although commonly overlooked climate change solution. The solution has huge scale-ability by reducing similar methane emissions.

Let’s look at this specific methane source, created by nature without human intervention. Importantly, this a case is where one can both extract natural gas and reverse carbon emissions. As the add-on in this special case, it can replace forest biomass as the region’s primary domestic fuel within 10 – 15 years. This change in fuel takes deforestation pressure off the mountain gorilla habitat in the Virunga Mountains in Africa. So RNG is an opportunity helping to buy time for the gorilla habitat and recreating a vast carbon sink.

More than that, the graphic below shows how we get to the hoped-for impact of buying time in the Climate Change context. Compare it to other methods listed for negative carbon emissions. Most lack much capacity or even credence. Well, this unusual one wasn’t on the list. It should be in time, not just as a one-off.

How carbon-negative is this renewable solution?

Climate activists commonly advocate that natural gas is not “low-carbon” enough and not part of the climate solution. Natural gas suppliers field demands to remove any claim of having real “low-carbon” investments. The louder calls are to advocate the use of hydrogen, or PV or wind. But while hydrogen is in many ways an ideal fuel, it comes with user difficulties, dangers of explosion and higher supply and distribution cost. It’s costly to transport, has low energy density and is near impossible to move by pipeline.

We should differentiate clean methane sources from conventional natural gas though. Some of them, like ours, can even be strongly negative on carbon emissions. That’s a long way better for the planet than neutral.

Purpose for Kivu gas extraction is evolving

The original Hydragas solution was needs-driven. It was created to deal with a threat at unprecedented humanitarian and environmental levels. Without acting on this threat in our lifetimes, millions of lives were at risk. It comes also with a one-time, catastrophic environmental hit. We can avert a one-day, 2-6 gigaton carbon emission by preventing lake Kivu erupting. In a relative sense, the climate impact is a bonus on top of all the lives saved, but still meaningful on a global scale.

Now sometimes we may think we have a great invention to talk about. But more importantly to market it, should we frame it in terms that resonate ? Ours has been a 20-year pioneering pursuit. So it isn’t just any cleantech project using available innovative technology. We now know it to be carbon negative. So it stands out as a high-impact climate changer with added carbon credits value.

It took decades to figure out how to do this project safely and effectively. We filled a need where effective recovery technology did not exist. It overtook an older extraction idea that never had such impact. We turned it around with an inventive breakthrough. Our motivation was at first about solving a gas extraction problem. Then it became about saving lives. Then it grew to be about turning around carbon emissions. The line must now be: “It saves millions of lives, averting gigatons of carbon emissions, making a country or two carbon-negative”. How is that going to sell the concept to investors?

Labeling is key; Can we call it a grid-scale battery?

So should we re-frame it further? We can make it focused on the climate change problem of the day – energy storage. Should we now claim how; “We see Lake Kivu as a giant battery with 263 TWh of renewable energy storage.” We can add that; “This battery trickle-charges itself at 2,600 GWh per year.” What is the key data to place with that label? Renewable gas can produce 600 MW of clean power for next fifty years.

Like a good battery we can stretch it out longer though. After the need to drop the danger level of gas build-up, for say 25 years, we can then produce over 200 MW of renewable, clean power for centuries.

Add a 576 MW hydro-power investment to the same lake

But there’s more to add to this battery. This same lake has been producing hydro power, from an old run-of-river station at its outlet, for over 50 years. The Ruzizi river cascade drops another 700 metres to Lake Tanganyika just 50km south of the lake’s outlet. A series of dam-free hydropower projects on this cascade can also deliver 576 MW. So the two projects in combination can yield 1200 MW for the next 25-50 years. The longer view is perhaps for over 800 MW in perpetuity. That’s one big, long-life battery!

An equatorial lake and a volcano,  a recipe for an energy opportunity or a nightmare
An equatorial lake and a volcano, a recipe for an energy opportunity or a nightmare?

So “whose definition is this definition?”

As we hear in the climate debate, any “natural gas” is placed in a basket of contentious climate value. It is grouped and assumed to be formed with its fossil relatives coal and oil. Let’s flex a defining piece of that narrative. In talking of semantics and messaging, what of biogenic gas? Does Mesozoic-age fossil-formed gas rank the same as “fresh” biogas from cow manure in bio-digesters? They are both GHGs. Its formation followed similar pathways, millions of years apart. I studied this comparison with some global experts. Today our conclusion must be that RNG categorises itself best as carbon negative renewable gas.

For this lake, we can specify and design systems to avoid any leaks in production and most delivery systems. This is where conventional natural gas has a poor record with leaks and emissions. The conventional gas supply chain has historically been a major source of fugitive emissions.

The carbon dioxide and methane in Lake Kivu in Africa is biogenic. It’s freshly brewed. Algae consumes dissolved carbon dioxide to grow biomass. Biomass biodegrades in anoxic depths to make methane and carbon dioxide. It uses the acetate process and also methanogens. The world’s largest bio-digester is part of a cycle making carbon-negative, renewable gas. Can we continue down this defining path and call it a bio-battery, powered by carbon-negative renewable gas?

CCUS: Is it a bio-battery or bio-digester?

Most of the gas in Lake Kivu now in situ is less than a hundred years old. A resource of tow gigatons of CO2e is already present. The bio-digester accumulates more new gas at another 0.5% a year. I verified this storage calculation by doing the formal calculation, as defined, while writing up a proposal for Breakthrough Energy Ventures competition. It is one of a number of initiatives where I was looking for funding for the Lake Kivu project.

The essential action on us now, with a GHG reserve building up, is to first harvest it to make it safe. The second it is to combust that methane in power generation or in home cooking. A third action can be to re-absorb the carbon dioxide made, into the deep lake. Here it is substrate for microbiology that can turn back to methane. A virtuous green cycle is thus possible. Again, it sounds like it works as a battery. Like any battery, its design and operation have room for enhancement. We could speed it up, but with due caution.

So we can treat it like a giant battery. We keep it in reserve and deplete it when we choose to and we are able to. We are now capable to do it safely, finally. Now is the time we must do it urgently to constrain climate change.

Defining CCUS

Must we prove to skeptics that it’s renewable and it has negative emissions? I met recently with Foresight, a group that champions clean energy solutions. I had this question: “If the gas is naturally biogenic, but not extracted continuously, is it still renewable?” The answer is yes, becasue it can be stored. But that answer would not be so if it leaks out to atmosphere. But it’s fully trapped. This is a huge, natural CCUS reservoir that can store 450 bcm of gas (at the safe-side limit). It is the definition of Carbon Capture, Usage and Storage (CCUS).

What is the risk if we don’t harvest this gas?

Actually, we must first deplete this reservoir (or battery) by 50% now for safety reasons. That is why we must extract methane for the next 25 years to use up half the partial pressure (or volume) of gas in place. Thereafter we can discharge it indefinitely at a lower rate, closer to its natural recharge rate. That would be sensible. But our first order of business lowers the risk of eruption by a factor of two. It makes the lake 100 times safer. We do this by depleting gas from the upper portions of the layered lake’s depths. These portions give rise to the most risk as they have the highest partial pressure.

With some caution we can research further into “farming” gas generation. We understand the micro-biology and bio-chemical engineering pathways of using the returned CO2 to generate new methane faster. Key to these actions will be in managing the nutrients flowing to the shallow biozone to enhance algae growth. This is done by water lifted from the nutrient-rich depths. That is the key to multiplying the energy potential in the long-term.

Safety Action: Preventing a catastrophic lake eruption

This is a very high-stakes resource management game. Those gigatons of gas, if left until they saturate the lake’s capacity, will erupt. The world’s limnology experts describe the mechanism as a limnic eruption. It’s much quieter, almost silent, but could be 50 times more deadly than Krakatoa’s explosion in 1883. Many casualties may result from lake tsunamis caused by a giant, surging column of gas and water. But it’s the toxic and asphyxiating blanket of cloud emanating from that eruption that is much more deadly.

So, gas extraction is our pre-emptive action to mitigate the chance of a catastrophe. It has to be done properly though. Some amateurish and ill-considered methods were used and more were planned. These are worse than doing nothing. They break all the safety rules and bring danger forward.

The safety plan is still built on a concept of removing the bulk of the lake’s methane in 50 years. After the first harvest, we would have then paused for perhaps 100 – 150 years to allow gas to regenerate. As the methane gas inventory would reach a viable concentration again, we can begin to extract once more. That’s still in the harvesting plan. The concept is written up in the rules for how Lake Kivu must be developed. But a review commencing in 2019 may revisit some of these options.

What’s in the envelope we evaluate?

The gases are produced biogenically in the world’s largest, contained bio-digester. Lake Kivu became one of the largest, manageable carbon sinks over millennia. I wrote it up in a breakthrough ventures application. I worked out the data in a painfully complex spreadsheet. It is a government-designed calculator to determine the carbon SSRs. There were guidelines. i.e. Use ISO 14064-2 Section 5.3 “Identifying GHG sources, sinks and reservoirs relevant to the project”. It was highly explicit about every value to be used.

I had already worked out the answer in 20 minutes by normal means. It took 150 hours using this standardized government-style spreadsheet. The answers were 1.01% different. The specified calculator gave the modestly higher answer. This is miniscule compared to the arguable range of tons CO2 per ton of CH4; the currently published range is between 25 and 103. There is a long explanation about which number applies when, based on when the reduction is most needed. For simplicity the calculator used 28. Using this range the averted carbon emissions varies from 1.9 to 6.3 gigatons. The high end of this range is very close to the total annual US emissions in 2014, published by the EPA, of 6.89 gigatons.

Why make it so complicated? Was it to ensure one didn’t cheat? In essence it defines the full envelope. It assesses GHGs and SSRs with a cumbersome methodology. One even includes the GHG impact of building and then demolishing the equipment. One must account for displaced energy when switching to a new source. It presents the data in a spreadsheet common for all applicants. But getting it done is way worse than doing your taxes. The outcome still shows this renewable gas is carbon negative.

Proving renewable gas is carbon negative

The adjacent figure (click on it to expand) shows L-R the improving trend of power generation from coal to natural gas. Hausfather presented the data to show the US power industry gains from replacing coal with natural gas. I added the final bar to show how the proposed Lake Kivu project outperforms. The linked article questions if natural gas is a bridge fuel to renewables. I would argue that RNG is itself a game changer that goes much further than carbon neutrality. But how can these special cases be replicated on a global scale? There are opportunities for scale-up of averting major emissions in my next post.

I added the final bar to show how the proposed Lake Kivu project outperforms. The linked article questions if natural gas is a bridge fuel to renewables. I would argue that RNG is itself a game changer that goes much further than carbon neutrality. It transforms from being a clean gas source to the most powerful, renewable battery out there.

But how can these special cases be replicated on a global scale? There are opportunities for scale-up of averting major emissions in my next post. That means going after the biggest resource of all, methane in the oceans.

But let’s not forget the gorillas. Before even considering deforestation, Africa’s equatorial forests are under threat and so is the gorilla’s mountain domain. Apart from land pressures, the region uses firewood and charcoal for 80% of its non-transport energy needs. Any action that reduces deforestation is also about protecting their shrinking domain. RNG will help, so let’s make carbon negative renewable gas.

What message sells to investors?

This project needs investment. This type and scale of project is desperately needed. People need to be assured of safety where they live. The gorillas need their forest back. So now we need to pitch the investment, but also the story to investors. The question is how? It’s a great impact investment with high returns. But they’re a skeptical lot, as they must be. Any claim we can make to amp up a valuation has to be discounted or countered by them when negotiating an investment deal.

This much carbon mitigation (whether 40 or up to 130 megatons per year) can be worth a lot. So, inevitably as founders, we should get quizzed on this point. And so it has been. We like to appeal to the investors’ better selves too, with the humanitarian and environmental impacts. The Lake Kivu project has huge impact. The priorities are first to people safety, then to the environment and finally to the community’s bottom lines.

How to sell “carbon negative renewable gas”?

As an aside, I would be interested in the stats on this. How many pledges are made to fund renewables? As many as are calling on others to do the funding? How many are calling for funding negative carbon projects? I have seen hundreds. Is it a cheap way to get position on the bandwagon? What ever came of Canada’s Prime Minister’s 2015 pledge at COP-21 in Paris to fund $2.6 B of clean energy projects in the developing world? How much more is being promised at COP-25 in Madrid?

On the other hand, how many of the valid start-ups with projects eventually do get funded? Worse still, how many are not? Who, among many innovators and developers, crosses the proverbial “valley of death” illustrated here by FCA? Where do these developers, looking and pitching for these funds, get the money? Their enthusiasm is more evident than that of corresponding investment funds. For that answer, it’s probably from intermediaries.

I should rather be an intermediary

This clean energy funding marketplace has seen a proliferation of financing intermediaries. They are aggregators of new project prospects, those that can’t afford to attend all the conferences. They’re not there to raise funds as start-ups, but to raise bigger tranches of funds to fund them. They step in, providing aggregating vehicles that can spend hard-to-pitch-for funds. They are able charge fees for their disbursement of other people’s money to projects. In doing so they are earning a 5% slice of the investment without carrying all the downsides of failed investments. It’s a sweet gig.

Perhaps the tactic for start-ups and developers lies in how to frame our projects for both primary or intermediary investors. What do they want to invest in? We need to connect with them in any way that works. So let’s present the options. Let’s label it a giant energy storage system or series of clean projects with gigatons of carbon-negative emissions reduction.We’ll colour it any way the market wishes, as long as we get to fund it. Some ways just cost more than others, but that’s still way better than zero investment.