Is Lake Kivu in Africa nature’s biggest multi-form battery?
Adjacent to it, Lake Victoria is like a gigantic hydro-power battery. Kivu’s not just a hydro energy battery, it might just be the world’s biggest bio-digester. It’s doing the same job with generating and storing renewable gas. It will contribute 40 megatons of carbon emission reductions every year when fully built and 1.2 GW of power on demand. So is hydro with carbon negative renewable natural gas (RNG) a real big climate changer? Does nature have some of the potential to get us beyond carbon neutral? Does this make it to the “really-good-for-the-planet” category of climate solutions? How can it also help this gorilla’s habitat survive?
“Carbon negative” projects can be the super-achievers in the great climate challenge of our times. And even hydrocarbons from cattle can be 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 Mt of carbon reduction by 2030. This one project on Lake Kivu in Rwanda and DRC achieves that target by itself. So how does it prevent gigatons of natural carbon emissions? What if a side benefit is reversing destruction of equatorial forests? In reality its benefits are a step-up, way above being carbon negative. So “RNG Neg” can be a vital, although commonly overlooked solution, with huge scale-ability.
Let’s look at this specific methane source created by nature without human intervention. Importantly, this a case is where one can both extract gas and reverse carbon emissions. As the add-on in this special case it can replace biomass as the region’s primary domestic fuel., This change 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. 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 your renewable gas 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, explosion dangers and higher cost. It’s costly to transport, has low energy density and is near impossible to shift by pipeline. We should differentiate clean methane sources from conventional natural gas though. Some can even be strongly negative on carbon emissions. That’s a long way better for the planet than neutral.
This 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 are at risk. It comes as a one-time, catastrophic environmental hit. We can avert a 2-6 gigaton Carbon emission by preventing lake Kivu erupting. In a relative sense, the climate impact is a bonus, but still meaningful on a global scale.
Now sometimes we think we have a great invention. But to market it, should we-frame it in terms that resonate in our time? This has been a 20-year endurance pursuit; it isn’t just any cleantech project using innovative technology. We know it is carbon negative; it makes renewable natural gas and clean power. It also stands out as an impactful climate changer.
To label its invention; is it a giant bio-battery?
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 idea, that never had such impact, and turned it around with an inventive breakthrough. It was at first about solving a gas extraction problem. Then it became about saving lives. Then it grew to be about carbon emissions. The line was: “It saves millions of lives, averting gigatons of carbon emissions”. Was that going to sell the concept to investors?
So why not re-frame it? Look at it again as an outlier idea. Should we now claim that; “We recognise this lake as a giant battery with 263 TWh of renewable energy storage?” The battery trickle-charges itself at 2,600 GWh per year.” Is that the right label? Renewable gas can produce 600 MW of clean power for next fifty years. We can stretch it out longer though. There is a short-term need to drop the danger level of gas build-up in say 25 years. We can then produce 200 MW of renewable, clean power forever after.
But there’s more. 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 700 metres to Lake Tanganyika just 50km south of the lake’s outlet. Well-studied hydropower projects on this cascade can also deliver 576 MW. So the two in combination can yield 1200 MW for the next 50 years and perhaps over 800 MW in perpetuity. That’s one big, long-life battery!
So “whose definition is this definition?”
But as we often hear in the climate debate, “natural gas” sits in a basket of contentious climate value. It is grouped and was co-deposited with its close relatives coal and oil. Let’s flex a piece of that narrative. In talking of semantics and messaging, what of biogenic gas? Does Mesozoic-age gas rank the same as “fresh” biogas from cow manure in bio-digesters? They are both GHGs. Their formation followed similar pathways, millions of years apart. I studied this comparison with some global experts. Today our conclusion must be that RNG is best defined as carbon negative renewable gas. For this lake, we can specify and design to avoid losses in production and delivery. This was where conventional natural gas has a poor record with leaks. The whole supply chain is a major source of fugitive emissions.
The carbon dioxide and methane in Lake Kivu in Africa is biogenic, 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 methanogens. The world’s largest bio-digester is making carbon-negative, renewable gas. Can we continue down this path and call it a bio-battery, powered by carbon-negative renewable gas?
Carbon capture & storage, bio-battery or bio-digester
Most of the gas now in situ is less than a hundred years old. Two gigatons of CO2e is already present and in the bio-digester it accumulates at almost 0.5% a year. I verified this storage calculation in writing up a proposal for Breakthrough Energy Ventures. I was looking for funding for the Lake Kivu project. The essential action, as this GHG reserve builds, is first harvesting it to make it safe. Then secondly it is to oxidize the methane in power generation. A third part can be to redissolve the carbon dioxide in the lake where it can turn it back to methane. A virtuous green cycle is possible. Again, it sounds like a battery.
Must I prove to skeptics it’s RNG and it has negative emissions? I had this question two weeks ago: “If the gas is naturally biogenic, but not extracted continuously, is it still renewable?” The answer must be yes. There is a huge CCS reservoir that can hold 50 years of gas usage at the safe-side limit, like a giant battery. So do we keep it in reserve or deplete it?
What is the risk if we don’t harvest the gas?
Actually, we must deplete the reservoir (battery) now for safety reasons. That is why we will extract the gas for the next 50 years. Or perhaps we should discharge it indefinitely at the lower rate, closer to its natural recharge rate. That can be sensible, but first order of business is the lower the risk of eruption by a factor of say two. That’s 100 times safer by depleting the layered lake’s depths that give rise to the most risk.
With some caution we can look further into the micro-biology and bio-chemical engineering pathways of using the returned CO2 to generate new methane faster. Key to these will be in managing the nutrients flowing to the shallow biozone with water lifted from the nutrient-rich depths. That is the key to multiplying the energy potential in the long-term.
This is all a high-stakes resource management game. Those gigatons of gas, if left until they saturate the lake’s capacity, will erupt. The world’s experts describe the mechanism of a limnic eruption. It’s much quieter, almost silent, but perhaps 50 times more deadly than Krakatoa’s explosion in 1883. While some casualties may result from tsunamis, it’s the toxic and asphyxiating blanket of cloud from the eruption that is instantly deadly.
So, gas extraction is our pre-emptive action to mitigate the chance of a catastrophe. It has to be done properly though. Some methods used and planned are worse than doing nothing. They break all the rules. After the first harvest, we must then pause for perhaps 100 – 150 years to allow gas to regenerate. As the gas reaches a viable concentration again, we begin to extract once more. That’s in the plan. The concept is written up in the rules for how Lake Kivu must be developed.
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 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 98. 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.
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. It presents the data in a spreadsheet common for all applicants. But getting it done is still way worse than doing your taxes. This was despite showing this renewable gas is carbon negative.
Proving renewable gas is carbon negative
The adjacent figure (click on it) shows L-R the improving trend of power generation from coal to natural gas. Hausfather presents the data to show the US power industry gains. 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.
What to tell 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 I 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 I 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 130 megatons per year) can be worth a lot. So, inevitably as founder, I should get quizzed on this point. And so it has been. I like to appeal to their 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 their bottom lines.
Again, how to frame it?
As an aside, I would like to know the stats on something. How many speeches and pledges are made to directly fund renewables? Probably fewer than those calling on others to do the funding. How many are now calling for funding negative carbon? I have listened to hundreds, probably read hundreds more. Is it an easy way to get a headline? What ever came of Prime Minister Trudeau’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 impactful projects eventually do get funded? Who among many innovators and developers makes their way easily across the proverbial “valley of death” illustrated here by FCA? Where developers are looking and pitching for these funds, the enthusiasm to push for action is more evident than commitment and action.
Perhaps the answer lies in how to frame the project for investors. Do they want to invest in the world’s largest renewable, self-charging, natural, 260 TWh battery. All we need to do is connect it up in a way that works. On the other hand we have a wonderful series of clean RNG projects with 2-6 gigatons of carbon-negative emissions reduction.