Agora Energy Technologies just won the 2021 Keeling Curve Prize for Capture & Utilization, sharing it with another firm this year. Earlier this year, it won first prize in the Hello Tomorrow global deeptech competition against 5,000 entrants from 128 countries. Agora’s technology is revolutionary, and the awards are well deserved. They picked up the Asian Alibaba Entrepreneur Fund Award in 2020, and the CEO, Christina Gyenge, PhD, is one of three 2021 Fellows in the Cartier Women’s Initiative science and technology global competition as well. As a result, they’ve been talking to global technology firms, and Canadian trade ambassadors for France and Hong Kong among others.

So, what is their award-winning technology, and what’s so great about it? For those interested in the deep electrochemistry, I recommend reading their peer-reviewed paper on their approach, The carbon dioxide redox flow battery: Bifunctional CO2 reduction/formate oxidation electrocatalysis on binary and ternary catalysts published May 31st, 2021 in the Journal of Power Sources (Impact factor: a very respectable 8.87 in 2021), but otherwise, here’s the low down.

Agora’s technology is a redox flow battery. That tech has been around for a while. NASA was working on them in the 1970s. The first one was stood up at the University of New South Wales, Australia in 1984, using the metal vanadium as a core component of its electrolyte. Commercial variants started appearing in the past decade, all using metals as the basis of their electrolytes. Bill Gates has invested in an iron-based one via Breakthrough, and it’s one of the few of his investments in climate solutions I consider to be a decent choice.

Where do redox flow batteries fit? I have an opinion, having gone deep on energy storage over the past few years, including a series on closed-loop, pumped storage hydro and looking at lithium-ion battery futures with a PhD student of Stanford’s Mark Z. Jacobson, as well as talking with Professor Jacobson directly about storage. In my opinion, lithium-ion in its various incarnations will deal with a lot of 4-8 hour demand management and ancillary grid balancing requirements, including some duck-curve issues. Redox flow batteries will compete a bit for same day storage, depending on the technology, and extend out for 1-3 days or even longer up to several weeks. Closed-loop, pumped hydro storage will mostly take over after 2-3 days and extend out to 2-3 week storage. A lot less storage is required than many people assert, but still a great deal of storage is required, and the solutions will overlap. In other words, redox flow batteries will be a big part of a big market.

Lithium-ion batteries are limited to short-term storage because their energy and power attributes scale in lockstep. The more MWh a lithium-ion battery can store, by definition the more MW it supplies. There are some hacks you can do with that, but effectively you get to a point where you don’t need that many MW at a time, so lithium-ion is unwieldy in the system. Great for demand management with the likely 20 TWh of lithium ion batteries in electric vehicles in the US alone by 2050 by my estimation, but that won’t help much for next day or next week storage.

Redox flow batteries dodge this. They use big tanks of chemicals separate from the bits that transform one type of chemical into another, storing the energy, or transforming it back or into something else, releasing the energy. That separates the power and energy attributes of the battery. You can scale up the MWh storage of the battery as much as you want, while maintaining the same MW of electricity capacity. They share that benefit with closed-loop, pumped storage hydro, but without the necessity to put 30-foot diameter tunnels through miles of rock.

Think of it like a car engine and a gas tank. The gas tank is the energy store, and determines how long you can drive for. The engine provides the horsepower, which says how much work you can do. Energy is MWh. Horsepower is MW. Lithium-ion batteries put both in a single package, and to get more energy, you have to add lots of both energy and power, meaning you end up with too much power a lot of the time. But redox flow batteries separate the gas tank and the engine, just like in car. That means you can get as much energy as you need, with only as much power as you need. And because they are stationary, you can make the gas tank as big as you want.

Not All Redox Flow Batteries Are Created Equal

Most of the technologies were patented decades ago. Except for Agora’s, they all use metals, often toxic ones, and usually expensive ones. They have weaknesses in terms of energy density or durability. The metals used for electrolytes and the semi-precious metals used for catalysts make them capital intensive. Many of the technologies have unsolved challenges. They are batteries, and that’s all they are. Many are good, but aren’t amazing. And they are comparatively expensive.

Then there’s Agora’s solution. First, the team.

The co-founders are Christina Gyenge and Elod Gyenge, both PhDs. Christina is CEO and in addition to her chemical engineering PhD has done post-doctoral work at Stanford and multi-disciplinary work across biology and biological systems chemical and energy engineering. Elod is the President of the company and CSO as well as a professor of chemical engineering at UBC. He is a leader in electrochemical engineering research and has been recognized with numerous international awards and honors. Elod has extensive industrial experience and has collaborated with Ballard and Fortune 500 companies on chemical engineering around fuel cells and related technologies. The Director of R&D at Agora is Dr. Pooya Hosseini-Benhangi. Pooya obtained his PhD at UBC in Elod’s group and has also spent time applying electrochemistry to gold mineral processing as a post-doctoral fellow. The core redox flow battery innovations are protected by patents in various stages of finalization in 52 countries, with the Israeli patent just awarded. Several electrochemical and chemical engineers round out the mix.

Christina and Elod started working in this space in 2012. They have three primary innovations that are unique as far as I am aware. 

The first is that they are using gaseous CO2 in the charging phase in a hybrid gas-liquid redox flow battery. Reversing it in the closed-loop model produces CO2 again, unpacking the energy. A major advantage of this is that CO2 and the other chemicals are cheap, non-toxic and common, unlike the metal-based electrolytes of vanadium and other metal-based redox batteries. As with many fields, paradigms are hard to dig out of, and batteries being metal-based is one of those tough paradigms. The closed-loop battery model doesn’t consume the CO2, but CO2 is very cheap by the ton, $30-$100, making the economics of this approach better than metal-based batteries, where the metals often cost thousands or tens of thousands of dollars per ton. Their work on CO2 gas diffusion exchange is cutting edge, well ahead of most others, and a massive technical differentiator as well as a strong value add.

The second deep insight is their catalyst. It’s a core part of their intellectual capital that they are protecting for a simple reason. The catalyst is a cheap and common substance, overcoming a different challenge for many other flow batteries and fuel cells, which typically use semi-precious metals such as platinum, which typically range from $30 – $60 per gram. While little of the precious metals is used per cell, when you start multiplying by thousands of cells, it starts to add up quickly.

But the biggest one in my opinion is the open-loop model. A closed-loop model transforms the CO2 from one chemistry to another, and then back. In the open-loop model when the energy is extracted, the CO2-based chemicals are transformed to carbonates or bicarbonates.

Why is that important? Well, there are a few reasons. The first is that carbonates and bicarbonates are big business. My assessment sees a $44 billion annual market for the chemicals that Agora’s tech can produce from waste CO2 and clean electricity. The second is that this displaces the Solvay process. I’ve looked at that industrial process, just as I’ve looked at cement production, and Agora’s approach is so much cleaner it’s painful. The Solvay process produces a net 2.74 tons of CO2 per tons of bicarbonates produced in the 1870s chemical process involving ammonia, heating with natural gas, and cooling in different steps. Every box of baking soda you’ve ever bought comes with an invisible 3 boxes of CO2 by mass, in other words. More on this in the next article.

In Agora’s process, lower-cost renewably generated electricity flows in at night or other times of day when it happens to be cheap, the process runs at room temperature, and no ammonia is involved. You could put Agora’s tech in a light-industrial building downtown and no one would notice. The third is that it consumes waste CO2, instead of producing a lot of CO2 as the Solvay process does. This is one of the few carbon usage models that makes fiscal and technical sense, and fits as an industrial component of the future. I know, I’ve spent a lot of time assessing carbon capture and industrial processes’ CO2 footprints.

Lazard unsubsidized levelized cost of storage with Agora’s technology annotated

But it’s the combination that’s key. It’s a battery. Shove renewable electricity into it, and get clean electricity back. Lots of tech does that. However, Agora’s tech has excellent energy density, and great durability too. It can store a lot of electricity for the mass and cycle it a lot of times. Using CO2 instead of metals makes it a lot cheaper. And their catalyst being cheap due to the chemistry makes it even cheaper. 

Relative ROI for different battery technologies by author

Those basic factors make it cheaper than most other forms of storage automatically. Cheaper to build. Cheaper to operate. Lower cost storage. Agora has done four fiscal case studies with LafargeHolcim for the technology applied to wind energy grid balancing and an integrated low-carbon cement plant of the future, so the numbers have been scrubbed backward and forward. 

And the kicker is the carbonate and bicarbonate production. It consumes waste CO2. It produces useful chemicals. Bicarbonates are in lots of things. Food. Toothpaste. Antacids. And they are worth from $200 – $600 per ton, depending on the chemistry and the purity. Imagine a battery that lasts a long time, eats CO2, and produces useful industrial chemicals. It’s a trifecta. 

Chart of relative carbon neutrality of different battery technologies chart by author

These battery technology comparison charts are early and indicative, not late, based on rock solid numbers, or seriously reviewed. I pulled them together based on discussions, but they haven’t been validated. My gut tells me that they are close to right in terms of scale, but there’s more work to do on them. And more variants of these assessments to produce. No wonder Hello Tomorrow, the Keeling Curve Prize Team and the Cartier’s Womens Initiative picked Agora. I saw this 20 months ago. The Agora team saw this close to a decade ago.

Their solution isn’t a thornless bed of roses, of course. 

The CO2 is transformed into an acid on the way through the process into the storage medium, so that requires care in handling. The set of chemicals include bromine variants. While bromine is an essential trace element in human biology, as with dihydrogen monoxide too much is lethal. The toxicity of the bromine is a concern that must be managed. Other alternatives are less efficient.

Technology readiness levels courtesy NASA

They are at lab efficiency levels right now. While projections indicate that they will get over 80% in terms of round-trip storage, this hasn’t been demonstrated. They are at the MVP stage or technology level four, and need to build a scaled prototype. That’s going to take 2-3 years, and another few million dollars.

They aren’t a manufacturing and distribution firm or a chemical commodity firm, but a technical innovation firm. They need a global manufacturing partner and a chemical commodity partner. Firms like that have been knocking on their door a lot in the past couple of years, and a lot more with the various prizes this year.

Agora’s CO2-based redox flow batteries will be a core technology assisting us to bend the Keeling Curve back down. Hello Tomorrow indeed.

Full disclosure. I have a professional relationship with Agora as a strategic advisor and Board observer. I did an initial strategy session with Agora about their redox flow battery technology in late 2019 and was blown away by what they had in hand, and my formal role with the firm started at the beginning of 2021. I commit to being as objective and honest as always, but be aware of my affiliation.