Removing carbon from the atmosphere has been earmarked as one of the tangible efforts to accomplish the net zero deadline of 2050 set by the Intergovernmental Panel on Climate Change (IPCC). This has led academics, entrepreneurs and policy makers to engage in ambitious projects to make this lofty goal achievable. You may be familiar with some CO2 removal technologies (also called “negative emissions technologies”) such as direct air capture, accelerated rock weathering, biochar, and reforestation. However, it is unlikely that you have heard about long-term sequestration of biomass in aboveground storage – a CO2 removal method being developed by Exaquest Carbon. (The name “Exaquest” refers to this nonprofit’s quest to remove 1 exagram (1018 grams) or 1 trillion tons of carbon from the Earth’s atmosphere.)
Exaquest’s co-founders John Lin and Dr. Amber Janda are chemical engineers who met while working in the same research group at Stanford University. Prior to coming up with the idea for Exaquest, John was enrolled in the Chemical Engineering Ph.D. program and focused on electrochemical CO2 reduction, while Amber was engaged in postdoctoral research to develop new heterogeneous catalysts for CO2 reduction. Despite the clear difference between their lab research, they share a strong impulse to act to stop climate change – an impulse that was originally stoked by Al Gore’s critical 2006 documentary, An Inconvenient Truth, and more recently by the obvious effects of climate change on our planet. After analyzing the CO2 removal challenge from first principles, their experience, innovation and ingenuity has yielded an unconventional approach that looks to sequester large amounts of carbon in the form of lignocellulosic biomass. In a brief chat with them, they spoke at length about Exaquest’s background, its scalability, their general thoughts on carbon reduction, and why their unique method for sequestering carbon is an inherent complement to Greenstand’s reforestation activities.
Loni: Hello John and Amber, can you briefly explain how Exaquest’s method stands out from other carbon capture techniques?
Amber: The main way our idea differs from one of the most popular carbon capture technologies (direct air capture) is that our idea takes advantage of the natural process of photosynthesis in plants to capture carbon. Plants and trees integrate carbon into themselves to grow, while direct air capture involves the use of machines, fans, adsorbents and chemicals in a factory setting to draw CO2 from the atmosphere. This is the main technical difference that distinguishes us from direct air capture (DAC) technologies. The processes of photosynthetic carbon capture evolved in nature over millions of years, and this makes plants and trees much more efficient in energy use than any DAC technology will ever be. Another standpoint from which our technique is distinct from DAC technologies and even other biomass-based methods is the way we intend to store or sequester the carbon. While DAC technologies gather carbon dioxide from the atmosphere to be stored in geologic formations underground, what we propose to do is store biomass (dead plant material and trees) in aboveground storage structures and just not let it decompose. Because if the biomass decomposes, it turns back into carbon dioxide, methane and other greenhouse gases. We believe that this process of storage will require less energy than the compression and injection of carbon dioxide into geologic formations.
The third factor that distinguishes Exaquest is that aboveground storage ensures that the biomass will be easily accessible when biomass becomes a more important resource in the future. Even though our technology is not ready for commercial scale deployment at the moment, we foresee a future where stored biomass can be easily accessed for useful conversion at large scale, and large supplies of biomass will be needed for this to work.
Loni: This sounds familiar. Is biomass the same as biochar or biogas?
John: Not really. Biochar is a biomass-based approach which involves immediate conversion of biomass into char, but it takes a lot of energy and capital investment, and the process can also pollute the environment. This is different from what we at Exaquest intend to do with biomass. Biogas involves adding some organic material with some special bacteria in a digester to manufacture methane as a fuel, and that is also not what we intend to do with our technique. Our approach is much simpler because we figured that for something to be feasible at the gigaton scale, it has to be really simple. We do not consider biomass storage to be technically trivial – obviously there needs to be research and development on ways to do it efficiently – but the basic concept is to do nothing (or as little as possible) with the biomass. As Amber was describing, there may be future demand for raw biomass for conversion processes that are more efficient than they are today. So, in the absence of an efficient conversion technology, the most we can do with the biomass is store it safely away until the time when we can optimally utilize it. Lignocellulose, which is essentially what wood and plant material is comprised of, is an excellent storage medium for carbon and plants give us that for free; so we are trying to leverage that as much as possible.
Loni: If your biomass sequestering approach is deployed, it will likely involve tweaking the process of natural decomposition. What are the trade-offs in that equation for the forest ecosystem, in terms of soil health for example?
John: Nothing comes for free. In a perfect version of our system, the plants will grow and produce lignocellulose (composed of carbon, hydrogen and oxygen) and you could completely separate lignocellulose from the valuable nutrient content (sulphur, nitrogen, phosphorus, potassium, etc.) of the plant. Part of Exaquest’s vision in future research is to improve technology for separating those nutrients from the lignocellulose. Currently with available technology, it is possible to separate 50-60% of the nutrient content from plant material and this is relatively efficient. Also, our operations focus more on wood than green plant material and the reason for that is because wood contains more lignin-cellulose and less nutrients compared to green plants. Therefore, sequestering wood is an effective carbon storage strategy that will not cause a major nutrient lock-up problem. Soil health is also a serious concern as soils are generally degraded around the world. Now let’s consider a situation in which our biomass storage technology can be deployed, and imagine a case in which a disease or storm comes through and kills a bunch of mature trees. Now in order to preserve soil health, 100% of that fallen timber does not need to decompose onsite. I have discussed this with several soil scientists and soil health is more of a function of what goes on underground in the soil rather than with aboveground biomass. Of course, fallen trees contribute to wildlife habitats and foster biodiversity and we do not suggest that the world’s forests should be stripped clean of dead aboveground biomass, but we do claim that a substantial fraction of the aboveground biomass can be harvested, as is done today with the timber industry. I think the concept of our biomass storage technology and soil health are not so directly linked and should be considered as separate issues.
Loni: How do you intend to handle the logistics of gathering biomass?
Amber: The logistics are going to depend a lot on the location. So, one idea that John and I have had for local implementation in California due to the abundance of dead trees from forest fires is to collaborate with nearby home owners and local companies that offer land clearing services and take advantage of the established logistical relationships there. And to get biomass from remote locations deep in the forest where no one lives, we hope that process will eventually be more automated with the potential use of robots. That is our plan locally for California. If we consider, for example, some of the rural locations where Greenstand operates as a use case, it will probably make sense to get individuals or small businesses to go around gathering biomass using available means in a way not so different from the Treetracker system that you currently have in place. We do not envisage our logistics operations to be “one size fits all.” It will be location-specific, as some locations will have established logistical partners, some locations will need automated robotization and in some other areas, the local population might be needed for mobilization. I have seen this before with an organization called Litterati, a non-profit organization that gathers and tracks the collection of litter and waste. People pick up litter and it is tracked and they post pictures of it on social media. They have quite a sizable following. I can draw significant parallels between what they are doing with litter and what Greenstand is doing with tracking trees. I believe it should also be possible to build social movements around reforestation and carbon sequestration efforts.
Loni: What do you consider the future of Exaquest to be? Do you intend to continue as a non-profit or are you considering the transition to a for-profit enterprise?
John: The idea that Amber and myself, two chemical engineers from Northern California, are going to save the world and store billions and billions of tons of biomass on our own is a little foolhardy. The purpose of Exaquest is to catalyze the efforts of others. What drove Amber and me crazy when we founded Exaquest was that nobody was focusing on long-term biomass storage as a CO2 removal technology. We are trying to change that in the realm of ideas and also practically in terms of developing the technology and research to demonstrate it. Everything we are doing at Exaquest is open-source. We are trying to show the world how to do this for free, and the patents and the entire content of our research will be available to the general public at no cost. The point is to inspire more people to take this seriously because there has been a bit of a failure in the scientific community to do so. Standard research scientists do not want to devote their time to 100-year-long experiments on biomass storage, this is just not compatible with contemporary science, which mostly revolves around publishing new papers in scientific journals every few months. Therefore, many scientists have ignored our approach even though the scientific foundations are solid and they need to be developed. At Exaquest, we are bridging the gap between the conceptual idea and practical applications in the real world. We are showing policy makers that this idea can be scalable and also showing business-people that long-term biomass storage can be profitable as well.
Loni: What are your general thoughts on the efforts to reverse climate change and other alternatives to reducing carbon emissions?
Amber: I believe the negative emissions community needs to keep in mind the fact that we are fighting climate change and not each other - And the way a lot of organizations (both companies and nonprofits) in the community engage each other is through competition rather than cooperation.This is because some stakeholders have underlined financial gain as a major priority. This is understandable because many professionals have spent their whole careers developing expertise in specific domains, and they want to use that expertise to come up with solutions to prevent climate change. People generally need to capitalize on their specific skill sets in the labor market to be financially secure and stable. I favor cooperation over competition in the fight against climate change. At Exaquest, we were in the fortunate position of being able to start up our organization before raising the funds to pay ourselves salaries. Thus, we were able to “opt out” of the usual financial interests or incentives that can be encumbering and focus squarely on pursuing our mission. I believe we need to de-risk this “opting out” for other professionals to encourage creativity as well as cooperation in the climate community.
Regarding the other alternatives to removing CO2 from the atmosphere, I would say photosynthesis remains the most energy-efficient way for now. But in terms of storage, the best way to sequester carbon has to be one that makes it easily accessible for use and conversion in the future. I don’t particularly like the idea of storing carbon dioxide as just carbon dioxide because there are not yet scalable processes that use CO2 as a chemical feedstock. So at this time, I tend to favor technologies that do not intend to store carbon dioxide as carbon dioxide and technologies that piggyback on nature like the reforestation activities that Greenstand supports. I believe that our long-term biomass storage technology in conjunction with global reforestation efforts will work together nicely.
Loni: At the dawn of every scientific or social development crusade, there are three stages; the propaganda stage, the pragmatic stage and the scalable stage. What stage do you think the fight against climate change is at on this spectrum?
John: I would say we are approaching the end of the propaganda stage, and the only reason why the propaganda stage is not going to last longer is because there is a real problem to solve here and you cannot play around forever. The climate has its own clock and the problems causing climate change have to be addressed. Right now, people are putting out solutions especially with regard to CO2 removal that are not particularly practical and scalable. We are reaching the end of the period where money will flow freely into start-ups and organizations with ideas that are not going to work in the long run, and we are soon going to begin the pragmatic stage where we sort out what can work and what will work. That is the stage at which Exaquest will flourish.
I would also like to tack on something that Amber slightly alluded to, which is that Exaquest is the natural complement for reforestation. So, as I understand Greenstand’s technology, you provide tree-tracking technology that enables people to accurately count trees and make sure they are living and growing. And then you assist with the monetization of the carbon storage within those trees. Now, the question we are usually asked about trees is, what if they die, what if there is a storm, disease, fire or drought? Exaquest storage is the natural, logical insurance scheme for the carbon in those trees. So, if a disease or similar disaster comes through and ravages a hundred acres of trees, the trees die of course but the lignocellulose in those trees have not decomposed yet, so the dead logs should be harvested and stored. That is the best way to deal with dead trees, and people will eventually realize that. I think we are in an interesting moment where people just do not think of wood that way and they don’t even see a decaying tree as an emitter of carbon, Exaquest is here to change that.
Amber: If you don’t mind, I would like to state that I think we are quite close to being able to change people’s mind about biomass, at least in the USA, because contemporary waste management is really being questioned right now. Recycling is almost a gimmick because most of what ends up in recycling bins doesn’t actually get recycled. People are questioning waste management, and I think the time is ripe to throw in more perspectives like “hey, maybe we don’t want all biomass to decompose.” It seems counter-intuitive but since people are questioning some aspects of waste management right now, they might actually be open to considering other approaches as well and I think that might also be in our future too. It looks almost inevitable.
Loni: So, let’s briefly discuss future collaborations; what kind of organizations or individuals do you have in mind?
John: Oh, anyone and everyone. That is the beauty of Exaquest. I think this is what Amber was alluding to when she was talking about moving toward a spirit of cooperation in the climate community. We all need to work together and we will work with anybody who is willing to help our research, anybody who is interested in this biomass storage idea, and anybody who is working on reforestation and needs some way to manage their dead trees. Obviously, we are committed to this particular approach [i.e., long-term biomass storage], so we will probably not have much common ground with organizations that are committed to other carbon capture technologies. But within the crowd thinking about biomass, it is an open book for us. We are not interested in competing with anyone or taking away market share. We are looking forward to people coming to us and finding new ways to make this work better.
I also foresee partnerships with businesses interested in the commercial potential of biomass storage. They could work with us to do foundational research and discover how long biomass can last in certain conditions. Ultimately, there are revenue streams to be earned from biomass storage beyond carbon credits. For example,you could sell a small percentage of the stored biomass or sell the volatile organic compounds in biomass or the nutrient content of biomass. Perhaps Exaquest the non-profit might even be a revenue generator someday.
Loni: Thank you for your time, John and Amber. I wish you good luck in your research endeavors.