On the 'Exaquest' [Spotlight on AirMiners]
10 min read

On the 'Exaquest' [Spotlight on AirMiners]

The third in the "Spotlight on AirMiners" series, with John Lin of EXAQUEST CARBON.
On the 'Exaquest' [Spotlight on AirMiners]

Cover image courtesy of motherearthnews.com, depicting a traditional method of drying wood. Not the Exaquest method, but close.

Welcome to the third edition of the Spotlight on AirMiners series. Click here for the first interview, with Ryan Shearman of Aether Diamonds, and here for the second, with Jason Grillo of AirMiners.

This time, we're talking with John Lin, whose carbon removal, or negative emissions, research nonprofit, Exaquest Carbon, qualifies him for a slot in the AirMiners series, even though we actually met through Work on Climate.

The mission of Exaquest Carbon (exaquest.org) is to conduct scientific research to develop open-source technologies that will enable safe, sustainable, and inexpensive long-term storage of carbon at the gigaton scale in the form of lignocellulosic biomass.

Here's a primer of the type of carbon numbers Exaquest is looking at, specifically at "microbial respiration & decomposition" (all units in gigatons of carbon):

Carbon Cycle. Source: US Dept of Energy

I've been hoping to find a viable air mine since getting involved in this space in 2017, and this is one of the most promising approaches I've found. The Exaquest Carbon approach collects decomposing biomass (think about the brush that contributes to the heat of wildfires, or other piles of "waste" wood), and slows its decomposition above ground or under water. Every unit of carbon that is not released into the atmosphere because of the slowed decomposition can feasibly count as a negative emission.

The purpose of the Climatetech Media Project is tell stories of cutting-edge climatetech workers, the faces behind the new technologies we read about elsewhere. If you enjoy this post, please subscribe at the level of your means. We will do the our best to provide continual value to you.

The ‘Exaquest’ is the quest to remove 1 exagram (1 trillion tons) of carbon from the Earth’s atmosphere.

According to research published by the U.S. Department of Energy, National Oceanic and Atmospheric Administration, among others, decomposing biomass emits approximately five times as much carbon per year as humans do. See 60 gigatons of carbon, for microbial respiration, as compared to 9 gigatons of carbon from humans, in the image above, via DOE, NOAA, IPCC.

Exaquest Carbon is oriented around the idea that slowing down the decomposition of biomass is a straightforward method of achieving direct negative emissions with minimal energy use. The current technology design is quite simple, the woody biomass is dried and prevented from decomposing. Part of the challenge of bringing this idea to the world is that there is no intended end use for that dried material. It is a carbon store, and it must sit.

I want to add that John is not against using biomass as a feedstock for the production of fuels, chemicals, or other useful products, but he does not believe that existing technologies are capable of efficiently using biomass for those purposes. He adds that if amazing biomass utilization technologies are in fact developed, Exaquest’s huge stockpiles of dry biomass will be in high demand.

Exaquest Carbon’s research seeks to develop low-energy methods for storing biomass for long periods of time, thus slowing down the rate at which photosynthetically-captured CO2 returns to the atmosphere.  The result is the net removal of CO2 from the atmosphere. This is a new type of negative emission that turns biomass that has already fallen to the ground into carbon storage by organizing it in a particular way.

What are negative emissions? Head over to the Climatetech Media Project negative emissions primer.

As I watched John's lecture from November 2020 (on Youtube), I grew to like his approach quite a bit. Drying woody biomass (or burying it underwater) as a carbon removal approach is a fabulous concept and method, and I think its simplicity is excellent. The way I see it, the Exaquest Carbon approach enables:

  • Disposal of woody waste biomass
  • Evaporation of water, which can be harvested on-site, and assessed for environmental toxins
  • Collection of volatile organic compounds and nutrients, both of which can be sold for additional revenue
  • Production of dried woody biomass, which can be used as a feedstock. Though every unit of stored carbon that gets used in a manner in which it degrades or combusted is losing a unit of stored carbon.

John and I have had great interactions, and if you want more of John and Exaquest, he was recently on "Make Peas Not Beef," a brand new podcast by Lilly Tong. Watch it on Youtube or in your favorite podcast app. I have had the pleasure of interacting with Lilly also through the Work on Climate community. Shoutout workonclimate.org for their visionary work to keep us connected.

Now onto the interview.

John Lin, President of Exaquest Carbon

M: What is Exaquest Carbon?

J: Exaquest Carbon (www.exaquest.org) is a 501(c)(3) research nonprofit based in San Francisco, CA that is developing open-source technologies that enable safe, sustainable, and inexpensive long-term storage of lignocellulosic biomass, either aboveground or buried underwater. Put simply, Exaquest Carbon is showing the world how to reduce carbon emissions by slowing down the decomposition of biomass (which emits ~5x more carbon per year than all of humanity).

Photosynthesis does the hard work by capturing ~450 gigatons of CO2 per year and then converting approximately half of that carbon into terrestrial biomass (i.e., plants and trees).  However, this huge amount of natural carbon capture is continually offset by an almost equally huge amount of biomass decomposition, which emits ~200 gigatons of CO2 per year – meaning that most of us are not aware of the huge amounts of carbon that move through the carbon cycle every year.  If we minimize the decomposition of biomass, we will maximize the amount of photosynthetically-captured CO2 that is stored for long periods of time, and we could potentially slow and then stop and then reverse climate change (i.e., reduce the atmospheric concentration of CO2 to a safe level).  This is Exaquest Carbon’s mission in a nutshell.

M: Why now?

J: It’s becoming clear that humanity will not be able to achieve net-zero CO2 emissions without also being able to remove many gigatons of CO2 from the atmosphere every year.  So everyone is suddenly interested in finding or inventing the best technologies for removing CO2 from the atmosphere.  I’ve thought long and hard about CO2 removal, and I believe that Exaquest’s long-term biomass storage will ultimately prove to be the technology that removes and stores the most CO2 per unit of energy input.

What’s really interesting is that, while I am not the first scientist to get excited about long-term biomass storage as a carbon removal technology, there is almost no research being done in the world right now on the kind of long-term biomass storage that Exaquest is proposing.  (There is some research being done on sinking seaweed to the ocean floor, and also on burying wood underground, but, for reasons that I don’t have time to explain here, Exaquest does not think those are great ideas.)  Most people would look at this situation and conclude that Exaquest’s proposed long-term biomass storage must be a bad CO2 removal idea.  But I’ve spent enough time in universities to understand that the scientific conventional wisdom is not always correct.

We clearly need better CO2 removal technologies, and Exaquest Carbon’s goal is to make long-term biomass storage the best CO2 removal technology.

M: What was the path that led you to found Exaquest Carbon?

J: I’ve always wanted to work on the world’s biggest problems.  When I graduated from high school in 1998, I honestly thought that the world’s biggest problems were in the realm of international affairs and diplomacy, so I studied economics and foreign languages in college and then went to law school.  During law school (2003-2006), I realized that international diplomacy was dying, and also that the world’s climate and energy problems were rapidly intensifying. However, I was locked into an inflexible career path as a lawyer, so I decided that I would give law a chance before switching careers. From 2006 to 2008, I clerked for a federal judge in Philadelphia, and then worked as a litigator in New York City until 2011, at which point I was ready (both financially and psychologically) to take a big risk and switch careers.

In 2011, the climate and energy problems still felt like scientific problems, so I felt I needed to re-educate myself to make a meaningful contribution.  This prompted me to earn a second bachelor’s degree in Chemical Engineering at the City College of New York (one of the few schools that allows older students to earn second bachelor’s degrees).  I graduated at the top of my class at CCNY, so I thought it made sense to continue my scientific re-education.  This led me to apply to a number of Chemical Engineering PhD programs and to accept a generous offer from Stanford University (which declining equally generous offers from Caltech and MIT).  I was in the Chemical Engineering PhD program at Stanford from 2015-2019, during which time I conducted research on electrochemically converting CO2 to fuels and chemicals as part of the U.S. Department of Energy’s Joint Center for Artificial Photosynthesis (JCAP).

I enjoyed my research at Stanford, but as I learned more about CO2 and the challenges involved in converting it into more useful chemicals, I realized two important points: (1) electrochemical CO2 conversion probably will not play a large role in stopping climate change during my lifetime; and (2) natural photosynthesis captures CO2 and converts it into biomass far more efficiently than any human-designed process probably ever will.  The first realization caused me to doubt whether I should finish my PhD; the second realization eventually led me to the Exaquest idea – i.e., the idea of maximizing the sequestration of photosynthetically-captured CO2 by minimizing biomass decomposition.  I spent about a year trying to convince Stanford (and nearby investors) to financially support my proposed research on long-term biomass storage, either as a for-profit startup or as part of my PhD work. When I was unable to attract any such support, I founded Exaquest Carbon as a 501(c)(3) nonprofit and left my PhD program (with just a M.S. degree) to run Exaquest full-time.

M: What are your aspirations for the next year?  The next 5 years?

J: Within the next 12 months, my goal is for Exaquest Carbon to conduct its first large-scale biomass storage experiments.  The major problem that I encounter when I explain Exaquest’s vision for long-term biomass storage is that people simply do not believe that it is possible.  Fortunately, Exaquest can solve that problem by showing people the results of real biomass storage experiments.  And those results should get people excited enough to donate the money that Exaquest will need to develop additional technologies for larger biomass storage projects.

Within the next 5 years, I want Exaquest’s long-term biomass storage to become one of the CO2 removal technologies that people always mention when they talk about how humanity should go about stopping climate change.  This could happen because of Exaquest’s successful research, but I think it is more likely that Exaquest’s initial work will inspire individuals, governments, and businesses all over the world to invest the time and money that eventually yields major progress toward developing long-term biomass storage as a CO2 removal technology.

M: How do you characterize the change in how people talk about carbon removal in your industry?

J: I first started thinking about carbon removal in 2018, when I was still a chemical engineering graduate student at Stanford.  At that time, the scientists I knew were beginning to talk about CO2 removal technologies, but they did not yet fully appreciate how important those technologies would be in the fight against climate change.  Since then, many more scientists have come around to understanding the importance of CO 2removal, and I think we’re now at the point where only a minority of scientists believe that the world will be able to stay below 2 °C of warming (i.e., the less ambitious Paris goal) without using any CO2 removal technologies.

M: What advice would you give someone curious about carbon removal?

J: Anyone who is curious about carbon removal should start by learning about the various carbon removal technologies (and also about CO2’s role in causing climate change).  Once this curious person has a basic understanding of carbon removal, CO2, and climate change, I would encourage her/him to (1) think creatively and (2) avoid the common trap of believing that it isn’t possible to contribute something new and valuable unless you’re a scientific expert.  It is true that scientific experts have done a lot of thinking about carbon removal, but it’s also true that the expertise of scientists generally doesn’t extend far beyond science – which means that scientists are usually no more knowledgeable or skilled than the average person when it comes to business, politics, marketing, psychology, art, and other important non-scientific aspects of life.

Something most people realize after thinking and reading about carbon removal/climate change for a while is that the core of the problem is social (and not scientific).  This is the case because, even though the technology already exists to do a lot to stop climate change (including by removing CO2 from the atmosphere), the average person does not yet want to change laws and/or his/her own life to help make that happen.  New technologies may emerge to make it easier for us to reduce CO2 emissions and/or remove CO2 from the atmosphere in our lifetimes.  However, I am starting to believe that the most important breakthroughs will be social breakthroughs that make people a lot more willing to change laws and their own lives to stop climate change.

We still need both technological and social breakthroughs to stop climate change, and the key to making those breakthroughs will be creative new ideas from people with the nerve to challenge every kind of conventional wisdom.  So be bold!

M:  Promote yourself! How can someone get involved with Exaquest?

J: Exaquest Carbon needs both donors and volunteers to achieve its goals!  (Right now, Exaquest has no paid employees and no regular volunteers, so I am essentially running Exaquest on my own for no pay.)  To get involved as either a donor or volunteer, please contact me at john.lin@exaquest.org, and please also visit our website at www.exaquest.org.

We are willing to work with donors so that the research that Exaquest does with their funds aligns with their goals.  We are also willing to allow volunteers to create their own roles so that they spend their time and effort on the tasks that they find most meaningful. (I should mention that, if Exaquest grows significantly in the near future, the individuals whom I would most likely hire as paid staff are the volunteers who have helped Exaquest get to that point.)


That's all folks - I hope you enjoyed this interview with John Lin of Exaquest. Please subscribe at the level that feels good to you, and I look forward to continuing to deliver unique stories about the individuals and organizations at the cutting-edge of climatetech and climate innovation. If you'd like to propose a series of interviews, please don't hesitate to reach out to Matthew.


Enjoying these posts? Subscribe for more