With a fully operational site on Hawaiʻi Island, Captura is a climate technology company with a proprietary, licensable Direct Ocean Capture (DOC) system removing carbon emissions from the sea and atmosphere, portending gains for ocean health, energy security and sustainability.
How has your space, robotics and direct air capture background been transferrable to your work at Captura?
A space guy going into climate change stuff may not seem obvious, but the space world is all about heavy capital expenditure into a solution you have to know is going to work. Once out in space, not a lot of fixes are available, so there is lots of rigor in research, testing, engineering and process. Bringing that discipline before fielding a solution so people have great confidence in it is probably the number one takeaway I brought from the space to climate side of my work. I am passionate about environmental issues, while being a pragmatist who develops solutions that will work and make a material difference.
What is Direct Ocean Capture?
The ocean, covering 78% of Earth, is the largest absorber of CO₂ on the planet. But CO₂ from the atmosphere is affecting ocean acidity, temperatures, coral reefs and marine life. Marine carbon dioxide removers want to utilize the massive absorption device that is the ocean more effectively, without causing more damage. One method is to absorb more CO₂ into the ocean, add biomass to absorb that, and sink it. Another is to change ocean alkalinity to increase the amount of CO₂ drawdown from the atmosphere. Captura takes CO₂ out of the ocean to activate an effect described by Henry’s Law, which governs the equilibrium between atmospheric gases and liquids. When you pour a can of soda into a glass and leave it on the table, bubbles come up and the drink goes flat. That is Henry’s Law–there is more CO₂ in the liquid than in the air, so the atmosphere pulls it out. We do the reverse by taking CO₂ out of the ocean so the ocean takes more CO₂ out of the air. CO₂ is 150 times more concentrated in the ocean than in the atmosphere, so the impact is great.
How does the technology physically work?
We can deploy our technology from the back end of power and desalination plants already pumping and expelling ocean water. Or, we can be a floating barge so the current underneath pushes water through our process. After pulling in ocean water, we take about half a percent out of the stream and soften it into pure brine by extracting natural magnesium and calcium ions. Captura’s proprietary electrodialysis system then separates and reforms these molecules into hydrochloric acid and sodium hydroxide. The hydrochloric acid goes into the remaining ocean water inside the facility and lowers the pH to about 4. The CO₂ in the ocean water reacts and you can physically vacuum it out.
Before returning the water to the ocean, we re-neutralize the alkalinity with sodium hydroxide and add back the magnesium and calcium ions. The output to this closed-loop system is CO₂ and ocean water that is depleted of CO₂. The captured CO₂ can subsequently be safely and permanently stored underground to deliver carbon removal, or it can be re-used to produce low-carbon products such as synthetic fuel. The CO₂-depleted ocean water, which is slightly more alkaline, can help reduce marine acidification locally before it reabsorbs CO₂ from the atmosphere. We create everything in our facility, starting with the resin that forms membranes and their coatings, assembled into what we call a stack. The chemicals we need are widely available and do not include rare earth or precious elements. Our system is also impervious to warm and cold, though efficiency is a bit different in coldness. So, where our technology goes is flexible.
How close is Captura to commercialization?
The Hawaiʻi plant with our partner Equinor proved our technology at scale–something nobody had done before. The plant was built in just 70 days from bare earth to being fully commissioned. I had never seen everything work the first time until we powered up this plant. We set a key performance indicator of 90% extraction and are achieving 96%. We worked with Equinor to qualify the technology for commercial readiness and are now scaling up at our facility in Pasadena, Calif. and evaluating candidate locations around the world for our first commercial plant. The aim is to start construction in 2027.
Does electrodialysis have applications beyond carbon removal?
Captura’s proprietary electrodialysis platform was first developed to power our DOC system, but has applications across multiple industrial applications where low-cost, on-site acid and base generation is critical. We are now manufacturing our membranes and electrodialysis stacks to serve a number of these industries, including direct lithium extraction, desalination and wastewater valorization. Applying Captura’s proprietary platform across these sectors can significantly improve efficiency, cost and sustainability performance. Another use is long-duration energy storage. Lithium-ion stores energy for up to about eight hours. The benign acids and bases of untreated ocean water can be stored indefinitely in two big tanks as one big battery, regenerating energy when run back through electrodialysis. A system the size of Denver International Airport could produce enough energy for an entire day of consumption in the United States. We use this kind of battery ourselves in our DOC plants. About 70% of our energy use is from electrodialysis–we overbuild these capabilities so that during off-peak hours, we relieve the renewable energy provider by storing the excess as acid and base for power during on-peak hours. We are using energy that is cheaper and even given away, without having to fight AI data centers, cities or charging stations for electrons.
What is next for Captura and DOC?
We recently announced the first close of a $12.5 million Series B financing round, which will enable us to expand domestic manufacturing of our electrodialysis platform for a range of markets. This funding signifies a new phase of commercial execution for Captura.
Our electrodialysis platform shows how basic chemistry can help address some of today’s biggest challenges, from climate change and energy storage to critical mineral extraction and water desalination. Captura’s technology is up to 10 times higher-performing than the best available solutions, at about a quarter of the cost. This appeals both to people who care about climate and those focused on energy security and affordability. While we have a strong set of investors behind us, DOC is still seen by many as a new technology. By diversifying our core electrodialysis technology across a range of industries, we are creating greater resilience and multiple revenue streams while continuing to advance our DOC climate solution in parallel.
More broadly, the success of climate technologies like DOC depends on demonstrating that they can be practical, scalable and affordable. Convincing skeptics about climate solutions is the hardest–they worry that addressing climate change means giving up things like flying or eating beef.
The more people realize that climate problems matter and are fixable with scalable and affordable solutions that already exist, the better.
