This is CDR is an ongoing series of online events to explore the range of carbon dioxide removal solutions that are currently in development. In past episodes, we’ve looked at many ocean-based CDR projects, generally using realkalinization to capture more CO2 in the ocean. This week’s talk is from a company exploring similar territory, but with an interesting source of alkalinity: processed mine tailings.
As you may remember, the ocean is one of the world’s largest carbon sinks; it holds about 25% of the world’s CO2, and absorbs more as CO2 grows more abundant in the atmosphere. That’s not without a cost, though, since absorbing excess CO2 also makes the ocean more acidic. As Mike Kelland of the startup Planetary Hydrogen explains, if we counter this acidification by putting alkaline material in the ocean, we can allow it to absorb more CO2, while also helping to restore marine environments and wildlife that have been damaged by rising acidity.
But where does the alkaline material come from? We’ve heard from scientists and entrepreneurs with many different answers to that question. Planetary Hydrogen’s approach uses electrochemistry to convert mine tailings into a pure mild alkaline solution. This is useful in several ways. For one, mine tailings already require CO2-emitting procedures to clean up, so cleaning them up in a carbon-negative way is already a bonus. The process also produces hydrogen, which can be used in mine vehicles to further reduce the mine’s carbon footprint. Lastly, Planetary Hydrogen’s electrochemical processor can be built at a mine site and powered with renewable energy.
Planetary Hydrogen calls this half of their work the “green process”; the second half, the “blue process,” involves getting that alkaline solution safely into the ocean. Using both processes together, they believe they’ll eventually be able to deliver measurable, verifiable carbon removal at under $100 per ton – a number which many in the field believe is a crucial threshold for making CDR economically viable. As if that’s not ambitious enough, they’re also aiming to remove one gigaton of CO2 per year by 2035 – and that’s good news for literally everyone on Earth. To learn more, check out the video above; Mike walks through a lot of interesting parts of the process and answers a number of detailed questions.
Be sure to check back next week for more This Is CDR, and check out the whole series on our resources page.