This Is CDR is an ongoing series of online events to explore the range of carbon dioxide removal solutions that are currently in development. This week, we meet Kaja Voss and Mike Carpenter of Inherit Carbon Solutions. Their company targets a vast sector that already captures gigatons of carbon dioxide every year–and, at present, releases a lot of it right back into the atmosphere. That largely untapped source of carbon removal is the waste processing industry.
Waste processing companies all over the world treat organic waste using a process called anaerobic digestion. Waste products–animal manure, food waste, sewage, and industrial waste streams like dead fish–feed into enormous containers largely devoid of oxygen. There, specific microorganisms are “seeded” into the raw material, and over a period of fifteen to thirty days, they break down the waste into soil and gases, about 60 percent methane and 40 percent CO2.
The methane is valuable as fuel; the carbon dioxide often just goes out of a vent. But at this point in the process, a waste processing company has already done most of the work of atmospheric carbon removal. All of the carbon in the waste they’re processing is from the atmosphere; it’s been captured in the form of CO2 through photosynthesis. Essentially, the organic matter in a waste treatment tank has already soaked up atmospheric CO2 like a sponge.
Right now, that sponge just gets squeezed out and the CO2 goes back into the atmosphere–often at over 99 percent purity! So what Inherit Carbon Solutions proposes to do is simple. They help waste processing companies monetize that CO2 instead of releasing it. Specifically, they act as an intermediary between the waste companies and buyers of carbon removal, selling removed tons of CO2 to buyers and using the revenue to install CO2 liquefaction units at waste treatment plants. Cooling and pressurizing the captured CO2 turns it into a liquid, which makes it easier to transport and then sequester underground. The company can document their whole chain and account for any emissions that occur along the way (for example, the energy required to liquify and transport the CO2), thereby insuring that they’re actually removing what they think they’re removing when all the inputs and outputs are summed up.
According to Mike, there are 12,000 anaerobic digestion plants in Europe and North America alone, of which 1000 are currently emitting pure CO2. Around eight million tons of CO2 comes out of these plants every year; global CDR potential from anaerobic waste digestion has been estimated at two gigatons per year. This is a biogenic, renewable source of carbon removal–we can and should stop burning fossil fuels, but we’ll always have waste to process. So while Inherit has only just gotten started (the company formed in August of last year and is just completing their first round of fundraising), there’s enormous potential here, all from a relatively straightforward idea. We’ll be very interested to follow their progress, and if you want to learn more specifics, be sure to watch Kaja and Mike’s presentation above. You can also catch up with the full series on our resources page.
