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Sequoia Breaks Into Carbon Capture, Backs Stealthy C12 Energy

Massachusetts-based carbon capture startup C12 Energy has just entered an exclusive group: cleantech companies backed by venture capital firm Sequoia Capital. The firm, which has been less gung-ho about the green space than many of its Silicon Valley peers, has joined several undisclosed investors in a $4.5 million funding round for C12 Energy, VentureWire reports.

The 6-month-old startup is keeping its strategy under wraps for now, but C12 co-founder Kurt Zenz House — the company’s chief scientist and president — has left a paper trail of his ideas for large-scale carbon capture and storage. We can’t say for sure what C12 has in the hopper, of course, but we do know that House has done a lot of research into storing CO2 in carbonate sediments — rocks, essentially.

Less than a year before C12 incorporated, House (with three other researchers) published a study in the journal Environmental Science & Technology on electrochemical weathering — a process meant to keep carbon dioxide captured from industrial flues and then stored in oceans from causing acidification. Biophile Magazine reported on House’s study at the time, and offered this explanation:

By electrochemically removing hydrochloric acid from the ocean and then neutralizing the acid by reaction with silicate (volcanic) rocks, the researchers say they can accelerate natural chemical weathering, permanently transferring CO2 from the atmosphere to the ocean.

Oceans naturally take up carbon dioxide, but at current emission levels the gas is decreasing the sea’s pH, presenting big problems for marine life and coastal economies. Whoever figures out how to store carbon underwater without raising the acid level (House has experimented with adding an alkalinic solution) could find huge demand from conventional fossil fuel energy producers — especially if pricing schemes for greenhouse gas emissions go into effect.

Getting a slice of the billions of dollars set aside for carbon capture in both the House and Senate versions of the stimulus bill could help take House’s scheme out of the lab. Not without risk, however: According to Biophile, a large-scale implementation of the kind of project that House initially envisioned  “would involve building dozens of facilities, akin to large chlorine gas industrial plants, on coasts of volcanic rock.” C12 may have a different vision. If it works, Sequoia’s cleantech batting average could get even better.

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