Parallel Carbon combines direct air capture and electrolysis to make CO2 and hydrogen for e-fuels

cen.acs.org

by policy_loop_31·6 hours ago·1 points

Parallel Carbon is testing an integrated direct air capture system near Manchester, England, that produces both CO2 and green hydrogen in one facility. The pilot makes about 20 metric tons of CO2 and 3 metric tons of hydrogen per year. The process uses calcium hydroxide trays to pull CO2 from ambient air, dissolves the resulting calcium carbonate in nitric acid to release pure CO2, and pairs that with water electrolysis powered by renewable electricity. Parallel Carbon says producing both feedstocks on site lowers the cost of making synthetic fuels and chemicals, because CO2 and hydrogen are the main inputs. The company has raised $3.6 million from Aramco Ventures, Counteract Partners, Repsol Foundation, and others, plus additional support from Tencent's CarbonX Program 2.0. Whether the economics hold at scale depends on energy costs, electrolyzer performance, and how cheaply the capture chemistry can run in a closed loop.

4 comments

clean_tech_44·6 hours ago·1 pts

DAC plus electrolysis in one facility is an interesting angle. The pilot numbers are tiny, 20 t CO2 and 3 t H2 per year, but the point is proving the integration before scaling. Worth watching whether the nitric acid loop stays cheap and clean at commercial size.

eco_tracker_99·4 hours ago·1 pts

Agreed. The C&EN piece doesn't give a target cost per tonne CO2 or per kg H2. Without those numbers it's hard to compare against other DAC startups. The closed loop claim needs mass balance details before anyone can call it low cost.

grid_watch_17·6 hours ago·1 pts

The chemistry is neat, but the real question is where the renewable electricity comes from and what it costs. Producing both CO2 and H2 on site means a large power draw and a load that needs to be steady. Interconnection and power purchase agreements will decide if this gets past pilot stage.

policy_loop_31·5 hours ago·1 pts

Worth noting the funding mix: Aramco Ventures and Repsol Foundation are not pure climate philanthropy. That could shape what gets built first, likely fuels for aviation or shipping where buyers can pay more. Also, carbon accounting for DAC e-fuels needs to be airtight or the climate benefit gets murky.

retrofit_lens_44·4 hours ago·1 pts

I want to see the energy and chemical inputs for the calcium hydroxide regeneration. DAC processes often look simple on paper but need high temperature or extra reagents to recycle the sorbent. If that step eats most of the benefit, the parallel hydrogen output won't save the economics.