Sucking CO2 From Air Is Cheaper Than Scientists Thought (technologyreview.com)

An anonymous reader quotes a report from MIT Technology Review: While avoiding the worst dangers of climate change will likely require sucking carbon dioxide out of the sky, prominent scientists have long dismissed such technologies as far too expensive. But a detailed new analysis published today in the journal Joule finds that direct air capture may be practical after all. The study concludes it would cost between $94 and $232 per ton of captured carbon dioxide, if existing technologies were implemented on a commercial scale. One earlier estimate, published in Proceedings of the National Academies, put that figure at more than $1,000 (though the calculations were made on what's known as an avoided-cost basis, which would add about 10 percent to the new study's figures). Crucially, the lowest-cost design, optimized to produce and sell alternative fuels made from the captured carbon dioxide, could already be profitable with existing public policies in certain markets. The higher cost estimates are for plants that would deliver compressed carbon dioxide for permanent underground storage. David Keith, a Harvard physics professor and lead author of the paper, is also the founder of Carbon Engineering, "a Calgary-based startup that has spent the last nine years designing, refining, and testing a direct air capture pilot plant in Squamish, B.C.," reports MIT. "Carbon Engineering plans to combine the carbon captured at its plants with hydrogen to produce carbon-neutral synthetic fuels, a process the pilot facility has already been performing." The company has secured $30 million, but is seeking additional funds to build a larger facility that will begin selling fuels. CNBC notes that Carbon Engineering is owned by several private investors, including Bill Gates.

Comments

Re:Now we know.

[K. S. Kyosuke]

An electric car can use something like 0.2 kWh/km. Let's say you drive 20000 km per year. That's around 4000 kWh of electricity per year. At a mediocre 0.15 capacity factor, that's the average output of a 4 kW array or so. Costs around $5000 where I live.

even with tracked arrays, you can collect for a maximum of around 8 hours a day with any efficiency, so you will need 3.5Kw of solar source over your 8 hours. Doesnt sound too bad does it? not figure in practical Solar load factor, around 20%, so you need 17.5 Kw of solar cells.

That's double accounting. The capacity factor already includes the fact that you don't have 24h of maximum output. Your 17.5 kW array with a 0.2 capacity factor generates almost 600 kWh per week on average, which is the of triple your requirement - not surprisingly the factor of three you mistakenly added in "you can collect for a maximum of around 8 hours a day with any efficiency".