This $1.5 billion startup promised to ship clear fuels as low cost as gasoline. Specialists are deeply skeptical.

The method

The method breaks down into 4 principal levels, in response to Prometheus’s investor supplies. 

In the first step, industrial followers attract air and blow it via a mixture of water and different compounds, which McGinnis says may embody sodium carbonate. That then readily reacts with carbon dioxide molecules within the air, shifting a lot of the carbonate to bicarbonate.

The ensuing answer then strikes right into a battery-like cell with a membrane within the center and electrodes on both finish, which makes use of electrical energy to spark a sequence of chemical reactions that produce complicated alcohols. It’s outfitted with a catalyst primarily based on know-how licensed from Oak Ridge Nationwide Laboratory. In an earlier description, that lab mentioned it had developed a catalyst constituted of tiny carbon spikes embedded with copper nanoparticles. When a voltage was utilized, it transformed carbon dioxide dissolved in water into ethanol “with a yield of 63%.”

Prometheus’s carbon nanotube membranes come into play in step three, separating the alcohols from the water. 

And in a remaining step, totally different catalysts are used to mix the alcohols and convert them into artificial gasoline, diesel, or jet gas. In 2020, Prometheus licensed separate technology from the Oak Ridge lab that can be utilized to supply jet gas from ethanol, via a multistep course of that depends on a novel although unspecified catalyst. 

The general course of is considerably totally different from the one different firms changing captured carbon into fuels are taking. As McGinnis defined in a Joule commentary, the Prometheus programs can function underneath normal atmospheric stress and at room temperature. The know-how additionally avoids the warmth power wanted to supply concentrated carbon dioxide in addition to the capital prices of an electrolyzer devoted to producing hydrogen. As a substitute, the corporate claims, it could actually synthesize alcohols straight from carbon dioxide dissolved in water, after which convert these into normal fuels.

In the event that they’ve certainly found out how to do that, it “may result in important power and value financial savings,” says Evan David Sherwin, a postdoctoral researcher at Stanford who produced the Environmental Science & Expertise examine.

One of many final slides within the investor supplies reveals a Prometheus-branded gas station, with a purple neon “Zero Internet Carbon” signal promoting gasoline costs of $3.50 a gallon and diesel at $3.75, nicely beneath present average US prices.