MIT engineers make converting CO2 into useful products more practical

The writer appears to be under the impression that CO2 is not a valuable commodity.

In fact, it is, so long as it's under enough pressure, and in the right place. In Montezuma County, Colorado, sits the McElmo dome, an ancient underground CO2 well. They pump it out, down a 500 mile pipeline, to Denver City, Texas, where it gooses oil wells into pumping more crude out. Other than making more oil and making it cheaper, not really much in terms of greenhouse gas contributions- the CO2 starts underground and ends up underground.

Kinder Morgan won't just let you back up your truck and buy some (it's already spoken for), and even if they would, they'd expect you to pay a pretty penny for what we widely consider to be waste gas.

I think MIT is doing some good work. Just wanted everyone to be mindful of the massive scale under which CO2 is already getting bought and sold.

Isn't it also used as input to basically every e-fuel which can replace fossil hydrocarbons?

No. The value of commercial co2 is its energy content -- what it takes to process it into useful form. There is no useful form of co2 for making fuel. The energy has already been extracted.

Exactly right. FTA: "The electrochemical process that converts CO2 into ethylene involves a water-based solution and a catalyst material, which come into contact along with an electric current"

That "electric current" is the challenge. It takes energy to convert CO2 into other chemicals. If that energy isn't carbon-neutral, you're just spinning your wheels.