Accidental Discovery: CO2 --> Ethanol

[Elite Engineer]

By now I would think at least 50% of the veteran members on this site would have heard about this news. If not, the story is here: http://www.cbsnews.com/news/scientists-make-potential-breakthrough-for-renewable-energy-by-accident/

 

It's been shared on alot of news sites and popular science pages.

 

At first I thought this was awesome news! I figured, it would end the "corn for food, not food debate", gives us ALOT of fuel for future endeavors, and would reduce the carbon footprint by taking out CO2 from the atmosphere and reduce emissions when combusted.

 

Upon talking with my colleagues, they sounded less than optimistic. They said it wasn't published in a legit science journal )it was published in "ChemistrySelect"), and that the thermodynamics of the process isn't that impressive... like negative gains in energy. At best it may make a decent battery, but that's it.

 

What are you're thoughts? Is this a big deal, or just the media blowing up a non-story?

 

~EE

[John Cuthber]

It's a non-story, except as a lab curiosity.(as a chemist, I think it's very interesting).

We have been making ethanol from CO2 since we learned to make beer or wine.

However in order to do it you need lots of energy (and the minimum energy requirement is the same whatever process you use).

For beer/wine the energy is supplied by sunshine on the plants.

In that news article, it's supplied by electricity.

 

But it still needs lots of concentrated energy- and we don't have that to spare.

[swansont]

At first I thought this was awesome news! I figured, it would end the "corn for food, not food debate", gives us ALOT of fuel for future endeavors, and would reduce the carbon footprint by taking out CO2 from the atmosphere and reduce emissions when combusted.

Since it takes energy to make it, if the energy source is not clean, then you have won nothing. You add whatever carbon footprint the energy source has.

 

CO2—>ethanol (much like H2) is not an energy source. It's a storage medium, like a battery.

[MigL]

Ah, but as a chemical storage system it would be useful.

We currently have a system where sometimes excess energy is produced, but it cannot be stored. Say a renewable source like solar panel generated electricity, which produces an excess in summer months ( at least in my part of the world ), uses some of this energy output to generate ethanol through this process, and then it is stored for use as fuel during the winter months.

Aside from inefficiencies in the process ( and entropy ) there is no net release of greenhouse gases. It effectively steadies the supply of energy generated by renewable sources like solar, wind and other 'variable' sources.