As I’ve blogged before, one of the old Lil Abner strips featured plans for a car that ran directly off of smog, which was Al Capp’s excuse to draw nervous fat cat oil executives. That was fiction. In 2008, the New York Times reported that two scientists at Los Alamos National Laboratory had a plan, Green Freedom, to remove smog from the air and turn it into fuel. Their plan was all based on existing technology, but was a net energy loser requiring a huge factory powered by a dedicated nuclear powerplant to be remotely feasible. That might as well have been fiction.
Now, Tailpipe to Tank, a feature article in Science Magazine reports on a solar reactor that could use the energy in sunlight to change carbon dioxide and water into hydrogen and carbon monoxide – which can be the basis for liquid hydrocarbon fuels, which they call, Sungas.
It is only one of the solar fuel technologies taking shape in labs around the world. They embody a dream: the prospect of one day bypassing fossil fuels and generating our transportation fuels from sunlight, air, and water—and in the process ridding the atmosphere of some of the CO2 that our fossil fuel addiction has dumped into it.
These schemes are no threat to the oil industry yet. In Licht’s device, parts of the reactor run at temperatures approaching 1000°C, high enough to require specialized materials to hold the components. Other researchers are pursuing an alternative approach, developing catalysts that could carry out the same chemical reactions at or near room temperature, using electricity from sunlight or other renewables to power the chemical knitting process.
Sungas would be costly, too, one favorable estimate being $2.61 per gallon – a penny more per gallon than predicted for the Los Alamos scheme. The low temperature reaction works best with gold as the catalyst, but less expensive materials could be made to work. The current challenge is that with low demand, crude oil has dropped to about $50 per barrel, so alternative fuels – even from tar sands – just cost too much to justify seed money.
Optimists in the science community believe that society will always need liquid fuels no matter the price. At Science Blogs, Greg Laden writes:
This and other methods of making a sun, water, and air based liquid fuel would at least initially be expensive. But who cares? If we convert most of our energy to motion machinery to electric, we won’t need that much, and the remaining uses will be relatively specialized. So what if a hospital has to pay $10.00 a gallon to have a thousand gallons of fuel for use as a backup source of energy to run generators during emergencies? That would be a tiny fraction of the cost of running a hospital. A tiny fraction of a fraction.
But it remains to be seen whether electric vehicles will prosper without massive government subsidies, and without motion vehicles, there may not be a sophisticated enough culture to produce and need expensive liquid fuels.
Update 20150918: At the Scienceblogs link above, in the comments, Laden makes the truly stunning argument that EROI – energy return on investment – is, “a red herring and not of much interest.” In a later comment:
In principle it is of interest. There are two or three problems
One is that in so many cases, especially when it comes to clean alternatives that are not even in production, the number is pretty much irrelevant to what would actually happen if we went into production.
Another problem is that it is just about energy and ignores other costs and benefits. These are often far more important.
Another (when comparing across totally different energy source types, as was bandied about above) is that if I need a liquid and you’re talking to me about the difference between a solid and a liquid, I don’t need to know that. I needed the liquid.
Similarly, there are simply certain pathways that we want to use no matter what. I might want to have no imports of petroleum into a region where there is nothing native. Comparing petroleum to non petroleum sources would be irrelevant. There may be something about storage under specific conditions that matters a lot more to me than EROI.
The real problem is the fetishizing of EROI. If something has a bad EROI then it has to dance backwards and in high heels, even if it is really a preferred energy source for a gazillion other reasons.
It is like Godwin’s law. Eventually the conversation will go off track because of EROI even if it shouldn’t.
So it is of interest, but of interest does not equal “the main thing.”