The key chemistry bit:
The receiver heats a gaseous heat transfer fluid which circulates in a closed loop, delivering the high-temperate process heat to the thermochemical reactor and the thermal energy store. In the reactor, CO2, water vapour, and methane sourced from biowaste are heated with the solar energy over a catalyst which produces a mixture of carbon monoxide and hydrogen known as syngas. This is then piped down the tower to a Fischer-Tropsch unit which converts it into a synthetic crude which a refinery would then process into kerosene for planes, diesel or methanol for ships and trucks, and petrol for cars.
Super cool. Chemical fuels (hydrocarbons or even plant oils) have ridiculous energy density, which is nice for e.g. cars but absolutely crucial for fast, long-range air travel. I don’t think we’ll be saying goodbye to jet engines for a long time, and it’s awesome that we have ways of making fuel in a somewhat sustainable fashion.
The US Navy has experimented with this, but I think the idea is to use nuclear power instead of solar energy. Makes sense for an aircraft carrier with a big reactor and thirsty jets.
I‘m not particularly hyped about synthetic fuels, but the application to low-carbon cement seems important to me, if this is possible at the scale required
There are plenty of applications where batteries simply won’t be sufficient, so synthetic fuels do have a place. Just not in land based transport.
Agreed. Or the heating of buildings and warm water. (edit: would also be very! inefficient)
Maybe in some remote, off-grid cabins, otherwise heating with synthetic fuels would be hugely inefficient.
Yes. That is how I meant the comment. I see now, it could be read both ways.
I’d really be interested to see a comparison between the costs of electrifying the rail network vs using synthetic diesel for freight throughout the US.
Unlike cars or semi trucks, diesel-electric locomotives are extremely efficient. On the other hand, electrifying the many thousands of miles of track that run through large, unpopulated areas of the US seems like a monumental challenge that would yield far fewer benefits over electrifying cars.
trains are actually one of the examples where you can get away with lower energy dense fuels, like methanol, ammonia or even compressed hydrogen. sure the range will go down, but for many connections this will not matter that much because it will still be possible to go 1000km with one tank if needed.
It worked on every other continent. Of course it would be harder to do in the US because they’ve neglected building out their railways for so long. But the Chinese built a high speed rail network in a few years. There’s no practical reason why the US wouldn’t be able to do it.
The U.S. can’t build like China does. Too many stakeholders to satisfy. Labour too expensive. Too many regulations. The high-speed rail line from San Francisco to LA is going to cost more than all of China’s high-speed rail projects combined!
Is agriculture land based transport? Short of an actual nuclear tractor, nothing but diesel has the energy density sufficient to run modern scale farms.
Chatting around the fire we’ve tried to imagine a solution like dragging a cable but with tractors pushing close to 1000HP now that’s about a megawatt. That’s a long, fat cable or an extremely dangerous voltage to drag around a field, probably both. And an insane grid infrastructure to get power to the field borders.
You wouldn’t believe how much fuel goes into agriculture, to the point where I believe it makes up nearly a third of emissions (possibly including land clearing, can’t remember the details). Synthetic fuels are the only net-zero option.
Well I’m kind of a fan of the nuclear tractor honestly but I kind of doubt it :)
Isn’t burning fuel still going to create green house gasses?
Not more than this process took out of the atmosphere before, so they are at least carbon neutral.
