5 ms·
Hi HN! I'm Rob, founder of Prometheus. Just saw this, catching up now and will try to answer any questions.
by rmcginnis 7y ago
Hi HN! I'm Rob, founder of Prometheus. Just saw this, catching up now and will try to answer any questions.
- PaulAJ 7y ago"Unburning" CO2 takes energy. Where does your energy come from?
- rmcginnis 7y agoWe use zero carbon solar and wind electricity. As long as the electricity source is zero carbon and low cost, it makes economic and practical sense to make zero carbon fuel.
- PaulAJ 7y agoSo what is the efficiency of your process? How many joules of chemical energy do you get from 1 kilowatt hour? (i.e. 3.6MJ)
- fallingfrog 7y agoOk but why not just use the zero carbon electricity, if you have so much of it?
- zamfi 7y agoThey're going after the use case of gasoline as energy storage, not gasoline as primary energy production. The reason, today, that cars are powered by gasoline and not electricity is not the cost of the energy itself, but the cost of storing it. Obviously it would be better to use the electricity directly. But it's hard to get that electricity to a moving car on the road (or a plane in the sky).
- fallingfrog 7y agoIt’s not that hard. You can just charge the car inductively with wires in the road, or better yet, just lay tracks for electric trains.
- zamfi 7y ago> It’s not that hard. You can just charge the car inductively with wires in the road I’m sorry, are you proposing this solution as being cheaper than either gasoline or batteries?
- ramraj07 7y agoThere's a difference between a regular car and a hotweels toy
- eMSF 7y agoYour "not that hard" solutions don't solve the problem you answered to. You can't move a single (production) car out there with wires in the road, or by laying tracks. Perhaps it's a bit harder then, after all?
- adrianN 7y agoHow do you put electricity in your tank?
- kirrent 7y agoYou seem pretty optimistic about the economics of your tech. Is that based on extracting CO2 from air or from more concentrated sources such as power plant flue gas?
- D_Alex 7y agoHi Rob. Why bother trying to extract CO2 out of "thin air" when there are far more concentrated sources available, for example exhaust of existing power plants (100,000 ppm CO2, instead of 400 ppm)? There are even streams of pure CO2 being vented to the atmosphere, eg: https://thewest.com.au/business/energy/woodsides-browse-lng-project-tipped-to-be-among-nations-biggest-polluters-ng-b881025569z https://thewest.com.au/business/energy/woodsides-browse-lng-...
- rmcginnis 7y agoPoint sources won't scale to the size of the problem. Easier initially, but to replace fossil fuels for transportation and heating, will need to get the CO2 from the air.
- D_Alex 7y ago>Easier initially... Then start with point sources initially. Considering a good portion of transportation and basically all of the heating can be replaced by electricity directly, you will not need to go beyond point sources anyway.
- credit_guy 7y agoThere is a much more efficient way to deal with point sources, if you have a clean energy source in their neighborhood: just shut them down and replace the energy they provide with the clean energy you would use to scrub the CO2 from the air.
- D_Alex 7y agoYes, sometimes this is practicable. But many locations do not have sufficient renewable energy available, and nuclear has become unpalatable for a variety of reasons. Scrubbing CO2 from boiler or turbine exhaust takes a small fraction (5%-ish) of the energy needed to convert it into fuel. If the source is a power plant, the CO2 can be captured at a cost of efficiency penalty of around 10%. Once it is captured, storing and transporting CO2 to a location with abundant clean energy is also relatively simple.