3 ms·

We should use anything edible for feeding people, not burn it for driving cars. Solar cells are far more energy efficient per area (about 10x) than any agricult

by _ph_ 11y ago

We should use anything edible for feeding people, not burn it for driving cars. Solar cells are far more energy efficient per area (about 10x) than any agriculture. And, while "grown" fuel might be CO2 neutral, it still produces the same poisonous combustion byproducts as fossil fuel (NOx, fine particles).

JupiterMoon 11y ago
The OP suggested fuel cells. This would replace IC engines and should result in complete conversion to CO2+H2O (with the whole process being carbon neutral because the CO2 came from the air originally). I.e no NOx, fine particles etc. I agree on feeding people however e.g. algae produced bio oil could be very space conservative -- and could be used to e.g. clean waste water. NB use of could and should rather than would throughout this post. Algae produced bio oils are a matter of research at the moment and I don't think that the fuel cells exist yet.
vlehto 11y ago
In large scale I'd agree that only using vegetable oil for car fuel seems like bad idea, because we seem to be running out of food at that point. But using electricity conversed to hydrogen with relatively bad efficiency (70%) we are soon running out of electricity too. Combine that with hopefully shift from fossil fuels to renewable, and the shit we are in deepens. Now if you could use batteries and electric cars for short trips you would have very high efficiency. Then shift to refueling capable system for long range needs. This is only possible if the "long range" system has very low infra needs. Optimally we would have some kind of standard that would allow you to swap battery to fuel tank + fuel cell unit in your electric car. I've ranted about that previously. https://news.ycombinator.com/item?id=10942912 https://news.ycombinator.com/item?id=10942912

3 ms·

We should use anything edible for feeding people, not burn it for driving cars. Solar cells are far more energy efficient per area (about 10x) than any agricult

by _ph_ 11y ago

JupiterMoon 11y ago
The OP suggested fuel cells. This would replace IC engines and should result in complete conversion to CO2+H2O (with the whole process being carbon neutral because the CO2 came from the air originally). I.e no NOx, fine particles etc. I agree on feeding people however e.g. algae produced bio oil could be very space conservative -- and could be used to e.g. clean waste water. NB use of could and should rather than would throughout this post. Algae produced bio oils are a matter of research at the moment and I don't think that the fuel cells exist yet.
vlehto 11y ago
In large scale I'd agree that only using vegetable oil for car fuel seems like bad idea, because we seem to be running out of food at that point. But using electricity conversed to hydrogen with relatively bad efficiency (70%) we are soon running out of electricity too. Combine that with hopefully shift from fossil fuels to renewable, and the shit we are in deepens. Now if you could use batteries and electric cars for short trips you would have very high efficiency. Then shift to refueling capable system for long range needs. This is only possible if the "long range" system has very low infra needs. Optimally we would have some kind of standard that would allow you to swap battery to fuel tank + fuel cell unit in your electric car. I've ranted about that previously. https://news.ycombinator.com/item?id=10942912 https://news.ycombinator.com/item?id=10942912