Hacker News Reader

Comment by liability | Hacker News Reader

I believe popular proposals involve the use of algae. Regardless, farming in general is something modern civilization already has a strong competency in. Synthesizing jet fuel from scratch might make sense for the USN since they have nuclear reactors and all the water they want, but I think it's fair to say our civilization in the general case struggles with generating huge amounts of clean electricity. Plants do it with solar energy on a scale we should be jealous of. And so what of they take a few months to do it? They take that long to grow the food you eat too and it's not like you starve for months waiting for them.

View on HN

Society uses absolutely mind-gobbling amounts of energy, mostly from fossil fuels. There's just not enough land available to produce even a significant fraction of that from biofuels. Never mind the ecological devastation that would be caused by converting the little wilderness left to intensive biofuel cultivation.

That is not to say biofuel don't have a role to play. Agriculture and forestry wastes, municipal biowaste, etc. can all be used for energy. And yeah, it makes sense to use the available biofuel for sectors that are otherwise very hard to decarbonise, such as aviation.

Algae, well, that has been researched for decades with very little to show for it. It has great potential, but it seems very difficult to make it actually work.

But this is my point; biofuel makes a ton of sense for aviation. Biofuels would be used in cases where there is no realistic alternative, particularly with airplanes. It's more practical and likely to succeed in this domain than hydrogen, and isn't a total pipe dream like battery powered planes. In other domains, like grid power or automobiles, solar/wind/etc are the way to go (I never suggested we run power plants off biofuel!), but there is still a fuckton of coal and natural gas plants that need to be replaced. Trying to also replace jet fuel with synth fuel at the same time will only set back efforts to close coal and natural gas plants. If we already had a surplus of clean electrical energy then things would be different, but we don't. Every solar farm dedicated to the production of synth fuel is a solar farm that isn't replacing a coal plant.

I just don't see any way that synthesis of jet fuel from atmospheric carbon makes any sense for anybody but a nuclear Navy.

The problem is twofold: The first is that biofuel doesn't scale. Maybe if we shifted all biofuel production to aviation we could do it. But the market is growing over the long term. Which means biofuels will eventually stop being a solution.

The other problem is that biofuel isn't actually all that green. It still needs lots of fertilizer, pesticides, farm equipment, etc., that ultimately gives it a relatively high GHG output.

At some point, we need to bite the bullet and go with hydrogen or one of its derivative fuels (e.g. ammonia, methanol, etc.). People are constantly trying to imagine a solution that avoids this outcome, but no one has come up with anything that looks like a viable alternative.

Reply on news.ycombinator.com