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The main thing that's turned me positive on "e-fuels" is that there's such a huge amount of petroleum that's used today in applications where we basically have
by semi-extrinsic 8y ago
The main thing that's turned me positive on "e-fuels" is that there's such a huge amount of petroleum that's used today in applications where we basically have no other options.
Think stuff like big jets, or container ships. If you sit down and crunch the numbers for any non-carbon energy carrier, you either end up sinking the ship or with a fuel tank twice the size of the cargo.
- berbec 8y agoPlastics! Zero-carbon plastics would be great. Pull CO2 from the air, mix with water and wind/solar elec and product bags, phones etc!
- icebraining 8y agoThe thought is kind of horrifying, but you could even make it a closed process - send your old phone to the factory, where it's burned to produce the plastics for your new phone.
- mrguyorama 8y agoThat would open up a pretty good avenue for "recycling" then, and could possibly reduce waste plastic in the environment
- codethief 8y agoAs I learned today in another thread [1], the only problem would be that plastic is usually doped with additional elements that I assume we would somehow have to deal with when burning it. [1] https://news.ycombinator.com/item?id=19845427 https://news.ycombinator.com/item?id=19845427
- stordoff 8y agoWhy is this horrifying? Is there some part of this I'm missing here?
- icebraining 8y agoIt just feels wrong to burn this stuff as part of an established cycle.
- buss 8y agoAbsolutely. A friend of mine founded a company to produce carbon-net-zero biodegradable plastics. Their seed round went well, and making great progress, and are currently raising a series A. If anyone's interested in learning more, email me steven.buss@gmail.com.
- Robotbeat 8y agoThe problem with e-fuels for jets is that a majority of the climate forcing comes from the high altitude water vapor in the exhaust, not actually the CO2. EDIT: I should point out here you COULD actually make an e-fuel without hydrogen and thus without water vapor as a combustion product. Carbon monoxide, for instance. The energy density is much lower, but it is sufficient. HOWEVER, there are obvious safety concerns with CO fuel that basically makes that a non-starter. Another option is a fuel cell that condenses the water output and stores it for periodic (possibly lower altitude) discharge in liquid form. But I agree container ships would be a good application of this. Container ships also have pretty high efficiency internal combustion engines (about 50%), meaning there's less advantage in electrification there than for land vehicles which often have 15-25% efficient engines. And it allows low particulates, which is one of the main forcing regulations on shipping powertrains nowadays, without the overhead of cryogenic LNG. However, container ships use ridiculously cheap bunker fuel instead of highly refined gasoline.
- effie 8y agoCO2 seems much worse pollutant than water long term, because it stays in the air. Water at high altitudes condenses, reflects some radiation back to space and then falls back down.
- Robotbeat 8y agoAt high altitude, the water stays up long enough and has such a huge impact that even its long term averaged impact is greater than the CO2.
- codethief 8y agoI have been completely unaware of this effect. Could you provide me with a source where I can read up on this?
- Robotbeat 8y agoGood overview: https://www.carbonbrief.org/explainer-challenge-tackling-aviations-non-co2-emissions https://www.carbonbrief.org/explainer-challenge-tackling-avi...