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Every time there’s a discussion about synthetic carbon fuels, there’s the same frustrating replies. I want to reply to those with one statement: the whole poin
by bit_logic 6y ago
Every time there’s a discussion about synthetic carbon fuels, there’s the same frustrating replies. I want to reply to those with one statement: the whole point is to use excess power from solar/wind. There’s always the same replies pointing out how it’s more efficient to use the power directly in EV batteries, laws of thermodynamics, and other similar things. Those completely miss the point. Solar/wind is going exponential and we have a big problem of storing excess power. Massive really massive amounts of batteries is one option. But converting that into carbon fuels that work directly in existing infrastructure and is effectively carbon neutral is a good option too. That’s where the discussion should be, not pointless arguments about efficiency of EVs.
- regularfry 6y agoI was going to ask if anyone knew what the efficiency of this process was. Obviously we can't get a perpetual motion machine out of it, so it must be taking more energy to form the syngas than gets released from the fuel in the first place, right?
- lstodd 6y agoRight.
- ZeroGravitas 6y agoYou don't need carbon to store energy, you can just stop at hydrogen (or use nitrogen to make ammonia). Processes can be refitted to use pure hydrogen or it can just be added in small increments to existing gas burning plants. Replacing anything that burns fuel with carbon in it with alternatives that dont is a better solution.
- p1mrx 6y agoLots of homes and buildings use natural gas for heat. It would be nice to replace that with something carbon neutral, but the infrastructure can't handle hydrogen levels above 10-20%.
- virtue3 6y agohydrogen is notoriously difficult to store. Being an atom "thick" generally means it leaks through containers regardless of what you try to do. And I don't know if you've played the game "Oxygen Not Included", but creating liquid hydrogen is no easy task either. A more dense energy storage substance (such as a hydrocarbon) would probalby be more efficient in terms of transportation / use / storage.
- pm90 6y agoI didn’t expect to see ONI in a hacker news thread! Yes, hydrogen is an absolute mess to handle in free form, while hydrocarbons... stable, energy dense, and something we’ve had experience working with for a couple of centuries now. A nice side effect would be that synthetic hydrocarbons might possibly reduce the dependency on oil for manufacturing plastics, dyes etc. It’s incredibly exciting... I don’t see how this isn’t a huge win.
- m4rtink 6y agoHydrogen leaks in an oxygen atmosphere (like the one here on earth) are pretty dangerous, as they are effectively invisible in daylight, due to almost all the energy going directly to infrared. Due to that NASA test engineers used to walk with a broom in front of them in areas where hydrogen leaks could happen. If the broom suddenly caught fire, there was a burning hydrogen leak in front of the engineer! A picture of this can be seen here: https://spinoff.nasa.gov/spinoff1997/ps1.html https://spinoff.nasa.gov/spinoff1997/ps1.html Not just leaks, hydrogen can destroy the structure of many metals and make them brittle: https://en.wikipedia.org/wiki/Hydrogen_embrittlement https://en.wikipedia.org/wiki/Hydrogen_embrittlement And another issue is the very low density - you van see it with hydrolox rockets, how big they are & how their liquid hydrogen tanks are compared to the LOX tanks. This adds up in tank weight, removing some of the energy/density benefits. This is one of the reasons many next gen rockets are opting for liquid methane instead of liquid hydrogen.
- wtracy 6y ago> the whole point is to use excess power from solar/wind. Thank you. > But converting that into carbon fuels that work directly in existing infrastructure and is effectively carbon neutral is a good option too. This approach seems really underrated, at least for transportation. Hydrocarbons still have the best energy density of the realistic options. We have a century of experience building ICEs with favorable power/weight ratios. Why throw all that away?
- bit_logic 6y agoToo often have environmentalists let the perfect be the enemy of good. I understand why they feel that way, for so long have they fought against fossil fuel companies and other interests. They feel like if they give an inch, they will take a mile and climate change is too urgent. And so they oppose any transitional technology. They want to push for only perfect solutions like EVs and batteries. But I want those environmentalists to sit down and think. Yes, climate change is urgent, and that urgency should make you stop asking for perfection. There are 1.4 billion cars in the world. Even a 100% ban today on ICE car production is not going to change that. Cars have an average usable span measured in decades. The projections for 2050 are catastrophic if carbon emissions don't go down. Green tech has one big overwhelming victory right now, solar/wind. It's annihilating coal and will eventually defeat natural gas as well. We can take that victory and use it to make the existing cars and airplanes carbon neutral. If you care about climate change, why is this not more exciting than EVs?
- deleted 6y ago[deleted]
- m_mueller 6y agoWell, is it such a big victory for renewable? I think the big winner atm. is natural gas from fracking, which could easily be the final nail in the coffin.
- skybrian 6y agoA problem with processes based on using excess power is that they use equipment inefficiently. If cheap power is only available for a quarter of the time then it would take 4x as long to pay for the investment in the equipment. Whatever scheme you set up to use excess power needs to be pretty cheap to make it worth running only a small part of the time, or it needs to be doing something especially valuable. Compare to the strategy of locating somewhere that electricity is always cheap and running all the time.
- bit_logic 6y agoSolar produces only during the day, but wind is at any hour. And these days, the idea of massive over-provisioning is being discussed to overcome the intermittent problem since solar/wind keeps getting cheaper and cheaper. The idea is simple, how to overcome the cloudy winter day issue? Simply overbuild a lot of solar/wind so it can still provide enough on a winter day. Then during summer, shutoff the excess power generation. But what a waste of potential to do that! All that overbuilt power generation, simply turned off during summer. Batteries don't help here, it would store it, but then the question of what to do with it is still here. If society goes the route of massive overbuilding solar/wind, then there's an opportunity to do something with effectively free power during summer. But it's ONLY during summer, so it needs to be something valuable that can also act as a energy storage. Carbon fuel is perfect for this. Millions of ICE cars exist and are still being produced. Long distance airplanes will be carbon fuel based for a long time. And so many other uses. I think another option is water. Water can also be seen as a valuable resource that acts as energy storage. Use the excess summer power to fill up a near empty dam with desalinated water? Sounds like a perfect fit for regions like southern California or Arizona.
- skybrian 6y agoOh, but look at the equipment that's shut down, doing nothing, all winter! What a waste. Sure, the electricity is a bit more expensive, but it's still fairly cheap so why not turn it on and get some use out of it? All processes have some waste. In the end, you need estimates done with real numbers to see if it's worth doing. We aren't going to settle it with casual chit-chat.
- carapace 6y agoBucky Fuller had the idea to just connect the world's electricity grids together. He called it "World Grid" I think.
- ashtonkem 6y agoThat’s more efficient, but difficult politically and logistically.
- Godel_unicode 6y agoHow would that be more efficient? The transmission loss would be outrageous between the summer and winter hemispheres. Compare that with transmission loss for LNG tankers at the moment, effectively 0 even with the occasional leak in transit.
- ashtonkem 6y ago1) The main loss for LNG wouldn’t be transit, it would be efficiency during synthesis. 2) Any inefficiency during transit of LNG isn’t leaks, it’s the fuel burnt moving it around. 3) The cost of building high efficiency LNG power plants wherever you need power is another cost that should be considered.
- nine_k 6y agoGeography may also be a problem. Running a gigawatt cable from sun-soaked Australia anywhere in SEA is enormously expensive. Instead, packaging the energy into carbohydrates produced from waste water (cleaning it in the process) and waste CO₂ may be much more economical and convenient. You can likely produce the best quality Jet A fuel or octane 98 gasoline with little other fractions by tuning the synthesis process (unlike an oil well which gives you a mix you can't control). Beside that, a transatlantic jet, let alone a Falcon 9, won't ever fly with battery power. You still need highly energetic fuels where power density is at a huge premium.
- selectodude 6y ago
- clouddrover 6y agoYes, it's worth making use of the excess power. The Orkney islands, for example, are using their excess wind and tidal power to produce hydrogen: https://edition.cnn.com/videos/business/2020/03/06/orkney-hydrogen-energy-lon-orig.cnn-business/video/playlists/business-global-energy-challenge/ https://edition.cnn.com/videos/business/2020/03/06/orkney-hy...
- adrianN 6y agoWhat's missing is a careful differentiation between doing what you said, storing excess energy, and approaches that are popularized, e.g. by carmakers unwilling to invest in R&D, where we keep on relying on hydrocarbons for things like transportation and heating and magically replace them with carbon neutral alternatives. The first approach of using hydrocarbons as an energy buffer makes perfect ecological and economical sense and is most likely strictly necessary for a carbon neutral energy grid (barring battery breakthroughs), once we reach 60-70% renewable energy in our grids. The latter approach however makes no sense at all, because we simply don't have enough space for wind and solar to feed our thirst for hydrocarbons with renewable power. The energy losses, both in the step creating the fuel, and in the step turning fuel to useful work, are just too great to fuel every car or heat every home in the world like that.
- jfkebwjsbx 6y agoHow big are the losses to make such a big impact as to say there is not enough space for enough solar/sun farms? 99% or what?
- adrianN 6y agoI think you're overestimating the amount of space we have realistically available for renewable energy. At some point I did the math for Germany. The average German needs around 144sqm of solar panels (located in Germany) to meet their primary energy demand of around 48MWh per year (taking into account average production of solar panels in Germany). Germany has a population density of around 4300sqm / person. So in the ideal case with no storage losses you need to cover more than 3% of Germany with solar panels if you want to meet primary energy demand with solar power. (Wind energy is slightly more dense in Germany, but I haven't done the math there). Realistically you might get something like 1% of the land area without huge resistance of the local population. Probably less, which is why offshore wind is popular. 100% renewable generation is only realistic because you can safely assume that large parts of the primary energy consumption are wasted. For example internal combustion engines are at best 40% efficient. Burning things for heating also only gets you 1J of heating per Joule expended, whereas heat pumps get you 2-3J. You just can't get away with losing another factor two to generate syngas, or even more if you want liquid fuels. Of course you can justify some inefficiencies if you're willing to transport energy from far away (say solar power from the Sahara), but that is ridiculously expensive compared to more local generation.
- D_Alex 6y agoBy golly, I agree! And I would agree even if I wasn't working on technology to achieve this. Unfortunately, the article does not say how the zinc oxide nanoparticles will help with being able to use solar/wind power to produce syngas. In fact it is not clear how these nanoparticles could actually be used to make an industrial catalyst. Current catalysts also use nanoparticles - on a substrate with enormous surface area/volume ratio, but these nanoparticles are created on that substrate. I am curious about what the researchers plan as the next step.
- 08-15 6y agoThe article provokes these replies by prominently making this absurdly stupid statement: This technology could be retrofitted to coal fired power plants. No, it can't! The power plant is run precisely when you don't have excess power to store. Conversely, you don't have concentrated CO2 when the power is available. It might work for a cement kiln, but not for a power plant. I'm sure you know that. But the idiot who put a picture of cooling towers into the article clearly doesn't. He probably doesn't know the first law of thermodynamics, either.
- twic 6y ago> The power plant is run precisely when you don't have excess power to store. Conversely, you don't have concentrated CO2 when the power is available. Unless you have some way of buffering the CO2. Biologically, this is what CAM photosynthesis does [1], and i have a vague memory of there being an industrial equivalent. Something like dissolving the CO2 in calcium hydroxide, to make calcium carbonate, then later on sparging it with hydrogen to recover the carbon? [1] https://en.wikipedia.org/wiki/Crassulacean_acid_metabolism https://en.wikipedia.org/wiki/Crassulacean_acid_metabolism
- 08-15 6y agoI was sort-of hoping for this comment. What it boils down to is, what is easier? Storing hydrogen, or storing both CO2 and a hydrocarbon, or is there another way? With lots of caveats, because the chemistry isn't exactly the same. (I think there is another way, and it's ammonia and/or hydrazine.) > Something like dissolving the CO2 in calcium hydroxide That's terrible. Calcium carbonate needs to high heat to release CO2. Unless you want to leave CaCO3 well alone (that's the enhanced weathering concept), this is approximately the last compound you want to make. Simply storing liquid CO2 under pressure (80 bar or so? not nice, but doable) sounds much more appealing. (Ammonia is better in every respect, though.)