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There’s no clear indication whether that would require some CO2 or a concentrated atmosphere of CO2 without O2. Extracting CO2 from the atmosphere at 0.4% is ex

• avar 3y ago
  "Must" is debatable, but I've got a propane patio heater of a fairly common model here (NL) that tops out at 13000 watts. If it were electric it would require a 13k/220 = 60 amp connection, triple the domestic wiring standard here.
  • bertil 3y ago
    You’d need a lot less power if you use infrared lights… Still: better grid connection or home batteries are much less complicated to install than a whole new CO2 conversion set-up, plus we are going to need those if people are going to drive electric cars. The cost (energy or money) of capturing CO2 in the atmosphere into concentrate for that catalytic process.
    • mschuster91 3y ago
      You have a lot of industrial processes that produce highly concentrated CO2 - for example, cement production which is responsible for about 8% of worldwide CO2 emissions.
      • bertil 3y ago
        I’m not convinced that the overall cycle is sustainable: cement >> concentrated CO2 >> electrolysis >> propane >> burn into the atmosphere still leaves that 8% of CO2 in the air.
        • ivan_gammel 3y ago
          It replaces equivalent 8% of CO2 from fossil fuels that would be burned otherwise.
        • yetihehe 3y ago
          Cement is absorbing some of that CO2 back when it's curing. Some of CO2 is emitted by processing (crushing and heating), that part could be eliminated by renewable fuels, some is inherent in making cement (releasing CO2 from limestone) but most of that part is absorbed back during curing. There are also carbon-negative alternatives in works[0]. That propane from cement could be used for synthesis of other materials instead of oil (not used yet because it's not needed only because we have cheaper oil) instead of being burned. [0] https://www.theguardian.com/environment/2008/dec/31/cement-carbon-emissions https://www.theguardian.com/environment/2008/dec/31/cement-c...
    • rocqua 3y ago
      We will need all the electrification we can get for electric cars and heat pumps. offloading some of that to other energy sources, using pre-existing infrastructure, would be amazing!
  • pjc50 3y ago
    Patio heaters: for when the planet isn't warming fast enough and you want to pump heat directly into the atmosphere.
    • PaulDavisThe1st 3y ago
      That's good. But also a bit misleading. Pumping heat into the atmosphere isn't really at the heart of climate change - adding insulation to the atmosphere is. It probably isn't great to pump heat into it either, but the mechanisms for radiative loss of that extra heat are (were) pretty good, and it would take a gigantic amount of heat (more than we've produced by burning fossil fuels) to shift the energy level in the atmosphere by much over longer time frames. However, effectively adding another blanket to the atmosphere is far more impactful. Last credible estimate I saw was the atmosphere now contains about an extra 8 peta-watts compared to pre-industrial times, and almost all of that comes from a reduction in "radiative forcing" (loss of heat to space, essentially) rather than additional heat generation.
      • SoftTalker 3y ago
        Yes, the amount of heat added to the atmosphere by human activities is negligible compared to what we receive every day from the sun. It's the heat that is retained that is the problem.
      • pjc50 3y ago
        This is true, but it's also explaining a joke. The real point is that patio heaters are necessarily very inefficient because they're operating in an uninsulated space that's open to the elements - almost all the heat will be immediately lost to the atmosphere. Heat lamps are better, but really patio heaters are used by people trying to cosplay an outdoor culture at a latitude or season that doesn't support it, and they should put some warmer clothes on or go inside.
        • PaulDavisThe1st 3y ago
          Your final observation might be true of parts of the USA. But go to Berlin in winter, or anywhere in northern Europe really, where "it's cold" and "being outside" are not considered oppositional. Take a winter walk down a Berlin street with outdoor restaurant seating, and see people sitting under blankets, with warm coats on, and hats ... enjoying dinner ... and patio heaters. They are not cosplaying at anything. It's just how it is.
  • goodpoint 3y ago
    Patio heaters should be illegal.
• mschuster91 3y ago
  > Are there use cases where we must burn propane because we can’t replace that process with electricity? Yes. Ships, for one - no way you can power an oceangoing large ship with batteries for the entire trip, but doable with LPG (which is essentially a propane/butane mix). Assuming that further technology (chemical or biotech) gets developed to combine it to form larger hydrocarbons, it can also be used as a precursor for airflight synthfuel.
  • speedgoose 3y ago
    One ship could always go nuclear, or use wind.
    • noir_lord 3y ago
      Russia tried that for nuclear, it wasnt a success. Though that was because it was badly mismanaged and the technology wasn't there yet.
    • mschuster91 3y ago
      Wind doesn't work with container ships, the sails are in the way of the cargo cranes at port. Might be an interesting idea for passenger ships though, but even there... there are ports which have a height limit (e.g. Hamburg) because ships need to pass below bridges. Nuclear in civilian hands is an absolute no-go for proliferation / terrorism concerns.
      • lucidguppy 3y ago
        Someone should tell theses guys about wind power. https://www.cnn.com/2023/08/22/travel/wind-powered-cargo-ship-cargill-bartech-climate-c2e-spc-intl/index.html https://www.cnn.com/2023/08/22/travel/wind-powered-cargo-shi...
        • sandos 3y ago
          Yep, and those smartly can fold down! Also used for storms I assume.
• aqme28 3y ago
  > Are there use cases where we must burn propane because we can’t replace that process with electricity? That's not relevant in the short term. There are so many things using propane right now and it's a lot easier send them "renewable propane" than to entirely retrofit them to be electric.
  • bertil 3y ago
    Not if it’s a lot more expensive.
    • fodkodrasz 3y ago
      You can run ICE cars on LPG (propane + butane, would probably work on pure propane as well), with minor (<1000$) modification in the fuel injection system and fitting a proper tank. This could make millions of older cars cleaner, also in the developing world. LPG is already cleaner, would benefit the developing world, and ICE engines can be produced without needing exotic materials, can be recycled 100% by smelting, are a proven, well known, durable technology, unlike lithium batteries (which are also proven, but recycling and exotic materials are problematic), and are and will be a popular technology in the developing world for a long time. Also it would allow for cheaper and cleaner cars in the developed world, where not everybody can afford the electric dream many here are living. It would also be somewhat suitable for long haul and heavy machinery, but most likely in a hybrid drivertrain setup. Also it would solve the big issue of the German home heating and industry: how to stove away the sun and wind from the summer to the winter, when in the windless dark days nowadays coal is burnt, as battery of hydro storage cannot be scaled beyond a few days capacity at extremes. There is already built, or cheap technology to gas powered solutions, no need to transition to new technology hastily. This would give runway to the green transition, as it could be net zero carbon footprint solution with less disturbance to the existing solutions.
      • coderenegade 3y ago
        This. There's no way the global car fleet is switching over to electric any time soon. Globally there are around 1.2 billion cars, with 65 million or so sold each year, which puts us at 15-20 years for the fleet to be replaced if every single car sold from today were electric. Like it or not, internal combustion cars have many advantages, a big one being that they can run on different fuels. Converting to green LPG or (my pick) methanol will have to happen if we're serious about reducing transport emissions, because it's the only immediate non-cost-prohibitive option.
• rocqua 3y ago
  > Are there use cases where we must burn propane because we can’t replace that process with electricity? I think this might slot in everwhere we currently plan to use hydrogen, with the added benefit of larger storage. Here in Europe we have massive natural gas storage facilities so we can buy gas during summer to use for heating in winter. We will need something similar but renewable. If we can fill that storage with green propane, that would be amazing. It would mean we can keep our heating infrastructure. And we have an amazing use for the solar over-production in summer. Honestly tho, this sounds to good to be true.
  • worldsayshi 3y ago
    > this sounds to good to be true. This post seems to have gotten a lukewarm reception. People are maybe extra sceptical after the lk99 dud.
  • konschubert 3y ago
    it’s probably still more efficient to burn the gas in power plants and use heat pumps for heating. Also saves us from maintaining a residential gas network.
    • wokkel 3y ago
      Maybe, but if everyone starts using heat pumps we have a problem in getting enough copper in the ground everywhere on time. So even if it's temporary (20 years or so) this is still a great solution.
      • apexalpha 3y ago
        The copper is mostly already in the ground. At least in the Netherlands it is. Apparently decades ago some absolute madman genius decided that we should put down 5 copper cables to every house and building for 3-phase power, even though they only needed one phase for the coming decades. You know. just in case.
      • teruakohatu 3y ago
        > Maybe, but if everyone starts using heat pumps we have a problem in getting enough copper in the ground everywhere on time. In New Zealand everyone uses heatpumps and there is no problem with everyone running them. Heatpumps don't use a huge amount of power even on cold days. If the grid can handle everyone cooking dinner at 6pm, it can handle heatpumps running throughout the day keeping the house warm. Fast electric car charging on the other hand draws a lot of current.
• garyclarke27 3y ago
  CO2 concentration in atmosphere is .04% not .4% But Yes is too low as a source for this process.
  • rocqua 3y ago
    Estimates I found (in one article, I linked it somewhere else) put the energy usage of CO2 capture from ambient air at about 2800kwh per ton of CO2, someone else calculated one ton of CO2 would produce 376kg of propane. Which is about 5254 kwh. So it would be a significant hit to efficiency, changing it from about 90% to 60%. But that doesn't bring the efficiency to stupidly low levels.
  • nonethewiser 3y ago
    So lets pump more CO2 into the atmosphere.
  • gcanyon 3y ago
    > .04%, not .4% Give it time, we're working on it...
    • zaroth 3y ago
      > Concentrations of CO2 in the atmosphere were as high as 4,000 ppm during the Cambrian period about 500 million years ago, and as low as 180 ppm during the Quaternary glaciation of the last two million years. So a range of 0.018% to 0.4% over the last 500 million years. We’re currently at ~420ppm, and human impact is estimated to have been about +140ppm since the 1700s where we had been at 280ppm for the ~10,000 years prior. If the planet ever hit 0.4% again it would be due to natural not anthropogenic reasons.
• emptybits 3y ago
  > Are there use cases where we must burn propane because we can’t replace that process with electricity? "Must", no. But hundreds millions of cars and trucks on the road right now can be converted to propane. It's relatively easy and well understood and you keep your same motor and drivetrain. Converting existing cars and trucks to electric is so intensive it's almost unthinkable ... cost, energy input, waste, etc.
  • bertil 3y ago
    That process relies on DAC, plus electrolysing H2 and that conversion processes, which means the propane would have to be at the equivalent of 15-45$ per gallon. What is less affordable?
    • coderenegade 3y ago
      It's a matter of time scales. If every car sold today were electric, it would still take 15-20 years for us to completely replace the fleet. Remember, there are a good 1.2 billion or so cars, and around 65-70 million are sold a year. If the cost of this technology could be brought down within a decade, it would be a way of reducing emissions for the large chunk of the fleet that isn't electric, in a cost effective manner. The other, more pragmatic, answer is that internal combustion engines aren't going anywhere. They have too many advantages over their competitors to ever fully go away, so we need cost effective ways of running them that are also carbon neutral or negative. Some of the links in this chain, like low cost electrolysis, are vital for other reasons (e.g. the food we grow uses fertilizer made from hydrogen split from fossil fuels. We need the fertilizer or the planet starves, and we need a source of hydrogen that doesn't also produce 11 tonnes of CO2 for every tonne of hydrogen produced).
    • bluGill 3y ago
      The current iteration does. Research often brings costs down, though there is no guarantee.
• _hypx 3y ago
  It's funny to see people suddenly say this is doable, even though many posters in the past have claimed that it is totally impossible. The problem ultimately is that CO₂ capture from the air is another expense that has to be paid, both in terms of cost and energy. Sure, if the entire process becomes so cheap and widely available that this no longer becomes issue, then we can certainly do it. But until then, it is a major stumbling block. The other problem is that if all you want is something more "practical" than hydrogen, you will stop at methane. Same basic idea as this, but you only need the Sabatier process. And we already have many facilities capable of dealing with methane. So we do not necessarily need to go further. But if you insist on long carbon chains, why stop at C3? Keep going until you reach C8, or even C12-20, at which point you have the equivalent of gasoline or diesel. Basically, get to the point where you have a liquid at room temperature, and it will be even more practical than propane.
  • jabl 3y ago
    > The problem ultimately is that CO₂ capture from the air is another expense that has to be paid, both in terms of cost and energy. Sure, if the entire process becomes so cheap and widely available that this no longer becomes issue, then we can certainly do it. But until then, it is a major stumbling block. That is, of course, very true. Per calculations upthread, the energy cost of DAC isn't that huge, but indeed it's for the time being a very immature technology that hasn't been demonstrated at scale. > The other problem is that if all you want is something more "practical" than hydrogen, you will stop at methane. Same basic idea as this, but you only need the Sabatier process. And we already have many facilities capable of dealing with methane. So we do not necessarily need to go further. In principle yes. I guess it's a question of cost. Is the cost of an H2 electrolyzer + the Sabatier reactors etc. lower than this propane electrylyzer? If this propane electrylyzer thing could be done cheaply, that could be the gamechanger. Not the fact that it's technically possible to manufacture synthetic hydrocarbons, we have multiple ways of doing that, though all of them tend to be both expensive in terms of capital cost and somewhat inefficient. > But if you insist on long carbon chains, why stop at C3? Keep going until you reach C8, or even C12-20, at which point you have the equivalent of gasoline or diesel. Basically, get to the point where you have a liquid at room temperature, and it will be even more practical than propane. Indeed, from a handling and transportation point of view, the longer hydrocarbons are pretty much optimal. But like above, it's a question of cost. Fischer-Tropsch installations tend to be very capital intensive, yield is an issue etc. So if this propane electrolyzer turns out to be industrially feasible at a low enough cost, maybe it's overall more efficient to deal with pressurized storage systems.