6 ms·

If we will have this much spare solar, can’t we just convert it to methane and reuse most of the current infrastructure for heating homes etc? The CO2 can be ta

If we will have this much spare solar, can’t we just convert it to methane and reuse most of the current infrastructure for heating homes etc? The CO2 can be taken from the air…

bryanlarsen 4y ago
I highly doubt that we'll have significant spare solar. Energy is just way too useful and valuable. Once we get close to a situation where the price goes negative, somebody will figure out a way to turn the spare solar into dollars. https://terraformindustries.com/ https://terraformindustries.com/ and SpaceX are planning on turning solar and atmospheric CO2 into methane. Not spare solar, but dedicated solar. It'd be silly to use it to heat your house. If electricity is cheap enough to make the process viable, then a heat pump will save you a huge amount of money.
- _hypx 4y ago
  That spare solar power will be used for hydrogen production most of the time.
  - Iwan-Zotow 4y ago
    And where is it? I mean, CA duck is already there, but not a single cf of hydrogen produced
    - ncmncm 4y ago
      Factories to make hydrogen electrolysers need to be built first. China got a jump on us and is selling electrolysers pretty cheap. Somebody is buying those.
      - tuatoru 4y ago
        To be cheap, they need to operate at multi-GW scale, have a long operating life, and good reliability.
        ncmncm 4y ago
        You say so, but hydrogen production capacity is additive. More electrolysers, more hydrogen, up to the power available. But, as with solar, wind, and storage, prices will fall fast as production ramps up.
        tuatoru 4y ago
        Which costs more to install, run and maintain: 100,000 10kW grid-connected PV installations, or one 1GW installation? I think it's the single installation. Likewise with hydrogen. Unless it is all used at the point of generation, and near enough at the time of generation (storing and transporting it is expensive energetically and in terms of capital assets, and risky), economies of scale apply. And domestic use isn't a good fit for "use it all now while the sun is shining".
    - tuatoru 4y ago
      Yes, advocates for hydrogen need to explain this. My guess: there are major engineering challenges that drive up the cost. Storing and transporting hydrogen (compressed, adsorbed/absorbed or liquid) are difficult.
      - ncmncm 4y ago
        The major use for hydrogen initially will be to push into underground reservoirs. It takes a long time to build out hydrogen handling infrastructure. After we are awash in cheap spare hydrogen, the handling infrastructure will grow by natural market forces. First things happen first.
    - _hypx 4y ago
      https://www.airproducts.com/news-center/2022/04/0422-air-products-and-world-energy-sustainable-aviation-fuel-facility-in-california https://www.airproducts.com/news-center/2022/04/0422-air-pro... A lot of facilities are coming online.
- discordance 4y ago
  On very sunny days in Australia the price frequently goes negative already.
  - ncmncm 4y ago
    That won't last.
FabHK 4y ago
Synthesising fuel could become very interesting, as the entire infrastructure is there already. Might also be interesting for aviation, as batteries are not really practical for a few more decades, it seems to me. https://en.wikipedia.org/wiki/Carbon-neutral_fuel https://en.wikipedia.org/wiki/Carbon-neutral_fuel
- ncmncm 4y ago
  Once LH2-fueled aircraft enter a market, kerosene-fueled craft will be wholly unable to compete. The rate will be limited by how fast retrofits or new airframes can be made, and secondarily by growth of LH2 synthesis infrastructure at major airports. Kerosene craft will be relegated to increasingly marginal routes. Amusingly, Russia could find itself fielding LH2 birds first just because they will need all new aircraft sooner than everybody else.
  - throwaway5959 4y ago
  - 41b696ef1113 4y ago
    Average aircraft age in the USA is 14+ years. A new passenger jet costs some $100+ million. We cannot even approve unleaded aviation gas, I am unsure a transition to LH2 will be speedy.
    - ncmncm 4y ago
      "General aviation" below turboprop-scale has been too small to command the attention needed for change. When you need an LH2 airframe to be able to stay in the market at all, that will accelerate conversion.
danans 4y ago
Generating synthetic hydrocarbon fuels from oversupply of renewables only makes sense for use cases that can't be easily electrified like aviation. The conversion process is very inefficient. Others here have pointed out that hydrogen could eventually be used directly in aviation, at which point hydrocarbon energy storage is even less relevant. Regarding home heating in the future, firstly the infrastructure we have is rapidly depreciating to the point of needing replacement: The gas distribution infrastructure in many areas is old and very expensive to maintain and operate, and furnaces only last a few decades at best. It makes more sense to electrolyse water to H2 and then convert to NH3 for long term storage, then convert that to electricity at a central plant in the heating season, and use the electricity to run heat pumps which can be 300+% efficient. Heat pumps even make sense (from a climate/CO2 perspective, not necessarily a household finance perspective) with the fossil natural gas derived electricity we still use today.
- aledalgrande 4y ago
  This is a thing I'm wondering. In Europe houses are old (i.e. not well insulated) and electricity is expensive. A heat pump to go through the winter would be insanely expensive for most households. Is there any solution that could fix this issue?
  - tuatoru 4y ago
    Insulation! Northern/Western Europe has a whole bunch of Ukrainian refugees. Why not solve two problems at once by putting them to work doing insulation retrofits?
    - deleted 4y ago
      [deleted]
  - danans 4y ago
    Insulation isn't that challenging. Houses eventually need to be upgraded and remodeled. That's usually a good time to insulate them better.
  - 4y ago
_hypx 4y ago
The next step is to use excess renewable energy to electrolyze water and make hydrogen. To get to the next step requires direct air capture of CO₂. We haven't solved that last problem yet. Also, it is not really necessary to go to that step in many cases. Steel can directly use hydrogen in production. Natural gas turbines can switch to hydrogen instead. So any kind of hydrocarbon quickly becomes a value-added cost that may only make sense if you need that particular hydrocarbon.
- marcosdumay 4y ago
  > Steel can directly use hydrogen in production. Well, yes, you can use hydrogen. But you will always have to use some carbon too.
  - ncmncm 4y ago
    In other words, steel is a long-term sink for carbon.
NickNameNick 4y ago
Only if the infrastructure for producing the synthetic fuel is cheap enough to leave idle part of the time.
- ncmncm 4y ago
  Fuel synthesis equipment will never be idle except when long-term storage is actually being drawn down. The output is too valuable for too many things. Everyone will massively overbuild generating capacity in order to keep their electrolysers busy at all times.
stephen_g 4y ago
Heat pumps are so much more efficient in many climates (and the tech is improving quickly for cold temperature air-source - newer model are reportedly much better than was available even five years ago) that it's better to go for electrification. That's even before the massive efficiency loss of producing gas from electricity. Burning gas also produces NOx emissions, which is something that would be much better to avoid, especially in and around houses. The air quality improvements to electrification are potentially massive for public health.

If we will have this much spare solar, can’t we just convert it to methane and reuse most of the current infrastructure for heating homes etc? The CO2 can be taken from the air…

bryanlarsen 4y ago

I highly doubt that we'll have significant spare solar. Energy is just way too useful and valuable. Once we get close to a situation where the price goes negative, somebody will figure out a way to turn the spare solar into dollars. https://terraformindustries.com/ https://terraformindustries.com/ and SpaceX are planning on turning solar and atmospheric CO2 into methane. Not spare solar, but dedicated solar. It'd be silly to use it to heat your house. If electricity is cheap enough to make the process viable, then a heat pump will save you a huge amount of money.

_hypx 4y ago
That spare solar power will be used for hydrogen production most of the time.
- Iwan-Zotow 4y ago
  And where is it? I mean, CA duck is already there, but not a single cf of hydrogen produced
  - ncmncm 4y ago
    Factories to make hydrogen electrolysers need to be built first. China got a jump on us and is selling electrolysers pretty cheap. Somebody is buying those.
    - tuatoru 4y ago
      To be cheap, they need to operate at multi-GW scale, have a long operating life, and good reliability.
      - ncmncm 4y ago
        You say so, but hydrogen production capacity is additive. More electrolysers, more hydrogen, up to the power available. But, as with solar, wind, and storage, prices will fall fast as production ramps up.
        tuatoru 4y ago
        Which costs more to install, run and maintain: 100,000 10kW grid-connected PV installations, or one 1GW installation? I think it's the single installation. Likewise with hydrogen. Unless it is all used at the point of generation, and near enough at the time of generation (storing and transporting it is expensive energetically and in terms of capital assets, and risky), economies of scale apply. And domestic use isn't a good fit for "use it all now while the sun is shining".
  - tuatoru 4y ago
    Yes, advocates for hydrogen need to explain this. My guess: there are major engineering challenges that drive up the cost. Storing and transporting hydrogen (compressed, adsorbed/absorbed or liquid) are difficult.
    - ncmncm 4y ago
      The major use for hydrogen initially will be to push into underground reservoirs. It takes a long time to build out hydrogen handling infrastructure. After we are awash in cheap spare hydrogen, the handling infrastructure will grow by natural market forces. First things happen first.
  - _hypx 4y ago
    https://www.airproducts.com/news-center/2022/04/0422-air-products-and-world-energy-sustainable-aviation-fuel-facility-in-california https://www.airproducts.com/news-center/2022/04/0422-air-pro... A lot of facilities are coming online.
discordance 4y ago
On very sunny days in Australia the price frequently goes negative already.
- ncmncm 4y ago
  That won't last.

FabHK 4y ago

Synthesising fuel could become very interesting, as the entire infrastructure is there already. Might also be interesting for aviation, as batteries are not really practical for a few more decades, it seems to me. https://en.wikipedia.org/wiki/Carbon-neutral_fuel https://en.wikipedia.org/wiki/Carbon-neutral_fuel

ncmncm 4y ago
Once LH2-fueled aircraft enter a market, kerosene-fueled craft will be wholly unable to compete. The rate will be limited by how fast retrofits or new airframes can be made, and secondarily by growth of LH2 synthesis infrastructure at major airports. Kerosene craft will be relegated to increasingly marginal routes. Amusingly, Russia could find itself fielding LH2 birds first just because they will need all new aircraft sooner than everybody else.
- throwaway5959 4y ago
- 41b696ef1113 4y ago
  Average aircraft age in the USA is 14+ years. A new passenger jet costs some $100+ million. We cannot even approve unleaded aviation gas, I am unsure a transition to LH2 will be speedy.
  - ncmncm 4y ago
    "General aviation" below turboprop-scale has been too small to command the attention needed for change. When you need an LH2 airframe to be able to stay in the market at all, that will accelerate conversion.

danans 4y ago

Generating synthetic hydrocarbon fuels from oversupply of renewables only makes sense for use cases that can't be easily electrified like aviation. The conversion process is very inefficient. Others here have pointed out that hydrogen could eventually be used directly in aviation, at which point hydrocarbon energy storage is even less relevant. Regarding home heating in the future, firstly the infrastructure we have is rapidly depreciating to the point of needing replacement: The gas distribution infrastructure in many areas is old and very expensive to maintain and operate, and furnaces only last a few decades at best. It makes more sense to electrolyse water to H2 and then convert to NH3 for long term storage, then convert that to electricity at a central plant in the heating season, and use the electricity to run heat pumps which can be 300+% efficient. Heat pumps even make sense (from a climate/CO2 perspective, not necessarily a household finance perspective) with the fossil natural gas derived electricity we still use today.

aledalgrande 4y ago
This is a thing I'm wondering. In Europe houses are old (i.e. not well insulated) and electricity is expensive. A heat pump to go through the winter would be insanely expensive for most households. Is there any solution that could fix this issue?
- tuatoru 4y ago
  Insulation! Northern/Western Europe has a whole bunch of Ukrainian refugees. Why not solve two problems at once by putting them to work doing insulation retrofits?
  - deleted 4y ago
    [deleted]
- danans 4y ago
  Insulation isn't that challenging. Houses eventually need to be upgraded and remodeled. That's usually a good time to insulate them better.
- 4y ago

_hypx 4y ago

The next step is to use excess renewable energy to electrolyze water and make hydrogen. To get to the next step requires direct air capture of CO₂. We haven't solved that last problem yet. Also, it is not really necessary to go to that step in many cases. Steel can directly use hydrogen in production. Natural gas turbines can switch to hydrogen instead. So any kind of hydrocarbon quickly becomes a value-added cost that may only make sense if you need that particular hydrocarbon.

marcosdumay 4y ago
> Steel can directly use hydrogen in production. Well, yes, you can use hydrogen. But you will always have to use some carbon too.
- ncmncm 4y ago
  In other words, steel is a long-term sink for carbon.

NickNameNick 4y ago

Only if the infrastructure for producing the synthetic fuel is cheap enough to leave idle part of the time.

ncmncm 4y ago
Fuel synthesis equipment will never be idle except when long-term storage is actually being drawn down. The output is too valuable for too many things. Everyone will massively overbuild generating capacity in order to keep their electrolysers busy at all times.

stephen_g 4y ago

Heat pumps are so much more efficient in many climates (and the tech is improving quickly for cold temperature air-source - newer model are reportedly much better than was available even five years ago) that it's better to go for electrification. That's even before the massive efficiency loss of producing gas from electricity. Burning gas also produces NOx emissions, which is something that would be much better to avoid, especially in and around houses. The air quality improvements to electrification are potentially massive for public health.