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Yeah, I am also on board with diverting excess electricity into transportation fuels if it literally can't fit on the grid. But every joule of electricity gene

Yeah, I am also on board with diverting excess electricity into transportation fuels if it literally can't fit on the grid. But every joule of electricity generated from renewables that makes it to the grid is a joule of electricity that wasn't generated with petrochemicals at the moment because natural gas peaker plants are still a thing. I had to once write a grant proposal for essentially the kind of thing you're talking about. It's exceptionally hard to make a good overall systems efficiency case for taking electricity and turning it back into fuels. I hope you agree that displacement of petrochemical electricity sources is far preferable to generating chemicals as a byproduct if the grid does have room for more electrons. The only way I was able to find to make it work economically was to take excess electricity and convert it into fairly high value chemicals -- but even there, just turning petrochemicals into those same chemicals would in almost every case be more efficient. I look forward to the day when we have so much renewable generation that we have no petrochemical electric plants left to displace. Hopefully it is not too far off, I like your optimism about solar and agree it may be warranted.

chipsa 6y ago
The spot price of electricity has gone negative in certain times and places. So power from then could potentially have not have been generated from petrochemicals (though, it might have been from a oil or coal fired steam plant). If we could change the natural gas peaker plants to ammonia powered peaker plants, we could also use plants that are more base-load(nuclear), and use the ammonia as a long term power storage.
- neltnerb 6y ago
  With 80%-90% losses -- Haber-Bosch is inefficient and so is combustion. I just have a hard time picturing that beating batteries. If it made a high value chemical maybe economically, but not on a purely energy basis, the efficiencies just can't add up. Haber-Bosch requires compression to ~100bar or greater to see much of any conversion and has something like 15% yield per cycle. It is not pretty. I find it impossible to imagine transitioning engines and fueling stations to ammonia before we get batteries light and reliable enough to meet the majority of people's needs. We put many power plants worth of petrochemicals into ammonia right now, replacing it would be great but it just doesn't seem like a low fruit to grab at.
  - Gibbon1 6y ago
    What I think is a lot of this is put out there as an attempt sideline workable technologies to keep the fossil fuel party going. 'Clean coal' 'Carbon Capture' 'Next Generation Reactors' 'Hydrogen economy' all unworkable trash.
    - neltnerb 6y ago
      I agree, I won't name and shame but the grant I was working on was clearly funded by some coal lobby or something because the premise was desperate on the face of it. I practically said "this won't work efficiently, you should just not burn the coal" because nothing else could be justified energetically even if it was maybe economical. I tried my best but I can't change thermodynamics.

chipsa 6y ago

The spot price of electricity has gone negative in certain times and places. So power from then could potentially have not have been generated from petrochemicals (though, it might have been from a oil or coal fired steam plant). If we could change the natural gas peaker plants to ammonia powered peaker plants, we could also use plants that are more base-load(nuclear), and use the ammonia as a long term power storage.

neltnerb 6y ago
With 80%-90% losses -- Haber-Bosch is inefficient and so is combustion. I just have a hard time picturing that beating batteries. If it made a high value chemical maybe economically, but not on a purely energy basis, the efficiencies just can't add up. Haber-Bosch requires compression to ~100bar or greater to see much of any conversion and has something like 15% yield per cycle. It is not pretty. I find it impossible to imagine transitioning engines and fueling stations to ammonia before we get batteries light and reliable enough to meet the majority of people's needs. We put many power plants worth of petrochemicals into ammonia right now, replacing it would be great but it just doesn't seem like a low fruit to grab at.
- Gibbon1 6y ago
  What I think is a lot of this is put out there as an attempt sideline workable technologies to keep the fossil fuel party going. 'Clean coal' 'Carbon Capture' 'Next Generation Reactors' 'Hydrogen economy' all unworkable trash.
  - neltnerb 6y ago
    I agree, I won't name and shame but the grant I was working on was clearly funded by some coal lobby or something because the premise was desperate on the face of it. I practically said "this won't work efficiently, you should just not burn the coal" because nothing else could be justified energetically even if it was maybe economical. I tried my best but I can't change thermodynamics.