3 ms·

For every 1 pound of polysilicon generated, you create 2-4 pounds of silicon tetrachloride. Even if the cost of a panel goes to zero, it makes no difference bec

For every 1 pound of polysilicon generated, you create 2-4 pounds of silicon tetrachloride. Even if the cost of a panel goes to zero, it makes no difference because the costs to dispatch and transmission energy exceed the useful capacity of solar in a large % of areas where it is deployed on the grid and the specific times in the grid, you end up consuming more nat gas per kwh than if you'd just burned nat gas from start to finish. I bought $UAN at $7-$9 and I'll continue buying between $75-$85. It's sort of a long call on natural gas - and for me a long call on ESG ridiculousness proliferating quickly. The nat gas bull run will rise again with the wide scale institutionally backed ESG funds that get pointed toward solar deployments.

fnordpiglet 3y ago
I’m sorry I lost you on the last point. Where does the natural gas consumption come from in a solar power plant, inclusive of presumably grid connectivity? I don’t understand the chemistry you state. My understanding is silicon tetrachloride is an intermediate for producing polysilicon, and is used multiple places in the process in a recycling through the hydrogenation reactor. It’s not a by product. Do you mean to produce polysilicon you need 4x the silicon tetrachloride? That’s approximately true. But chlorinated ferrosilicon is typically the route for production and this can be achieved without natural gas, if that was where you got your nat gas assertion.
- kumarski 3y ago
  https://www.sciencedirect.com/topics/earth-and-planetary-sciences/silicon-tetrachloride#:~:text=Silicon%20tetrachloride%20is%20a%20by,tetrachloride%20liquid%20waste%20are%20generated https://www.sciencedirect.com/topics/earth-and-planetary-sci....
  - fnordpiglet 3y ago
    https://en.m.wikipedia.org/wiki/Silicon_tetrachloride https://en.m.wikipedia.org/wiki/Silicon_tetrachloride Read the uses section. It doesn’t make sense that silicon tetrachloride is a byproduct of purifying silicon. Why would you leave the silicon atom attached to the chlorine if the silicon atom is what you are after. The ratio makes sense - there’s one silicon atom and four chlorine atoms, but the statement that it’s a waste product is strange to me as it’s not. It is a intermediate and you do have to house it, and you can leak it and that’s not great (but as they state in the article you linked it’s not stable around water so I wouldn’t lose a huge amount of sleep over it’s pollution.
- kumarski 3y ago
  When the sun stops shining, natural gas peaking plants are the backup.
  - B1FF_PSUVM 3y ago
    Unless it is batteries and battery-like hydro.
  - epistasis 3y ago
    Batteries are already eating the lunch of natural gas peaking plants, and as time goes on the economics are going to tip ever further in favor of batteries. Natural gas is a transition fuel, not the end game.
  - adrianN 3y ago
    It's not too difficult to replace that natgas with hydrogen. I also don't see how burning gas only when the sun doesn't shine consumes more gas than burning gas all the time...
- imtringued 3y ago
  Take a look at the site he linked in his profile: https://engineersf.com/energy/ https://engineersf.com/energy/ >I’m of the mindset that you should be weary of and ignore the comments of software developers, physicists, and electrical engineers’ viewpoints on the hard sciences unless the prove otherwise as it relates to energy. Ah yes, physicists viewpoints on the hard sciences are particularly untrustworthy. And here is the claim mentioned above: >For every 1 pound of polysilicon you make, you make 4 pounds of the nasty stuff-silicon tetrachloride. >Okay, so some green hippie nutbags will tell you that you can just recycle this silicon tetrachloride stuff into new polysilicon because it requires less energy, but that’s bullshit because it costs a lot to do so. Wow! Very convincing arguments! Ok now a random google search: https://www.globenewswire.com/news-release/2021/03/05/2187708/0/en/Silicon-Tetrachloride-Market-Size-to-Worth-Around-US-3-32-Bn-by-2030.html https://www.globenewswire.com/news-release/2021/03/05/218770... >Silicon tetrachloride is the colorless inorganic fuming liquid and is used to produce high purity silicon. It can be produced by using several methods and compounds including chlorine, metal silicon, and coke among others. Moreover, it can be also produced as a byproduct after treating metallurgical grade silicon to form polysilicon. For each ton of polysilicon, 3-4 tons of silicon tetrachloride is generated. Polysilicon manufacturer’s further process the waste silicon tetrachloride generated and reuses it after processing. This saves the energy cost and raw material cost however, required an expensive set of machinery to process waste silicon tetrachloride. Wait a minute. So there is one process where it is an undesired byproduct and another process where it is actually the primary input? >Hence polysilicon manufacturers prefer silicon tetrachloride instead of raw silica to save on cost, energy, and time. Moreover, the government from various countries has enforced laws to prevent unauthorized dump of toxic silicon tetrachloride. For instance, in China, 98.5% silicon tetrachloride produced as a byproduct is required to be recycled which compels manufacturers to adopt silicon tetrachloride as a raw material for polysilicon production. Turns out China is a green hippie nutbag country.
  - fnordpiglet 3y ago
    Ah thanks. I felt like I had lost my mind there for a bit.

fnordpiglet 3y ago

I’m sorry I lost you on the last point. Where does the natural gas consumption come from in a solar power plant, inclusive of presumably grid connectivity? I don’t understand the chemistry you state. My understanding is silicon tetrachloride is an intermediate for producing polysilicon, and is used multiple places in the process in a recycling through the hydrogenation reactor. It’s not a by product. Do you mean to produce polysilicon you need 4x the silicon tetrachloride? That’s approximately true. But chlorinated ferrosilicon is typically the route for production and this can be achieved without natural gas, if that was where you got your nat gas assertion.

kumarski 3y ago
https://www.sciencedirect.com/topics/earth-and-planetary-sciences/silicon-tetrachloride#:~:text=Silicon%20tetrachloride%20is%20a%20by,tetrachloride%20liquid%20waste%20are%20generated https://www.sciencedirect.com/topics/earth-and-planetary-sci....
- fnordpiglet 3y ago
  https://en.m.wikipedia.org/wiki/Silicon_tetrachloride https://en.m.wikipedia.org/wiki/Silicon_tetrachloride Read the uses section. It doesn’t make sense that silicon tetrachloride is a byproduct of purifying silicon. Why would you leave the silicon atom attached to the chlorine if the silicon atom is what you are after. The ratio makes sense - there’s one silicon atom and four chlorine atoms, but the statement that it’s a waste product is strange to me as it’s not. It is a intermediate and you do have to house it, and you can leak it and that’s not great (but as they state in the article you linked it’s not stable around water so I wouldn’t lose a huge amount of sleep over it’s pollution.
kumarski 3y ago
When the sun stops shining, natural gas peaking plants are the backup.
- B1FF_PSUVM 3y ago
  Unless it is batteries and battery-like hydro.
- epistasis 3y ago
  Batteries are already eating the lunch of natural gas peaking plants, and as time goes on the economics are going to tip ever further in favor of batteries. Natural gas is a transition fuel, not the end game.
- adrianN 3y ago
  It's not too difficult to replace that natgas with hydrogen. I also don't see how burning gas only when the sun doesn't shine consumes more gas than burning gas all the time...
imtringued 3y ago
Take a look at the site he linked in his profile: https://engineersf.com/energy/ https://engineersf.com/energy/ >I’m of the mindset that you should be weary of and ignore the comments of software developers, physicists, and electrical engineers’ viewpoints on the hard sciences unless the prove otherwise as it relates to energy. Ah yes, physicists viewpoints on the hard sciences are particularly untrustworthy. And here is the claim mentioned above: >For every 1 pound of polysilicon you make, you make 4 pounds of the nasty stuff-silicon tetrachloride. >Okay, so some green hippie nutbags will tell you that you can just recycle this silicon tetrachloride stuff into new polysilicon because it requires less energy, but that’s bullshit because it costs a lot to do so. Wow! Very convincing arguments! Ok now a random google search: https://www.globenewswire.com/news-release/2021/03/05/2187708/0/en/Silicon-Tetrachloride-Market-Size-to-Worth-Around-US-3-32-Bn-by-2030.html https://www.globenewswire.com/news-release/2021/03/05/218770... >Silicon tetrachloride is the colorless inorganic fuming liquid and is used to produce high purity silicon. It can be produced by using several methods and compounds including chlorine, metal silicon, and coke among others. Moreover, it can be also produced as a byproduct after treating metallurgical grade silicon to form polysilicon. For each ton of polysilicon, 3-4 tons of silicon tetrachloride is generated. Polysilicon manufacturer’s further process the waste silicon tetrachloride generated and reuses it after processing. This saves the energy cost and raw material cost however, required an expensive set of machinery to process waste silicon tetrachloride. Wait a minute. So there is one process where it is an undesired byproduct and another process where it is actually the primary input? >Hence polysilicon manufacturers prefer silicon tetrachloride instead of raw silica to save on cost, energy, and time. Moreover, the government from various countries has enforced laws to prevent unauthorized dump of toxic silicon tetrachloride. For instance, in China, 98.5% silicon tetrachloride produced as a byproduct is required to be recycled which compels manufacturers to adopt silicon tetrachloride as a raw material for polysilicon production. Turns out China is a green hippie nutbag country.
- fnordpiglet 3y ago
  Ah thanks. I felt like I had lost my mind there for a bit.