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Comment by bryanlarsen

1 day ago

Sure, thermal is great where it's possible. But there aren't that many places where district heating is viable.

I'm not talking about district heating. I'm talking about high temperature storage for conversion back to electricity. Round trip efficiency could be around 40%, better than green hydrogen burned in combined cycle plants.

  • Standard Thermal's website's front page only covers heat delivery; did you mean to link to somewhere else?

    Those are 2 very different use cases.

    Thermal is low rate extraction. It's 1 cycle per year, but the extraction is performed over months so is low rate.

    Electricity long term storage is high rate extraction. It's only used a few times a year, but when it is used it needs to cover roughly 100% of the entire grid's needs. I doubt thermal storage is suitable for high rate extraction, but I'd love to be wrong.

    Edit: rereading your parent comment you seem to think thermal is suitable for a different use case? Could you elaborate further? When is "prolonged discharge" useful?

    • That's what they're focusing on to start with, but the temperature is high enough to drive heat engines to make power. There's more on the concept at the seed company's (Orca Sciences) web site and at Austin Vernon's blog.

      https://www.orcasciences.com/articles/standard-thermal

      https://austinvernon.substack.com/p/building-ultra-cheap-ene...

      They talk about temperature up to ~600 C, which I believe is limited by the desire to use cheap steal (much hotter and creep becomes a problem). This is also perhaps not coincidentally about the temperature of steam from a coal fired boiler, so one of the eventual goals is to repower retired coal fired power plants with this storage providing the heat instead of coal combustion.

      You're right this is not good for something needed "a few times a year" for relatively short periods, for example to cover Dunkelflauten. Combustion of an e-fuel is better for that. But it's well suited to seasonal storage of solar energy, as that would be extracted over months, more or less continuously. The resistive heaters should also be much cheaper per W than electrolyzers.

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