• Blue_Morpho@lemmy.world
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    14 hours ago

    It looks at the cost of power generation

    Yes.

    But then you added the requirement of 90% uptime which is isn’t how a grid works. For example a coal generator only has 85% uptime yet your power isn’t out 4 hours a day every day.

    Nuclear reactors are out of service every 18-24 months for refueling. Yet you don’t lose power for days because the plant has typically two reactors and the grid is designed for those outages.

    So the only issue is cost per megawatt. You need 2 reactors for nuclear to be reliable. That’s part of the cost. You need extra bess to be reliable. That’s part of the cost.

    • iii@mander.xyz
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      6 hours ago

      But then you added the requirement of 90% uptime which is isn’t how a grid works.

      I’m referring to the uptime of the grid. Not an individual power source.

      Assume we’ve successfully banned fossil fuels and nuclear, as is the goal of the green parties.

      How much renewable production, and bess, does one need to achieve 90% grid uptime? Or 99% grid uptime?

      If you want a balanced grid, you don’t need to just build for the average day (in production and consumption), you need to build for the worst case in both production and consumption.

      The worst case production in case for renewables, is close to zero for days (example). Meaning you need to size storage appropriatelly, in order to fairly compare to nuclear. And build sufficient production so that surplus is generated and able to be stored.

      If we’re fine with a blackout 10% of the time, I can see solar + bess beating nuclear, price wise. If the goal instead is a reliable grid, then not.

      As an example: take Belgium. As a result of this same idea (solar/wind is cheap!) we ended up with both (1) higher greenhouse gas emissions and (2) costlier energy generation, as we now heavily rely on gas power generation (previously mainly russian, now mainly US LNG) to balance the grid. Previous winter we even had to use kerosene turbine generation to avoid a blackout.

      • Ooops@feddit.org
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        48 minutes ago

        How much renewable production, and bess, does one need to achieve 90% grid uptime? Or 99% grid uptime?

        About 115% to 130%. Depending on diversification of renewable sources and locations. The remains are losses in storage and transport obviously.

        But shouldn’t you actual question be: How much storage is needed?

        For a quick summary of those questions you can look here for example…

        • iii@mander.xyz
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          42 minutes ago

          What would 130% grid uptime even look like? 475 days a year without blackout?

          I think we’re talking about different things.