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WanderingEng  ·  2687 days ago  ·  link  ·    ·  parent  ·  post: Coal is dead, because nobody wants to build coal-fired power plants.

    Shouldn't we take power when we can get it (solar, wind) and then store it for when we need it?

Having more flexible load has been talked about for years, but nobody has made much progress on it. Little load is flexible. Around a home, refrigerators have to run regularly to keep food safe. Businesses have to keep running to sell their goods. Industry needs to keep running because while they may have high energy bills, if they aren't running they can't pay for their capital needs.

Storage is definitely a big deal. Today, energy is stored in piles of coal and gas pipeline pressure. Doing a little math, this link says a 500 MW coal plant burns about 1.4 million tons of coal per year. I think coal plants usually store about two weeks worth of coal, so let's say they have 50,000 tons on hand.

Wolfram Alpha says coal has about 7000 kWh/ton, so that coal plant has about 350 million kWh worth of energy sitting in a big pile outside. Only about 35% of that will go out the wires; the rest will go up the stack or into the lake or river. But that's still 120 million kWh of usable energy.

As far as I know, this 120 thousand kWh battery is still the largest single battery out there. It would take a thousand of these just to equal the storage capacity of a coal plant's backyard, and you still haven't produced a single watt.

The problem isn't impossible, but we're still so far away from the solutions being easy.