Comment by rtkwe

3 days ago

Correct it's massively energy intensive to filter the salt out the newest best ideas still use ~2 KWh/m3 of water and that's a lab system in perdue that batches the process instead of having it run continuously which is why current RO desalination systems require so much energy.

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rtkwe

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zahlman  2 days ago

> it's massively energy intensive to filter the salt out the newest best ideas still use ~2 KWh/m3 of water

Am I alone in thinking that doesn't sound like a lot? That would be something on the order of 10% of what major cities charge for tap water?

smm11  3 days ago

California pays other states to take its excess solar energy. Power for a project like this isn't the issue, actually building the system is the issue.

  • JumpCrisscross  3 days ago

    > California pays other states to take its excess solar energy

    Intermittently. Essential services like water (with expensive fixed costs) aren’t a good fit for absorbing variable supply.

    > Power for a project like this isn't the issue

    California has the country’s most expensive power [1] in part due to policymakers constantly assuming it’s free.

    [1] https://www.electricchoice.com/electricity-prices-by-state/

  • rtkwe  3 days ago

    They wouldn't if you switched just Urban water use from natural sources to desalination. To do that you need to replace the ~5 million acre feet of water, ~6,167,400,000 m3, that goes into the Urban bucket which is all of the water used to keep people alive, clean, and all industrial uses of water. [0] That comes to ~ 12BkWh of energy needed to scale up batched reverse osmosis to take over just the life and job required water needs which is about 25% of the total solar power generated in all of 2025 via grid-scale solar farms. CA does export some during the day due to excess solar but is still a net importer of power.

    [0] p2 of https://cwc.ca.gov/-/media/CWC-Website/Files/Documents/2019/...

    • bombcar  3 days ago

      Those are the numbers I was looking for - that means that (ignoring build-out costs) total desalination for CA would be on the order of 10% of the 3 gorges dam yearly output (max).

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