4 ms·

is the expense of desalinization the electricity? Which would go down with adoption of solar?

• stcredzero 8y ago
  You also have to maintain equipment, but I think the electricity is the major thing.
• jerf 8y ago
  I imagine the idea is something more like one way to dump excessive solar capacity would be to desalinate water during the times of maximum power generation. Or perhaps I just steelmanned the argument.
• philipkglass 8y ago
  This is a decade old, but I think that the proportions are still about right: https://desline.com/Geneva/Banat.pdf https://desline.com/Geneva/Banat.pdf See the slide "Cost composition for a typical seawater RO (reverse osmosis) plant" Fixed charges (primarily capital cost): 31% Energy: 26% Maintenance and parts: 14% Membrane replacement: 13% Supervision and labor: 9% Chemicals: 7% Really cheap solar electricity could reduce the second largest expense (energy costs), but right now that's just an improvement for daylight hours. Battery-stored solar electricity is getting cheaper but it's not cheap enough to actually reduce nighttime desalination costs yet. And if you run the plant only during the day, you get less value out of the very largest expense (capital cost).
  • rsynnott 8y ago
    That's reverse osmosis. In a scenario where energy is very cheap (even if only for part of the day) there are other processes which require less maintenance, but more energy.
    • philipkglass 8y ago
      The previous slide in that presentation also shows a cost breakdown for a thermal process, multi-stage flash desalination. Fixed charges (primarily capital cost) 42% Energy 41% Maintenance and parts 8% Supervision and labor 7% Chemicals 2% Energy is nearly even with fixed costs for MSF, but fixed costs are even larger here. Leaving this type of plant idle between dusk and dawn would again raise per-unit costs a lot.