5 ms·

Article is 15 years old, energy and labor prices have increased a lot. We need a new cost estimate.

pstuart 3y ago
Solar prices have plummeted, and that use case can skip storage issues (just run when there's power available). Obviously land, labor, and infra cost are not so simple.
- nerdawson 3y ago
  If you use solar to generate electricity then the cost of that electricity is whatever you’re missing out on by not selling it to the grid.
  - Libcat99 3y ago
    On the other hand, you could have a system that pumps out water or power, depending on current needs and market.
  - jes5199 3y ago
    grid-connected solar generation often gets “curtailed” on very sunny days, so it’s market value is $0. On those days, desalinate.
- fbdab103 3y ago
  As a consumer, falling solar prices have not led to a noticeable decrease in my electrical bill.
  - cronix 3y ago
    As a recent convert to solar, we no longer have any electric bill, period.
    - ourmandave 3y ago
      They haven't tried to bill you for "maintaining the grid" cost?
      - markdown 3y ago
        No, but hopefully they do soon, or tax me somehow. Having a grid is important.
  - dpierce9 3y ago
    What do you think the price would be without solar? The answer: higher.
    - redeeman 3y ago
      sure, but only because they purposely exclude those that would be cheaper :)
  - etimberg 3y ago
    At some point the price of the bill is dominated by the fixed transmission costs which won't go away as long as there is a power grid.
- ehnto 3y ago
  Desal plants need to be running constantly and incur untennable startup costs otherwise, if I am not mistaken. Perhaps state of the art has fixed that issue.
scythe 3y ago
Desalination seems to be well-positioned to take advantage of variable energy prices, particularly in dry-summer climates where demand for water increases at the same time as solar energy availability. If you run the desalination system when energy is cheapest, your energy storage problem becomes a water storage problem, but a simpler one than with pumped-hydroelectric storage. I haven't seen a detailed analysis, but this could look good for California, notwithstanding the other problems with desalination (ecological).
- 10u152 3y ago
  Absolutely, but it's a scale problem. Say you want to produce 1000m3 a day. Well you can build a small plant that makes 41m3 ish an hour and run it 24/7. If you want to produce 1000m3 a day in the three or four hours where solar energy is very cheap you need a plant that does 250m3 an hour - or about 5x the size. So your energy is cheaper but your capital cost is 5x or so.
  - scythe 3y ago
    If you save enough on energy, you can switch your system to save on capital. RO has a fancy nanostructured membrane but electrodialysis or MSF might be easier to build at the cost of 20-50% worse efficiency.
  - gonzo41 3y ago
    If you build a few batteries next to the plant and that problem is solved.
    - 10u152 3y ago
      That also increases capital costs, putting us back to square 1. Also, have a look at the energy requirements of desal plants. "a few batteries" is pretty gargantuan hand waving
    - dimitar 3y ago
      Or you can build reservoirs for freshwater
pstuart 3y ago
Another thing I'm curious about -- Dean Kamen's "Slingshot". Seems like we'd be well served if his vision was realized: https://www.slingshotdoc.com/the-film https://www.slingshotdoc.com/the-film

Solar prices have plummeted, and that use case can skip storage issues (just run when there's power available). Obviously land, labor, and infra cost are not so simple.

nerdawson 3y ago
If you use solar to generate electricity then the cost of that electricity is whatever you’re missing out on by not selling it to the grid.
- Libcat99 3y ago
  On the other hand, you could have a system that pumps out water or power, depending on current needs and market.
- jes5199 3y ago
  grid-connected solar generation often gets “curtailed” on very sunny days, so it’s market value is $0. On those days, desalinate.
fbdab103 3y ago
As a consumer, falling solar prices have not led to a noticeable decrease in my electrical bill.
- cronix 3y ago
  As a recent convert to solar, we no longer have any electric bill, period.
  - ourmandave 3y ago
    They haven't tried to bill you for "maintaining the grid" cost?
    - markdown 3y ago
      No, but hopefully they do soon, or tax me somehow. Having a grid is important.
- dpierce9 3y ago
  What do you think the price would be without solar? The answer: higher.
  - redeeman 3y ago
    sure, but only because they purposely exclude those that would be cheaper :)
- etimberg 3y ago
  At some point the price of the bill is dominated by the fixed transmission costs which won't go away as long as there is a power grid.
ehnto 3y ago
Desal plants need to be running constantly and incur untennable startup costs otherwise, if I am not mistaken. Perhaps state of the art has fixed that issue.

scythe 3y ago

Desalination seems to be well-positioned to take advantage of variable energy prices, particularly in dry-summer climates where demand for water increases at the same time as solar energy availability. If you run the desalination system when energy is cheapest, your energy storage problem becomes a water storage problem, but a simpler one than with pumped-hydroelectric storage. I haven't seen a detailed analysis, but this could look good for California, notwithstanding the other problems with desalination (ecological).

10u152 3y ago
Absolutely, but it's a scale problem. Say you want to produce 1000m3 a day. Well you can build a small plant that makes 41m3 ish an hour and run it 24/7. If you want to produce 1000m3 a day in the three or four hours where solar energy is very cheap you need a plant that does 250m3 an hour - or about 5x the size. So your energy is cheaper but your capital cost is 5x or so.
- scythe 3y ago
  If you save enough on energy, you can switch your system to save on capital. RO has a fancy nanostructured membrane but electrodialysis or MSF might be easier to build at the cost of 20-50% worse efficiency.
- gonzo41 3y ago
  If you build a few batteries next to the plant and that problem is solved.
  - 10u152 3y ago
    That also increases capital costs, putting us back to square 1. Also, have a look at the energy requirements of desal plants. "a few batteries" is pretty gargantuan hand waving
  - dimitar 3y ago
    Or you can build reservoirs for freshwater

pstuart 3y ago

Another thing I'm curious about -- Dean Kamen's "Slingshot". Seems like we'd be well served if his vision was realized: https://www.slingshotdoc.com/the-film https://www.slingshotdoc.com/the-film