8 ms·

Wouldn't solar be much better for powering desalination than nuclear power? It is way cheaper per energy produced than nuclear, especially in those countries, w

by _ph_ 5y ago

Wouldn't solar be much better for powering desalination than nuclear power? It is way cheaper per energy produced than nuclear, especially in those countries, which need desalination most. Also, it doesn't take a decade to set up. Not even mentioning proliferation issues.

bin_bash 5y ago
Solar doesn’t provide nearly as much energy and for desalination you need a surprising amount. Nuclear is a great use-case since the problem with nuclear is it needs a constant water source. If you’re desalinating you’ve got that problem covered.
- stavros 5y ago
  Does nuclear need fresh water? I'd imagine salt water would wreck all the equipment, and you probably don't want to use up all the fresh water you generate...
  - b0tzzzzzzman 5y ago
    You need very pure water for most portions of a nuclear power plan.
    - gruez 5y ago
      that'd depend on the reactor type, no?
    - justshowpost 5y ago
      Not really. Pure heavy water along with pure uranium and pure CANDU reactors are imported components. The quality of cooling water and feed water doesn't matter much. Remember, nuclear power plant is merely a very large heat engine. The main problem is terrorism there.
  - AngryData 5y ago
    The turbines do but you can recycle much if not nearly all of that water by cooling the steam and condensing it, which you could use sea water to heat exchange to for it.
  - akiselev 5y ago
    The water is just there for thermal mass to conduct waste heat away from the condenser. The water that gets heated by the reactor core and turns the turbines is isolated and highly purified, since many of the internals can only be accessed during refuels. Some designs go further and separate the reactor coolant system from the steam generator to prevent contamination, but AFAIK there isn't a single commercial design that allows outside water to feed into the reactor cooling or power generation systems. The parts of the condenser that touch the external body of water are basically just blocks of metal that have to be scrubbed on the outside from time to time.
  - m4rtink 5y ago
    You have heat exchangers between saltwater and clean freshwater that circulates through the sensitive parts of the plant.
- gruez 5y ago
  > Solar doesn’t provide nearly as much energy and for desalination you need a surprising amount. Are there numbers for this? One one hand solar might provide more energy than nuclear if you're only interested in heat generation, but on the other hand using heat to desalinate (ie. boiling water) is also less efficient than using reverse osmosis.
- _ph_ 5y ago
  Solar doesn’t provide nearly as much energy and for desalination you need a surprising amount. That statement doesn't make any sense to me. If you need more power, install more panels. Space certainly isn't an issue in like northern Africa. It is cheaper to order a gigawatt or more of solar panels than building a new nuclear reactor, and faster to set up too. Even Germany today has way more solar capacity than it ever had in nuclear, and it is less a great place for solar than Africa.
  - scraptor 5y ago
    > Even Germany today has way more solar capacity than it ever had in nuclear That's because it never had much nuclear capacity, not because it now has a lot of solar
    - _ph_ 5y ago
      I don't know what you mean by "much", but Germany has a peak power capacity of 56 GW of Solar. On good days the output comes close to the nuclear output of France, which is mostly nuclear in power production. German wind power occasionally eclipses French nuclear power production.
  - akiselev 5y ago
    The vast majority of our freshwater comes from sources that cost us effectively zero in energy: the water cycle moves water towards higher elevations and it flows down towards our populations. Worst case scenario, water in ancient underground reservoirs is pumped to the surface. If we had to desalinate all that water and actively distribute it instead, it'd be a significant fraction of our current global power consumption. The power sources need to be concentrated near the desalination plants and at least half the world lives 100km+ away from a coastline. At 3 kWh per m^3 of water[1] and ~3.5 m^3 per person per day [2], that's an extra ~3800 kWh per year, which would increase per capita energy consumption by 25-30% [3] in the United States just for desalination. We have enough challenges replacing existing power infrastructure with solar and wind. Placing the burden of desalination on top of that is unrealistic, especially since the NIMBY fight over solar installations of that size would probably be just as fierce as for a nuclear reactor. [1] https://res.mdpi.com/d_attachment/energies/energies-12-00463/article_deploy/energies-12-00463.pdf https://res.mdpi.com/d_attachment/energies/energies-12-00463... [2] https://www.usgs.gov/special-topic/water-science-school/science/total-water-use-united-states?qt-science_center_objects=0#qt-science_center_objects https://www.usgs.gov/special-topic/water-science-school/scie... [3] https://data.worldbank.org/indicator/EG.USE.ELEC.KH.PC?locations=US https://data.worldbank.org/indicator/EG.USE.ELEC.KH.PC?locat...
- lebuffon 5y ago
  Last I checked Algeria has a bit of solar energy hitting it. :)
  - deleted 5y ago
    [deleted]
- jeroenhd 5y ago
  Nuclear power is severely restricted and building a nuclear power plant in a country dealing with active terrorist movements is probably something to be avoided. Solar is relatively inefficient, but it can't be used to build a dirty bomb or worse. With large patches of uninhabit{ed,able} desert, many African countries have more than enough space to build large solar farms if they can find a solution to the sand blowing onto the panels.
- koyote 5y ago
  The Sydney desalination plant is entirely powered by Wind: https://www.sydneydesal.com.au/caring-for-the-environment/100-renewable/ https://www.sydneydesal.com.au/caring-for-the-environment/10...
state_less 5y ago
Yes, solar is dirt cheap energy and you wouldn’t need much of a battery (or any?) in this case, since you can store the excess product water in a tank. I power my water maker with about 1400 watts and can make 35 gallons an hour. The panels, electronics and water maker were ~ $5000. I did the work myself at a slow pace, so not sure what the labor costs would be. I set my system up in about 2 weeks. The requirements are a bit of time, seawater access and some capital. https://seawaterpro.com/ https://seawaterpro.com/
- jeroenhd 5y ago
  $5000 in a third world country is quite a lot. For context, according to CEIC data [1], the average salary in Algeria is about $300 per month. That "dirt cheap" project of yours is more than a year's worth of labor. Locally priced goods may be cheaper, but the US does benefit from a more direct shipping line with China (where most of these products come from, especially cheap solar panels). There's repair costs to be taken into account and if these become a necessity, you'll also have to take into account some kind of protection for when those without the means to buy one of these setups become desperate. It's true that solar is relatively safe and cheap compared to other power sources, but projects like these are difficult to map to places where they can make a life-or-death difference. If things were that easy, we'd probably cover a patch of Sahara desert with solar panels and power the entire African continent for decades, with power to spare to export to other continents. [1]: https://www.ceicdata.com/en/algeria/average-monthly-wages https://www.ceicdata.com/en/algeria/average-monthly-wages
  - state_less 5y ago
    Yeah, it’s tough out there. I think the capital cost might be around $15 to $40 a month depending on how generous the lender is. Evaporative is interesting too, but solar isn’t too bad to maintain. Most of the maintenance would probably be keeping the filters, pumps and membranes in working order.
- Johnny555 5y ago
  That seems like a lot of cost and complexity for a rural installation in a 3rd world country. How does the water output compare with, say, spending $1000 a simple evaporation design? The size of the evaporation pool would be larger than 1400W worth of solar, but it's much simpler and easy to repair.
drran 5y ago
Yep, evaporator + condenser works very well in nature for billions of years. For example: https://news.mit.edu/2020/passive-solar-powered-water-desalination-0207 https://news.mit.edu/2020/passive-solar-powered-water-desali...

by _ph_ 5y ago

bin_bash 5y ago

Solar doesn’t provide nearly as much energy and for desalination you need a surprising amount. Nuclear is a great use-case since the problem with nuclear is it needs a constant water source. If you’re desalinating you’ve got that problem covered.

stavros 5y ago
Does nuclear need fresh water? I'd imagine salt water would wreck all the equipment, and you probably don't want to use up all the fresh water you generate...
- b0tzzzzzzman 5y ago
  You need very pure water for most portions of a nuclear power plan.
  - gruez 5y ago
    that'd depend on the reactor type, no?
  - justshowpost 5y ago
    Not really. Pure heavy water along with pure uranium and pure CANDU reactors are imported components. The quality of cooling water and feed water doesn't matter much. Remember, nuclear power plant is merely a very large heat engine. The main problem is terrorism there.
- AngryData 5y ago
  The turbines do but you can recycle much if not nearly all of that water by cooling the steam and condensing it, which you could use sea water to heat exchange to for it.
- akiselev 5y ago
  The water is just there for thermal mass to conduct waste heat away from the condenser. The water that gets heated by the reactor core and turns the turbines is isolated and highly purified, since many of the internals can only be accessed during refuels. Some designs go further and separate the reactor coolant system from the steam generator to prevent contamination, but AFAIK there isn't a single commercial design that allows outside water to feed into the reactor cooling or power generation systems. The parts of the condenser that touch the external body of water are basically just blocks of metal that have to be scrubbed on the outside from time to time.
- m4rtink 5y ago
  You have heat exchangers between saltwater and clean freshwater that circulates through the sensitive parts of the plant.
gruez 5y ago
> Solar doesn’t provide nearly as much energy and for desalination you need a surprising amount. Are there numbers for this? One one hand solar might provide more energy than nuclear if you're only interested in heat generation, but on the other hand using heat to desalinate (ie. boiling water) is also less efficient than using reverse osmosis.
_ph_ 5y ago
Solar doesn’t provide nearly as much energy and for desalination you need a surprising amount. That statement doesn't make any sense to me. If you need more power, install more panels. Space certainly isn't an issue in like northern Africa. It is cheaper to order a gigawatt or more of solar panels than building a new nuclear reactor, and faster to set up too. Even Germany today has way more solar capacity than it ever had in nuclear, and it is less a great place for solar than Africa.
- scraptor 5y ago
  > Even Germany today has way more solar capacity than it ever had in nuclear That's because it never had much nuclear capacity, not because it now has a lot of solar
  - _ph_ 5y ago
    I don't know what you mean by "much", but Germany has a peak power capacity of 56 GW of Solar. On good days the output comes close to the nuclear output of France, which is mostly nuclear in power production. German wind power occasionally eclipses French nuclear power production.
- akiselev 5y ago
  The vast majority of our freshwater comes from sources that cost us effectively zero in energy: the water cycle moves water towards higher elevations and it flows down towards our populations. Worst case scenario, water in ancient underground reservoirs is pumped to the surface. If we had to desalinate all that water and actively distribute it instead, it'd be a significant fraction of our current global power consumption. The power sources need to be concentrated near the desalination plants and at least half the world lives 100km+ away from a coastline. At 3 kWh per m^3 of water[1] and ~3.5 m^3 per person per day [2], that's an extra ~3800 kWh per year, which would increase per capita energy consumption by 25-30% [3] in the United States just for desalination. We have enough challenges replacing existing power infrastructure with solar and wind. Placing the burden of desalination on top of that is unrealistic, especially since the NIMBY fight over solar installations of that size would probably be just as fierce as for a nuclear reactor. [1] https://res.mdpi.com/d_attachment/energies/energies-12-00463/article_deploy/energies-12-00463.pdf https://res.mdpi.com/d_attachment/energies/energies-12-00463... [2] https://www.usgs.gov/special-topic/water-science-school/science/total-water-use-united-states?qt-science_center_objects=0#qt-science_center_objects https://www.usgs.gov/special-topic/water-science-school/scie... [3] https://data.worldbank.org/indicator/EG.USE.ELEC.KH.PC?locations=US https://data.worldbank.org/indicator/EG.USE.ELEC.KH.PC?locat...
lebuffon 5y ago
Last I checked Algeria has a bit of solar energy hitting it. :)
- deleted 5y ago
  [deleted]
jeroenhd 5y ago
Nuclear power is severely restricted and building a nuclear power plant in a country dealing with active terrorist movements is probably something to be avoided. Solar is relatively inefficient, but it can't be used to build a dirty bomb or worse. With large patches of uninhabit{ed,able} desert, many African countries have more than enough space to build large solar farms if they can find a solution to the sand blowing onto the panels.
koyote 5y ago
The Sydney desalination plant is entirely powered by Wind: https://www.sydneydesal.com.au/caring-for-the-environment/100-renewable/ https://www.sydneydesal.com.au/caring-for-the-environment/10...

state_less 5y ago

Yes, solar is dirt cheap energy and you wouldn’t need much of a battery (or any?) in this case, since you can store the excess product water in a tank. I power my water maker with about 1400 watts and can make 35 gallons an hour. The panels, electronics and water maker were ~ $5000. I did the work myself at a slow pace, so not sure what the labor costs would be. I set my system up in about 2 weeks. The requirements are a bit of time, seawater access and some capital. https://seawaterpro.com/ https://seawaterpro.com/

jeroenhd 5y ago
$5000 in a third world country is quite a lot. For context, according to CEIC data [1], the average salary in Algeria is about $300 per month. That "dirt cheap" project of yours is more than a year's worth of labor. Locally priced goods may be cheaper, but the US does benefit from a more direct shipping line with China (where most of these products come from, especially cheap solar panels). There's repair costs to be taken into account and if these become a necessity, you'll also have to take into account some kind of protection for when those without the means to buy one of these setups become desperate. It's true that solar is relatively safe and cheap compared to other power sources, but projects like these are difficult to map to places where they can make a life-or-death difference. If things were that easy, we'd probably cover a patch of Sahara desert with solar panels and power the entire African continent for decades, with power to spare to export to other continents. [1]: https://www.ceicdata.com/en/algeria/average-monthly-wages https://www.ceicdata.com/en/algeria/average-monthly-wages
- state_less 5y ago
  Yeah, it’s tough out there. I think the capital cost might be around $15 to $40 a month depending on how generous the lender is. Evaporative is interesting too, but solar isn’t too bad to maintain. Most of the maintenance would probably be keeping the filters, pumps and membranes in working order.
Johnny555 5y ago
That seems like a lot of cost and complexity for a rural installation in a 3rd world country. How does the water output compare with, say, spending $1000 a simple evaporation design? The size of the evaporation pool would be larger than 1400W worth of solar, but it's much simpler and easy to repair.

drran 5y ago

Yep, evaporator + condenser works very well in nature for billions of years. For example: https://news.mit.edu/2020/passive-solar-powered-water-desalination-0207 https://news.mit.edu/2020/passive-solar-powered-water-desali...