[akiselev]

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...

[2] https://www.usgs.gov/special-topic/water-science-school/scie...

[3] https://data.worldbank.org/indicator/EG.USE.ELEC.KH.PC?locat...

[_ph_]

I have never claimed, that we would replace all fresh water used on this planed by desalinated water. This certainly is neither feasably nor necessary. At best, it can be an important contribution to water supply in many regions.

I was only answering to the original post which suggested we would build nuclear power plants to desalinate water. There I commented that solar would be cheaper (and more environment friendly) for the same task.