Info about seawater desalination

Seawater desalinators can be very expensive. That's why we'd try to run them 24h/day (use a smaller one and run it around it the clock rather buying a larger one and having it sit idle for 60% of the time).

Several desalinations can be considered for arrid, coastal areas:
a) RO (reverse osmosis) filters
b) Evaporators

RO systems can be compared with extremely fine filters that allow water molecules to pass through but not NaCl molecules or others, larger than H₂O. This type of system uses very high pressure to press water through the small "holes of the membrane". These pumps will need electricity.
The filter has to be cleaned regularly by "backwashing", usually programmable, thus automatic.

Evaporators are best if you want to keep the salt that's in the water. If, however, you weant to keep the water and get rid of the salt - as in our case - you have to make sure the water/steam doesn't escape. The captured steam then has to be condensed - cooled down. Often the cooling down will require the use of electricity.