On 19 Oct 2014
Desalinization: A permanent solution to CA water problem,
New Renter said:
You can use solar energy directly to produce fresh water. Just build an Oceanside dome of clear plastic and pump in seawater to cover the floor. Sun evaporates the water which condenses on the dome and runs down the sides to collection basins. It would be land intensive and not very fast tho. But you could use undesirable land for it.
I've posted here on PatNEt extensively on this very subject. RO desalination is a terrible solution. It consumes far too much energy and can only purify 50% of the input water, the rest leaqves far saltier than it entered. This isn't so important for plants with ocean access but for inland plants this is a big problem.
There is a company - WaterFX (And no, I have no affiliation with them) - which has developed a solar desalination method using mineral oil as the heat reservoir.
This allows the plant to operate even at night and cloudy days (provided not too many cloudy days in a row). It also purifies 93%+ of the input water, is modular, can be constructed quickly, and is FAR cheaper to build and operate than plants such as the one in Carlsbad.
Note that the Carlsbad plant was begun in the mid 1990's drought and abandoned when the rains returned. This is the problem with desalination plants they are the hot ticket when water is scarce and abandoned when water is plentiful. Unfortunalty they are also damned expensive and the bills continue even when there is no need for the extra water.
There is also the problem of logisitics. Agriculture uses 80% of the state's water, NOT coastal cities. Desalination plants need to be located inland, not on the coasts.
To summarize, RO desalination plants are expensive, use tremendous amounts of high value electricity, are inefficent at making fresh water, and take forever to construct, are not modular, and have a large footprint in valuable coastal areas.
Solar Desalination plants are far less expensive, use little high value electricity, are highly efficient at creating fresh water, are modular, and have a large footprint in low cost inland areas.
I 'd go with solar. By far.