Interesting thing about LA. I saw a table that showed how much energy was required to deliver water from each source. Some their sources of water require almost as much energy as desalination. Something like 30-50%.
I've wondered about using solar for desalination. Big issue though is desalination plants are capital intensive. So you really want to run them 24/7.
Desalination can be done effectively with thermal cogeneration. It's still inefficient, but since it is using waste heat it's "free" energy so to speak. Saudi Arabia has built such plants. The Soviet Union also built a fast reactor that was cooled with salt water, which was condensed and used as a freshwater supply [1].
Since ~80% of the world population lives on the coast, using seawater as coolant and capturing the condensate could represent a substantial source of freshwater.
> Big issue though is desalination plants are capital intensive.
I thought the main cost was the running cost of replacing the membranes. I saw a video recently of a modular desal plant that was equipment in shipping containers.
Cost about $1b to built. Energy costs are $49-5m a year. Total cost $108 million.
That's inline with my rough memory that 45% of the cost is capital, 45% energy, and 10% maintenance. Fudge those numbers as you will.
When I think about the economics it seems complex. Cheap power offsets extra capacity somewhat. Someone that actually manages, designs, plants probably knows real numbers.
I've wondered about using solar for desalination. Big issue though is desalination plants are capital intensive. So you really want to run them 24/7.