Reply To: Direct conversion

[tcg]

Using Zapkitty’s figure of 233 tons of purified water per day from a 5 MW power plant, I did the math to calculate how many homes would that quantity serve in the area where I live.

Hereabouts, typical annual water usage is about four acre-feet per acre for typical residential use, inside the house and for landscaping — rainfall only is about one foot per year during winter, so we have to irrigate everything all the time. From these numbers the average house ( at five per acre ) would use 34,400 cu. ft. of water per year, or about 97 per day, about 800 pounds.

The figure of 233 tons per day times 2000 divided by 800 yields the number of houses which would have enough water, 580 in a community which has 7,500 houses. But wait! I have already calculated that it would take about a dozen 5MW plants to supply enough electricity for 7,500 houses, so 580 X 12 = 6960 homes.

Even considering that efficiencies would not be 100%, I am still mightily impressed with these numbers. It looks like the “waste” heat from power generation could supply at least half of our exorbitant water usage at absurdly low prices. The supply described above, coming from seawater, would be uninterruptable, and the means to secure the remainder of our water usage cheaply from the same source look very feasible.

TCG