Reply To: turn heat into electricity

[Dr_Barnowl]

I think the big win might be desalination, in terms of the developing world.

Conservatively, a 5MW unit could desalinate 350,000 gallons an hour (at a cost of ~ 14kWh per 1,000 gallons [1]) ; maybe more if you were to use the waste heat as well.

If you assume American patterns of water usage, at 100 gallons per person per diem, that’s enough water for 84,000 people.

And it could even be the salvation of the West – if the primary use of the water is irrigation, that ties up a tremendous mass of carbon, gets the water cycle working again (all that transpiration == clouds == more rain == more plants). More clouds also means a greater albedo, and lower global temperatures.

Instead of spending hundreds of billions on oil wars, line the coast of the horn of Africa with desalination plants, turn the desert into an oasis, plant oil crops to feed the remaining internal combustion engines until electrical energy storage problems are cracked and people transition gradually to electric vehicles. No need to junk a whole generation of working vehicles, just go with normal obsolescence, and all that plant matter that’s not turned into fuel (stems, leaves, etc) is fixing carbon and literally saving the planet. There are even market motivations for this – if it was just food, there would be no market motivation to increase production so much without an attendant increase in population. But with the grease-guzzling giant of the Western automotive industry to feed, it’s not just an exercise in green-earth gardening, there’s a way to get big capital interested in funding it.

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[1] http://www.livescience.com/4510-desalination-work.html

Note that this is the *worst* figure I could find for desalination energy cost. The Wikipedia article on desalination implies that most modern processes use about 3kWh per cubic metre (1,000 litres), which would be about 11kWh for 1,000 gallons, and that Siemens have allegedly invented a process that consumes only 1.5kWh per cubic metre.