Story link: http://www.goodnewsindia.com/index.php/Supplement/article/tube-wells-in-the-sky

Water is a big issue today in India. Scarcity of it and the societal problems looming ahead have been well enough stated. But what of solutions? They range between touching local efforts, which are alas, not numerous and the grandiose ones like linking of rivers and big dams proposed by minds, which are alas too numerous.

Let me throw this idea in the ring. Why not, wind powered desalination?  In this proposal windmills along the edge of the sea coast are used to power desalinators.

But these windmills don’t generate electricity. They generate friction and consequently heat. This heat will be used to power flash evaporators in which under a moderate vacuum, sea water is converted to potable water. This is a proven idea: almost every sea going vessel has a system for its water needs; they use the main diesel engine’s waste heat to obtain this by-product water for free.

Cost of production of water is likely to be far lower than the reverse osmosis [ro] systems. Power, maintenance and operator skills are are very low. Flash evaporators are almost zero-cost maintenance systems.

The windmill itself would come cheaper because the expensive generator, gear boxes and regulation systems would not be required. They need scarcely be reefed in. Their speed does not matter. The shaft would drive a ‘windage’ machine made of some sort of ceramic. An armature would rotate in a stator with engineered air gap between them offering friction. The generated heat would be carried away by a closed loop fluid system and circulated in coils placed in the flash evaporator. Or superheated air itself can be circulated.

There are many other synergies built into this idea.
For one, north India has more perennial rivers than the south which has a very long coastline.
Two, the wind powered electricity schemes having peaked out, this new application area will motivate windmill makers afresh to fund development of the idea.
Three, the cost of entry for wind-water-entrepreneurs would be lower than for wind-electricity ones.
Four, the market for water is vast unlike for power where there is usually just one buyer, --a sticky one at that-- the state.
Five, since water here is ‘produced’ and not tapped from traditional sources, opposition to ‘privatisation’ would not be there. [Incidentally, why not mandate that all bottled-water companies and soft-drink makers must ‘produce’ their own water?]
Six, as each plant is autonomous and self contained, it can be bought in a box and deployed along the coast to deliver water locally as needed.
Seven, the Government may safely rest its weary brow as the means of financing the idea of linking rivers and leave the idea of wind-water-farms to be financed entirely privately. Panchayats can become businesses too selling water to the cities.
Finally, though this idea may have come a little too late to prevent the Narmada dam, it may have a bearing on increasing its height further. Why can’t Gujarat get into wind-water-farms to supply the remoter parts now without water?

With suitable legislation and subsidies the idea can be taken off-shore and fresh water piped home or brought in barges. All this high-teching will be worth lavishing on water. Already in India milk is cheaper than bottled water. Soon petroleum maybe too.