MOLECULAR ENGINEERING

The connection with energy?

Water. Most of the globe's surface is water, yet the continents thirst for it; water is the most common substance on the planet, yet 97.2% is spoiled by the salt in it. And to desalinate sea water takes energy about 2.3 kWh per gallon just to raise the water to the boiling point, and though theoretically it is possible to recoup some of that energy when the distillate condenses, most of it is usually lost.

With enough water, the deserts could be made to bloom. Australia, for example, is as big as the continental US, but most of it is desert. That desert could be made fertile and support 10 times the present population of 14 million if the energy were available. (Actually it could be made available from Australia's fabulous high grade uranium deposits, but those are still being kept in the ground by the no growth obstructionists.)

The California desert could be made to look like coastal California, instead of the other way round, as could happen if Jerry Brown out's policies are followed. It's all a question of energy.

Or it used to be. It is no longer necessary to desalinate sea water by thermal processes such as distillation; the salt can be filtered out by one of the new membranes for an energy cost as little as 0.014 kWh per gallon.

And the process is already commercial. Allied Water Corporation, a small San Francisco company, claims to have created "the Singer sewing machine of the water desalination business" with its portable $4,700 machine that produces 200 gallons of fresh water per day at a cost of $2.50 per 1,000 gallons. Homeowners on Catalina Island off Los Angeles pay up to 10 times as much for fresh water barged in.

The membranes that do this, RO ("reverse osmosis") membranes, are a little more complicated than a mere sieve whose holes determine what size molecule will go through.

Let's see how they work.