Disillusioned commentary on Australian financial sector, politics, business, media... with attention occasionally distracted to the world outside... and intermittent reminder that rage is a more life-conserving irrationality than despair.

Monday, January 24, 2005

Science... but not as we know it, Jim

Headline in the Sydney Sunday Sun-Herald yesterday:

Sea water provides the energy
to put wind back in your sails

Reporter Daniel Dasey reports on a startling development - an American-designed yacht which extracts its energy from sea water.

Perhaps Dasey was unlucky I thought: maybe the sub-editor who crafted that headline had an M.A. in Phoenician, and didn't understand about thermodynamic equilibrium. But no.

He goes on to write:

The secret of the independence from fossil fuel lies in the fact that water is composed of hydrogen and oxygen.

To generate power, the yacht sucks water on board where it undergoes a purification process.

The water is then channelled to an electrolysis unit where it is broken down into hydrogen and oxygen.

No question, hydrogen can be extracted from water, a process almost as magical as extracting heat beads from the resulting ashes in your barbecue - because water is essentially hydrogen ash. A kilogram of hydrogen, when burned or used in a fuel cell (the resulting product, water, is the same in either case) produces around 120 megajoules of energy. To produce it by electrolysis "breaking down" water requires rather more energy than that.

Where would the electricity come from? Solar cells on the sails perhaps? God?

Why not simplify the process; cut out the hydrogen stuff, and simply propel the yacht with an electric motor, with auxiliary batteries like the Toyota Prius?

And if somebody is desperate to over-complicate matters by turning water into hydrogen and oxygen and then turning it back again, why bother to purify sea water? Hydrogen extracted from a litre of water has much the same energy as a litre of petrol.

Was Dasey the butt of some obscure practical joke, or is this what passes for science in the quality press?


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