Wave power is one of the renewable sources of energy that the British government wants to develop. Yet many gates and nodding ducks, which are used to capture energy from the surface waves, have been destroyed by a furious sea; only devices with no moving parts seem to have a future. Daedalus recalls that waves are not merely a surface effect. Much of their energy is stored deep under the water, in the form of circular or elliptical closed currents that reach right down to the sea bottom (which is why waves gain height in shallow water). And because sea water contains salt, it conducts electricity. So a fully submerged, static, electrical device should be a good bet.

Electrochemists hold that a piece of metal dropped in an electrolyte gives off positive ions. They dissolve; it takes up the opposite negative charge and attracts them. The result is a double layer, the negative metal sheathed in positive ions.

So, says Daedalus, imagine two pieces of metal held apart in the water by an insulator. Ions would be released from both sides. If the ions are pushed from one side to the other by a current in the water, the arrangement should gain energy. DREADCO engineers are now designing webs of such electrical conductors to be implanted on the sea bed, out beyond the low-tide mark. Much of the technology has already been perfected by gas-drillers and other marine engineers. Each unit will damp the wave over it and generate rather a lumpy alternating current. Rectifiers will turn this into direct current; all the units will be coupled in series. Statistically the final voltage should be fairly smooth, its intensity depending on the vigour of the incoming sea. It will be led ashore directly, through delivery leads.

To the waves above, this steady loss of energy will 'feel' like an energy-absorbing sea bed. A big distributed damping installation should steal so much energy from the seas that only safe little waves will hit the shore. If so, the new system will not only provide energy, but will also reduce the need for sea walls and other marine defences. Even the wildest sea will give safe, useful energy.

Considerable cunning will be needed to find the best layout for the system. Daedalus likes the idea of close pairs of conductors aligned to cut the most likely wave ellipses; but the final design must depend on empirical insights. Ships should also welcome the system — it will damp rough weather. Anchoring would not be advisable, however; it would damage the system.