Break, break, break on our cold grey ducks, O sea

Wave power may yet meet Ireland's energy needs, and we may not need nuclear power after all.

By the end of this century, Ireland could find itself among a small group of European nations awash with clean and endless energy - and the envy of most of her EEC partners. Such energy wealth would have nothing to do with a lucky find of uranium in the mountains of Mayo, nor any new inngenious technique developed by Bord na Mona to get more heat out of turf. It will rest entirely on the great Atlantic waves bearing down on the West Coast.

Ireland is one of only four nations in Europe that is blessed with a long Atlanntic seaboard lashed by some of the most powerful waves in the world. New techhnologies are being developed in Japan, Britain and the United States to harness the energy. If they succeed in doing so economically, the beneficiaries will be France, Portugal, Scotland and, esspecially, because of her size and energy needs, Ireland.

Work on waves in British waters has already established that the average power density of waves in the North Attlantic is about 80 kilowatts per metre. It has been shown that waves down the Scottish coast could provide all the elecctricity now used in the United Kingdom. Waves off the Irish coast could produce perhaps twenty times the electricity now used in the Republic.

Wave energy work is still in its innfancy, but the British Government reecently decided to invest a further £2.9 million into wave research. Progress on four wave projects in Britain is so proomising that full scale demonstration wave energy machines may be in the seas within ten years.

In this context, Ireland's extraorrdinary wealth of waves has already atttracted envious glances in the UK. Early this year, the UK House of Commons Select Committee on Science and Techhnology was told by one expert that it might, in the future, be expedient for Britain to try to reach an "accornmoodation" with Ireland to buy some of her surplus wave energy.

Wave energy has been an inventor's pipedream for years, but its recent deevelopment is partly due to an attack of flu suffered by Stephen Salter, an en ginnneer at Edinburgh University during the 1973 oil embargo. His wife told him to stop lying there looking sorry for himmself and to solve the energy crisis. So spurred, Salter did a few rough calculaations about the amount of energy in waves and was amazed at the amount of ' power that seemed to be available.

His first thought for a wave machine was "something like a lavatory balllcock bobbing up and down and working a pump." He did tests and found that the ballcock in a laboratory tank used about 15 per cent of the available enerrgy in artificially-made waves. Then he discovered that if he tipped the balllcock so that the hinge was below the water, the efficiency was much higher: about 60 per cent.

After many experiments with diffferent kinds of wave machines, Stephen Salter came up with' something he calls "a pregnant duck", These designs, now known as "Salter's ducks," can use 90 per cent of the wave energy.

Today Salter and a team at the Deepartment of Mechanical Engineering at Edinburgh University are testing ducks and other equipment in a huge new waye-rnaking tank recently completed at the university. The tank can duplicate many different kinds of waves and seas, and enables the team to test their ducks' efficiencies and behaviour.

Another team of wave researchers, led by Norman Bellamy from Lancaster University, has conducted trials with l/l Oth scale models on Loch Ness. In the south of England, Christopher Cockerell, inventor of the Hovercraft, has designed wave machines known as "contouring rafts". His 1 /l Oth scale model has been tested in the So lent esstuary.

It is too early to tell which design will prove the most effective, though some observers believe that Stephen Salter's approach will work. He claims that the capital cost of his ducks could be as low as £400 per kilowatt, near the cost of nuclear power.

If Salter's ducks are ever used, innquisitive yachtsmen eager to see a working wave energy machine will have to sail out perhaps 20 miles or further to where the sea is about 160 feet deep. At this depth, waves are at their optimum size and power.

The yachtsmen will see a 1600-foot string of ducks attached along a commmon backbone. The string will be lying parallel to the oncoming waves, which will drive the ducks (which will be 30 to 45 feet in diameter) up and down. The duck strings will generate electricity out at sea, using radial piston units and hyydraulic oil under high pressure. Underrsea cables will take the power from the generators to the shore.

There are many simple doubts about wave energy's practicability. Won't the ducks be smashed to bits in a storm? Won't ships run into them? Stephen Salter is careful not to oversell his ducks, and he admits he fears the North Atlanntic in a storm when "the power density can exceed one megawatt per metre." But the design of the ducks, the fact that they are semi-submerged and recent advances in sea cables lowers the risk. He says that shipping routes can keep clear of the machines.

But he adds, "no system of human devising is perfect and there will be many small accidents, some medium ones and a few large ones."

The wave machines will mean some environmental problems. When the cables come ashore, pylons will have to be built to take the electricity to the parts of Ireland that need the most power, especially the East Coast. So several more high power overhead cable lines are expected, perhaps running through beautiful landscapes in the West.

But wave power introduces no new chemicals and leaves no noxious polluutants. It will slightly reduce the size of waves to the leeward of the generators, but that should make life a bit easier for shipping and fishing. Beaches should not be affected, but if they are, the machines can be moved. .

It is' possible that Stephen Salter, Christopher Cockerell and their cosearchers may solve all the engineering problems but find that wave-generated power is too expensive. In the longer term, though, the outlook for wave power is bright: at some time, other ways of making energy are likely to prove more expensive than wave power. A sound betting man could put his money on the likelihood that some time in the next century, Ireland will be on the crests of the waves .•