POWER FROM THE SEAS.

Taranaki Daily News, 9 July 1921, Page 10

POWER FROM THE SEAS.

THE BRITISH PROPOSALS. The British Isles seem at first thought to be a most unpromising field for the creation of hydro-electric power, owing to the lack of high mountains, waterfalls and swift-running rivers. Yet it is in England that engineers propose to develop 1,500,000 h.p. in one huge scheme. The proposal, which is outlined in a recent number of the Scientific American, is to utilise the tidal flow in the estuary of the Severn. The estuary is two and a half miles wide, and the tide rises thirty feet at its highest. It is proposed to build a great curved dam across the estuary, three and a half miles in length. This dam will serve two purposes—it will carry a railway viaduct, much needed by the Great Western Railway Company, and it will house a larger number of turbines, to be actuated by the tide waVrs penned up behind the dam.

The scheme, which is the first of its kind on the grand scale dealing with tidal waters, presents some unusual problems. For instance, the tide will operate the turbines for only seven hours a day, but continuous output of power is essential. To get over this it is proposed to use half of the 1,000,000 h.p. which the dam turbines will generate to fill a reservoir on the River Wye. This reservoir in turn will supply 500,000 h.p. at a time when the dam turbines have ceased to turn. Means have also been devised, it is stated, of dealing with the problems created by the rapid change in the head of water. The turbines will start running under a five-foot head, which increases in three and a half hours to twenty or twentyfive feet and then ebbs again. It is planned to generate current at a voltage of 5'25, transformed to 60,000 for transmission.