Expensive toys

Shirley Seaton (Letters, 28 December) is correct with regard to small-scale hydro schemes: they are possible. Indeed, the first domestic electricity came from such a source – at Cragside in Northumberland. A hydro scheme simply requires a constant and sufficient flow of water at a sufficient speed through the turbines of a generator of sufficient capacity to produce the required power.

Simply? Even the old watermills that she mentions would rarely have such attributes; although they were usually located on the most favourable sites they would be unlikely to be anywhere near the point of use.

Ms Seaton mentions economy. The Cragside scheme, which was the brainchild and the pride and joy of its mega-rich owner, would probably cost millions today it and only supplied light to his (admittedly very large) house.

Micro hydro schemes, I’m afraid, would be like the mini wind turbines that we may have been tempted to buy – expensive toys. Economy of scale is essential, and, as Ms Seaton rightly states, Scotland is not so well endowed with the requirements for this as may be imagined. We simply cannot count on much expansion of our existing schemes.

DR A McCORMICK

Kirkland Road

Terregles, Dumfries