That solitary wind turbine in the quarry at Haworth has just passed its 20th birthday, and next year the 23 turbines on Ovenden Moor, just over the Halifax boundary, will pass the same milestone.

Despite occasional periods of high pressure, with gentle winds, both sites have earned their keep over two decades, by first taking less than nine months to pay off the energy used and the carbon dioxide produced in their construction, and then providing CO2-free energy for 5,000 homes.

Since they were erected, there has been considerable progress in design leading to larger turbines that generate much more power. The four proposed for Thornton Moor are almost 100m to the top of the blade, so they will produce nearly as much electricity as the 23 just over the hill that are only half that height.

A particular problem with wind turbines is joining them up to the National Grid and that’s one of the benefits of having them reasonably close to urban areas so they can be linked up easily without considerable extra expense, unlike the problem facing a new wind farm in Shetland.

There permission has recently been granted for the Viking wind farm, 103 turbines, each generating three Megawatts, and taller than those proposed for Thornton Moor.

They’ll be dotted up the central spine of the main island facing some of the strongest and most persistent winds in Europe. The resulting electricity will support 175,000 houses, 16 times more than the number in Shetland – and there lies the problem, as there isn’t a link south to Scotland.

However, there soon will be with the approval of an expensive high-voltage direct current submarine interconnector to take the power south, and it will need to be in place by 2017 when the Viking turbines spin.

It's likely that this will point the way for future electricity supplies from distant parts, and following the long-standing cross-Channel link to France, and a more recent one to Holland, talks are taking place with Iceland about a submarine link that will give us access to the geo-thermal power of that volcanic island. A similar one could tie us into Norway, with its abundant hydro-electricity, and in due course, a European Supergrid could mean that some of our electricity comes from solar stations in North Africa.

However, until all this happens, perhaps by 2050, we will need wind farms close to where we live and a recent study for the RSPB and Scottish National Heritage found little, if any, evidence of damage to birds through collisions and noise once the turbines are working, though there were concerns about the disturbance caused to nesting sites during construction.