ALAN J Sangster writes that it is a "myth" that wind power is unreliable (Letters, February 14).

The 25% capacity factor (CF) he quotes for a single wind farm is an estimate used by the wind industry when assessing the viability of a wind installation, to reflect the unreliability of wind, and the actual measured CFs of all wind installations confirms this using the data which is readily available on the Renewable Energy Foundation website.

As for the claim that, if there were enough wind turbines across the European continent, they could be generating electricity 100% of the time, this makes no practical sense. On a few days in the past month, out of a national grid metered total capacity of all installed wind turbines in the UK of around 7,300MW, less than 500MW was actually being generated – a far cry from 100%, not to mention a highly inefficient use of the high capital investment involved.

As for the highly theoretical concept of combining and co-ordinating wind and solar electricity generation with other renewable generation systems across Europe incorporating a low-loss high-voltage DC grid plus associated massive electricity storage, this can only be classified as a wishful thinking. Even if all the technology were commercially available, this proposal would be prohibitively expensive.

Recent measurements of Arctic ice shows the highest gain in ice levels since satellite measurement records began in 1980.

Dr G M Lindsay,

Whinfield Gardens,

Kinross.