EVERY now and then one of your readers will write on the subject of renewable energy. This usually prompts a response after the letter by other regular readers (they know who they are) decrying such renewable sources as “windmills” (sic), with “the huge amount of concrete and steel used in their construction “not to mention the bird ‘slaughter’”. It’s almost as if power stations using fossil fuels like oil, gas and coal – or nuclear ones, for that matter – were “concrete-free”. Much of the construction material in the latter stations can be recycled; however, it takes a bit more effort and money to recycle the fuel of nuclear power stations.

When it comes to bird and bat deaths – yes, birds have been known to fly into wind turbine blades with deadly results, but the total numbers are fairly well known (except to the hysterical “smash the windmills” brigades. Collisions with these turbines kill approximately 33,000 birds in the UK every year (Wibley Bird Guide figure). This is certainly a high number, but should be put into some sort of context by comparing it to other causes of bird mortality.

Wind turbines are, I believe, an “easy target” since they are more visible and, I’d suggest, more “obvious”. However, their impact is dwarfed by cars (two million per annum), pesticides (three million), cats four million) and high tension wires (180 million). However, the biggest "killers" by far are glass windows (100-1000m every year). So, unless we want to give up our windows, domestic electricity and motor vehicles, maybe it would be best to get educated on the subject, rather than giving knee-jerk reactions.

Barry Lees,

12 Denholm Street, Greenock.

ALAN Sangster (Letters, April 16) attacks my letter of April 12 on wind power. In my letter I presented six statistics which are 100 per cent factual whereas Mr Sangster, typically of those who promote renewables, presents no numbers, preferring instead phrases like “rapid” and “massive”.

Mr Sangster claims that Britain’s four hydro pumped storage schemes are capable of providing more power than Hinkley nuclear power station. He doesn’t specify which Hinkley but, assuming he means Hinkley C, this is wrong. Hinkley C is 3,200 MW (megawatts) whereas the four pumped hydro schemes are 2,788 MW in total. But crucially, nuclear stations can continually generate for around 18 months whereas our four pumped hydro schemes would run out of water in under 24 hours.

If Britain were to construct a pumped hydro fleet of sufficient size to provide for when renewables can’t cope we would need in the order of 300 schemes minimum. SSE has had planning permission to build scheme number five for several years but hasn’t begun construction because it’s not economically viable.

Mr Sangster talks about “rapid developments” in battery technology. Actually, scientists have been seriously developing batteries since the First World War, spurred on by submarine warfare. Battery efficiency is measured by a combination of cost, size/weight, charging losses and time till battery replacement is needed. Studies suggest that, since the First World War, battery efficiency has only increased five to seven fold. For batteries to power Britain their efficiency would need to improve 100-fold at a minimum.

Geoff Moore,

Braeface Park, Alness.

JUDGING by recent remarks regarding energy, your reader just arrived from Mars might think that we are still in the dark ages, relying on wind and sun for our power, plus various other schemes such as dropping weights down mineshafts and burning wood; while discarding nuclear fission, a clever process that makes cheap and endless electricity without atmospheric pollution.

We are not yet in the dark ages, but certainly just about to enter them.

Malcolm Parkin,

Gamekeepers Road, Kinnesswood, Kinross.