IN response to an earlier letter from myself (April 16), Geoff Moore (Letters April 19) accuses me of providing no factual data. However, if he revisits my letter he will find a range of facts, although not in electrical form, supporting renewable energy storage development. For correspondence to a general news outlet it has been my observation that introducing dimensions such as KW or MW or MW-h or MJ merely turns off readers of a non-scientific persuasion. Quoting a statistic like 2788MW, which is of unhelpful precision, is likely to be incomprehensible to most readers.

Mr Moore notes that "scientists have been seriously developing batteries since the First World War". This is obviously true, but battery research and development has moved on considerably from the traditional lead-acid type, and this has occurred mainly in the past two or three decades. Nickel-cadmium and nickel-zinc batteries have been shown to be potentially capable of much higher storage densities than lead-acid types. Calculations, and prototype testing, suggest that alkali metal batteries are potentially the best source of energy for electric power propulsion and can now compete with the internal combustion engine for power delivery and range. Many combinations of reactive chemicals have been researched in the pursuit of battery solutions offering higher energy densities than the staple lead-acid version. Four chemical combinations give considerable hope that a major advance in storage capacity is close – namely, sodium-sulphur, lithium-sulphur, lithium-chlorine and zinc-chlorine. These advanced batteries, and in particular the sodium-sulphur couple using a solid electrolyte, and the lithium-sulphur couple using a fused salt electrolyte, are reported to have reached the prototype stage of development.

On the same letters page Malcolm Parkin infers that climate change could be better averted by large-scale adoption of nuclear power. However, there are reasons for bypassing the nuclear option, which have little to do with distrust of radioactivity and of radioactive waste.

First, given that amelioration of climate change requires a global commitment to phasing out the use of all fossil fuels by mid-century, nuclear power stations would require to be built at two per week for the next 20 years to replace coal, oil and gas by that date. Even if this build-rate were possible, it is predicted that economically extractable uranium and thorium would be depleted by 2050.

Secondly, while the planned massive growth in renewable power generation can be viewed with relative equanimity, simply because engineers can confidently handle a rapid growth in this benign technology, this is not true of nuclear technology. A nuclear reactor is a very complex system in engineering terms, and any experienced engineer will soon tell you that for such systems it is best not to ignore the laws formulated by that well known sage, Edward A Murphy Jr (of Murphy’s law renown). In particular, he has observed that for any complex system designed, operated and supervised, by fallible human beings, we should be aware that: “if anything can go wrong it will”. A reactor "going wrong" can of course be catastrophic. This becomes increasingly likely as the majority must be built close to the sea, as dictated by cooling requirements. In a period of frequent storms and rising sea levels large scale precautionary "shut downs" will presumably become commonplace. In such a scenario what is plan B?

Alan J Sangster,

37 Craigmount Terrace, Edinburgh.

REGARDING Malcom Parkin’s letter, I write to express a very different view. Assuming Martians are peaceable and mankind still here to be wondered about, inter-planetary visitors would be even more amazed that nations use products and skills from nuclear power generation to terrify their fellows with nuclear bombs.

As there are ways to provide electricity in emergency situations I would rather learn to live without 24-hour electricity than with the ever-increasing danger of mutual assured destruction. Two major accidents with nuclear power are too many. Can anybody persuade the Westminster Government to at least read and consider the UN Treaty for the Prohibition of Nuclear Weapons, cancel the exorbitant expensive Hinkley C nuclear power station and stop the future expansion of this unpredictable form of energy?

Sandra Phelps,

10 Kelvin Drive, Glasgow.