Luca Garzotti observes (Letters, 22 January) that serious challenges face the production of energy from processes based on thermonuclear fusion, but failed to mention a crucially important alternative, low-energy nuclear reactions (LENR), commonly known as cold fusion.
Readers of the Guardian’s 2012 obituary of Martin Fleischmann will know that the situation regarding cold fusion is more complicated than that commonly assumed: that the claims of Fleischmann and Stanley Pons for the process were discredited. The reality is that subsequent research showed that it was the critics who were wrong, something not widely known because editors of the main journals, under the impression that the claims were false, blocked the publication of papers suggesting otherwise.
For a long time, difficulties with making the process work reliably, or in making useful amounts of energy using cold fusion, meant that LENR had no practical value, but now the situation is very different. In the time since the original discovery there has been much progress, a number of companies having been able to make these reactions work quite reliably, one at least confirming claims of genuineness by powering a device from its output.
Apart from removing the current reliance on fossil fuels, together with processes requiring the large-scale disposal of radioactive material, such devices would have the advantage of being small in size, and usable in any location. Some companies are now working on making such devices commercially viable, and recently there has been support from governmental organisations such as APRA-E in the US and Horizon 2020 in the EU. More needs to be done, however, to accelerate the rollout of such devices, thereby ameliorating the damaging effects of climate change.
Brian Josephson Emeritus professor of physics, University of Cambridge
David J Nagel Research professor, George Washington University
Alan Smith International Society for Condensed Matter Nuclear Science
Dr Jean-Paul Biberian Honorary professor, Aix-Marseille Université
Yasuhiro Iwamura Research professor, Tohoku University
