When ice storms strike as they did in Canada and the American north-east in 1998, power lines can become so encrusted with ice that they collapse, leaving millions without electricity.

Victor Petrenko, at Dartmouth College in New Hampshire, thinks he has the answer – use the ice itself as the element.

Working with a consortium of US and Canadian power companies, he has developed a system that sends high-frequency electrical signals along the cables to create a current in the ice build-up and melt it.

It runs off small power units placed along the lines every 100 kilometres or so. The signal does not reduce electricity transmission through the cables, and because it uses around 50 watts per 100 kilometres of line it should cost a fraction of what it normally takes to keep the lines clear.