Iceland may soon spread its vast wealth of geothermal energy to the UK. But how can two islands separated by more than 1,000 km of ocean share electricity? The answer lies in undersea high-voltage cables.

"Interconnectors are an incredibly effective way to counter the argument that you need to back up each gigawatt of wind with a gigawatt of gas — they quite clearly show you do not." -- Charles Hendry, UK Energy Minister