Research found that a typical salmon, which zips through waters at a top speed of 12 metres (40ft) per second, can over a 100m (330ft) stretch generate enough electricity to make 18 cups of tea, while the more shy rudd will only trigger enough power for three cups.
Multiplied many times over by the millions of fish that thrive in rivers and waters, scientists estimate the amount of electricity generated could power around 30,000 homes a year.
A three-month trial of the technology was conducted last summer at a secret location, of course, which has seen salmon numbers increase to record highs. In that period enough electricity was generated to power a typical family home for a year. Now how's that for a clean energy?