Smart meters enable Cornwall's sunshine tariff trial
Residents in a town in Cornwall are being offered ultra cheap energy... when the sun is out.
They are on a sunshine tariff, which is aimed at persuading households to shift energy use to take advantage of locally-generated solar power.
The trial is possible due to the installation of smart meters, effectively ending estimated bills and allowing energy companies to offer different prices at different times of the day.
The BBC's John Moylan has been looking at whether the benefits of smart meters outweigh the costs.