Consumers will save up to £40bn thanks to a revolution in the way electricity is made, used and stored, the government says.

New rules published today will make it easier for people to generate their own power with solar panels, store it in car batteries and sell it to the national grid.

Phil Taylor, professor in energy systems at Newcastle University, told Radio 4's Today programme these technologies are already available but are "expensive" and not yet "proven" to work on a large scale.