Ever wonder what would happen if we lost all power? No lights, no phones, even the computer you're watching right now would cut out.
But the way the UK currently generates energy can't carry on forever, and new government rules mean there are going to have to be big changes to where we get power from.
Every day this week Joe's travelling the UK in order to find out what these changes are, and what it'll take to power Britain in the future.
For this report he's investigating the problems with relying on coal for power.