Rehearsals briefly resume amid uncertainty over the band's future. Following a productive meeting with Harrison, the Beatles agree to abandon the idea of a live show and relocate to their Apple Corps studio to formally record the new album. Billy Preston, a musician the group met in Hamburg, joins in on the sessions on electric piano.

The meteoric rise of renewable energy has consequences for our electricity supply. While coal and gas fired power stations can generate electricity whenever you need it, renewables are intermittent by nature. So we need a backup plan for when the wind stops or the sun goes down.
All over the world, engineers and scientists are racing to solve one key problem; how to safely and efficiently store electricity at a huge scale but at a low cost. The quest is producing some truly remarkable ideas and this episode details three of them.