This week, we are in the company of James Williams, a start-up entrepreneur who hopes his idea – to incentivise people to charge their electronic devices at times of the day when clean energy systems are at their most productive – has legs.

We also catch up with Vikki Knowles for the latest news from across the world of sustainable business, featuring Boeing, Levi Strauss and the new solar cell technology that can make energy from water as well as light.