Can bitcoin mining ever be green?

The cryptocurrency business tries to boost its green credentials with the formation of a 'Bitcoin Mining Council' and the help of Elon Musk. Will it make a difference? Jaime Leverton, boss of Hut 8 Mining, and finance writer Frances Coppola discuss. Plus a BBC investigation finds the Chinese trying out technology that claims to sense your mood, and airplane engine maker Rolls Royce let us into its factory to look at how data is powering its business. Presented by Rory Cellan-Jones, with senior tech reporter Jane Wakefield.