Tom Heap explains how huge resources of geothermal steam beneath East Africa's Great Rift Valley are starting to be exploited, bringing an energy revolution which has the potential to lift millions out of poverty and cut greenhouse gas emissions.

You can find out more about the revolution electrifying Africa in Tom Heap's reports on BBC Newsnight on Monday 25th February 2013 at 10.30pm on BBC Two and Costing the Earth on Radio Four on Tuesday 26th February 2013 at 3.30pm, repeated on Wednesday 27th February 2013 at 9pm.

Both programmes will also be available afterwards on the BBC iPlayer.