Overview: In the past 50 years, the world's energy use has doubled. In the next 50 years, it will double again. Can we keep up with demand - or will we plunge into darkness? Across the world, engineers are going to extreme lengths to keep the lights on: harnessing the power of the longest river on Earth, tapping into the raging heat of a live volcano, and building one of the largest offshore wind facilities in the world. This is Project Impossible: Battling the Blackout.