The production of electricity remains an expensive and often dirty industry. Just think of fossil fuels or nuclear reactors. But nuclear fusion may hold the key to the world’s energy problems. It’s clean and sustainable. The only thing is, nobody’s been able to create it yet. So, the race is on. Frédéric Zalac of CBC/Radio-Canada's Découverte looks at companies in California and British Columbia that are trying to develop technology to create nuclear fusion. And he visits France, where the largest nuclear fusion project is being built.