Question: Do you think that scientists will successfully develop nuclear fusion reactors in the future? Also do you think this will solve our energy problems? (from elhermano and sister, lahermana)

David Pyle answered on 18 Mar 2011:

Hola hermanos!

Yes – there are several experimental ‘tokamak’ instruments in use or development around the world. One of the most successful of these is the Joint European Torus at Culham, Oxfordshire (well worth a visit – as you can walk inside the prototype!). These fusion reactors use a massive array of magnets to hold the hot plasma in the shape of a doughnut, or torus. At the moment, these reactors are a little way off actually producing useful amounts of energy. At Culham (and I think that this is true elsewhere) it takes more energy to ‘spin up’ the system, than is generated in the short-lived fusion reactions – but once the technology is in place to produce a stable plasma this should change. The first planned prototype commercial tokamak (DEMO) is unlikely to be producing power for another 20 years, assuming that the necessary develolpments are achieved in time. It’s likely to be at least 30 – 40 years before tokamaks contribute substantially to the European electricity grid.