A sun in your own living room

The holy grail of power generation is nuclear fusion. That’s the process by which stars are powered – simply put, hydrogen turns into helium and releases energy in the process. What makes it so perfect is that there is pretty-well a limitless supply of hydrogen on the Earth, tied up in the copious quantities of water in our oceans.

However, realising nuclear fusion in practice is rather tricky. The problem is to get it to work you need to get your hydrogen hot. Really, really hot. The kind of temperature inside the sun sort-of-hot (10 million celcius or so).  Actually, even hotter than that, because the pressure on earth is a lot less than inside the sun.

One method for trying this has just been ‘set-up’ in the US. It involves heating a small pellet of fuel with lasers – the idea is that the small pellet will get hot enough for nuclear fusion to occur, and release far more energy than put in. This ambitious concept is, however, only a proof-of-principle – to provide usable power on a large scale there needs to be a continuous supply of fuel. At this point the skeptic in me starts getting a bit active. Can this really be achieved?

 

An alternative method is using magnetic fields to heat confine an extremely hot plasma of fusing material. This is the idea behind the Joint European Torus Tokomak project. This is equally ambitious – to date, it hasn’t really demonstrated that it can work on a large scale.

With these things the experts generally will tell you that it will be achieved on a useful scale about 20 years in the future. The trouble is, they said that 20 years ago. (A bit like Transmission Gully?)

Anyway, have a read, and judge for yourself. Interesting technologies – what is certainly true is that if they work (or just one of them works) a source of power for the future is assured.

(PS Can you spot the annoying error in the BBC report? Using ‘watts’ as a unit of energy. Grrrrr. Someone should teach these journalists a bit of physics.)

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