It is extremely difficult to recreate here on Earth the source of energy that supplies the sun. Doing so involves finding a way to get fusion reactions happening constantly in a plasma (an ultra-thin ionised gas) heated to 100 million degrees. But with ITER, the international experimental reactor being built at the Cadarache facility in the south of France, fusion researchers are getting very close to being able to demonstrate a plasma that can produce this energy.
It has taken a long time to get here. Shortly after research began in the 1950s, it became clear that intensive basic research was needed to understand the highly complex processes and manifold chain reactions in plasma. Ever since then, researchers have been working one step at a time. The first plants were 50 million times removed from the values needed to make plasma burn. Today, that gap has shrunk to about just one order of magnitude. The Joint European Torus experiment (JET), located in Culham in the UK, has produced 16 megawatts of fusion power. Although that’s a world record, JET’s plasma volume is too small to produce a net energy gain.
That task has now fallen to ITER, and to the researchers from all over the world who work at the facility. ITER has been designed to produce 500 megawatts of fusion power – ten times more than the amount needed to heat the plasma. The next step will be to construct a demonstration plant that performs all the functions of a future fusion power plant. Given the time needed for planning, building and commissioning ITER and its successors, it seems likely that we’ll have a fusion plant supplying economically useful energy sometime around 2050. It’s a long journey, but worth every step. The world has an almost inexhaustible supply of the fuel needed for fusion (deuterium and lithium, which produce tritium in the plant). And a single gram could release as much energy as eleven tonnes of coal.
Isabella Milch, director of Public Relations from the Max Planck Institute for Plasma Physics (IPP) answered this question.