The Max Planck Institute for Plasma Physics in Germany turned on the Wendelstein 7-X nuclear fusion reactor - the largest ‘stellarator’ reactor ever built - in December 2015. Researchers have begun the advanced testing stage with a view to demonstrating that nuclear fusion has the ability to bring about a significant reduction in carbon dioxide emissions and, at the same time, to ensure the continuity of energy resources as the world's population continues to grow rapidly. The team at the Max Planck Institute, led by Professor Thomas Klinger, has been working on designing and developing the W7-X stellarator for 15 years. Now that the reactor has been switched on (and provided that it keeps its promises), nuclear fusion could emerge as a new primary energy source with the potential to make a significant contribution to global supplies. The results achieved using nuclear fusion had previously been hindered by the difficulty of keeping machines running continuously since the reactor had to contain boiling plasma in order to function. This is no longer a problem, as Klinger explains: “The W7-X stellarator is so magnetically effective that it is the first nuclear fusion reactor capable of containing plasma for more than 30 minutes at a time. Initial plasma creation tests were short, lasting only a tenth of a second, but reached a temperature of around a million degrees Celsius. The times are now being gradually increased during the testing stage.

It is perfectly understandable that Klinger and his team should be excited about the project's potential, but the World Nuclear Association (WNA) takes a somewhat more cautious view of the matter. Indeed, as Jonathan Cobb, Senior Communications Manager at the WNA, explains, “this is a promising step, but we're still talking about an experimental reactor. If we think about the contribution it could make to the future generation of traditional energy, we will probably be looking at the second half of the century before nuclear fusion technology - and it should be possible to develop it to the point where it can be commercially distributed - starts generating significant amounts of electricity that would enable it to contribute to clean energy production”. Watch this space, then... It certainly took a year to build the W7-X and the project has already cost many millions of dollars. The components needed to make it work are heavy and the construction of the stellarator is complex, but despite these obvious difficulties, the initial findings from the test stages are promising. As Cobb explains, “we will need to produce significant amounts of low-carbon capacity as of 2050, so nuclear fusion could play an important role in achieving our long-term goals”, and it doesn't end there. “Even before then we still need to reduce these emissions if we are to achieve the temperature stability targets set at the COP21 in Paris.

Nuclear fission, which is the nuclear energy we are already using, provides many countries around the world with inexpensive, reliable, low-emission electricity. As Cobb explains, “statistics published by organisations like the International Energy Agency show that fission could provide over 17% of the world’s electricity by 2050 - more than any other single technology”. Achieving such percentage will, however, require some 1000GW of nuclear capacity (whilst the figures from the Nuclear Energy Institute indicate that global capacity stood at around 379GW in 2015). Klinger, in turn, continues by pointing out that the W7-X is just the first step towards the ultimate goal of nuclear fusion as a primary energy source. “One of our goals is, in fact, to maintain the relevant parameters of the plasma in fusion for around thirty minutes, thus proving that an optimised stellarator can function under stable conditions. This is an ambitious programme that aims to present the optimised stellarator as the best candidate for a future nuclear power plant. In any case, the W7-X alone cannot provide answers to all of the technical and scientific questions that might arise”. Then, of course, there is the other issue that is at the forefront of everyone’s concerns when it comes to nuclear power: safety. Again, as Cobb explains, “It is important to distinguish between the safety concerns relating to a particular production technology and the actual level of safety that it offers. Whether the safety of fusion reactors is perceived differently than that of fission reactors remains to be seen. The fact remains that current nuclear technology is among the safest of all energy-producing technologies, whether fossil or renewable, meaning that the new fusion technology will offer a high level of safety that is equal to or even greater than the levels offered by the current ones. With its excellent safety and environmental protection credentials, there is a very strong chance that fusion will become an increasingly important source of energy over the coming years. Whether the W7-X helps to make it a sustainable option we can only wait and see...