German scientists were likely feeling quite proud of themselves when they created their W-7X fusion reactor. Using 2 megawatts of microwave radiation, they produced a hydrogen plasma at 80,000,000°C for a quarter of a second. Sadly, their efforts have been quickly outstripped. Although Chinese scientists claim to have only managed a measly 50,000,000°C (still three times hotter than the sun), it was maintained for an astounding 102 seconds.
You may ask why either of these achievements are worthy of our attention? Well sometime in the Stone Age mankind twirled a stick and made fire before sitting back and admiring his work for a few thousands of years. He tweaked it a little when digging a deep hole and discovering other flammable materials, namely fossil fuels. However, we are now beginning to realise that fossil fuels are not the most ideal of energy sources.
Only in the 20th century did we take a different approach in the form of nuclear fission. This process of smashing huge nuclei apart for energy may not produce any greenhouse gasses but it does produce radioactive waste which is arguably more of a problem. Enter nuclear fusion, an entirely different process and the solution to all problems. Well, almost.
Theoretically, fusing two types of hydrogen together holds immense amounts of potential energy. Bringing deuterium and tritium together, in the same process that powers our sun, can yield a whole lot of energy with only helium and a neutron as by-products. The energy would be practically inexhaustible and completely clean without nuclear waste or greenhouse gases but, of course, there’s a catch.
The incredibly high temperatures achieved in Germany and China are required to generate a hydrogen plasma for fusion. In order to contain and maintain the immense temperatures, the plasma must be suspended in a magnetic field within the reactor, which is not the easiest of tasks. What is more, neither of the two nations have actually achieved the temperatures required to initiate fusion which is estimated to be around 100,000,000°C!
Despite these problems, we are heading in the right direction, albeit via slightly different routes. The Experimental Advanced Superconducting Tokamak (EAST) reactor design used in China claims to have solved some of the previous problems with the aging Soviet design. Furthermore, hydrogen plasma production had a relatively low cost of $35 million and took less time than its German rival.
Similarly, the stellarator design used in Germany has been knocking around for a while but is less well developed. With a budget of over $400 million, the reactor from the Max Planck Institute of Plasma Physics does represent significantly worse value for money. However, the stellarator design is believed to offer the best possibility of steady state operation and therefore a better chance of ultimate success.
Following these experiments, both teams claim they are capable of bigger and better feats. China’s ultimate goal is to hit the magic 100,000,000°C and sustain it for over 10 times what was managed by the first attempt. Whereas, the German team ambitiously claims they could maintain their plasma for up to 30 minutes. Only one thing is for sure; that we are a couple of steps closer to making the dream of clean, safe and reliable energy a reality.