Although its capacity to generate electricity at a commercial scale is several decades away, nuclear fusion can become an encouraging alternative to replace fossil fuels as the world's leading energy source and could have an important role to play in finding a solution for climate change.
Following on from the Hydrogen Economy blog piece, Nuclear fusion has been described as the “holy grail of energy technology” due to the theory it can produce limitless energy with virtually no radioactive waste at all, which would end both global energy scarcity and also halt climate change.
Current nuclear reactors rely on fission and the splitting of an atom which leaves toxic waste. This waste must then be carefully stored for potentially tens of thousands of years. On the other hand, a nuclear fusion power plant, it is said, would not create greenhouse gas emissions, nuclear waste, or safety hazards meaning that adoption of the technology worldwide could stop climate change in its tracks. As well as that, a plants’ relatively small fuel needs mean that nuclear meltdowns like the Chernobyl disaster or Fukushima accident would not be possible, essentially surpassing all current techniques with regards to a more efficient and safe energy source.
Fusion is the central energy source of the universe, powering our sun and the distant stars. When two hydrogen atoms join together to form a single, heavier atom (helium), a colossal amount of energy is released – i.e. heat at several times the temperature of the sun's core is generated. This is the primary nuclear reaction that keeps our sun and other stars burning for billions of years — which is why a fusion reactor is sometimes likened to a "star in a jar." No carbon emissions or radioactive waste are produced in the reaction, and ocean water is all the fuel you need for a hundred thousand years of operation.
However, the challenge with fusion lies in channelling and controlling the unstable reaction. The problem is that the process only produces net energy at very high temperatures of hundreds of millions of degrees – too hot for any solid material to withstand. To get around that, fusion researchers use magnetic fields to hold in place the hot plasma, a gaseous soup of subatomic particles that fuels the process, to stop it melting through the metal reactor. The ultimate goal of fusion research, yet to be achieved, is creating a fusion reactor that produces more energy than it took to ignite and contain the process.
ITER Director-General, Bernard Bigot said: “When we prove that fusion is a viable energy source, it will eventually replace burning fossil fuels, which are non-renewable and non-sustainable. Our mission is to provide a new option which is safe, sustainable and economically competitive. Fusion will be complementary with wind, solar and other renewable energies.”
While large scale experiments such as ITER continue, nearly two dozen start-ups are working on a variety of devices, fuels, and approaches, using new technologies. These start-ups are backed by venture capital funding.
A private nuclear-fusion company, UK-based Tokamak Energy, has heated a plasma of hydrogen to 15 million degrees Celsius in a new reactor for the first time — hotter than the core of the sun. Tokamak Energy says the plasma test is a milestone on its chase to be the first in the world to produce commercial electricity from fusion power, possibly by 2030.
Mila Aung-Thwin, director of the award-winning documentary about the quest for fusion energy, Let There Be Light, said: “It’s great that there are more private entities supporting innovation. Perhaps we are at the level of technology now where start-ups can compete with national labs and agencies, as they seem to be in space travel.”