What is the next step after the breakthrough of nuclear fusion?

What is the next step after the breakthrough of nuclear fusion?

Earlier this week, Lawrence Livermore National Laboratory (LLNL) announced a major breakthrough in the exploitation of controlled nuclear fusion. LLNL’s National Ignition Facility (NIF) performed “ignition” – a fusion experiment that produced more energy than was consumed by the lasers needed to operate it. This science news received significant publicity, even briefly capturing the front pages of major news outlets. What does all this mean?

Nuclear fusion powers our sun and all other stars. In it, light hydrogen nuclei fuse into heavier helium nuclei and generate huge amounts of energy. The hydrogen used in fusion is an incredibly dense energy source, containing more than a million times more energy in a unit mass than natural gas. As hydrogen is easily produced from water, commercial nuclear fusion would effectively offer an unlimited source of energy without greenhouse gas emissions. Compared to its established relative, nuclear fission – which is used in commercial nuclear power plants and works by breaking down heavy nuclei – radioactive waste from fusion is said to have a shorter lifespan and be easier to handle.

But the problems abound. One of the main ones is that fusion is difficult to start, requiring high temperatures comparable to those of the sun, which creates an unusual state of matter called plasma. These temperatures are reached by extremely powerful lasers, which generally consume more energy than fusion generates. This is the heart of the NIF announcement: for the first time, they have produced 50% more energy in a fusion experiment than that consumed by the lasers that power it.

What does this mean for the role of fusion in our future energy supply? The discovery of NIF is undoubtedly important, but there is still much to be done. The amount of power generated is still tiny, about 0.9 kilowatt hours (kWh) from about 0.6 kWh input. By comparison, an average American home uses about 900 kWh per month. The next obvious task is to increase both absolute output and the ratio of output to input energy. That task will fall to the International Thermonuclear Experimental Reactor (ITER), currently under construction in southern France (with the United States as one of three dozen partner nations) and slated for commissioning in 2025. D ‘by the end of the decade, ITER aims to produce 500 MW of power, similar to the power of a medium-sized coal-fired power plant, using only 50 MW of laser power to start the process.

However, even ITER is only a proof of concept: fusion will produce heat, not usable electricity delivered to the grid. Based on the information expected from ITER, a new generation of even larger demonstration reactors (DEMO) will be built that will use fusion to generate electricity. These DEMO reactors are not expected to operate until the late 2040s, which will make this energy source unlimited in about two decades. The announcement of the NIF is on the right track with this timetable: it is progress, but is it enough?

Unfortunately, that may not be the case. Our energy landscape will have to change quickly and radically to avoid the worst consequences of climate change. Nuclear fusion will most likely be late to the party, not entering commercial use in time to participate in this change. Critics point out that we already have a functioning but underutilized fusion reactor: the sun delivers enough energy to Earth in 90 minutes to meet all of our annual energy needs – and yet global solar energy use remains minimal. If billions of dollars invested in fusion development were deployed to improve and subsidize solar panels, the problems of climate change could be solved much sooner.

The dream of developing controlled fusion may touch on more than concerns about energy supply and climate change. Humans have developed many innovative technologies, replicating and improving nature’s ingenuity. But they never came close to making their own sun – that remained firmly the domain of the gods. Perhaps getting closer to that dream, to moving our knowledge beyond a long impossible limit, is the real cause for celebration. Along the way, advances in fusion-inspired physics and materials science will influence our world far beyond nuclear fusion.

Ognjen Miljanić is a professor of chemistry at the University of Houston, where he teaches energy and sustainability. He is the author of “Introduction to Energy and Sustainability”, published by Wiley. Follow him on Twitter: @MiljanicGroup

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