What next after the breakthrough of nuclear fusion?

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

Nuclear fusion powers our sun and all other stars. In it, light hydrogen nuclei fuse into heavier helium nuclei and generate enormous amounts of energy. The hydrogen used in fusion is an incredibly dense source of energy, contains more than 1 million times more energy in a unit of mass than natural gas. Since hydrogen is easily produced from water, commercial nuclear fusion would effectively offer an unlimited source of energy with zero greenhouse gas emissions. Compared to its established relative, nuclear fission, which is used in commercial nuclear power plants and works by breaking apart heavy nuclei, the radioactive waste from fusion would be shorter-lived and easier to handle.

But problems abound. One key is that fusion is difficult to get going and requires high temperatures comparable to those of the sun, creating an unusual state of matter known as plasma. These temperatures are achieved by extremely powerful lasers, which typically consume more power than is generated by fusion. Here’s the gist of NIF’s announcement: For the first time, they produced 50 percent more power in a fusion experiment than was consumed by the lasers that power it.

What does this mean for the role of fusion in our future energy supply? The NIF discovery is certainly significant, but much work remains to be done. The amount of power generated is still small, around 0.9 kilowatt-hours (kWh) from an input of around 0.6 kWh. Compared, an average American household uses about 900 kWh per month. The next obvious task is to increase both absolute production and the ratio of power output to power input. This task will fall to the International Thermonuclear Experimental Reactor (ITER)currently under construction in the south of France (with the US as one of three dozen partner countries) and is scheduled to start operating in 2025. By the end of the decade, ITER aims to produce 500 MW of power, similar to the output of a medium-sized coal-fired power plant, using only 50 MW of laser power to push – start the process.

However, even ITER is just a proof of concept: fusion will produce heat, not usable electricity delivered to the grid. According to the expected knowledge of ITER, A new generation of even larger demonstration (DEMO) reactors will be built that will use fusion to produce electricity.. These DEMO reactors are scheduled to operate only in the late 2040s, making this limitless source of power some two decades away. The NIF announcement is on track with this timeline – it’s progress, but is it enough?

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

The dream of developing controlled fusion may affect more than concerns about energy supplies and climate change. Human beings have developed many innovative technologies, reproducing and improving on nature’s ingenuity. But they have never come close to making their own sun, that remained firmly the domain of the gods. Perhaps getting closer to that dream, of taking our knowledge beyond a long impossible limit, is the true reason for celebration. Along the way, fusion-inspired advances in 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. His is the author of “Introduction to Energy and Sustainability”, posted by Wiley. Follow him on Twitter: @MiljanicGroup

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