Will Nuclear Fusion Ever Power the World?


Image: Benjamin Currie (Gizmodo)

Only an unusually naive child, or a fossil fuel executive, could sincerely argue that our current energy situation is sustainable. For over 50 years now, well before the scope of the climate crisis was clear, scientists have been working toward an alternative: fusion power (i.e., using the heat from nuclear fusion reactions to generate electricity). Since its inception as a field of study, viable fusion power has always been just around the corner—but this time, that might actually be true. For this week’s Giz Asks, we talked to a number of experts to see if and when fusion power might actually power the world.


Assistant Professor of Engineering Physics, University of Wisconsin-Madison, whose research on the Pegasus-III Experiment is focused on developing innovative fusion reactor startup technologies

If funding for fusion energy development continues to increase, then yes, fusion will power the world in the future. Since the 1990s, funding for fusion research in the United States has been for the science of fusion, not for the development of an energy source. The rest of the world has a wide portfolio of fusion research as well, and we are all racing to harness the power of fusion. Major recent advances in technology and a U.S. fusion community consensus to shift the focus to fusion energy development are bringing us closer to powering the world with fusion. It’s a grand engineering challenge to solve and we are getting closer to commercializing fusion energy. I’m really excited about the direction our research is heading!

Fusion has the potential to provide clean, green energy to the world with zero carbon emissions. The fuel for fusion is extremely energy dense—using the deuterium found in one bathtub’s worth of water combined with the lithium from two laptop batteries (used to breed tritium), this provides enough energy for your entire lifetime with no pollution. This tiny amount of fuel for fusion energy is equivalent to 230 tons of coal that would release 380 tons of pollution. As the world transitions to renewable energy, fusion can step in to complement a diverse energy portfolio (fusion is independent of geography, environmental conditions, and has a compact footprint). The fuel for fusion is hydrogen isotopes, making it widely available and an essentially inexhaustible source of energy.

In the U.S., the fusion community (universities, national laboratories and private companies) has just completed a two-year strategic planning process to identify the remaining challenges to harnessing the power for commercial fusion energy. This effort was kicked off by a National Academies report on creating the conditions for fusion, and resulted in several reports (community consensus report, a FESAC report, and a fast-tracked National Academies report) focused on designing and constructing a fusion pilot plant to demonstrate electricity generation by 2035.

This is a bold and exciting direction for fusion energy research in the U.S. and is backed by recent advances in technology. Researchers have made huge improvements in creating the conditions for fusion by making more efficient and compact tokamaks as well as major advances in laser technology. Advances in additive and advanced manufacturing allow the use of new materials and design of complex structures to survive the harsh fusion environment. High performance, exascale computing enables modeling of entire fusion reactors to design and predict performance in fusion pilot plants. High-temperature superconductors provide access to more compact reactors, which can be a game changer when it comes to fusion power. Interest and investment from private companies provides necessary partners when it comes to realizing fusion as a solution to climate change. And on the horizon is the operation of ITER—the first fusion device that’s been designed to demonstrate we can produce more energy than is used to run the device, a demonstration of a self-sustaining fusion reaction.

Just recently, the fusion field has had two major breakthroughs, with MIT and Commonwealth Fusion Systems’ successful demonstration of their high-temperature superconductor and the National Ignition Facility achieving record-breaking yields in laser fusion.

“If funding for fusion energy development continues to increase, then yes, fusion will power the world in the future. Since the 1990s, funding for fusion research in the United States has been for the science of fusion, not for the development of an energy source.”

Associate Research Professor, Nuclear, Plasma, and Radiological Engineering, University of Illinois Urbana-Champaign

The running joke in fusion is that, every year for the last 50 years, it’s been 50 years away. But this time, I think we’re really getting close.

Potentially, in the next 20-30 years, we’ll have a realistic demonstration of fusion technology as a power source. The International Thermonuclear Experimental Reactor (ITER) in France is going to be a huge stepping stone towards that goal. It will be the first demonstration of our ability to get fusion above q=1—that is, to get to the break-even point, where the output energy is equal to the input energy that we need to get the fusion reaction going. But it is also designed to go far beyond that—to get a 10x greater energy output. Which means that, with an input of 50 megawatts of heating power, you’d get 500 megawatts of fusion power.

To be clear, this “output power” will not be going onto the grid or producing electricity. We’re not demonstrating electricity—we’re just demonstrating that we can actually get a plasma and generate the nuclear reactions that we need to do it.

From there, the next step is to get a pilot plant up and running: the first demonstration of putting power on the grid. The National Academy of Sciences put out a report saying that we should get to this point in the U.S. by 2050. We’re not aiming for anything crazy—only 20 megawatts of power onto the grid—but we need to start somewhere.

There are grander designs out there: in Europe and Japan, scientists are looking at a machine called the DEMOnstration Power Plant, which is designed to produce 1-2 gigawatts and could legitimately power cities. In theory, we know how this should work, but the technology is not yet fully developed. One challenge, here, is that the materials you need to build these fusion reactors with—i.e., materials that can survive in the hellish conditions we create inside of these machines—are extremely expensive. So part of the question moving forward is: can we design these things to be nicer to materials? It’s a huge thing, and not entirely understood.

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“One challenge, here, is that the materials you need to build these fusion reactors with—i.e., materials that can survive in the hellish conditions we create inside of these machines—are extremely expensive.”

Co-Founder and CEO of CTFusion, Inc., a company dedicated to the development of fusion energy

As a fusion scientist, I’m a bit biased—but my answer is: yes, of course.

This happens to be a very exciting time for the field as a whole. For upwards of 50 years now, we’ve been working on building the scientific foundations of fusion energy—mainly through research and development funded by the Department of Energy, but with substantial international contributions, too.

That foundation is now in place, and a host of private fusion companies are building on it, in the hopes of developing a viable commercial energy source and actually getting it onto the grid. Multiple companies will be demonstrating net gain operation within the decade, with many planning the first commercial units for the 2030s. So this is no longer the perennial “energy of the future”—it will be here (relatively) soon.

As with any new technology, the biggest challenge is building the very first one; after that, the challenge becomes scaling up production to really capture market share. Hopefully, by the end of the 2030s and going into mid-century, you’ll see market share expand, hopefully displacing fossil fuel generation and conventional nuclear energy, and working with renewables like wind and solar to basically do decarbonization, which is our goal here, for climate change.

Technical risks still remain. But in aggregate, that risk is diminishing as far as plasma physics and core technology; we’re now shifting our focus to engineering these systems. That involves technologies like heat exchanges and turbines and compressions. We’ve done that for hundreds of years with heat engines, so we know how it works—we just have to customize it for a fusion heat source.

So there is absolutely still a lot of work to be done—but we’re getting closer and closer.

“As a fusion scientist, I’m a bit biased—but my answer is: yes, of course.”

Associate Professor, Mechanical Engineering, University of Maryland, Baltimore County

The answer is yes, fusion will eventually power most of the world’s energy needs. Over the past 60 years, there has been skepticism and cynicism on the ability for fusion energy to be a viable source of energy. There is a running joke that “fusion is only 20 years away… and will always be.” (The years in the joke vary depending on who you ask, but the punchline is the same.) In the early days of fusion research, there was indeed a high level of optimism, but after decades without fusion, jokes like this one are no surprise. However, to better understand the seeming lack of progress in fusion research, one has to look at the history of fusion funding and how this funding has varied and even stopped for long periods of time. In the 1970s, fusion funding worldwide increased fivefold, but it started to decline in the 1980s until it reached a minimum in the mid-2000s. Pronounced ups and downs in funding have made continuity of experiments and retaining experienced personnel difficult, but the overall funding trend is finally upward and poised to accelerate.

To have an energy reactor powered by fusion energy, you need enough particles confined at high enough temperature for long enough so they can collide head on and fuse (and in the process release enormous amounts of energy). This is called the triple product: density, temperature, and confinement time, and it can be used to compare progress towards net energy gain across different reactor concepts. Tokamaks, the donut-shaped machines that have the best triple product performance so far, achieved the conditions for net gain over 25 years ago, although for very short times. These machines performed as designed and were meant to be an intermediate step toward the ultimate goal of high net energy gain commercial reactors. The natural next step was to fund tokamaks that would have achieved net gain for long periods of time. However, it took until 2006 for the European Union, the U.S., Russia, Korea, Japan, India, and China to agree to build such a machine (now called ITER). The first experiments in ITER are expected in the next four years, even though these were originally scheduled for 2016. The reasons for these delays are not scientific but largely political. The good news is that, in all this time, our modeling and understanding of tokamaks has improved through simulation and experimentation in existing machines, and there is high confidence that ITER will achieve its stated goals. Just as with the computers and cellphones we buy, computer simulations and diagnostics for fusion-relevant experiments have become much better and affordable compared to just a few years ago, enabling refinement of complex physics models with an ever-increasing level of detail.

An eventual fusion reactor may not look like ITER, since its size and cost may make it commercially unattractive. Nevertheless, there have been important developments in critical technologies such as superconducting magnets (required in a tokamak fusion reactor) that will allow for much better confinement than was possible just 10 years ago. This will enable smaller fusion reactors that could be cost effective and with a shorter path to market. The urgency of addressing climate change and decarbonizing our energy sources have given renewed interest in funding fusion energy research.

The number of private companies pursuing commercial fusion continues to increase, with hundreds of millions of dollars already poured into those companies in the last 20 years by both public and private investors. Many of these new ventures are banking on concepts different from the tokamak and, if successful, these would add to the range of fusion reactor options that could power everything from massive electrical generators to small shipping vessels. ITER results will be very important to the entire fusion research community, as many technologies common to all concepts will be tested there. While there is much work to do before getting to the first commercial reactor, including in engineering, regulation, and public acceptance, the pace of development and funding toward that goal is accelerating. At this point, it is not a question of whether we can have fusion reactors to power our world, it is a question of how quickly we can make them affordable and commercially viable.

“Pronounced ups and downs in funding have made continuity of experiments and retaining experienced personnel difficult, but the overall funding trend is finally upward and poised to accelerate.”

Chief Scientist for the Inertial Confinement Fusion Program at Lawrence Livermore National Laboratory

In the distant future, fusion will likely be part of the energy mix powering the world. Over the next couple of decades, at least, I don’t think it’s realistic to expect fusion to play a role. While there has been great progress in fusion research over the past decade, as we are approaching scientific breakeven, it will take much more energy gain than breakeven to make fusion practical for energy production. Why so long? Even with old known technologies, like fission power, it takes at least a decade to build a power plant. For now, fusion is still a science experiment.

Do you have a burning question for Giz Asks? Email us at tipbox@gizmodo.com.


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