Just north of UC San Diego’s campus, past the eucalyptus forest and the Seventh College, sits a facility where scientists are working to harness a nearly limitless source of energy. Completed in 1986, U.S. Department of Energy’s DIII-D National Fusion Facility is managed by General Atomics under a cooperation agreement with DOE, which owns the facility equipment. In this complex web of ownership and operation, research teams consisting of “private companies, national laboratories, and academic institutions,” have been working for decades to solve one of the 14 Grand Challenges for Engineering in the 21st Century: provide energy from fusion.
Right now most people on Earth are supplied with electricity generated from fossil fuels like coal, gas, and oil. These fuels are burned in power plants to produce heat which boils water into steam that generates energy by spinning turbines. That energy is then transferred to your local power grid, and into your home. The problem with using fossil fuels, aside from the environmental harm, is that fossil fuels are in limited supply. Experts say there is a real risk of fossil fuels becoming extremely scarce and difficult to extract in the coming decades.
Despite the progress of wind and solar to address this looming crisis, there is actually a process of harnessing energy that takes up less land, and can cleanly produce millions of times more energy than equivalent amounts of fossil fuels. That process is called nuclear fusion.
What is nuclear fusion?
Nuclear fusion is the process of smashing two light nuclei together to form a single, heavier nucleus, and harnessing the energy that is released. This process was discovered in the 1920s when astrophysicist Arthur Eddington proposed that stars are powered by massive amounts of energy released as a result of that very process. Since this discovery, much research and funding has gone into finding ways to understand fusion in the stars, produce it here on Earth, and do it in a controlled way to allow that energy to be harnessed.
The implications of making fusion energy viable are potentially world-changing according to experts. The U.S. Department of Energy says producing energy from fusion would provide “enormous” benefits to humankind, with effects that would be “far-reaching and significant” for human civilization and the planet.
Once you understand fusion, it’s not hard to see why experts are excited and why billions of dollars are being poured into research. Not only does fusion energy provide a massive carbon-free energy source, it also releases millions of times more energy than equivalent amounts of fossil fuels. According to a report by the Kleinman Center for Energy Policy,
“A single kilogram of fusion fuel releases the same amount of energy as 13,000 tons of coal.“
Fusion fuel consists of deuterium, which is abundant in seawater, and tritium, which is a rare isotope. While tritium is naturally occurring, it can also be produced artificially by irradiation of lithium in nuclear reactors, or through a method called “tritium breeding” which is still being studied.
So how close are we?
We didn’t have to wait long to produce artificial nuclear fusion on Earth. In 1934, Mark Oliphant demonstrated nuclear fusion in an experiment, proving that fusion reactions are possible and they do release energy. In 1952, the U.S. tested the Ivy Mike hydrogen bomb, marking the first time fusion energy was weaponized. And after decades of steady progress, yet another major breakthrough came on December 5, 2022, when the National Ignition Facility in Livermore, California, recorded the first nuclear fusion experiment to achieve what scientists call “scientific breakeven.” That is, they got more energy from fusion than they put into the process.
Although we can now achieve nuclear fusion, and even get more energy from fusion than we put in, there are still unresolved challenges of achieving breakeven consistently, harnessing the produced energy, and scaling up the process to commercial levels. Right now, dozens of companies across the globe are actively working to make fusion energy viable. In 2023, Helion, a Washington-based company, announced an agreement to provide Microsoft with power from its first fusion power plant by 2028. TAE Technologies, a California-based company, is also reportedly aiming for a commercially viable fusion power plant by 2030. If either company hits their target, commercial fusion energy could become a reality within the decade.
The road to nuclear fusion
Where we are in 2026
Will it be cheap?
On the surface, one would think that near-unlimited energy means that it will also be cheap. But experts caution against that thinking. In a recent study, researchers at ETH Zurich found that fusion power plants are not going to get cheap as fast as people expect. Technologies typically get cheaper the more they are built, but researchers found fusion will cheapen far more slowly than assumed, getting cheaper at a rate of 2–8% per doubling of capacity compared to the current estimates of 8–20%.
A similar view is reflected by ITER, an international nuclear fusion project. “As with many new technologies, costs will be more expensive at first, when the technology is new, and gradually less expensive as economies of scale bring the costs down.”
Even if fusion energy proves costly in its early years, the long-term payoff could justify the investments many times over.
A world with fusion
Nuclear fusion is expected to work similarly to today’s systems of energy delivery. The reaction produces heat, which boils water into steam to drive turbines, which generate power and send it to the grid. With this near limitless source of clean and reliable energy, the benefits would be immense.
First, and most obviously, we will end our reliance on coal, oil, and gas, solving the resource depletion problem. With less CO2 being produced as fusion expands, we might finally get climate change under control, though scientists remain skeptical that warming can be kept below the 1.5°C target by 2050, even with fusion energy. Energy from fusion could also help with water desalination as energy costs are currently the biggest barrier to removing salt from seawater.
With the rapid rise of AI in recent years, there has also been growing controversy surrounding data centers pushing up energy bills for nearby residents. Nuclear fusion could emerge as a solution to this problem, providing the massive amounts of power these facilities need without straining local grids.
Moving beyond Earth, NASA has been exploring nuclear fusion for space exploration through its research into Fusion Driven Rockets. According to NASA, if realized, this technology could be used for manned interplanetary travel.
In 2010, speaking to Time magazine, Stephen Hawking said “I would like nuclear fusion to become a practical power source. It would provide an inexhaustible supply of energy, without pollution or global warming.” In 2010, there were only 11 companies working on fusion energy. In 2026, with over 40 companies now racing to make fusion viable, and breakthroughs like the 2022 NIF experiment, the clean energy revolution may arrive sooner than the world expects.
