How Close Are We to Nuclear Fusion for Limitless Energy?

It’s no secret that nuclear energy has had something of a bad-boy reputation in the past, filled with toxic baggage and catastrophic meltdowns. Repairing the image of this energy source has been an uphill battle, but recent achievements of its more elusive, yet more powerful, sibling—nuclear fusion—could change that. If achieved, it could provide humanity with an effectively limitless and clean source of energy by replicating the kind of reactions that take place inside the Sun.

In December 2022 the Lawrence Livermore National Laboratory (LLNL) announced that its National Ignition Facility (NIF) had achieved a new milestone toward achieving nuclear fusion by generating more power (over 3 megajoules, or 1 megajoule shy of a kilogram of TNT being detonated) than they had initially put in using a process called inertial confinement—more on that later.

This result may sound meager for an energy source that is modeled after the core of burning stars, but for scientists who have been chasing this science for decades like Omar Hurricane, chief scientist of the fusion program behind this result, it’s proof that their efforts may finally be paying off.

“[T]he December result were milestones that demonstrate that there is no physics obstacle standing in the way of fusion power generation,” Hurricane told Motherboard in an email. “I like to describe our results as an ‘existence proof.’”

Hurricane added that while NIF’s approach could potentially be used for commercial fusion down the road, it’s currently focused on “fusion science and National Security applications,” such as evaluating the US’s nuclear stockpile.

While scientists have known how to create nuclear fusion for many years, actually creating this potentially self-sustaining power source has been the field’s white whale. NIF’s new achievement, as well as a growing private sector, might just be the push fusion needs to finally come into its own. More than just a scientific achievement, a new era of fusion power could be a huge step towards a more sustainable energy future, Stephanie Diem, assistant professor at the University of Wisconsin-Madison and principle investigator of a fusion energy experiment, told Motherboard in an email.

“Ultimately, a fusion-based power plant can be used to replace our current, fossil-fuel burning power plants and can power our homes, industries and businesses,” Diem said. 

With this fresh advancement in mind, it’s worth taking stock now: Just how close are we to achieving nuclear fusion, and solving humanity’s energy woes?

If nuclear fusion has so much potential, it may seem unclear why its counterpart, nuclear fission, can’t go toe-to-toe. While both reactions are nuclear, meaning they both involve energy changes at the center of atomic nuclei, they are actually polar opposites in many ways. 

Nuclear fission is at the heart of nuclear power plants around the world and works by breaking apart the atoms of radioactive elements like uranium to create a burst of energy. This energy is then used to heat water and create steam in order to turn turbines which create electricity. Depending on their size, nuclear power plants like these have an annual generating capacity of roughly 500-1000 megawatts, equivalent to up to the power of 1.3 million horses per plant.

The downside of this approach is that using radioactive atoms as the reactors’ energy source results in dangerous waste products and can also be susceptible to dangerous meltdowns like those that took place at Chernobyl in the 80s and Fukushima in 2011. Even if new fission reactors can overcome these pitfalls, the energy source is still finite.

Nuclear fusion, on the other hand, has the potential to be self-sustaining once it's properly sparked, a process that nuclear scientists call ignition. This energy source works by slamming light atoms together (e.g. hydrogen isotopes deuterium and tritium) to form one heavier atom (e.g. helium.). This is the same process by which the Sun generates the energy that we attempt to capture on Earth with solar panels.  

“The theoretical energy production possible per unit mass of fusion fuels… far exceeds that of other known sources of energy,” Hurricane said. “The deuterium isotope hydrogen is also plentiful in sea-water and there are schemes to breed tritium from lithium (also plentiful in seawater) in proposed fusion power plants.”

Similar to nuclear fission power plants, nuclear fusion technology will create electricity through the creation of steam to turn a turbine, but at four times the amount and without harmful byproducts.

Harnessing the power of a burning sun on Earth is no small feat. To achieve this, there are two main methods that scientists use: lasers and magnets. 

“These confinement approaches broadly fit into the following categories: magnetic fusion energy utilizing magnetic bottles called tokamaks and stellarators, inertial fusion energy and magneto-intertial fusion—a combination of the previous two techniques,” Diem said. “The most mature technology is MFE using magnetic bottles called a tokamak.” 

The NIF experiment was created using laser-based inertial confinement. In a nutshell, close to 200 high-powered lasers were bounced around a capsule containing the hydrogen isotope fuel. In a matter of seconds, the energy from these lasers heated up the capsule from the outside which first compressed the fuel and then created an outward explosion of energy. 

Many other government and private projects alike, including France’s highly anticipated ITER (International Thermonuclear Experimental Reactor), use tokamaks to heat up their star fuel. Originally designed by Soviet scientists in the late 1950s, tokamaks work by using magnets and a vacuum to compress and heat up hydrogen atoms until they transform into a plasma. Continued pressure on this plasma then forces it to undergo fusion. 

In recent years nuclear fusion breakthroughs like NIF’s energy gain, Europe’s Joint European Torus (JET) sustained energy pulse, and private UK-based Tokamak Energy’s improved heating have been scraping away at the requirements for nuclear fusion, but Diem said that right now they’re not much more than science experiments. 

“Now that we have demonstrated that controlled fusion is possible, next, we will need to tackle the engineering challenges required to generate electricity,” she said.

To make commercial fusion viable, scientists and engineers will need to develop new materials that can withstand the fusion environment as well as develop new ways to create fuel for these reactions, such as harvesting the ingredients from seawater. The search for fuels has even caused scientists to look at outer space, where a helium isotope called helium-3—a promising fuel for nuclear fusion reactors—is largely found. China, for example, has claimed to find helium-3 in moon dirt. In a planetary twist, however, scientists have recently discovered that there’s more helium-3 on Earth than previously thought, although its source remains mysterious. 

Towards these goals, the Biden-Harris administration announced in April 2022 funding for two pilot fusion power plants totaling $50 million, although there’s skepticism of how this funding will pan out. Even then, researchers believe that nuclear fusion may still be decades away.

But when—or maybe, if—it pans out, it could have ripple effects that go far beyond greener energy, Diem said.

“In a world where we have fought wars over energy and access to resources used for energy production and where we are seeing accelerated impacts of climate change, fusion brings us hope and an amazing challenge,” she said.

“While there are still many challenges that lie ahead for fusion, the potential benefits are huge and I’m incredibly excited to see what’s next in this field as we continue to push innovation and drive towards a cleaner, more sustainable, equitable and just future.”