Nuclear Fusion Startup Transforms Plasma Energy Directly Into Electricity In First For Private Sector

On June 19th, 2026, Madison-based nuclear fusion startup Realta Fusion collaborated with the University of Wisconsin-Madison to showcase direct electricity generation using its prototype nuclear fusion device. 

Like most energy generation technologies, no matter how high-tech, fusion devices are expected to generate most of their electricity by heating water to drive a turbine. In this case, however, some of the energy from charged particles generated inside the Wisconsin HTS Axisymmetric Mirror (WHAM) was converted directly into usable electricity.

“We have demonstrated the conversion of a portion of our input power… directly into electricity on WHAM. In future devices designed for high fusion power production, a greater fraction of this converted power will be coming directly from fusion,” the company explained in a blog post about the recent demonstration.

Nuclear fusion has long been hailed as a potentially safer, cleaner, and effectively limitless energy source. Fusion reactions release almost four million times more energy than the equivalent mass of fossil fuels, such as oil, gas, or coal. It is also four times more energetic than power generated by today's nuclear reactors. 

While existing nuclear reactors rely on fission – the process of splitting atoms to release massive amounts of energy – fusion works by forcing two light atoms together to form a heavier one. This process releases even more energy and is the same mechanism that powers the Sun.

Although fusion has the potential to solve many of our energy problems, it is extremely difficult to achieve in a meaningful or practical way that can be harnessed for electricity generation. One major issue is that we generally lack the ability to maintain fusion reactions for extended periods or to contain the extreme pressures and temperatures they produce.

How it works

First-generation fusion reactors use hydrogen fuel composed of two forms – deuterium and tritium. When these light atoms are forced together, they release energy in two ways: 80 percent of it is carried away in the form of high-energy neutrons, while the remaining 20 percent is released as helium nuclei or alpha particles. A "moderating blanket" absorbs the neutrons, converting their energy into heat to spin turbines and make electricity. 

The reaction forms an extremely high-temperature plasma that is contained using magnetic traps, sometimes called magnetic mirrors. Because the plasma has an electric charge, the magnets hold it in place and prevent it from contacting the physical walls of the containment vessel, helping to stop them degrading.

In most fusion reactors, this type of containment isn’t perfect. At either end is an escape route through which the plasma particles can scatter. This is called a “loss cone” and is a well-known problem. By using larger magnetic fields, generated by high-temperature superconducting (HTS) magnets, it becomes possible to shrink the size of the loss cone and improve plasma confinement. But it turns out the loss cone can have its own uses.

“Confident about our path toward a viable power balance in a fusion power plant, we now consider the leakiness of magnetic mirrors as a compelling feature rather than a hurdle to overcome," the team said.

The demonstration

In its demonstration, the company installed a prototype direct energy converter on WHAM. This converter slows down charged particles as they escape the magnetic trap using an electrostatic potential – effectively carefully arranged electrical fields – that converts some of their motion into electrical current.

The energy produced by the prototype in this way was enough to power a few light bulbs. Although that may seem trivial, it’s real proof that the technology works.

The leakiness of magnetic mirrors also has the benefit of keeping the fusion plasma fuel clean by allowing waste products to exit the chamber, thus helping maintain continuous fusion power, the statement said. 

“By then capturing a large fraction of both the alpha power and input power in the system using [direct energy containment] in the expander region of our mirrors, the total efficiency of the system can be improved significantly," said the team. 

"You can think of a [deuterium-tritium] fusion power plant with DEC like a hybrid powertrain in a vehicle – it generates heat to push pistons (or in our case, spin turbines) for most of the power but with an electric component to improve efficiency.”

“We believe we can generate enough electricity using [direct energy containment] in our design points to completely cover the input power requirement of the system for continuous operation, leaving the heat component for either direct use or the generation of electricity for customers.”

Despite its promise, the team stressed that this isn't a demonstration of a fusion power plant generating enough energy for an electrical grid. 

It does show it is possible to gather electricity from charged particles leaving the mirror trap, but it doesn't represent a “demonstration of net electricity production nor large-scale conversion of fusion-born power directly into electricity – these are milestones we will achieve on our future devices at Realta,” the company said.