Zap Energy, a fusion energy startup working on a low-cost path to commercializing electricity generation, said last week that it has taken a major step toward testing a system its researchers believe will ultimately generate more electricity than it consumes.
This is seen as a milestone in addressing the world’s energy challenges while moving away from fossil fuels. A burgeoning global industry of nearly three dozen start-ups and heavily government-funded development projects is pursuing various concepts. Seattle-based Zap Energy stands out because its approach — if it works — will be simpler and cheaper than what other companies are doing.
Today’s nuclear power plants are based on fission, which captures the energy released by splitting atoms. In addition to high temperatures, byproducts of the process include waste that remains radioactive for centuries. Nuclear fusion, on the other hand, replicates the process that happens inside the sun, where gravity fuses hydrogen atoms into helium.
For more than half a century, physicists have pursued visions of commercial power plants based on controlled fusion reactions, essentially bottling solar energy. Such a power plant would produce many times more electricity than it consumes, with no radioactive by-products. But none of the research projects came close. Still, interest in the technology has grown as concerns about climate change have grown.
“We think it’s critical that convergence is part of our energy mix,” said Zap Energy President Benj Conway.
While many competing efforts have used powerful magnets or laser pulses to compress plasma to initiate fusion reactions, Zap is pursuing an approach pioneered by physicists at the University of Washington and Lawrence Livermore National Laboratory.
It relies on a shaped plasma gas — an energetic cloud of particles often described as the fourth state of matter — that is compressed by the magnetic field created by the current as it flows through a two-meter-long vacuum tube. The technique is called “shear flow Z-pinch”.
Zap Energy’s “crunch” approach isn’t new. It may have been observed in the effects of lightning strikes as early as the 18th century, and has been proposed as a route to fusion energy since the 1930s. While pinching occurs naturally in lightning strikes and solar flares, the challenge for engineers is to stabilize electrical and magnetic forces in pulses long enough—measured in millionths of a second—to generate radiation to heat surrounding Molten Metal Curtain.
Brian Nelson, a retired University of Washington nuclear engineer and chief technology officer at Zap Energy, said the company has successfully injected plasma into the core of a new, more powerful experimental reactor. It is now completing a power supply designed to provide enough energy to enable companies to demonstrate that it is possible to produce more energy than is consumed.
If their system proves to be feasible, the Zap researchers say it would be orders of magnitude cheaper than competing systems based on magnet and laser confinement. It is expected to cost about the same as conventional nuclear power.
Researchers experimenting with the Z-pinch design found it impossible to stabilize the plasma, and abandoned the idea in favor of a magnet approach, known as a tokamak reactor.
University of Washington physicists have made progress in stabilizing the magnetic field created by flowing plasma, which led the group to form Zap Energy in 2017. The company has raised more than $160 million, including a series of investments from Chevron.
According to the Fusion Industry Association, recent technological advances in fusion fuels and advanced magnets have led to a dramatic increase in private investment. There are 35 fusion companies worldwide with more than $4 billion in private funding, including tech names from Sam Altman, Jeff Bezos, John Dole, Bill Gates, and Chris Sarkar investor. Mr. Gates and Mr. Sacca invested in Zap’s most recent funding round.
But there are still some skeptics who argue that progress in fusion energy research is largely a mirage, and that recent investments are unlikely to translate into commercial fusion systems anytime soon.
The U.S. is in the middle of another round of “fusion heat,” which has come and gone every decade since the 1950s, Princeton University retired plasma physicist Daniel Jassby wrote in the American Physical Society newsletter last fall. He argues that claims by startups that they are successfully building systems that generate more energy than they consume are unfounded in reality.
“It is widely believed that these claims are due solely to effective publicity by promoters and lab spokespersons,” he wrote.
Physicists and executives at Zap Energy said in interviews last week that they believed they had demonstrated within a year that their approach could reach the long-sought-after energy break-even point.
If they do, they will succeed where a series of research efforts (dating back to the middle of the last century) have failed.
Physicists at Zap Energy say they’ve demonstrated their method’s ability to “scale” to produce dramatically increased neutrons in a series of peer-reviewed technical papers that document what they will soon begin testing. Computer generated simulation.
A power plant version of the system would coat the reactor core in moving molten metal to capture the intense heat-generating bursts of neutrons, which would then be turned into steam, which would then generate electricity.
Each reactor core will generate about 50 megawatts of electricity, roughly enough to power at least 8,000 homes, said physicist Uri Shumlak, co-founder of Zap Energy and a professor at the University of Washington.
Their technical challenge now, he said, is to confirm what they simulated with the computer. This will include ensuring that the Z-pinch fusion portion of the plasma remains stable, and that they can design electrodes that can survive the intense fusion environment of the reactor.
Mr. Conway said he hoped Zap would be able to prove their concept quickly, without the massive, expensive development efforts of the past, like “making a billion-dollar iPhone prototype every 10 years.”
