Zap Energy, a fusion energy start-up working on a low-cost way to commercially produce electricity, said last week it had taken an important step toward testing a system that the researchers believe it will eventually produce more electricity than it consumes.
That point is seen as a milestone in solving the world’s energy challenge as it moves away from fossil fuels. An emerging global industry, made up of nearly three dozen start-ups and heavily funded government development projects, is pursuing a variety of concepts. Seattle-based Zap Energy stands out because its approach — if it works — would be simpler and cheaper than what other companies are doing.
Current nuclear power plants are based on nuclear fission, which captures the energy released when atoms split. In addition to intense heat, byproducts of the process include waste that remains radioactive for centuries. Nuclear fusion, on the other hand, mimics the process that takes place in the sun, where gravitational forces fuse hydrogen atoms into helium.
For more than half a century, physicists have pursued the vision of commercial power plants based on a controlled fusion reaction, essentially bottling the power of the sun. Such a power plant would produce many times more electricity than it consumes and without long-lived radioactive by-products. But none of the research projects came even close to the goal. But as fears of climate change mount, interest in the technology grows.
“We believe it is vital that fusion becomes part of our energy mix,” said Benj Conway, president of Zap Energy.
While many competing efforts use powerful magnets or bursts of laser light to compress a plasma to initiate a fusion reaction, Zap is following an approach developed by physicists at the University of Washington and the Lawrence Livermore National Laboratory.
It is based on a formed plasma gas – an activated cloud of particles often described as a fourth state of matter – which is compressed by a magnetic field generated by an electric current as it flows through a two-meter vacuum tube. The technique is known as “sheared flow Z-pinch”.
Zap Energy’s ‘pinch’ approach is not new. It may have been observed in the effects of lightning strikes as early as the 18th century and has been suggested as a pathway to fusion energy since the 1930s. While sniffles occur naturally during lightning strikes and solar flares, the challenge for engineers is to stabilize the electrical and magnetic forces in pulses — measured in a millionth of a second — long enough to produce radiation to create a surrounding curtain of molten metal. to heat.
Brian Nelson, a retired nuclear engineer from the University of Washington and chief technology officer of Zap Energy, said the company had successfully injected plasma into a new and more powerful experimental reactor core. It is now completing a power supply designed to provide enough energy so that the company can prove that it is possible to produce more energy than it consumes.
If their system proves workable, the Zap researchers say, it will be orders of magnitude cheaper than competing systems based on magnet and laser confinement. It is expected to cost about the same as traditional nuclear power.
Researchers trying the Z-pinch design found it impossible to stabilize the plasma and dropped the idea in favor of the magnet approach, known as a Tokamak reactor.
Advances in stabilizing the magnetic field generated by the flowing plasma created by physicists at the University of Washington led the group to found Zap Energy in 2017. The company has raised more than $200 million, including a series of investments from Chevron.
According to the Fusion Industry Association, recent technical advances in fusion fuels and advanced magnets have led to a surge in private investment. There are 35 mergers worldwide and private funding has risen to more than $4 billion, including from well-known technology investors such as Sam Altman, Jeff Bezos, John Doerr, Bill Gates and Chris Sacca. Mr. Gates and Mr. Sacca have invested in Zap’s most recent financing round.
But there are still outspoken skeptics who argue that advances in fusion energy research are largely a mirage and that recent investments are unlikely to translate into commercial fusion systems anytime soon.
Last fall, Daniel Jassby, a retired plasma physicist at Princeton University, wrote in an American Physical Society newsletter that the United States was in the midst of another round of “fusion energy fever” that has come and gone every decade since the 1950s. . He argued that claims by start-ups that they were on track to successfully build systems that produced more energy than they consumed were in fact untrue.
“The widespread adoption of these claims is solely due to the effective propaganda of lab promoters and spokesmen,” he wrote.
Zap Energy’s physicists and executives said in interviews last week that they believed they could prove within a year that their approach was capable of reaching the long-sought energy break-even point.
If they do, they will have succeeded where a series of research efforts dating back to the middle of the last century have failed.
The physicists at Zap Energy said they had argued for the “scale” power of their approach to produce a surge of neutrons in a series of peer-reviewed engineering papers documenting computer-generated simulations they would soon test .
A power station version of the system would encase the reactor core with moving molten metal to accommodate bursts of neutrons, resulting in intense heat, which would be converted into steam that would in turn generate electricity.
Each reactor core will produce about 50 megawatts of electricity, about enough to power at least 8,000 homes, said Uri Shumlak, a physicist and professor at the University of Washington who co-founded Zap Energy.
Their technical challenge now is to confirm what they simulated with the computer, he said. This means, among other things, that the Z-pinch fusion portion of the plasma remains stable and that they can design an electrode that can survive in the intense fusion environment of the reactor.
Mr. Conway said he hoped Zap could prove their concept soon, as opposed to the large, expensive development efforts of the past, which have been like “building a billion-dollar iPhone prototype every 10 years”.
