Zap Energy, a fusion energy startup based in the US, has made a strategic shift to add nuclear fission to its lineup as it looks to meet the soaring demand for energy to power data centers. With this shift, the company expects to begin generating revenue as early as next year, even as it continues to develop its fusion energy technology. 

The meteoric rise of artificial intelligence (AI) in the past few years has pushed demand for new data centers. Alongside chips that will run AI applications, companies are also scrambling for energy to power them. Tech giants like Google and Microsoft are neglecting their green energy goals and racing to build their data centers. 

In such a scenario, nuclear fission offers a carbon-free source of electricity, and companies are expected to make a beeline for this ‘cleaner’ power in the future. While Interesting Engineering has previously reported how nuclear fission is poised to make a comeback, a fusion energy company adding fission to its lineup is definitely a first. 

What is Zap Energy? 

Based in Everett, Washington, Zap Energy is a spin-off of the University of Washington and aims to develop fusion energy in a highly compact, cost-effective setup. Unlike the tokamak and stellarator approaches used by other companies, Zap Energy has ditched superconducting magnets and a cooling system to generate its plasma. 

Called Shared Flow Stabilized (SFS) Z-pinch, the approach uses a powerful electric current to generate a magnetic field within which plasma is generated and heated to fusion-grade temperatures. The technology was developed at the University of Washington over the decades and is being commercialized by Zap Energy, which has raised Series D funding as well. 

In 2024, the company achieved record plasma pressures of 1.6 gigapascals while also testing other supplementing technologies, such as liquid-metal walls and pulsed power. Since fusion technology is unlikely to be ready to power data centers anytime soon, Zap Energy is adding fission to its lineup as a strategy to get to the market faster. 

Relying on Japanese tech

Zap Energy’s strategy involves integrating a small-scale fission reactor into its fusion energy prototype, which can deliver carbon-free power with a shorter time horizon. The fission reactor design was originally developed by Japanese firms, Toshiba and the Central Research Institute of Electric Power Industry. 

Called Super Safe, Small and Simple, or 4S reactor, the design features a fast neutron microreactor cooled by liquid sodium. Zao Energy is betting on this, since the microreactor can operate for decades without the need to refuel. 

Although the 4S reactor design faced hurdles in obtaining approvals from the US Nuclear Regulatory Commission (NRC) in the past, Zap Energy is confident it can leverage its expertise in fusion technology to overcome them. 

“Fission and fusion are two sides of the same coin,” Zabrina Johal, newly appointed CEO at Zap Energy, told a major tech outlet. “They have so many challenges that are congruent with each other.”

Zap Energy is planning a 10 MW variant of the 4S reactor that can be installed in a sealed vault about 100 feet (30 m) below the ground and not be refueled for 30 years.

While such a reactor will not begin powering data centers immediately, it will begin generating revenue for the company as it meets milestone payments from companies looking to reserve its production capacity and the completion of federal programs led by the Department of Defense and Department of Energy.