Last Energy Secures $100M for Micro Reactor Tech

Nuclear energy startups are experiencing a significant resurgence, with Last Energy, a pioneer in micro reactor technology, recently announcing a successful $100 million Series C funding round. This substantial investment will fuel the development of its innovative steel-encased micro reactors, including a 5-megawatt pilot project slated for activation in Texas next year.

Bret Kugelmass, founder and CEO of Last Energy, reflected on the shifting perception of nuclear power.

“For the first half a decade that I was telling people I was doing nuclear, I had to convince them, ‘Hey, here’s why nuclear is important,’” Kugelmass told TechCrunch. “Now everyone just comes to us saying, ‘Oh yeah, of course nuclear is a key part of the solution.’ I’m like, okay, great, I’m glad everyone’s caught up now.”

Driving the Future of Energy

Last Energy specializes in building small modular reactors (SMRs) — compact nuclear power plants designed for mass manufacturing to reduce costs. Each of the company’s commercial reactors is engineered to produce 20 megawatts of electricity, enough to power approximately 15,000 homes.

The $100 million Series C round was led by the Astera Institute, with notable participation from AE Ventures, Galaxy Fund, Gigafund, JAM Fund, The Haskell Company, Ultranative, Woori Technology, and other investors. This funding round underscores a broader trend of increased investment in nuclear startups, largely driven by the insatiable power demands of modern data centers.

Last Energy joins a growing list of companies in the sector that have recently secured significant capital. Google-backed X-Energy raised $700 million last month, while microreactor developer Antares secured $96 million just two weeks prior. In August, Aalo Atomics also raised $100 million for its prototype reactor development.

An Innovative Approach to Reactor Design

What distinguishes Last Energy from its competitors is its unique approach: the company leverages an established pressurized water reactor design originally developed decades ago by the government. This initial design was famously used for the NS Savannah, the world’s first nuclear-powered merchant ship. While the Savannah’s power plant was about one-tenth the size of Last Energy’s planned commercial reactor, Kugelmass confirms that their updated design will produce 20 megawatts of electricity.

The company is commencing its development with a smaller-scale project. Last Energy is constructing a 5-megawatt pilot reactor at a site leased from Texas A&M. Kugelmass stated that the new funding will fully finance this pilot project and facilitate the initial delivery of its commercial products. The pilot reactor is expected to be operational next year, with the larger 20-megawatt commercial-scale units projected to enter production by 2028.

A core innovation of Last Energy’s reactor is its design for minimal maintenance. The reactor core is permanently encased in 1,000 tons of steel. Kugelmass estimates this metal casing will cost approximately $1 million, noting,

“Most people think concrete is cheaper. But not when it’s nuclear-grade concrete.”

These reactors will arrive on-site pre-fueled with a six-year supply of uranium. Beyond electrical and control connections, the steel wall remains unbroken by any other penetrations. Heat generated from the fission reactions warms the steel, and water circulating through external pipes harvests this heat to power a steam turbine.

Upon reaching the end of its operational life, the reactor will remain on-site, with the robust steel chamber serving as its own waste cask, thereby eliminating the need for separate disposal facilities.

Vision for Scalability and Affordability

This innovative design, combined with advancements in manufacturing, is expected to significantly drive down the cost of nuclear power. While Kugelmass refrained from committing to a specific price point, he drew parallels to other industries that have achieved a halving of prices for every tenfold increase in production.

“I don’t think it’s going to be that good in nuclear because there are always some extra fixed costs that you have in nuclear regarding some of the special regulations, but that’s the type of trend you can see,” he explained. “We don’t think in ones and twos, we think in tens of thousands.”