Last Energy Secures $100 Million to Advance Mini Nuclear Reactors

Last Energy, a nuclear startup based in Austin, has successfully secured $100 million in Series C funding. The investment round, led by the Astera Institute with participation from various investors including AE Ventures and Galaxy Fund, positions the company to further develop its small modular nuclear reactor technology. This funding comes at a critical time as demand for power, particularly from data centers and advanced computing systems, continues to accelerate.

The capital raised will primarily support the commercialization of Last Energy’s innovative reactor designs, which aim to provide a scalable solution to the growing energy needs of artificial intelligence systems. Founded in 2019 by Bret Kugelmass, who previously established the Energy Impact Center, Last Energy focuses on creating reactors that can produce 20 megawatts of electricity—enough to power approximately 15,000 homes.

Revolutionizing Nuclear Energy

Unlike traditional large-scale nuclear projects, Last Energy’s reactors are designed for mass production using standardised components and manufacturing processes. This approach is intended to significantly lower costs and reduce construction timelines. The reactor’s design is based on a pressurized water reactor concept first developed by the US government for the NS Savannah, the world’s first nuclear-powered merchant ship.

Last Energy has modernized this design to achieve a 20-megawatt output, maintaining familiar architecture for regulators and engineers. The use of off-the-shelf components for essential systems also streamlines production, aiming to avoid the complexities of bespoke supply chains.

Before reaching commercial scale, the company plans to deploy a 5-megawatt pilot reactor at a site leased from Texas A&M. The funding raised will fully cover this pilot project, which is anticipated to come online in 2024. The company’s goal is to commence production of commercial-scale reactors by 2028.

Ensuring Safety and Cost-Effectiveness

A notable feature of Last Energy’s approach is its sealed reactor design. Each reactor core is encased in approximately 1,000 tons of steel, providing structural protection and shielding during operation. This robust design results in an estimated cost of $1 million per unit for the steel enclosure.

Each reactor is pre-fueled with six years’ worth of uranium upon arrival at the installation site. The heat generated within the core warms the steel casing, while water flowing through external pipes captures that heat to generate electricity. The design minimizes complexity by having no penetrations other than electrical and control connections, which reduces operational risks.

At the end of its operational life, the reactor remains on-site, with the steel casing serving as a long-term waste container, thus eliminating the need for separate disposal solutions. This innovative approach, combined with manufacturing efficiencies, has the potential to drive down costs for nuclear power as production volumes increase.

Last Energy’s strategy focuses on smaller reactors that can be built and deployed more flexibly and cost-effectively. As global electricity demand rises—especially from data-intensive infrastructure—the company aims to present itself as a viable solution to meet this increasing need.

In a statement, Bret Kugelmass emphasized the significance of this funding, noting, “This financing fully capitalises our DOE pilot project and positions us to transition swiftly into commercialization of our production power plants.” As Last Energy continues to develop its technology, the company is poised to play a pivotal role in the future of nuclear energy.