Last Energy: pressurized water micro-reactors

Last Energy is an American startup founded in 2020, developing 20MWe pressurized water micro-reactors using “conventional” technology and running onenriched uranium. Their differentiating factor is their format, their marketing method (energy sales) and their speed. Indeed, they could develop new plants in 24 months, and be ready for deployment as early as 2025.

Conventional pressurized water microreactors

Last Energy’s small modular reactors would have a power output of 60MWth / 20MWe and, like our French nuclear reactors, would be Pressurized Water Reactors (PWR), using enriched uranium oxide (< 4.95%) in bundles of 17×17 fuel rods (like our reactors). The fact that they used “conventional” technology is claimed by their founder:

“We came to the conclusion that using technology that was already available was the best way to scale up. […] We don’t innovate in nuclear process or components – we innovate in systems integration and business model.”

Bret Kugelmass, quoted by Canary media

The plant is divided into a “nuclear island”, containing the reactor core, and an above-ground section to manage the flow of steam. Refuelling would be complete, and the company even envisages replacing the entire core (rather like pre-charged scooter batteries) every 6 years, which would then bring production to a standstill for 3 months. Cooling would be mainly air-cooled. The footprint would be 0.5 acres, less than a soccer field.

Last Energy’s innovation: execution

To understand Last Energy’s innovation, we need to look at the genesis of the project. Bret Kugelmass was the founder of Titans of Nuclear, a podcast in which he got nuclear industry players to talk. His conclusion was that the nuclear industry was “ossified and stagnated”.

In contrast, newcomers such as Terrapower and Newcleo are mostly focused on new technologies, which pose new challenges and make projects more difficult to execute. In this niche, it competes with GE Hitachi’s Nuscale (BWRX-300) and Holtec. However, their model is smaller, 20MWe versus several hundred.

Their role would be that of prime contractor. The business model would also be original: the company would not sell the power plants, but the energy they produce. In this way, the co-contractor would not have to bear the high costs. A reactor could be produced and delivered in 2 years, at a capital price of $3,000/kWe, including the cost of decommissioning.

History and progress of Last Energy

Last Energy is an American startup founded by Bret Kugelmass in 2020, following on from the Energy Impact Center and then the Titans of Nuclear podcast. It has already signed a contract to build 10 modular reactors in the Legnica Special Economic Zone. They plan to finish construction by 2025.

The company has raised a total of $24 million (Feb 2023), of which $21 million comes from Gigafund. Other investors include First Round Capital and David Marquardt, former president of Microsoft. The company would have 40 employees.

On March 20, 2023, it reportedly signed 4 agreements worth $18.9 billion to build 34 small 20MW modular reactors in Europe. The sum corresponds to the amount the company would receive over the life of the contract.