Last Energy
PWR-20 microreactor developer with aggressive 80+ MoU pipeline. Deployment claims disputed by independent assessors
SectorsNuclear
Market Metrics
MoU Pipeline
80+ Memoranda of Understanding
Mostly Eastern Europe + UK + Texas; conversion to firm contracts pending regulatory clarity
PWR-20 Output
20 MWe per unit
Intentionally small; targets industrial co-location vs grid-scale utility deployment
Capital Raised
~$140M+
incl. a $100M Series C (Dec 2025) led by the Astera Institute
First US Deployment
Texas A&M RELLIS pilot
targeting criticality by mid-2026; Wales site-licence decision targeted 2027
Updated at 2026-Q1
Funding History
Total raised: ~$140M+ equity · Latest valuation: Undisclosed
| Round | Date | Amount | Valuation | Key Investors |
|---|---|---|---|---|
| Seed | 2020 | Undisclosed | - | Bret Kugelmass (founder, ex-Energy Impact Center) |
| Series A | Oct 2022 | $24M | - | Gigascale Capital (lead)MCJ CollectiveValor Equity PartnersMaC Venture Capital |
| Series A Extension | 2024 | ~$15M (reported) | - | Existing investor syndicate |
| Series C | Dec 2025 | $100M | - | Astera Institute (lead)Galaxy InteractiveGigafundWoori Technology Investment |
Updated at 2026-Q1
Product Specifications
| System | Type | Status |
|---|---|---|
| PWR-20 | 20 MWe small pressurized water reactor (intentionally small, factory-built, modular) | Design + initial manufacturing; first commercial site pending regulatory approval |
| Modular Deployment Model | Container-shipped reactor + power-block units; 24-month site-to-energy claim | Aspirational. No commercial unit operating |
Updated at 2026-Q1
Partnerships & Investors
Welsh Government / Bridgend CouncilSite Host
Bridgend Wales site lease for first European deployment; UK / Wales regulatory engagement underway.
Polish Industrial Customers (LoIs)Customer (MoU only)
Multiple letters of intent with Polish industrial companies; targets coal-replacement and industrial heat.
Texas Industrial Customers (MoUs)Customer (MoU only)
Texas-sited MoUs for data-center and oil-gas industrial customers; Texas regulatory environment more permissive than federal NRC.
Gigascale CapitalLead Investor
Climate-focused VC; lead Series A investor.
Valor Equity PartnersInvestor
Earlier-stage backer; energy-tech thesis.
Updated at 2026-Q1
Key Milestones
2020
Company Founded
Bret Kugelmass (also founded the Energy Impact Center think tank) launches Last Energy in Washington, DC
2021
PWR-20 Design Released
20 MWe small pressurized water reactor concept; intentionally small + factory-built + modular
Oct 2022
Series A at $24M
Gigascale Capital leads; first significant institutional round
Q1 2023
Wales Site Lease
Site rights secured at Bridgend Wales for first European deployment
2024
MoU Pipeline Cross 80
80+ Memoranda of Understanding signed across Eastern Europe + UK + Texas; mostly with industrial customers + data-center developers
2024
Independent Assessment Skepticism
MIT + IAEA + nuclear-industry analysts publicly question whether Last Energy's 2025-2027 deployment claims are achievable given NRC + EU regulatory timelines
Q3 2025
First Prototype Manufacturing
Initial PWR-20 module manufacturing begins; deployment at Wales site targeted but regulatory path not yet secured
2025
Texas A&M RELLIS Pilot
Plans a PWR-20 pilot at Texas A&M-RELLIS (Bryan, TX), its first US deployment, targeting criticality by mid-2026; also plans 30 microreactors in Haskell County, TX for data centers
Dec 2025
$100M Series C
Oversubscribed round led by the Astera Institute (Galaxy Interactive, Gigafund, Woori); lifts equity raised past ~$140M
2027 (target)
Wales Site Licence Decision
Four 20 MWe units planned at the decommissioned Llynfi coal site (Bridgend); UK site-licence decision targeted Dec 2027 after a completed Preliminary Design Review
Updated at 2026-Q1