Last Energy, a developer of modular nuclear technology, raised more than $100 million in an oversubscribed Series C round led by the Astera Institute. The company intends to use the capital to finish its PWR-5 pilot reactor and advance the commercialization of its PWR-20 model.
The startup focuses on factory-manufactured microreactors designed for industrial and data center customers. Last Energy is currently participating in a U.S. Department of Energy pilot program, with a criticality test anticipated for 2026. Its product-based approach aims to provide a scalable source of clean power through integrated steel containment systems and established pressurized water technology.
In addition to its U.S. operations, Last Energy is pursuing regulatory pathways in the U.K. The company plans to strengthen its manufacturing presence in Texas to support its global pipeline of microreactor projects.
