Avalanche Energy wins $5.2M DARPA alphavoltaic contract

Avalanche Energy’s radiovoltaic converter prototype undergoes high-energy ion-beam irradiation testing as part of the DARPA Rads to Watts alphavoltaic direct energy conversion programme

(Image courtesy of DARPA)

Avalanche Energy has secured a $5.2 million DARPA contract that advances a core challenge in fusion energy: converting energetic charged particles directly into electricity at scale. The Seattle-based fusion start-up will build solid-state, micro-fabricated cells that convert kinetic energy from radioisotope-produced alpha particles into electricity. The 30-month program targets power densities above 10 watts per kilogram, enough to run a laptop-class system for months.

Alphavoltaic direct energy conversion for defense and space

DARPA’s Rads to Watts program targets power systems for defense and space missions where conventional batteries, solar power, and refuelling are not viable. Avalanche will develop cells that function analogously to photovoltaics, substituting alpha particles for photons. The cells must sustain performance in the harsh radiation environment of space, where conventional electronics degrade rapidly. Avalanche will validate operational resilience using both particle accelerators and active radioisotopes.

The technology also feeds directly into Avalanche’s fusion roadmap. The underlying physics of alphavoltaic direct energy conversion, extracting electricity from energetic charged particles, is the same physics needed to pull power from fusion reactions efficiently. Degradation-resilient micro-chips developed under the Rads to Watts contract will handle radioisotope-produced alpha particles first, then transfer to fusion-derived particles in Avalanche’s compact machines.

Alphavoltaic cells build a supply chain flywheel for fusion

The contract creates a reinforcing loop between Avalanche’s nuclear battery work and its core fusion platform. The fusion machines that produce high-energy alpha particles also produce high-energy neutrons. Those neutrons efficiently create the radioisotopes required for the Rads to Watts program, tying radioisotope supply directly to Avalanche’s core fusion platform.

Avalanche leads a multi-institutional team for the contract. Partners include the University of Utah, Caltech, Los Alamos National Laboratory, and McQuaide Microsystems. Together they will pursue a near-term nuclear battery deliverable while advancing the industrial scaling capabilities Avalanche needs for commercial fusion deployment.

The contract adds to a run of funding that also includes a $29 million private round announced in February 2026 and a $1.25 million AFWERX contract for advanced materials development. Target applications span remote military bases, space propulsion and power systems, underwater unmanned vehicles, data centres, and grid-challenged communities. Avalanche’s modular compact fusion design is intended to stack for near-endless power applications, giving the power conversion efficiency work done under this DARPA contract direct relevance to commercial and defence scaling goals across Avalanche’s broader fusion programme.

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