Researchers seek to revolutionize power generation by converting waste heat and radiation to electricity

THE MIL & AERO BLOG – U.S. military researchers are zeroing-in on new ways to generate electricity from unconventional sources for aerospace and defense applications, in an all-hands effort to enhance the efficiency of military power generation and consumption.

Over the past couple of months, the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., sent out solicitations to industry to generate electricity from microelectronics waste heat, as well as to generate electricity directly from nuclear radiation.

These projects, if successful, could help computers provide electric power to help run themselves, and also could be one of the first steps in revolutionizing nuclear power generation by enhancing safety and efficiency.

On 30 April 2025 DARPA issued a request for information (DARPA-SN-25-70) for the Embedding Electricity Generation from Heat in Microsystems project, which seeks to capture waste heat from microelectronics at the chip, substrate, and package levels, and convert it into electricity.

Microelectronics waste heat

The DARPA Microsystems Technology Office seeks to identify commercially available graphics processing units (GPUs), central processing units (CPUs), neural processing units, monolithic microwave integrated circuits (MMICs), and laser diodes that could demonstrate generating electricity from waste heat.

The agency also wants industry suggestions on how to use electricity converted from dissipated heat in chips and microsystems. This project is closely related to program announced earlier in April, called Microsystem Electricity Generation (DARPA-SN-25-69), which seeks to develop technologies for microsystem packages that can capture waste heat and reclaim it as useful electricity.

The waste heat from commercial and defense microelectronics today is transported through pathways to a heat sink and rejected into the atmosphere. Instead, these projects seek to gather and transport electronics waste heat from its sources to an embedded reclamation device that provides electricity for later use. It would spell the difference between using waste heat productively, rather than simply throwing it away, as is generally done today.

In another revolutionary approach to power generation, DARPA in late May announced an upcoming project to convert nuclear radiation directly to electricity for long-term unattended power in military applications.

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The future Rads To Watts project will explore approaches for converting energy from nuclear radiation directly into electricity, without taking the interim step of converting radiation to heat. Today's nuclear power plants use radiation to heat water into steam, which turns turbines that generate electricity.

Rads To Watts, on the other hand, will focus on radiation voltaics -- also called radiovoltaics -- which converts the energy from ionizing radiation directly into electricity using semiconductor materials. The radiation excites electrons and creates electron-hole pairs in the semiconductor to generate an electrical current. As of late May, no official solicitation for Rads to Watts had yet been released.

Rads to Watts seeks to convert high-power nuclear radiation into kilowatts of electricity for long-term high-power generation in military applications that must operate in harsh and remote areas.

Radiation-induced defects in today's radiovoltaics can degrade the performance and lifespans of these devices at the materials and device levels when exposed to high-power radiation sources.

Radiation to electricity

Instead, Rads to Watts will encourage contractors to go beyond typical low-power radiovoltaic architectures and semiconductors with low-fluence tolerance for long-lived high power conversion.

So how might these projects influence the long-term future of power generation? That's an open question now, but the results could be profound. The world is in an energy crunch today, with the rise of power-hungry hyperscale data centers, electric cars and aircraft, and related applications; it's clear we'll need a lot more power in the near future.

Hyperscale data centers consume massive amounts of electricity, and generate huge amounts of heat. Imagine if they could help power themselves by converting their waste heat to electricity?

Also, imagine a clean, safe source of nuclear power that first could provide electricity to remote military bases and battlefields, but eventually might be able to scale-up to make big contributions to the power grid. In a world desperate for more electric power, these projects might be heading in the right direction.