Wireless energy transmission one step closer thanks to DARPA

“This project has the potential to advance power beaming by orders of magnitude, which could radically reshape society’s relationship with energy,” said Dr. Paul Jaffe, who leads the POWER program at DARPA. “A wireless energy web could unlock power from new and diverse sources, including from space, and rapidly and reliably connect them to energy-starved consumers," he added. In order to accelerate progress, POWER's phase one will showcase the optical energy relays through pods attached to existing aircraft airframes in preparation for further testing in phase 2.

As DARPA points out, power beaming has the potential to make future aircraft smaller and less costly by significantly decreasing fuel and engine space. This will be researched through conceptual models in phase one. Ultimately, these new, smaller, dispersed platforms could offer cost-efficient aircraft with near-unlimited range and endurance to aid military operations.

The assessment of each relay design will be based on its ability to redirect energy accurately and efficiently, correct wavefronts to ensure high beam quality, and harvest energy with the adjustable throttle. During the last and most important stage of the program, the relays will be tested in an airborne optical pathway to deliver 10 kilowatts of optical energy to a ground receiver that is 124 miles (200 kilometers) away from the ground source laser.

“Energy underpins every human activity, including defense. We need ways to deliver energy that overcome the vulnerabilities and other shortcomings of our current paradigm,” explained Jaffe. “The next leap forward in optical power beaming could hinge on relay technologies," he added.

This is important, as effective relays will play a crucial role in creating a practical, versatile, and adaptable wireless energy network. They will address the issue of conversion losses that arise when converting propagating waves into electricity repeatedly in a multi-hop system. In addition, relays enable more efficient high-altitude transmission, which is superior to beaming power through the turbulent lower atmosphere. By creating a high-altitude optical layer, the wireless energy network can establish a long-range, high-throughput backbone.

“Each of the selected teams proposed unique technical approaches to the power beaming relay problem, ranging from novel combinations of existing technologies to high-risk, high-reward technological innovations,” explained Jaffe. “The range of proposed solutions encompasses a balance of assured performance and potential breakthroughs in size, weight, and power to enable small distributed systems for the future wireless energy web," he said.

Over-the-air power distribution

"The first phase will include benchtop demonstrations of critical technologies and is expected to last 20 months with the potential for a three-month option of additional risk reduction efforts. The second phase will involve an open solicitation in early 2025 and will focus on the integration of the relay technologies onto an existing platform for a low-power, airborne demonstration," said DARPA.