The Defense Advanced Research Projects Agency (DARPA) has set a new record for wireless energy transmission, successfully beaming more than 800 watts of power across 5.3 miles (8.6 kilometers) using a laser.
The test, conducted at the U.S. Army’s White Sands Missile Range in New Mexico, is part of DARPA’s Persistent Optical Wireless Energy Relay (POWER) program. The latest demonstration transmitted a 30-second pulse of power with approximately 20% efficiency, a major step in developing systems capable of beaming electricity to remote or inaccessible areas.
“Energy is a fundamental requirement for military operations, and traditional means of getting energy to the edge (battlefields, disaster zones, etc.) are often incredibly slow, risky, and resource intensive,” DARPA stated following the test.
The laser beam traveled from the source through a compact aperture, struck a parabolic mirror, and was then directed onto solar cells inside the receiver structure, known as the Power Receiver Array Demo (PRAD). This setup converted the incoming light back into usable electricity. According to DARPA, a portion of the received energy was used to make popcorn during the demo, referencing a scene from the film Real Genius.
The record-setting trial surpassed previous milestones in the POWER program, which earlier transmitted 230 watts over 1.7 kilometers (1 mile) and a lesser, undisclosed amount over 3.7 kilometers (2.3 miles). “It is beyond a doubt that we absolutely obliterated all previously reported optical power beaming demonstrations for power and distance,” said Paul Jaffe, DARPA’s POWER program manager.
DARPA’s long-term goal is to establish networks of airborne energy relays that could transmit power to needed locations in real-time. This would enable logistical and operational flexibility for field units and remote installations. Future tests will include power beaming across multiple relays and vertical transmission into the upper atmosphere, where reduced air density improves efficiency.
“It’s a lot easier to send a power beam directly up or down relative to the ground because there is so much less atmosphere to fight through,” Jaffe noted. “For PRAD, we wanted to test under the maximum impact of atmospheric effects.”
Though current conversion efficiency remains modest, the team is focused on power and distance metrics in this phase. The goal by Phase Three of the POWER program is to install laser relays in conventional aircraft capable of transmitting 10 kilowatts of energy across 125 miles (200 kilometers).
“This demonstration broke through misconceptions about the limits of power beaming technology, and it is already spurring industry to reimagine what’s possible,” Jaffe said.
DARPA sees wireless energy transfer as a potential solution to the high logistical burden of supplying power in military and humanitarian contexts, reducing dependence on fuel convoys and fixed infrastructure.
