DARPA Breaks Record in Wireless Laser Power Transmission
The U.S. defence research agency DARPA has achieved a significant milestone in wireless energy transfer through its Persistent Optical Wireless Energy Relay (POWER) programme. The system recently transmitted 800 watts of power over a distance of 5.3 miles (8.6 km) using a laser, marking a major step forward in untethered power delivery.
Traditional energy supply to remote or hostile locations often relies on extensive logistics chains involving fuel transport and temporary power stations. These solutions are costly, vulnerable, and inefficient—especially in military or disaster-relief operations where power lines or pipelines are impractical. DARPA’s aim is to overcome these limitations by sending energy wirelessly through laser beams.
The latest success builds on earlier trials that managed 230 watts over a mile. In the new demonstration, a laser beam was transmitted through the air into a compact receiver known as the Power Receiver Array Demo (PRAD). The PRAD uses a small aperture to direct the beam onto a parabolic mirror, which then disperses the light across an array of photovoltaic cells. These cells convert the laser light back into usable electricity.
The current system achieves around 20% efficiency—low by conventional standards but acceptable at this development stage, where power and range are the focus. Further improvements are planned in both efficiency and beam control as the system matures.
While the recent test used ground-based equipment, the ultimate goal is far more ambitious. DARPA plans to deploy relay stations on high-altitude drones or aircraft. These airborne relays would receive, redirect, and transmit power beams over long distances and above obstacles such as terrain, buildings, or atmospheric disturbances. By operating in thinner air, beam losses can be reduced significantly.
The programme is currently in Phase One of a three-phase roadmap. This stage involves perfecting beam direction, improving wavefront correction, and reducing losses during conversion. Later phases will scale the system, culminating in the ability to deliver up to 10 kW of optical energy across distances of up to 125 miles (200 km).
This technology holds the potential to create a flexible, wireless “power web,” where energy can be transmitted on demand across vast areas without physical infrastructure. It could revolutionise how power is delivered in both military and civilian contexts—particularly where mobility, speed, and resilience are critical.
Source: New Atlas
