Defense Advanced Research Projects Agency (DARPA) Persistent Optical Wireless Energy Relay (POWER) program is bringing futuristic visions closer to reality by achieving record-setting results in long-distance, wirelessly beamed power. This initiative aims to revolutionize the delivery of electricity, particularly for military and humanitarian operations where the logistics of providing energy across challenging terrain are a substantial hurdle.
Modern military and relief operations hinge on dependable energy supplies. However, moving electricity to remote areas—often the “last mile”—remains difficult. Traditional solutions, like power lines or fuel convoys, are frequently impractical, unsafe, or logistically burdensome. Fuel must be carried by hand over rough terrain, and deploying infrastructure in hostile or inaccessible locations is often impossible.
DARPA’s POWER program aims to replace traditional transmission lines with “lines of light.” Through advanced laser technology, energy is sent wirelessly, offering near-instantaneous delivery regardless of the environment. The project is focused on:
- Maximizing transmission distance
- Increasing the amount of power sent
- Enhancing system efficiency
- Developing relay systems for flexible targeting and delivery
DARPA previously demonstrated beaming 230 watts over a mile (1.7 km) and an unspecified amount up to 2.3 miles (3.7 km). In its latest milestone, the program achieved transmission of 800 watts over 5.3 miles (8.6 km) for 30 seconds, significantly surpassing its prior capabilities and setting a new benchmark for wireless power transfer.
Central to the demonstration is the Power Receiver Array Demo (PRAD):
PRAD Design: A ball-like receiver comprising a compact aperture for laser entry, a parabolic mirror to scatter light, and an array of photovoltaic cells to reconvert light into electricity.
Current Efficiency: The overall system efficiency currently stands at about 20%. While low, this is acceptable in the prototype phase, with future versions aiming for higher conversion rates.
Ground-based Set-Up: Both the emitter and the receiver were stationed on the ground during the test. However, future implementations envision drone-mounted relays at high altitudes. These would minimize energy losses, avoid obstacles (like buildings and birds), and extend reach.
The POWER program is in the first stage of a three-phase development roadmap. Key near-term tasks include: 1. Improving beam targeting precision and quality, 2. Enhancing throttling and control over the energy beam, and 3. Reducing conversion losses at each relay stage. By the final phase, DARPA aims to have relay systems capable of delivering 10 kW of optical energy across 125 miles (200 km) via conventional aircraft platforms.
DARPA’s success is challenging long-held notions regarding the feasibility of power beaming. The project’s accomplishments are not only accelerating technological progress in this arena but also inspiring renewed industry interest in the concept of energy transmission without wires. Such systems could eventually reshape how electricity is distributed in both military and civilian contexts, reducing logistical costs and enabling new applications in remote or disaster-stricken areas.
The DARPA POWER program’s latest milestone marks a significant advancement in wireless energy transfer. By pairing powerful lasers and advanced photovoltaic receivers, DARPA is demonstrating a viable path toward practical, long-range power beaming. If the program’s future goals are achieved, wireless power transmission could become a cornerstone technology for energy delivery across distances and terrains previously thought inaccessible.
More information is available here.
Image: Artist’s concept of the laser power relay in action. DARPA
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