The US Defense Advanced Research Projects Agency (DARPA) has commissioned Raytheon to design and develop a wireless airborne relay system to "deliver energy in contested environments" as part of its Energy Network Dominance Program.
Under a two-year, $10 million DARPA contract, Raytheon will create a Persistent Optical Wireless Energy Relay (POWER) system using a series of high-altitude unmanned aircraft equipped with laser power reception and transmission capabilities. The energy will be transmitted high into the sky and then relayed through the necessary jumps to reach the target area.
The target may be on the ground, or it may itself be another autonomous flying platform, in which case it can remain in the air for as long as necessary and its batteries can be continuously recharged at a distance.
If there are enough such power relay aircraft in the sky, the POWER system will form an "energy network" that military logistics personnel can use to transport energy to where it is most needed at any time. This is an aerial supply line capable of providing unlimited endurance to land-, air- or sea-based robots, or delivering the same energy elsewhere when strategically required.
"This is the Internet of Energy, using resilient, multipath networks to move energy from abundant sources to energy-poor consumers," said Col. Paul Calhoun, POWER program manager in DARPA's Tactical Technology Office. "The energy challenges facing the military are particularly acute, and this is what drives innovation. We often must operate far from established energy infrastructure and rely on liquid fuels that require unstable supply lines."
There are downsides to this, of course, and in this case, quite a bit of energy needs to be consumed in order to achieve this kind of flexibility. When electrical energy is converted into light energy in a laser, some energy is lost - about 20%. Even more is lost when converting the laser light back into electrical energy at the receiver, perhaps 50%. In this relay station setup, power is lost at every step.
You know, transporting fuel from refineries to tankers to trucks already consumes a lot of energy, and this airborne supply line will eliminate the personnel risk usually involved in transporting energy in war zones. And power can be delivered from a place where it can be easily and conveniently produced in bulk - perhaps even directly from the nearest grid - so efficiency is likely to be the highest priority.
The U.S. Defense Advanced Research Projects Agency (DARPA) seems to be optimistic about this technology, not only using it for military purposes, but also for distributed power sources in civilian life. Calhoun said: "We believe that the next energy revolution will be enabled by wireless energy networks. It will greatly compress transportation time and flexibly provide distributed energy to consumers in the air, land, ocean, undersea and space."