Darpa

What are 800 watts? More or less what a microwave consumes running at medium power. And 8.6 kilometers? It is an approximate distance between the stations of Atocha and Chamartínin Madrid. It is actually somewhat lower, but it serves to get an idea. That is the scale of Darpa’s last experiment: a system that managed to transmit real energy with a laser, in a straight line, without cables and with a receiver that turns the light into usable electricity. It may seem little, but it is not. The important thing was not the amount, but the test. And it worked. What exactly Darpa has done. The United States Advanced Defense Research Projects (Darpa) has successfully completed The first phase of a program called Power, designed to explore new ways of transmitting long distance energy. In their most recent test, carried out in New Mexico, they managed to send a laser beam that delivered about 800 watts for 30 seconds to a receiver located 8.6 kilometers. The figure is important because it exceeds the previous records: until now, the best documented result was 230 watts at 1.7 kilometers. Although the agency has not revealed how much power it was originally issued, it is known that the system was able to maintain energy flow for periods even longer than those officially reported. According to those responsible for the project, it was not about demonstrating efficiency, but viability. The essential thing was to check if it was possible to build a functional system in a short time. And they did it in just three months, from the initial design to the final execution. The receiver was developed by Technc Technologies and uses commercial solar cells already available in the market. The objective was not to optimize performance to the maximum, but to prove that this technology can be launched with accessible components and without complex manufacturing processes. How this technology works. The idea behind the experiment is simple to understand, although technically complex: send energy through the air with a beam of light, and that when it arrives it can be used as electricity. The DARPA system is based on an infrared laser that points directly to a receiver composed of a conical mirror and solar cells. The mirror captures the ray and redirects it towards the panels, which convert light into electrical energy. Part of the equipment used during the test The interesting thing is that no exotic components or photovoltaic cells were used to measure, as in many laboratories. Commercial cells were used, ready to use, which reinforces the idea that this technology can be viable out of paper. As we say, the performance, for now, was not the priority. Receiver efficiency is around 20 %. The Power Receiver Array Demo system achieved a new record by transmitting laser energy with more power and greater scope than ever During the test, diffractive optics were also used, an unusual resource in this type of transmissions, and an integrated cooling system was implemented directly in the optical parts, manufactured with additive printing techniques. None of these innovations was scheduled at the beginning. They were solutions that arose on the march, as they faced the challenges of the experiment. Why do it with laser and not with radio waves. Transmitting long distance energy is not a new idea. For decades it has been investigated how to do it with radio or microwave waves, but these technologies have physical limitations that include their effectiveness. As IEEE points outto work, they need large antennas and systems of Beamforminga technique that allows the signal to be concentrated in one direction. The longer the distance, the greater the issuer must be, and the more difficult it is to focus the beam with precision. Compared to radio waves, the laser can focus much better: a narrow beam can be created almost without dispersion, at least in ideal conditions, According to Eric YeatmanVice President of the College of Science and Engineering of the University of Glasgow. Of course, not everything is advantages. The lasers also disperse with fog, clouds or dust. In adverse atmospheric conditions, microwaves remain more reliable. But for certain applications, especially if we talk about aerial networks or transmissions in clear environments, the laser is difficult to match. For the Power project leader in Darpa, Paul Jaffe, if it does not work with optics, it will not work in any way. What does this advance mean (and what is not). Darpa’s experiment did not solve all the challenges of wireless energy transmission. Efficiency remains low, the system is not yet prepared to operate in adverse conditions, and the transmitted power, although notable, is far from what a commercial infrastructure would need. But that was not important. The important thing was to demonstrate that technology can work outside the laboratory, with accessible components and in realistic terms. Images | Darpa (the main image shows an earlier test in 2019, at a lesser distance) In Xataka | Antimony under another flag: the Chinese mineral that continues to enter the US disguised for Thai or Mexican export