Power Beaming Is Coming

Every nerd knows that we want to transmit power wirelessly.  It’s actually astonishing that we really built a power grid using wires.  I mean, it’s a gigantic investment laying Astronomical Units worth of cables all over the planet.  It took a century to build out, with untold ecological damage along the way. And this huge, point-to-point, network is fragile, as we all know.  If a handful of key points falls out, everything goes dark.

We are all familiar by now with wireless recharging, which works at a distance of a few centimeters.  But what we want is wireless power transmission over kilometers, like wireless communication.

The problem with wireless power transmission, AKA, “power beaming”, is that it’s hard to get enough power in the beam without cooking anything that stumbles into the path.  Transmission wires can be dangerous, but you can see them, encase them, and fence them off.  Wireless beams can be deadly, and they are hard to make safe. 

It doesn’t help, either, that death rays have been favorites of popular fiction for a century and more.

This spring Paul Jaffe of the US Naval Research Lab discusses recent progress in power beaming [1].  It’s not difficult to understand why NRL would be keenly interested in usch technology.

‘These include extending the flight times and payload capacities of drones, powering satellites in orbit when they are in darkness, powering rovers operating in permanently shadowed regions of the moon, sending energy to Earth’s surface from space, and distributing energy to troops on the battlefield.”

(From [1])

Power beaming on Earth is all about sending focused beams through the atmosphere, which is a moderately complicated physics problem.  Different wavelengths work differently, and there is a tradeoff in power density versus safety. And there is weather to consider, reflections, and lots of living things everywhere that aren’t very radiation proof.

Technology has advanced on a lot of fronts since Tesla.  For one thing, we have a lot more wavelengths that can reasonably by used, including lasers.  For another, we have a lot of digital control capability, that can make these systems something other than brute force death rays. Notable, antenna design is in a golden age, empowered by computer modelling.

On the safety front, Jaffe reports on one system that has a “virtual enclosure” that detects an intrusion and shuts down the beam–and then turns it back on.  “Think of it as a more sophisticated version of a garage-door safety sensor, where the interruption of a guard beam triggers the motor driving the door to shut off.” ([1])  Sounds neat, and certainly the kind of thing you’d want.

Now, power beams still make me very nervous.  I grew up in an era when lasers and high energy EM were nothing but dangerous in the wild.  But it’s clear that power beaming is coming.

For one thing, it’s just the thing for space based solar power generation, consumed on Earth or in orbit.  And, as Jaffe suggests, “Imagine drones that can fly for indefinite periods” – without heavy batteries on board!

So yeah.  I know why you want it, and there seems to be a big economic incentive to build it. So, here it comes.

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1. Paul Jaffe, Practical Power Beaming Gets Real, in IEEE Spectrum – Energy, May 21, 2022. https://spectrum.ieee.org/power-beaming