[bracketfocus]

They mentioned that it was 20% efficient at a closer distance.

So likely much lower than that.

[PaulHoule]

20% efficiency in terms of light -> electricity. A 50% laser efficiency (electricity -> light) is really good, possible for some diode lasers, if you pump a fiber laser with diodes to get a high quality beam for cutting materials or weapons purposes maybe you get 25%.

That demo would require about 45 kW of laser power with good beam quality which would be totally possible with a fiber laser

https://www.rp-photonics.com/wall_plug_efficiency.html

[throwaway81523]

Wow that's a long way from the proposals for sending GW of microwave power from satellites.

[aurizon]

Those sat to ground power sources use gallium arsenide switched FETs = synchronous rectification, avoiding the voltage drop of diodes has been tested on a small scale, the 10GW orbital 35% efficient solar arrays, maybe next week... Solar boilers, end to end, are more efficient than solar cells, but mechanical complexity(leaks, corrosion, worker avarice) made one US plan in the South West non viable. As we sit silicon-perovskite tandem solar cells will top out around 42-45% - unless Schockley is end runned? Ternary -??. A good lecture = https://www.youtube.com/watch?v=Ft0VJX0_Td0&t=2s&ab_channel=...

[pfdietz]

Laser power beaming from space could be useful at lower power levels than that, for example for powering aircraft.

[conradev]

But pretty close to powering drones from ground stations