Highly tuned wavelength-specific photovoltaic sounds interesting. > The receivers for optical power transmission are specialized photovoltaic cells designed to

Highly tuned wavelength-specific photovoltaic sounds interesting. > The receivers for optical power transmission are specialized photovoltaic cells designed to convert a single wavelength of light into electric power with very high efficiency. Indeed, efficiencies can exceed 70 percent, more than double that of a typical solar cell. I'm still thinking of the last power-beaming example, a Navy microwave-based one, which showed up a month ago (and in this article) & was hyped up but ended up being pretty crazy low end-to-end efficiency if you read the fine fine print. If these folks really can do real 50% end-to-end efficiency- major congrats to them. At some point, I think solar concentrators probably do make great sense. We already have some pretty big scale solar-thermal plants. These can have nice thermal storage capacity, for off-peak usage. The idea of launching some satellites & trying to point lasers or concentrators down at an on-the-ground collector seems more promising than microwaves, given what lukewarm at best efficiencies we've seen out of attempts to leverage microwaves. That said, the article itself contra-indicates: > But there have been improvements in efficiency and increased availability of devices that operate at much higher frequencies. Because of limitations imposed by the atmosphere on the effective transmission of energy within certain sections of the electromagnetic spectrum, researchers have focused on microwave, millimeter-wave, and optical frequencies. While microwave frequencies have a slight edge when it comes to efficiency, they require larger antennas. So, for many applications, millimeter-wave or optical links work better. [1] https://newatlas.com/energy/us-navy-beams-1-6-kw-power-kilometer-microwaves/ https://newatlas.com/energy/us-navy-beams-1-6-kw-power-kilom... https://news.ycombinator.com/item?id=31128267 https://news.ycombinator.com/item?id=31128267 (245 points, 33 days ago, 194 comments)