Does anyone know about theoretical minimum losses from this kind of power transmission?
But keep in mind that the transmission losses are at ~5% because that's a level that people consider economical. They could be higher, or lower. The losses also tend to be around that value for any power grid you look, it doesn't matter if it's a minuscule country or a continental one, people just improve their grid until it gets there.
Unless you have matched emitters and PV cells? For example [1] cites 53.4% conversion efficiency for monochromatic light. (The 40% figure was presumably sunlight conversion efficiency?)
The main limit to long distance, even genuinely global[0], electrical power grid is that it would take several years of current global metal mining to build. But we don’t have to do it all at once, so even this isn’t really a show-stopper.
[0] 5% loss per Mm is 64% loss over 20 Mm with existing HVDC products, and yet because you can place the PV in the globally optimal location where it costs $US13.5/MWh at source and therefore $US37.5/MWh on the antipode, it’s still cheaper. But even for just the electricity worldwide today you need to think in terms of square meters of cross section, and that’s a lot of metal to mine.
If your 5% loss per Mm is at 500kV, increasing that to 1MV (entering the territory of UHVDC) means that you're only talking 1.25% loss per Mm which translates to "just" 22% loss over 20Mm, or even just 5% over the ~4Mm that separates Phoenix and NYC.
That tech exists. We just haven't begun to build it in the US. (There are plenty of obstacles beyond just the materials cost.)
Then again, if we had that technology available then it would make the most sense to have solar panel satellites beaming their acquired energy down to receiver stations rather than generating it on earth and sending it elsewhere.
I wonder how much London, New York, LA, or Dubai would pay for electricity that also cuts 1% of the sunlight overhead while it is being generated, making the weather cooler and decreasing the amount of electricity needed in the process?
The fact that this article omitted all details about efficiency, and omitted any numbers that we could use to calculate it, say it's probably not beating the standard induction charger's efficiency.
I think this technology is more in the stage of "It's possible to do this!" rather than "it's practical to do this"
“it’s impractical to shop for a house in a war zone” and “it’s impractical to buy a house in San Francisco” are two very different definitions of “practical”.
It feels like that’s what’s going on here.
Electricity price differences throughout the USA[1] are much more than 5%, so a 5% loss does not (in itself) seem to make long distance transmission uneconomical.
[1] https://www.energybot.com/electricity-rates-by-state.html
The percentage losses are irrelevant, except in the context of substitutes. An ICE could be 1% efficient if the next best substitute cost 100x more to operate. Likewise, 5% losses in transmission might add up over very long distances to mean that it makes more sense to build wind in the appalachians or off-shore from NY than it does to power the NE with solar installs in Arizona. OR, beaming energy eating 50% while costing even more due to the amount of exotic materials in construction.
(Eg: if you can gather it sustainably, small batches, can that be used to supplement things other than solar like wood, wind, and hydro? If so shipping that around might make sense.)
I don't know if you'll get many detailed numbers, I got the sense that's the real "business intelligence", not meta level ideas like the one I just expressed, when I was having a series of informal conversations about green energy.
From where?
> small batches
The capex cost of handling equipment ruins this. That's why so much natural gas is already flared.
LNG efficiency in large modern plants appears to be about 80% per https://static.conocophillips.com/files/resources/smid_016_w...
> "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."
It seems likely that water vapor is the big issue, and that's pretty variable across a lot of regions, and fog and cloud formation would be an additional issue. Hence, this is probably going to be more for relatively short-distance applications (the demo they discuss is a few hundred meters) on Earth. However, in space-to-space applications this doesn't seem to be an issue. Maybe something like solar satellites in orbit around the Moon beaming power to Moonbase would be an option.
For really long-distance energy transport on Earth, the transport of stored chemical or nuclear energy (hydrocarbons or uranium basically, or maybe iron?) are really the only plausible options.