What is the advantage of microwaves over sunlight? Seems like it would be better to just make better solar panels, sunlight is already pretty high-wattage.
From a geostationary satellite you have 99.5% uptime over the course of a year, with most days having 24 hours of full power. Unlike ground solar you don't need batteries, long-distance wires, excess capacity, or demand management. Over 24 hours, a panel in orbit collects five times as much energy as it would on the ground.
Surely sunlight is less filtered above the atmosphere than below/in it?
Also, maybe microwaves pass through the atmosphere with less absorption?
The current plan for solar power stations entail using mirrors to focus it to one spot anyway, so the evolution of that might be space mirrors that convert it to a single frequency before beaming it down to a focal point.
Also, the panels/mirrors can be sun-synchronous to receive sun all the time, reducing the amount of them needed (surface panels would not get peak sunlight all the time, and half the time will be shadowed by earth).
Less affected by cloud albedo and thus more effectively contributing to global warming by increasing the amount of energy that makes it through the atmosphere. That's tongue-in-cheek of course, but I do find it interesting that not many seem concerned about this problem. The experiments have almost no effect of course but if this were ever done on a large scale...
There are a few more "advantages" (if one wants to frame it that way) over collecting sunlight on the surface, for one the sun always shines in space and depending on the satellite's orbit it could collect energy almost 24/7. It could also be sent to different ground stations depending on demand. In theory, if it ever became viable.
>I do find it interesting that not many seem concerned about this problem. The experiments have almost no effect of course but if this were ever done on a large scale...
That's because they're on a completely different scale. The Sun is constantly producing absolutely gargantuan amounts of energy, on the order of 173,000 terawatts hitting the Earth constantly.
Comparatively, the entire world population uses about 15 terawatts. Even if the entire Earth switched to microwave beam power, it would be miniscule in comparison.
You likely misunderstand what albedo means and how global warming works. Most of that radiation never reaches earth, and of the tiny amount that does a lot is reflected back into space before it reaches the surface.
If it didn't matter to introduce new energy into the system, we could burn all the oil we want since all it does is increase the greenhouse effect, i.e. capture more solar energy and trap it below the stratosphere. Which is exactly what you're doing when you collect energy in space and convert it to a wavelength that can pass more unhindered through the atmosphere.
No, you're misunderstanding the scale. The amount of energy the sun already pours into Earth is orders of magnitude above anything we are doing. So while yes there is a technical increase when beaming power in from space, the effect would be negligible in comparison.
The number I quoted isn't the wattage that the sun produces. It's just the amount that hits the Earth.
The greenhouse effect isn't the kind of thermodynamics that people are used to in a straight "energy in versus energy out" scenario. The issue with "burning all the oil we want" isn't that we're adding energy to the system, it's that it reduces the energy that can escape. The Sun's energy is the absolute operative factor here, not whatever pittance we generate on the surface.