We're talking about Japan here. Japan is a small island that is already very densely populated, and the few unpopulated regions that they do have are mountains. It makes perfect sense for them to consider more radical solutions than would be appropriate for Europe (try to cooperate with North Africa to get massive solar in the Sahara) or the US (carpet New Mexico with solar arrays).

The scale of that project is insane, and the energy transmission is a problem. However, except for the energy transmission, this project is perfectly feasible with current technology. The only missing piece is the political and/or economic will to implement it.

Or is it that the atmosphere heavily interferes with the efficiency of solar panels or something?

Yep, astronauts had to wear some damn expensive shades when they were up there.

Good luck with that. As the saying goes, the Devil is in the details. I think it's more constructive to focus on earth bound problem solving and implement solutions down here.

except for the energy transmission, this project is perfectly feasible with current technology

That's a massive except though..

Actually, I figured (rabbit out the hat) what you just described would cost the same amount as the LHC. Solar panel ring around the moon would definitely be technlogical feat for mankind. Period. I'd be OK with getting my taxes raised for such a project.

I would be not, as saving energy ("nega-watts") would be massively cheaper and faster to implement.

So... why do we have to put solar panels on the moon? Why not just find somewhere on earth to put them? Or is it that the atmosphere heavily interferes with the efficiency of solar panels or something?

It's the day/night cycle that interferes with their efficiency. They only work for half a day on average.

Not quite. Efficiency of a solar cell is a function of construction. The law of physics make for an hard limit: a top-notch, perfect solar cell will be 33% efficient. This means that if a 1m[sup]2[/sup] panel gets 1000W of solar power, it'll pull out ~333W of juice. Efficiency is not affected by weather and it's typically declared by the producer.
What Kian notes is another concept which is the energy yeld, often "unofficially measured" in kWh/kWp/year. The yeld is well known across the world. I'm fairly sure you can find the yeld in the US as well.
The atmosphere is indeed a filter which absorbs the energy before entering the equations. The amount of absorption is a function of thickness and has been named "Air Mass", sometimes improperly called "Atmospheric Modulation" in the field. On earth, there's about 1000W/m[sup]2[/sup] at AM1.0 and about 700W/m[sup]2[/sup] at AM1.5 - accurate values on WP:EN.
So in short, yes, the system is affected by the atmosphere.

We're talking about Japan here. Japan is a small island that is already very densely populated, and the few unpopulated regions that they do have are mountains. It makes perfect sense for them to consider more radical solutions than would be appropriate for Europe (try to cooperate with North Africa to get massive solar in the Sahara) or the US (carpet New Mexico with solar arrays).

No, it doesn't, as the tecnology allows improved utilization of already urbanized surfaces. The document is a bit dated nowadays but the concept still applies.

[color="#0000ff"]U.S. Department of Energy Energy Efficiency and Renewable Energy
Contrary to popular opinion, a world relying on PV would offer a landscape almost indistinguishable from the landscape we know today.[/quote]

I think it's more likely that any space-based solar-power sats will be placed in geosynchronous orbit, rather than on the moon. The advantage of space-based solar is that your panels are in space, where there's no atmosphere to eat up some of the light, where you have infinite space (effectively) and no gravity, meaning that you can have larger, more frail structures out there than you could on Earth (meaning you can maximize your collection area), and your solar panels can be in constant daylight, meaning a continuous stream of energy. Disadvantages include construction costs (hooo, boy), infrastructure costs, and the fact that we don't know what a microwave laser being constantly fired into the atmosphere from orbit will actually do, long term. It's a cool technology if you have lots of money, or have already settled the solar system enough that you can import raw materials from places with small enough gravity wells that don't need as much energy to escape them.

The thing with the Earth is that putting stuff in orbit is goddamn expensive because of the scape velocity. If we get to somehow bring a factory to the moon, we could make the solar panels there and put them in orbit with a magnetic (solar powered) catapult. We just need a good spot on the moon with easy access to water (ice). For starters the station could be dig in the ground and sealed simply with a couple of doors we take there.