[Schroedingersat]

Firstly you're comparing silicon with vastly more expensive panels, there are a number of techs that have ~10-15% capacity factor (not 10% of 20%) in winter in the area 80% of the populations lives (and within easy transmission distance of 95% of the rest). Secondly you're comparing tracking with fixed systems.

Area is not remotely a limit, so the real question is can your space boondoggle go up for <10x the price per nameplate watt without wrecking the ionosphere, eliminating 2.4GHz comms, damaging ecology, and being unavailable to the 70% of the world that don't have a space program?

Then even if you do that, is the petajoules of energy you need to put it up there ever going to pay off or are you better off just burning the thousands of tonnes of methane or hydrogen required?

[midoridensha]

>there are a number of techs that have ~10-15% capacity factor (not 10% of 20%) in winter in the area 80% of the populations lives

I'm pretty sure these numbers are completely false for central Europe.

[Arnt]

More to the point, irrelevant.

The article claims that someone wants to put power stations in space and transmit the power over long distances. If you're willing to do long-distance transmission (to central Europe), there are enough low-population area with much sunlight in winter, and the technology to generate solar power on the surface of the planet is cheap and getting cheaper.

[midoridensha]

>there are enough low-population area with much sunlight in winter

Like where? And are they under the political control of Europe? If not, then they're useless.

[Arnt]

Parts of Italy and Spain. Landscapes like this: https://upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Al...

Solar requires surprisingly little space. The city where I live now generates about 90% as much renewable electricity as its total average use, and it doesn't really show. Visitors don't say "wow, there really are a lot of solar panels here!" or anything like that. You don't have to look far to find some solar panels, and there a few geothermal facilities, but it's not immediately noticeable. It's been retrofitted to a densely populated city and doesn't really show.

[zajio1am]

> Solar requires surprisingly little space

Not really. If i look on average production for utility-scale power plants (e.g. [0]), i get average net production of 5 MW/km^2. Germany has average total primary energy consumption ~387 TW, so to satisfy it with solar, one would need to use ~20% of Germany area for solar power plants.

It is very rough estimate, on one hand, primary energy is often less efficient than electricity, on the other hand, it completely ignores the issue of seasonality of solar power, just comparing yearly averages.

[0] https://en.wikipedia.org/wiki/J%C3%A4nnersdorf_Solar_Park

[Schroedingersat]

You've cherry picked a project at 53 degrees north and come up with a value that is barely area constrained once you include wind in the mix. There are numerous countries south of 40 degrees where existing projects produce over double the power per area. Example: Nunez de Balboa which is mid latitude spain has an average capacity factor of 20% at a latitude where winter capacity is usually around 60% of summer -- easily hitting the constraints of >10% and within transmission distance where geopolitical, cost, and efficiency factors are manageable. Southern spain, italy and greece have some areas that are even better.

Moreover, the existence of a plant at 53 degrees with under half the capacity factor achievablein europe is strong evidence for the thesis that solar is both sufficiently cheap and small, otherwise it would have been built near munich, not hamburg.

Moreover you need to compare like for like. When the proposal is to spend tens or hundreds of euros per net watt on multi junction panels that can handle shock loads of 1000s of Gs using launch capabilities that don't exist, then compare against something other than the cheapest available previous generation modules.

A 29% efficient hybrid silicon perovskite panel would be an example. This would produce double to triple the net wattage again as they perform much better in partial cloud or with sunlight further from normal and with realistic projections for cost would be around €1 to €2 per net watt installed as a dedicated facility including land.

In total you're around a factor of 5-15 over what is necessary.

A reasonable proposal then puts your "20%" figure at something more like just putting panels on top of the built up and paved areas starting south of Nuremberg and only going north when you run out of space. So to conclude

> Solar requires surprisingly little space