[Florin_Andrei]

Yup. Some things (not all) are impossible in a literal sense.

Want to extract 2 kW / m^2 from solar radiation somewhere near the Earth? Won't work, the Sun doesn't pump out that kind of power density (the max is 1.whatever kW). Literally impossible.

[eric_arrr]

Wrong -- we could move the earth closer to the sun. Or make the sun burn hotter. Either way, totally possible.

/s ;)

[thrownaway2424]

Can't I just put a lens above the surface to concentrate it? I think you picked a poor example.

[TheSpiceIsLife]

No you can't, because you're increasing the surface are of the collector so the 1.366kWh / square meter still stands.

From Wikipedia:

Average annual solar radiation arriving at the top of the Earth's atmosphere is roughly 1366 W/m2. The Sun's rays are attenuated as they pass through the Atmosphere, leaving maximum normal surface irradiance at approximately 1000 W /m2 at sea level on a clear day.[1]

Therefore it is impossible to get more than about 1kW / m2 from any solar panel. Until such times as something fairly fundamental changes, like a loss of atmosphere or an increase in energy output from the sun.

1. https://en.wikipedia.org/wiki/Insolation

[mjevans]

Well, you're mostly correct; but not technically correct.

From /just/ a solar panel it isn't possible to achieve higher density, however you can use reflectors in the spectrum that your solar panel operates in to increase the energy available for capture at a focal point.

[simoncion]

So, there's this: http://what-if.xkcd.com/145/

But there's also TheSpiceIsLife's opening comment which says:

> ...you're increasing the surface are of the collector so the 1.366kWh / square meter still stands.

It feels like your second sentence

> ...[H]owever you can use reflectors in the spectrum that your solar panel operates in to increase the energy available for capture at a focal point.

plays rhetorical games by ignoring the existence of large parts of your solar collector (namely the reflectors) in order to arrive at an inflated energy density figure.

[gvb]

No. Your lens is the collection surface area.

Trivia: According to https://en.wikipedia.org/wiki/Sunlight#Solar_constant The sun puts out approximately 1.361 kW/m²

[etendue]

No. In addition to the others, another link of interest might be on etendue: https://en.wikipedia.org/wiki/Etendue

[theresistor]

The lens wouldn't be "somewhere near the earth".

[thrownaway2424]

Exactly my point!