You can see from maps, that if you use solar panels which are fixed, in the best areas in the US, you get a yearly solar radiation of about 7 kw/h per day. And with directional mounts you get an average of about 8 Kw/h per day.

So that with directional mounts, in best locations with solar power of efficiency possibilities ranging from say 5% to 25%
you get .4 to 2 Kw/h per day per Sq meter.

But most solar panels people normally use aren't directional and the cheapest solar panels per their power rating are
around 5% efficent. For example:

"The ultimate goal of Aten Solar is to market PV modules that generate solar electricity at the
lowest possible cost. While a-Si modules have an efficiency of 5-6%+ compared to c-Si's
10%+, thin-film modules are typically significantly more cost effective particularly in applications
where area is not an issue."
http://www.atensolar.com/14.html
They sell 32 panels for $4,032.00

So, in areas with best solar power, these would get about average .35 kw/h per sq meter per day.
But if you didn't put these in an area with the most amount of solar power per year, such as most areas in Oregon or the state of New York where one has about 5 kw/h average per year, you would get about .25 kw/h per sq meter.
In addition, if you have solar panels in Canada, or the UK and especially in Germany, you are likely to be in areas of
2 Kw or less.

I guess my point is that if you were to mine iron ore, you generally go to places which had a high concentration of Iron in the ore [at least this is a significant factor], with solar power, we seem less concern about having solar power in location with highest amount of solar radiation per year.
And btw, in space, one would get about 4 times the amount of solar energy per sq meter as compared to the best locations in the US.
Of course, if you want to go to Venus or Mercury distance- one would receive far more than 4 times.