solar energy technology and Moore's Law

I've been trying to understand theoretical maximums, etc.. for solar energy.  This article by Ramez Naam in O'Reilly Radar captures a lot of what I am in interested in learning.

See: http://radar.oreilly.com/2011/04/solar-power-moores-law.html  Apparently this article was originally in Scientific American.

Valuable snippet:

The sun strikes every square meter of our planet with more than 1,360 watts of power. Half of that energy is absorbed by the atmosphere or reflected back into space. Seven hundred watts of power, on average, reaches Earth's surface. Summed across the half of the Earth that the sun is shining on, that is 89 petawatts of power. By comparison, all of human civilization uses around 15 terrawatts of power, or one six-thousandth as much. In 14 and a half seconds, the sun provides as much energy to Earth as humanity uses in a day.

I'd like to understand more about the impact of latitude and weather on the theoretical maximum in any particular location.   Latitude changes mean changes in angle of sunlight, affecting energy density I suppose.  Also,  average cloud cover in a particular location obviously makes a big difference.

Anyone really good with maps mashups?  Given a Google map of a particular location, calculate and display theoretical max energy from sunlight.   Maybe, given appropriate weather table data this would be an application for Fusion Tables.  Any takers?  Or perhaps someone has already done this.   If only I had any free time at all....