Original links are included though some may have expired.

The Numbers:

Solar Land Surface Radiation: 223,400 trillion kilowatt-hours/year
World electricity consumption: 17.48 trillion kilowatt-hours/year
World solar-cell energy capacity: 0.07 trillion kilowatt-hours/year

What They Mean:

From Frederic Bastiat's 1845 Petition from the Manufacturers of Candles, Tapers, Lanterns, Sticks, Street Lamps, Snuffers and Extinguishers, and from Producers of Tallow, Oil, Resin, Alcohol, and Generally of Everything Connected With Lighting:

Dear Deputies [of Parliament]: We are suffering from the ruinous competition of a rival who apparently works under conditions so far superior to our own for the production of light that he is flooding the domestic market with it at an incredibly low price. This rival is none other than the sun ... We ask you to be so good as to pass a law requiring the closing of all windows, dormers, skylights, inside and outside shutters, curtains, casements, bull's-eyes, deadlights, and blinds -- in short, all openings, holes, chinks, and fissures through which the light of the sun is wont to enter houses, to the detriment of the fair industries with which, we are proud to say, we have endowed the country."

Sixteen decades later, the ruthless competition of the sun menaces energy-industries rather than tallow companies and candlestick makers. In only 18 sunny days, the Earth's land surface receives as much energy from sunlight as its crust holds in recoverable reserves of coal, oil, and natural gas; just 42 minutes of daylight contains enough energy to power the world's electrical power utilities for a year. To catch it, or some of it, is to find an efficient, clean, essentially limitless flood of energy.

Can it be done? This decade's energy-price boom of 2006 and 2007, combined with European policy directives, sparked a surge in investment in solar cells, doubling world photovoltaic power capacity since 2006. The cells, using photovoltaic technology to generate electric current, have sprouted like dandelions as sources of power for calculators, homes, emergency telephones and road signs, water pumps and electrical grids in many countries, most of all in Germany. Germany uses more of it for power than any other country: Germans installed 1131 megawatts of solar cells in 2007 -- up from 81 megawatts in 2001 and 5.3 in 1995 -- and now have 3862 megawatts of solar cell capacity. This is nearly half the world's solar-cell megawattage. The panels produced 4.3 billion kilowatt-hours of electricity last year, or 0.7 percent of Germany's total 621 billion kilowatt-hours of electricity. By comparison, America's solar cell capacity is now 830.5 megawatts, and combined with concentrated solar power contributes about 0.2 percent of America's electricity.

Germany also makes solar cells, manufacturing enough last year to produce 842 megawatts of power. Americans produced 266 megawatts' worth. Japan and China lead the world as manufacturers, though; as of 2007, Japan was at 923 megawatts' worth of solar cells and China 1700. Leading Chinese producer Suntech is a designer as well as assembler of technology (unusual for Chinese manufacturing). Like Bastiat, but happily, billionaire founder Shi Zhengrong insists that sunshine is unlimited.

Further Reading:

Fun fact -- Over a single year, a square meter of ground gets from the sun roughly the same amount of energy contained in a single barrel of oil. The World Energy Council explains solar radiation and its potential energy:
http://www.worldenergy.org/publications/
survey_of_energy_resources_2007/solar/720.asp

Three countries:

Germany -- EU policy seeks 20 percent of energy from renewable sources by 2020. Germany is at 15 percent now. The solar-power surge results from, among other things, a "feed-in tariff" encouraging companies and households to install solar cells and sell the power to the national power grid at a high price fixed for 20 years. Renewable energy supplies nearly 15 percent of Germany's electricity generation: http://www.worldenergy.org/publications/
survey_of_energy_resources_2007/solar/720.asp

The United States -- Data on renewables, including solar cells and other technologies, from the Department of Energy: http://tonto.eia.doe.gov/energy_in_brief/
renewable_energy.cfm

China -- Reporting from Scientific American:
http://www.sciam.com/article.cfm
?id=chinas-big-push-for-renewable-energy

The OECD's International Energy Agency has data on solar cell production and use by country:
http://www.iea-pvps.org/

Estimate of worldwide solar panel production from the Earth Policy Institute, somewhat at odds with IEA:
http://www.earth-policy.org/Indicators/Solar/2007.htm

Trade -- The United States may trail Germany, but is not inert. Trade data shows a tripling in solar-cell technologies over the last three years:

	2006	2007	2008
U.S. Exports	$374 million	$472 million	$942 million
U.S. Imports	$318 million	$553 million	$1.02 billion

What is it? A solar cell is composed of two separated semiconductor materials, one being silicon and the other gallium, indium, cadmium, or other suitably exotic material. Light knocks the excess electrons from the silicon, causing them to flow and generate electric current. To make such a thing, assemblers melt silicon at 1600 degrees Celsius, purify it and recast it into molds. These molds are then "doped," or infused with phosphorus or boron to create the excess electrons and holes, grooved with lasers, fitted with thin metal rods, and coated with a material that reduces the reflection of sunlight. The cost is above $1 million per megawatt of photovoltaic cell capacity. After manufacture, solar cells are assembled into modules and installed. The most efficient solar cells convert 40 percent of incoming solar radiation into electricity.

And be warned -- Bastiat's Petition: http://bastiat.org/en/petition.html

Note: Research and drafting for this Fact by PPI spring research associate Alex Smith.