Stats

• World Military Spending - $1.7T
• USA Military Spending - $640B - $2k per capita spending
• $40B organics market - http://www.ers.usda.gov/topics/natural-resources-environment/organic-agriculture/organic-market-overview.aspx. That makes it
• Annual sustainable forest yield of 12.5B cubic meters or 105 exajoules - [1], p. 615

• Annual energy use by USA - 94 exajoules

• US energy consumption by sector - 40% electricity, 30% transportation - [2]

• Total USA energy use - 25 PWhr - [3] - (petawatt hours (See Metric Prefixes))
• Equivalent to 90 exajoules, consistent with Renewable Energy "Blue Bible" above.

• 250GW of PV is installable on existing rooftops - Cosservative estimate (50% of residential rooftops) - [4]

• Per year, let's take average insolation as 6 hours per day * 365 days - or 550 TWhr per year. That is 2% of USA's energy use, or 5% of USA's electric use. This is JUST RESIDENTIAL ROOFTOPS. Needs to add commercial rooftops, parking lots, roadway medians.

• USA road density - 67 km/ 100 sq km of area - [5]
• USA area - 10 million sq km
• USA roads - 6.7 million km. Assume an average road is 2 lane with shoulder - each lane has 12 foot (3.7m) standard in the USA - [6] - or an area of about 100,000 sq km. This could power 1/4 of the world's energy needs (oil, nukes, eaTaeri
• Area required to power all of the world with PV is 400,000 sq km - [7]