- National Solar Radiation Data Base. Insolation data for more than 1,000 locations in the United States.
- PVWatts calculator determines the energy production and cost savings of grid-connected photovoltaic (PV) energy systems throughout the world.
- Solar Calculator, Great Circle Studio. Information regarding solar altitude and azimuth for every date and location. Interesting factoid with relevance to photovoltaic systems: in temperate zones, for several weeks before and after the summer solstice, the sun (the "apparent solar azimuth") may move 45 degrees or more in one hour in the middle of the day.
- Solar Energy for Kids -- U.S. Department of Energy
- Solar energy faces an economic test at Moscone Center 9/17/02. This article, published before the Moscone Center photovoltaic system was installed, correctly predicted that the system would not be cost effective.
- An interview with PG&E's CEO 11/18/07. PG&E's efforts to go green. Of interest is the statement that "Traditionally, the problem with solar [photovoltaic] is the cost of solar has been about 30 to 40 cents per kilowatt hour. So it's been a great technology when one thinks about the environment, but it's like three times as expensive." Solar thermal electricity is said to cost about 12 to 14 cents per kilowatt hour.
- "I don't care about the arguments against it. I care about the arguments for it." 3/4/08. Mayor Gavin Newsom, a leading proponent of solar installations in San Francisco, about harnessing tidal power.