Capacity factor is the actual output compared with full nameplate output if operated at full capacity for an entire year.

The Renewable Energy Taskforce Advisory Committee revealed that the Vote Solar Initiative
Study disclosed the capacity factor for photovoltaic cells (i.e., solar panels) was 14 percent in Delaware. In sunnier Arizona it is 19%, and Massachusetts 12-15%

According to the Energy Information Agency, capacity factors for coal, natural gas, and advanced nuclear are all above 85 percent. Per unit of energy produced, photovoltaics receive more than 100 times the federal subsidies as compared to coal and 50 times that of natural gas.

Summary

Typical capacity factors
Photovoltaic solar in Delaware 14%
Photovoltaic solar in Massachusetts 12-15%
Photovoltaic solar in Arizona 19%
Wind farms 20-40%.
Hydroelectricity, worldwide average 44%, range of 20% - 75% depending on water availability
Coal, natural gas, and advanced nuclear are all above 85 percent
Nuclear energy 90.5% (USA 2009)

For Solar Power&Water® Inc. SPPs, assume five days per year for maintenance. Thus
360/365 x 100% = 98.63% capacity factor for our SPPs. Except the pond stays online, continuing to receive and store solar energy as usual. The SPP capacity will be 1,000 kW but capable of 1,250 kW overload, enabling the SPP back online to run in overload to play catchup. Net result, 100% capacity factor. Moreover the SPP will receive no subsidies.
Solar Power&Water® Inc. SPP 100% capacity factor. (forecast)