By ADAM KANKIEWICZ February 18, 2014
The PV Power Map is a report of national solar resource availability as illustrated by the monthly energy output of a nominal 1-kilowatt (kW) photovoltaic (PV) system by location. The monthly difference in PV solar energy production due to seasonal transition is highlighted during October and November.
Above-average PV energy production continued to prevail across the Southwest United States during both October and November as drought conditions continued in the region. In the rest of the country, PV energy production was near average or slightly above average in October, but slipped to below-average production conditions due to increased cloud cover and precipitation in November.
The decrease in PV energy production between October and November is also intensified by the sun’s seasonal retreat towards the southern hemisphere. In autumn, shorter days combine with lower sun angles to rapidly decrease potential PV energy production. This is observed in the Southwest where weather did not significantly modulate the seasonal-induced drop in PV energy production between October and November.
The PV Power Map can be used by anyone to quickly gauge the generation potential of a new PV system, or benchmark the performance of an installed system, in a given location. Simply multiply the power output indicated on the map by a project’s capacity, in kilowatts, to calculate the total estimated power output for the month.
For example, a 4-kW PV system in Macon, Ga., would have produced approximately 500 kilowatt-hours during October (125 kWh x 4 kW = 500 kWh). A 4-kW system in Boulder, Colo., would have produced approximately 460 kWh during November (115 kWh x 4 kW = 460 kWh).
To gain an understanding of the production of a particular system over a period of time, you can view PV Power Maps from the past.
The PV Power Map is created with power output estimates generated by SolarAnywhere services from Clean Power Research; these include simulation capabilities and hourly satellite-derived irradiance data with spatial resolutions from 1 to 10 kilometers. The calculations are based on a PV system with a total 1-kW nameplate rating that is configured as five 200-watt PV panels with a 1.5-kW inverter; fixed, south-facing panels with 30 degree tilt; no shading; panel PVUSA Test Conditions rating of 178 watts; and inverter efficiency of 95.5 percent. Visualization and mapping provided by GeoModel Solar. Access free historical irradiance data at solaranywhere.com.
Adam Kankiewicz (askcpr@cleanpower.com) is a research specialist at Clean Power Research.