PV POWER MAP
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. This issue contains two maps: one generated using SolarAnywhere’s satellite time-series irradiance data, and the other using National Renewable Energy Laboratory Typical Meteorological Year (TMY3) data. Comparing these two maps highlights why TMY3 data are not recommended to predict short-term performance.
TMY3 data are drawn from a large pool of historical measurements concatenated monthly, and are valuable in predicting long-term performance. By comparison, production estimates from SolarAnywhere reflect actual weather conditions, making it useful in assessing actual performance.
The distance from the TMY3 data collection site to the installation can also affect accuracy. For example, based on March SolarAnywhere data, output for identical systems in the region surrounding the TMY3 site at Wilkes-Barre Scranton International Airport in Pennsylvania varied by as much as 25 percent, depending on distance from TMY3. This difference is often magnified in microclimates, such as those found in Hawaii.
To use the PV Power Map to calculate the generation potential of a PV system in a given location, multiply the power output indicated on the map by a project’s capacity, in kilowatts. The result is the total estimated power output for the month.
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.
This article appeared in the June 2012 issue of SOLAR TODAY. Subscribe today and don’t miss an issue.