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 highlights the difference in real-time production when compared to annual averages. The first map illustrates total estimated power output for the month of April 2012. The second shows the average monthly PV power output in 2011.
It’s a given that solar resources can vary on an hourly basis, but a comparison of these two maps shows that local differences in any given month can also be considerable. While April is typically close to annual averages, production in April 2012 throughout the U.S. Northeast and Midwest outpaced the average monthly production for 2011.
The April PV Power Map was created using real-time irradiance estimates that provide an accurate depiction of current weather conditions. This information is most useful for assessing the actual production of an existing PV power production system. The monthly average value, which in this case was calculated by averaging annual total PV power output by location, is best suited for comparing long-term performance of potential PV sites.
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 July/August 2012 issue of SOLAR TODAY. Subscribe today and don’t miss an issue.