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. Comparing monthly maps makes it possible to see how irradiance and associated PV system power output vary over time from region to region, often with unexpected results.
For example, compare January and February solar resource availability on the eastern seaboard with the Gulf Coast. During this time, the total power output of a 1-kW system in New York City and New Orleans was virtually identical, at approximately 195 kilowatt-hours (90 + 105 kWh) and 200 kWh (115 + 85 kWh) respectively. When viewed over time, solar resource availability in northern states often exceeds expectations.
Looking at the February map in the Maine region, the northern Rockies and the northern Great Plains, a limitation common to all satellite-derived solar irradiance data sources is evident. Persistent snow cover in these regions was in some cases misinterpreted as cloud cover, leading to an underestimation of irradiance. An updated model that integrates infrared data to better estimate atmospheric conditions will reduce these effects. Currently being used for select customers and regions, the new SolarAnywhere model will provide accurate, low-cost data even in high-albedo situations for all users as it’s rolled out broadly.
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. Go to solartoday.org/pvpowermap to reference maps throughout the year, or access free historical irradiance data at solaranywhere.com.
The PV Power Map is created with power output estimates generated by SolarAnywhere services from Clean Power Research, which 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 May 2012 issue of SOLAR TODAY. Subscribe today and don’t miss an issue.