1C kwh-kwp chart-3Not all PV systems are the same! Many installed PV systems are underperforming their potential production through sub-optimal design, installation or maintenance practices.

The above graph of a selection of publicly available commercial roof-mounted PV system kWh/kWp performance for 2010 in the Boston, MA area demonstrates the great variation in solar PV system performance and the opportunity for significant improvement. For 15 systems, kWh/kWp values range from 758 to 1,417 with an average of 1,133 for the year.

621 Energy, LLC uses the best project management, up-front engineering, installation, commissioning, monitoring/analysis and maintenance processes to provide a high-performing (kWh/kWp) PV system in a cost-effective manner.

What is kWh/kWp Performance?

The peak kilowatt (kWp) rating for a solar PV module represents the instantaneous DC power output rating of an individual module under standard testing conditions. For multiple modules connected as a PV system, module kWp ratings are summed to establish the kWp PV system rating.

The PV system generates AC electrical energy measured in kilowatt-hours (kWh). kWh/kWp is a measurement of the PV system performance in the field for a period of time and varies depending on the local solar resource, module characteristics (i.e. temperature coefficients, degradation rate) and system installation factors (shading, tilt, orientation, inverter efficiency, etc.). For a given location, kWh/kWp provides the best means of comparing installed PV system performance and is independent of system size or module efficiency rating.