Solar Resource Assessment

Wireless pyranometer in Lanai, HI

Solar resource is one of the most important inputs to PV power plant yield and performance evaluations. It is also one of the most difficult quantities to measure and estimate accurately.

Sandia’s Solar Resource Assessment program researches and develops models and algorithms for estimating, predicting, and forecasting the solar resource. Current research efforts at Sandia include

• understanding the spatial and temporal patterns of irradiance fields and how these patterns affect PV plant output,
• defining metrics for understanding irradiance and PV plant output variability,
• developing techniques and metrics to determine the operational value of solar forecasts for utilities, and
• improving methods to translate solar resource data (e.g., horizontal to plane-of-array irradiance models).

Recent Accomplishments

• The Variability Index: A New and Novel Metric for Quantifying Irradiance and PV Output Variability (Stein et al, 2012)
• Global Horizontal Irradiance Clear Sky Models: Implementation and Analysis (Reno et al., 2012)

Analysis of errors in Clear Sky Models (Reno et al., 2012)