Open Source Software as a Service for Solar Forecast Evaluation

Case ID:

The Solar Forecast Arbiter is an open source evaluation platform for solar forecasting. The platform enables evaluations of solar irradiance, solar power, and net-load forecasts that are impartial, repeatable, and auditable. The Solar Forecast Arbiter is designed to support all solar forecasting stakeholders.

A major concern surrounding solar power is the variability and unpredictability of sunlight. This inherent variability poses issues with grid reliability and the expenses associated with operating the solar units. Errors in solar forecast accuracy arise either from the weather prediction or PV simulation step. Forecasting is just one part of the puzzle – “what next” is the key issue. If one deviates from the forecast, should they be penalized, and by how much? These are key issues. There is inherently a limit to perfection in forecasting; however, tools are improving, so average errors decreasing and the time-periods of confidence are improving as well.

The Solar Forecast Arbiter is a technology that will allow for evaluation of solar forecasts to evaluate methods and practices used to develop the forecasts. The technology includes a data validation toolkit, reference data sources, data privacy protocols, and benchmark forecast capabilities for intra-hour and day ahead forecast horizons to improve upon current solar forecasting software.


  • Solar forecast evaluation
  • Wind forecast evaluation


  • Impartial
  • Repeatable
  • Support for multiple forecast strategies
Patent Information:
Contact For More Information:
Lewis Humphreys
Licensing Manager, Eller College of Mngmt & OTT
The University of Arizona
Lead Inventor(s):
William Holmgren
Antonio Lorenzo
Leland Boeman
Aidan Tuohy
Adam Wigington
David Larson
Justin Sharp
Clifford Hansen