Investigations of site-specific long term average albedo determination for accurate bifacial system energy modeling
Rhonda Bailey1, Patrick Keelin2, Richard Perez2, Justin Robinson3, Gwen Bender3, Julie Chard3
1Recurrent Energy, Walnut Creek, CA, United States
/2Clean Power Research, Napa, CA, United States
/3GroundWork Renewables, Sand City, CA, United States

Abstract  —  In recent years, bifacial modules have been attracting industry interest due to the potential for significant contributions to energy generation from the module rear side. Albedo is a critical parameter needed to determine rear side irradiation and accurate albedo values representing both long-term and evolving conditions are needed to quantify the impact of the additional energy generation for financing solar projects.  In this paper, the authors identify multiple sources of long-term albedo data and compare to shorter term on-site measurements in Utah and California. An evaluation of on-site albedo measurement techniques is presented. Finally, we evaluate methods to reduce higher-frequency measured or long-term albedo data to monthly values commonly needed by industry-accepted software, such as PVsyst.