University of California (UC) Merced assistant professor Alberto Cerpa has received a $568,000 grant from the National Science Foundation for his project, “MRI: Development of ASSIST: Affordable System for Solar Irradiance Sensing and Tracking.” The project, on which Cerpa is working with Carlos Coimbra, an associate professor, and Quinghau Guo, an assistant professor, measures and traces the amount of sunlight that reaches ground level where photovoltaic panels and solar concentrators collect light for solar energy systems.

Recognizing that weather conditions vary and cloud cover affects the amount of sunlight collected and thus impacts the amount of energy generated by a solar system, ASSIST aims to make solar forecasting more precise and enable electricity providers to better plan and manage solar generation systems within their electrical grids.
The system will be developed and tested in California’s Central Valley and will use a network of sensors that collects data on solar irradiance at ground levels. The sensors will measure and track cloud cover, aerosol content, and the presence of gases such as water vapor and carbon dioxide—all of which can reduce the amount of sunlight a solar cell can collect—in the Earth’s lower atmosphere and stratosphere.  
ASSIST will work in conjunction with two existing solar observatories at UC Merced and UC Davis, and will integrate stand-alone wireless global irradiance sensors with a new dome sensor, eliminating the need for devices with costly moving parts, such as automatic solar trackers.