Intermittency of solar power production is one of the major challenges utility operators face today. There’s nothing to be done to control atmospheric conditions, but now the National Center for Atmospheric Research (NCAR) is spearheading a three-year, nationwide project to create unprecedented, 36-hour forecasts of incoming energy from the sun to inform and alert solar-energy producers and power plants.

In addition to helping utilities use solar energy more effectively, predicting cloud cover over specific areas at specific times can also improve the accuracy of shorter term weather forecasts.

“It’s critical for utility managers to know how much sunlight will be reaching solar-energy plants in order to have confidence that they can supply sufficient power when their customers need it,” said Sue Ellen Haupt, director of NCAR’s Weather Systems and Assessment Program and the lead researcher on the solar-energy project.

Solar-energy output is affected not just by when and where clouds form, but also by the types of clouds present. The thickness and elevation of clouds have greatly differing effects on the amount of sunlight reaching the ground. Wispy cirrus clouds several miles above the surface, for example, block far less sunlight than thick, low-lying stratus clouds.

The research will draw on techniques at leading government labs and universities across the country, in partnership with utilities, other energy companies, and commercial forecast providers.

“Improving forecasts for renewable energy from the sun produces a major return on investment for society,” said Thomas Bogdan, president of the University Corp. for Atmospheric Research, which manages NCAR on behalf of the National Science Foundation. “By helping utilities produce energy more efficiently from the sun, we can make this market more cost-competitive.”

The team will test these advanced capabilities during different seasons in several geographically diverse U.S. locations: the Northeast, Florida, Colorado/New Mexico, and California. The goal is to ensure that the system works year-round in different types of weather patterns.

Once the system is tested, the techniques will be widely disseminated for use by the energy industry and meteorologists. NCAR also is creating advanced prediction capabilities to enable wind farm developers to anticipate wind-energy potential anywhere in the world.