UH team wins HECO Challenge to improve reliability of solar power

Solar energy, including photovoltaics, will contribute to Hawaiʻi’s goals for renewable. (photo credit: John Cole, HNEI)

University of Hawai‘i (UH) at Mānoa researchers and a graduate student recently won the Hawaiian Electric Company (HECO) Innovation Impact Challenge. UH Information and Computer Science (ICS) assistant professor Peter Sadowski, ICS graduate student Kyle Hart and Atmospheric Sciences assistant professor Giuseppe Torri were awarded a grant to develop short-term forecasts of sunshine that can reach rooftops and solar panels.

The goal of this pilot initiative is to develop innovative new products and tools through collaboration between the utility company and the university.

During the next three months, the team will develop a forecast tool to predict cloudiness over Hawai‘i—just 15 to 60 minutes in advance.

“These ‘nowcasts’ could be created by running a weather forecasting model at a very high resolution, but this would end up being too computationally expensive,” said Torri. “For this reason, we decided to use a machine learning approach. In essence, we will train a computer algorithm to ‘learn cloud patterns’ using existing satellite data, and we will use this to predict what clouds are expected to appear in the very short term.”

At any given time of day, the amount of sunlight hitting Earth can be calculated. With that information, and knowing how clouds interact with incoming solar radiation, the team’s predictions allow them, and HECO, to determine the amount of sunlight reaching solar panels that generate electricity for homes and businesses across the state.

It is not surprising that clouds are bad news for solar power—low clouds in particular tend to reflect back to space the sunlight that could be used by solar panels to generate electricity. This can significantly reduce the efficiency of the solar panels.

“It is easy to imagine scenarios where sudden changes in cloudiness create equally sudden spikes of electricity demand on the grid,” said Torri. “Our project promises to help HECO manage these spikes by giving them a systematic way to predict them with enough advance that some auxiliary generators may be turned on.”

“As we work toward a clean energy future, our industry will face technological challenges and opportunities along the way,” said Jim Alberts, Hawaiian Electric senior vice president of business development and strategic planning. “Innovation and collaboration such as this is critical for Hawaiian Electric to continue providing reliable service as we transition to 100 percent renewables by 2045.”