Performance investigation of batteries supporting solar power in U.S.

The use of batteries in energy storage power plants in the United States has increased significantly. A prime objective of the plants is to provide power in times of peak demand after being charged with renewable sources, mainly solar power. Modeling of solar adoption is largely dependent on understanding how solar and batteries work together, including the need to quantify the battery efficiency. In this study, the efficiency of the energy storage plants in U.S. was calculated based on U.S. Energy Information Administration (EIA) data. A mathematical model is proposed relating the efficiency and the number of cycles per month, grouping plants by installation year. We conclude that newer plants show higher efficiencies, and in the case of experiencing an average of one cycle per day, the newer plants show efficiencies of around 90%. Also, we see a lower efficiency for plants cycled less than five times per month. The efficiency is observed to be between 80% and 90% for batteries experiencing more than five full cycles each month.