Intermittent and variable: these two adjectives continue to dog renewable solar and wind power energy. It’s energy for which there is no control over when it is produced and no possibility of storing the electricity. Or is there? On Reunion Island, EDF and its partners have developed a special system. By smoothing electricity production and storing it depending on weather conditions, the system provides a partial answer to renewable energy intermittence – and so to the challenges facing island electricity systems.