There is an ongoing discussion whether to use light sensors or astronomically calculated set points. Which is safest, and where do we get the best savings?
Amplex has made a study in 9 cities in Denmark, Sweden, Germany and Luxembourg, and found that using a light sensor saves up to 22% compared to astronomically calculated set points. Energy savings will actually be even larger, as the energy is unevenly consumed through the night. At sunset and at sunrise, the light is usually fully on, while during the night many lights are dimmed. When optimising the on/off time of the streetlights, the optimisation will happen when the lights are fully on, thereby providing an even larger saving.
More details – read the full report here.