This description is for solar powered street lights, which are an energy efficient and cost effective way to light up roads and streets. These lights are powered by the sun, using solar panels to capture and store energy during the day, and then using that energy to power the lights at night. They
From Wikipedia
Solar street lights are raised light sources which are powered by solar panels generally mounted on the lighting structure or integrated into the pole itself. The solar panels charge a rechargeable battery, which powers a fluorescent or LED lamp during the night.