Solar street light are street lights powered by solar panels. The solar panel charges a rechargeable battery, which powers a fluorescent or LED lamp during the night. The typical solar street lights starts ranges from 9 watt to 18 watt. The cost of solar street light depends on the wattage of the light (12 W, 18 W etc), autonomy needed (12 Hr, 24 Hr etc), height of the pole (4 m, 5 m etc),  location and also on the quality of the products and services. The cost of a 18 W solar street light is around Rs 18,000.