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 are of 18 Watt. However, it can be anywhere between 6 Watt to 200 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.