According to relevant estimates, the total number of existing street lights in China is about 100 million (also estimated at 200 million), and it is growing at a rate of 20% per year. If this billion street lights can be converted into 60 million 250-watt street lights, Assuming that all 60 million street lights are converted into solar street light , a total of 15 million kilowatts of power can be saved. Assuming that each street lamp works 12 hours a day, it will save 65.7 billion kWh of electricity in one year. The Three Gorges Hydropower Station generated a total of 61.603 billion kWh of electricity in 2007. Therefore, the energy saved by changing all the street lights in the country to solar street light will exceed the annual power generation of a Three Gorges Hydropower Station. This is an extremely alarming number. We must know that the total investment of the Three Gorges Project exceeds 180 billion yuan, plus more than 40 billion of transmission and distribution projects totaling more than 220 billion yuan. And there are more than one million immigration issues, plus many unpredictable issues about the ecological environment.