<human>:  When did China’s solar revolution begin?
<bot>: The solar revolution in China began in the late 1980s. At that time, China had a large population and a lot of coal, which is a good source of energy. However, China was not able to use this coal efficiently because of its high sulfur content. In order to make the coal more efficient, China needed to develop new technologies. This is when China began investing heavily in solar energy.