There may be another incentive behind China’s drive to build solar farms in some politically sensitive regions. In recent decades, many have observed that China has been keen to encourage infrastructure investment in and around Tibet – an autonomous region that is home to many who reject China’s claim on the territory. Some argue that such investment is politically motivated in part – an effort to cement Chinese authority and support ethnic Chinese who have moved to these areas.

One extraordinary venture uses solar panels to heat an underground grid designed to melt permafrost, so that trees will grow on the reclaimed land. It is reportedly an attempt to make the area more appealing to Chinese settlers.

But building gigantic solar farms in the middle of nowhere has its downsides. To understand why, we need to look at China from above once more. In 1935 geographer Hu Huanyong famously drew what is known as the “Hu Line” from north-east to south-central China. It divides the country into two roughly equal portions. Less equal is the population distribution. The vast majority of China’s people, 94%, live in the eastern portion. The remaining 6% live to the west.

“The distribution of China’s wind and solar energy resources [is] entirely the opposite,” says Yuan Xu at the Chinese University of Hong Kong.

Many of the country’s solar panels are therefore located as far as can be from the large towns and cities that need them. The result of this is a staggeringly low capacity factor – the percentage of electricity actually taken from any given resource.