In the past few years, the title of “largest solar farm in the world” has been a rather short-lived distinction. For a period in 2014, the Topaz Solar Farm in California topped the list with its 550-megawatt (MW) facility. In 2015, another operation in California, Solar Star, edged its capacity up to 579 MW. By 2016, India’s Kamuthi Solar Power Project in Tamil Nadu was on top with 648 MW of capacity.

As of February 2017, Longyangxia Dam Solar Park in China was the new leader, with 850 MW of capacity. These images, both of which were acquired by the Operational Land Imager (OLI) on Landsat 8, show how the solar park grew over a four-year period.

By January 5, 2017, solar panels covered 27 square kilometers (10 square miles) of Qinghai province. According to news reports, there were nearly 4 million solar panels at the site in 2017.

The rapid expansion at Longyangxia coincides with China’s fast-growing solar power sector. In 2016, China’s total installed capacity doubled to 77 gigawatts. That pushed the country well ahead of other leading producers—Germany, Japan, and the United States—to become the world’s largest producer of solar power. However, those three countries (and several others) produce more solar power per person.

It is unlikely that Longyangxia will remain the largest solar park in the world for long. A project planned for the Ningxia region in China’s northwest will have a capacity of 2,000 MW when it is finished, Bloomberg reported.

NASA Earth Observatory images by Jesse Allen, using Landsat data from the U.S. Geological Survey. Caption by Adam Voiland.