At about 11,000 feet, a Tibetan Plateau solar farm still used for sheep grazing made nearby soil freeze earlier and thaw later

High up on the Tibetan Plateau, in a spot so cold that grass barely grows past ankle height, China built a solar farm that does something nobody probably expected. It made the ground colder, not warmer. According to a peer-reviewed study published in Atmospheric Chemistry and Physics, researchers tracked a 50-megawatt solar plant for a full year and found the soil beneath it stayed frozen for about 50 extra days annually. That works out to roughly seven more weeks of winter, just from bolting panels over a meadow.

A power plant where sheep still graze
The site, named the Dongneng plant, is situated near the town of Maqu in China's Gansu province at an altitude of about 11,000 feet. That is higher than many ski resorts in Colorado. From May to September each year, local herders continue to bring their sheep to graze there, weaving in and out between rows of panels tilted at 36 degrees. It looks like a normal pasture with solar equipment on top.

To learn what the panels were doing to the land, the research team built two tall measuring towers. One was inside the solar array. The other was in a pristine part of the same meadow, some 180 meters away. Each tower recorded temperature, wind and soil measurements every 10 minutes for a full year, June 2023 through May 2024.

Why this matters more than it sounds
Sometimes called the “Third Pole,” this area contains more frozen freshwater than anywhere else on the planet outside the Arctic and Antarctic. According to a review titled ‘The imbalance of the Asian water tower’ by glaciologist Tandong Yao and his co-authors, this frozen reserve feeds major rivers that supply water to nearly two billion people across Asia. Anything that affects how fast that ice melts or refreezes can have ripple effects far beyond a single meadow.

The science behind the freeze
Dark solar panels would seem to hold heat, like asphalt on a hot day. But, the study found, the opposite happened here. The panels blocked wind, reduced the amount of sunlight that reached the ground, and kept the soil shaded most of the day.

By the end of the year, the panels had increased the net radiation at the ground by nearly 29 percent, and the ground reflected about 32 percent less sunlight than did the open meadow. In winter, the rows of panels acted as a fence and lowered wind speed near the surface by about 36 percent.

The air temperature told a split story. On summer days, the air under the panels was up to 1.6 degrees Celsius warmer than the open meadow. On winter nights it ran nearly a degree cooler. It was warmer during the day, colder at night, and the daily swing added up over the seasons.

That swing is what pushed the soil calendar off track. The soil immediately beneath the panels froze 27 days earlier and thawed 20 days later than the open meadow. In the inter-row spaces, freezing occurred 20 days earlier, while thawing was delayed by a whole month, or 31 days behind the unworked earth. The same study found that soil beneath the panels retained moisture longer, drying up to three-and-a-half times more slowly than the open meadow during dry spells.

Not the first time solar panels have surprised scientists
It’s not the first time that a solar farm has behaved differently than engineers expected. In Arizona, ecologist Greg Barron-Gafford and colleagues studied a solar plant in the desert and found the opposite. The study titled ‘The Photovoltaic Heat Island Effect: Larger solar power plants increase local temperatures’ in Scientific Reports found that temperatures above the panels at night were 3 to 4 degrees Celsius warmer than the surrounding desert, an effect the team dubbed the photovoltaic heat island.

Two solar farms, two very different outcomes. The difference comes down to what the land looked like before the panels went up. A hot desert cools down under shade. A cold alpine meadow gets locked into an even longer winter. The panels themselves aren't behaving any differently; it's the land underneath that decides the outcome.

What comes next
The research team behind the Tibetan Plateau study is careful not to oversell their findings. This is one plant and one year of measurements. They say clearly that more years of data are needed before anyone can confirm this effect will meaningfully slow permafrost loss over time. There are tradeoffs, too. A shorter growing season could mean the meadow absorbs less carbon from the air, and splitting the ground into wetter gaps and drier patches under the panels will likely reshuffle which plants grow where.

Still, it is a reminder that renewable energy projects can reshape the land in ways nobody designs for on paper. Sometimes that means more grass. Sometimes it means seven extra weeks of winter, quietly locked into the soil at 11,000 feet.