China's Massive Solar Arrays Don't Generate Much Energy

China easily has the world’s largest solar generation capacity with an incredible 880 gigawatts of utility-scale solar in 2024. Of that, 277 gigawatts were installed in 2024 alone.

Solar now represents 26 percent of the 3,348 gigawatt generating capacity for the country, and there are plans to continue this growth into the next decade like the Great Solar Wall.

But while China’s massive array of solar panels is a sight to behold, it doesn’t generate much energy for its size. That’s because solar nameplate capacity is a theoretical estimate based on ideal conditions. China could potentially generate 880 gigawatts of solar energy at one time with clear skies and direct solar radiance, but it wouldn’t generate that amount all year round due to changing weather conditions, nights without sun, varying angles of the sun across the year, or other variations of insolation.

Instead, China generated only about 341 terawatt-hours in 2021 from solar out of a possible 3,408 terawatt-hours based on its nameplate capacity (277 gigawatts x 24 hours x 365 days). That’s a production ratio of only 10 percent based on Energy Information Administration (EIA) data.

Compared with other fuels, solar represented 15 percent of capacity that year, but only represented 4 percent of actual energy generation.

That may not be unreasonable. For example, sunnier Australia produced 46.7 terawatt-hours from solar in 2024 based on 35 to 40 gigawatts of installed photovoltaic capacity, which works out to a production ratio of 13 to 14 percent.

Solar’s Low Generation Versus Other Sources

While the production ratio for solar is low, certain other energy sources are low as well. For example, the production ratio for petroleum is 5 percent. For natural gas in China it’s 13 percent.

That’s because those sources aren’t commonly used for generation but as backup at times of high demand. In 2021, natural gas only represented 3 percent of total energy generation. Petroleum was less than .2 percent. Instead, China runs mainly on coal, which represented 63 percent of generation, and a decent amount of hydroelectric power.

But there’s a significant difference between an idle natural gas turbine and a low generation solar farm; solar farms take up a vast amount of space.

The amount of energy produced by a solar panel varies by the type of panel and the environment it is in, but a common estimate for capacity per size of a photovoltaic puts it at 10 to 20 watts of capacity per square foot.

For China’s 880 gigawatts of utility-scale solar, that works out to 1 to 2 million acres of solar panels. And China’s solar farms are certainly massive. The recently built Urumqi farm in Xianjing, possibly the largest in the world, is 32,947 acres (although previously reported as 200,000 acres).

Which seems low. If those numbers are correct, the Urumqi farm has a capacity of only 2.4 watts per square foot, and actual generation would be around 1/10th of that.

Urumqi capacity per square foot = (3.5 gigawatts x 1,000,000,000 watts/gigawatt) / (32,947 acres x 43,560 square feet per acre) = 2.4 watts/square foot