Inner Mongolia cuts water use in solar sector

Ordos authorities have vowed to further tap the potential of reclaimed water in meeting demand from its booming solar industry, especially because the city is located in an arid area with scarce water resources in the Yellow River Basin.

The per capita water resources in Ordos is only 1,287 cubic meters, compared to the national average level of 2,100 cubic meters. While the city's annual precipitation ranges from 150 to 350 millimeters, the city's evaporation levels stand between 2,000 and 3,000 millimeters.

Despite this, the city has 30 solar panel manufacturers and supporting enterprises, covering the entire industrial chain, according to a statement from the department of industry and information technology in Ordos in response to inquiries from China Daily.

While the output of polycrystalline silicon in the city decreased by 43 percent year-on-year in 2024, the city registered significant increases in the production of monocrystalline silicon and many other materials and components for solar energy development, the statement said.

Output of monocrystalline silicon reached 48,700 tons last year, a 431 percent increase on the year prior. The production of silicon wafers in the city, for instance, surged by 503 percent to 3.8 billion slices, while the manufacturing of solar cells saw a significant spike of 1,825 percent to 23.3 gigawatts.

Silicon wafers are the most commonly used semiconductors in solar panels. Positive-type and negative-type wafers are combined in a solar cell to convert sunlight into electricity through the photovoltaic effect.

The production of wafers is a crucial step in panel manufacturing that requires water consumption. Water is essential for cooling and lubricating the cutting tools, as well as for cleaning the wafers. Usually, producing one regular silicon wafer requires approximately 500 milliliters of water, equivalent to a regular bottle of water.

Ordos has effectively addressed the constraints of water resources on its photovoltaic sector by utilizing reclaimed water, drainage and mine well water, as highlighted by the city's Department of Water Resources.

There are 25 operational wastewater treatment plants in the city, primarily situated in urban areas and industrial parks, with a daily processing capacity of 520,000 cubic meters. Ordos has also completed the construction of four projects for storing reclaimed water to enhance its utilization.

Almost 91 percent of the reclaimed water generated in the city was collected and utilized last year, the department reported. It emphasized that the city will continue its efforts to leverage these unconventional water sources to meet the water demand of its crystalline silicon industry.