Tina Zhang

From a depleted coal mine to a floating solar farm: A case study at Huainan, Anhui Province, China

Rising Energy Demand

Environmental Degradation

Climate Change

Anhui Province, located in eastern China, is one of the country's major coal-producing regions. As China transitions away from coal and many mines exhaust their resources, the region has been left with numerous closed and abandoned coal mines. The Huainan Coalfields is one such site. It consists of various coal mines, including the Dingji Mine, Zhangji Mine, Pansan Mine, etc (Figure 2). Following coal extraction, various coal mines within the Huainan Coalfields experienced significant ground subsidence and flooding, resulting in the formation of multiple lakes. In a transformative effort, Huaihe Energy, the company that owns the Huainan Coalfields, developed a series of floating solar farms atop one of the lakes. One of the biggest is the one in Dingji Village No.1 Floating Solar Farm (Figure 3). Spanning an area of 3.5km2, these panels at Dingji generate 221,096,000 kWh/year of clean energy that connect directly to the national grid. (Personal Interview, Huaihe Energy, 2025).

Read more about the floating solar farm on TIME.

Geographical boundaries of the Huainan Coalfields (Anhui is a Province; Huainan is a city in Anhui that host the Huainan Coal fields; The Huainan Coalfields has multiple coal mines, each located in different villages within Huainan)

Source: Health risk assessment of heavy metals in groundwater of coal mining area: A case study in Dingji coal mine, Huainan coalfield, China

The input and output of the floating solar panel

Currently, the floating solar farm at Dingji spans 5,300 mu (~353 hectares), consisting of 61 photovoltaic arrays and approximately 370,000 solar modules. The project required a capital investment of 18.4 billion RMB and is designed with a 25-year operational lifespan due to the limit of solar panel longevity.

Each year, the solar farm contributes to:

Saving approximately 1.65 million tons of standard coal
Reducing 4.29 million tons of carbon dioxide emissions
Delivering clean energy directly to the national power grid

The transition from coal mining to solar energy has brought significant structural and social benefits to the local economy:

The company has diversified from a single-sector coal enterprise to a multi-sector energy company integrating renewable energy.
Many former coal miners have been retrained and redeployed to work in solar energy, supporting over 1,300 local jobs.

Land Use Challenges at the Huainan Solar Farm

Under China’s “occupy and replenish balance” policy, any farmland lost to development—such as coal mining or solar installations—must be restored within the same year. This puts Huaihe Energy under significant annual pressure to meet farmland restoration targets.

To comply, the company often purchases farmland restoration credits from provinces like Ningxia, where land is more available but less fertile. This creates ecological and spatial mismatches, as Anhui’s productive farmland is offset by lower-yield land elsewhere, requiring larger areas to meet quotas.

Even when restoration happens locally, labor shortages pose a challenge. With fewer people returning to traditional farming, restored land risks being left uncultivated. Questions of how to use land more efficiently and how to engage a changing labor force remain unresolved.

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relevant Readings:

relevant Readings:

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