Coal Belt to Sun Belt : using former mine-mouth coal plants for utility-scale solar photovoltaic generation in ERCOT

Market changes in the Texas electric grid have forced the retirement of coal-fired generation in ERCOT. Low wholesale power prices, cheap and abundant natural gas, and increased renewable energy generation have made coal generation no longer profitable. This retirement of the coal-fired power plants in ERCOT and the closure of their adjacent mines abandon significant public investment in transmission infrastructure. Siting a new solar farm on former mine land could responsibly reuse the public investment in existing power infrastructure while offering a range of additional benefits to the grid and to rural East Texas. This paper explores the viability of repurposing a portion of the Monticello Winfield Mine in East Texas to install a utility-scale solar photovoltaic plant. The viability of solar for this site was evaluated in two parts. The EPA RE-Powering America’s Land Initiative Solar Photovoltaic Decision Tree was used as an initial screening tool to identify the appropriate site characteristics. The NREL System Advisor Model (SAM) used hourly weather data and financial metrics to demonstrate solar performance and project value across different sized installations. Results indicate that the site could be favorable for solar vii generation based on the land availability, sufficient insolation, and accessible transmission infrastructure. The SAM model estimated generation from a range of capacity sizes using an industry standard module and inverter and cost estimates using the latest information from NREL. These results indicated that solar PV could be a valuable investment. Additional benefits not captured in the model may include avoided costs of transmission as well as avoided opposition to greenfield energy projects. Further analysis could explore alternate financial structures like property tax incentives for renewable generation, the broader grid benefits offered by solar generation, or the ability of these sites to serve regional sustainable development goals.Energy and Earth ResourcesPublic Affair