Repurposing coal assets for a decarbonized digital economy

Coal has long driven the U.S. economy, but in recent years, competition from natural gas and renewable energy technologies have led to a rapid decline in U.S. coal production. In 2020, coal production hit a record low of 535 million short tons, the lowest since 1965, with 11 of the 14 top coal-producing states experiencing a decline in production of over 40% in the last decade. Kentucky’s coal production shrank by over 80% - the highest of any state. In line with that decline has been a downward employment trend in the industry; in fact, employment has more than halved in a decade. As the U.S. sets decarbonization targets in the power sector and across the economy, these transitions will accelerate.While these changes are driving significant economic and cultural shifts in many coal-producing communities, they also present new opportunities. Because coal mines have large-scale power supply and transmission systems, as well as other beneficial infrastructure, they can potentially be repurposed to support the transition to a post-coal economy. For example, a significant amount of land in Appalachia and the Interior basins has been cleared for reuse after coal mine closure. With proper planning and investment, these lands can be repurposed for a variety of applications, such as renewable energy development, data center development, agriculture, and recreation, among others. Such efforts would benefit both local communities and contribute to the country’s sustainable development goals, turning environmental liabilities into climate solutions and new economic drivers.Much reclaimed mine land is being targeted for renewable energy projects. The Environmental Protection Agency (EPA), through the RE-Powering America’s Land program, tracks hundreds of projects in the United States that installed renewable energy systems on current and formerly contaminated lands, landfills, and mine sites.1 Many mine sites already offer the power infrastructure necessary to transmit renewable energy to population centers. That infrastructure, along with mines’ many unique qualities, can make them excellent sites on which to develop various types of power storage, including pumped hydro, solid gravity, and compressed air energy storage.The digital economy is an economic driver drawing considerable interest. Data centers are the engines of the digital economy, and their development, powered by renewable energy, on former mine sites is a focus of this study. Mines offer reclaimed land and the electrical infrastructure to support data center needs. Cooling is often a data center’s second biggest electrical load, and significant quantities of water are used in the cooling process. Groundwater in mines and their adjacent aquifers offer an opportunity to save energy and water in data center cooling, providing a site-specific benefit not widely available at other sites. The ability to incorporate renewable energy into the project compounds the financial and climate benefits. Data centers use approximately 2% of our electricity and are a ready market for renewable energy. Moreover, data center waste heat can be recovered for activities such as indoor farming, further expanding community economic benefits and avoiding the carbon fuels that might otherwise be used for heating in those facilities.