Impacts of Summer Drought and Climate Change Conditions on Hydropower Resources and Power System Reliability in the PJM Region

The United States power grid is a large, complex, and interconnected system that involves the coordination of numerous entities (e.g., power plant owners/operators, regulators, stakeholders, etc.). As such, any type of extreme event can potentially threaten the economic, safe, and reliable operation of the grid. One such example is summer drought (i.e., events predominantly characterized by elevated temperatures and reduced precipitation), which have impacts spanning all aspects of the power system, especially generation resources through changes in water availability and temperature. Additionally, although heavily dependent on region, climate change can potentially increase the likelihood and severity of drought conditions, illustrating the necessity for understanding the potential impacts of droughts within a climate change context. Accordingly, our analysis investigated the impacts of nine drought and climate change conditions on hydropower plants in the PJM region as of 2030, relative to a historical baseline, using the Hydrologic and Water Quality System (commonly referred to as HAWQS). We found that the historical drought of 2007 was the worst-case scenario in terms of overall generation reduction, followed by proposed 2030 moderate and severe climate change drought conditions, respectively. Because the most similar technology to hydropower is natural gas combustion turbines (in terms of ancillary grid services), replacement of lost generation can induce significant economic consequences for the region's electricity producers and consumers alike. Furthermore, impacts also affect broader grid reliability via reduced generation capacity available to satisfy electricity demand | this was found to not be an issue in the forecasted 2030 PJM generation set, but if coal plant retirement is accelerated beyond current plans, then an inability to satisfy peak demand becomes apparent across most scenarios post 50% retirement.