Assessing Vulnerability of Electricity Generation Under Potential Future Droughts

Abstract:

In the past few decades, the western US experienced increased sever, frequent, and prolonged droughts resulting in significant water availability issues, which raised questions as to how electricity sector might be vulnerable to future droughts. To improve our understanding of potential risks of electricity generation curtailment due to drought, an impact analysis was performed with a series of modeling tools including climate downscaling, competitive water-use calculator, hydrologic model for various hydrologic processes, and power-plant specific models. This presentation will demonstrate the predicted effects of potential droughts on power generation at a local level of the USGS 8-digit watersheds and individual power plants within the context of current and future characteristics of power system and water resource system.

The study identified three potential drought scenarios based on historical drought records and projected climate changes from the GFDL and the PCM global climate models, for greenhouse gas emission scenarios A1B, A2, and B1 defined by the IPCC. The potential impacts under these three drought scenarios were evaluated with a hydrologic model constructed for the Pacific Northwest River Basin and California River Basin. The hydrologic model incorporates competitive water uses, climate forcing data corresponding to each of drought scenarios, and all major reservoirs that are currently supporting water withdrawal for various sectors and hydroelectric power generation. The hydrologic responses to drought scenarios predicted for each of the USGS 8-digit watersheds and reservoirs are used as input to power-plant specific models to quantify potential risk of curtailment at each power plant. The key findings from this study will help to improve understanding of spatial distribution of vulnerable power plants and watersheds as well as the scale of potential reduction of electricity generation under various drought scenarios. Beyond impacts to the existing fleet of power plants, the results also provide insights to the sitting of future power plants to support the long-term transmission planning.