Evaluating the intensity, duration and frequency of flexible energy resources needed in a zero-emission, hydropower reliant power system

AbstractRapid increases in global temperature are motivating governments to restructure the energy sector towards emissions-free electricity generation. One of the key factors affecting the viability of emissions-free power systems is the joint variability of renewable resources and drivers of energy demand across spatiotemporal scales. This study evaluates the impact of multi-scale hydroclimatic variability on the reliability of a zero-emissions power system in a case study of New York State (NYS), which recently passed the Climate Leadership and Community Protection Act (CLCPA) requiring zero-emissions electricity generation by 2040. We first analyze covariation between renewable energy generation and energy demand, including large-scale hydropower generation on the Great Lakes, and develop a stochastic generator to simulate an ensemble of plausible realizations of this joint variability. Using a simplified energy balance model of the NYS power system, we then quantify resource gaps across spatiotemporal scales that emerge under load and generation scenarios projected under the CLCPA. We focus on the intensity, duration, and frequency of these gaps, which will have to be filled with carbon-free, dispatchable resources not prescribed under the CLCPA. We show that the covariability between load and wind can lead to major short-term resource gaps, which is exacerbated by transmission constraints. We also show that long-duration hydropower droughts increase the likelihood of co-occurring renewable resource deficits and extended periods (weeks to months) of energy shortage. We conclude by discussing the implications of these results on the need for alternative, carbon-free, and dispatchable resources to support zero emission, hydropower-reliant electric grids.