As more renewable energy sources are integrated into the power system, additional reserves are required to ensure the functionality and reliability of the system. Conventional generators provide reserves by holding back some capacity so that they can ramp up or down to balance demand-supply mismatch. However, this can result in less efficient generator operation and increased air pollution. Distributed energy storage (DES), such as batteries, is a promising alternative to generators for providing such reserves because, in general, these resources are more responsive than conventional power plants and their costs are increasingly competitive. Due to their low emissions during operation, DES systems are often assumed to reduce environmental impacts. However, due to the complex nature of power systems and their operational strategies, the use of DES may lead to negative outcomes under certain system configurations, generation mixes, and reserve requirements. Thus, it is important to thoroughly evaluate the environmental impacts of introducing DES for reserves.
In this project, we propose a framework to integrate life cycle assessment (LCA) and power system dispatch algorithms to study the full environmental impacts of DES providing reserves. Fossil fuel combustion is expected to be a major contributor to life cycle environmental impacts; however, the relatively short product lifetime of DES indicate that the upstream and downstream impacts may also be substantial - hence the need for LCA to determine environmental performance. We first formulate and solve an optimal power flow (OPF) problem that includes DES capable of providing reserves. Then we develop and deploy a consequential LCA model to evaluate the life cycle environmental impacts of providing system reserves with DES. This LCA model uses the generator/DES dispatch results as determined by the OPF in the first step. We will use test cases to investigate the space of plausible environmental outcomes and isolate the key system drivers. The findings will help us understand the tradeoff between system operation costs and environmental benefits, informing system operators and policy makers.