Reliability-based Sizing of Energy Storage for Systems with Very High Renewable Penetration

The share of electricity generated from renewable energy resources (RERs) is increasing steadily as jurisdictions around the world enact and enforce policies to fight climate change. While RERs generate cleaner electricity, they introduce new challenges to the reliability of the power grid due to the intermittent and non-dispatchable nature of the most prevalent RERs, namely wind and solar. Energy storage systems (ESSs) can be deployed to manage imbalances in the supply and demand of electricity resulting from high shares of intermittent RERs. This paper presents a framework to determine the size of ESS required to attain a desired level of reliability in a system where up to 80% of the installed capacity is composed of RERs. A probabilistic methodology involving Monte Carlo simulation is developed, which considers a wide range of scenarios involving forced outages of conventional generators and the uncertainty associated with RERs. Data-driven techniques are used to incorporate a large number of RER profiles into the proposed probabilistic framework. Several case studies are performed using the RTSGMLC test system to illustrate the ESS requirements of future power grids with very high penetration of renewable energy. Results indicate that large volumes of long duration ESS will be required for reliable power supply in future systems.