Storage Options and Sizing for Utility Scale Integration of Wind Energy Plants

Electric energy storage has been discussed as an option for increasing the marketability of wind energy facilities by reducing output variation. Utility scale wind plants face economic exposure to tariff charges for output variation as well as depending on volatile market prices for success. Wind speed variability and associated changes in wind plant output raise specific challenges to design engineers sizing electric energy storage systems. Evaluation of prospective Wind/Storage applications depends on the characteristics of individual wind plant output and the choice of storage technology. Energy storage options range from traditional lead acid batteries and pumped hydro storage to recently commercialized electrochemical flow battery systems. Selection and sizing of energy storage for wind plants vary with the time frame for each application. Different time frames correspond with the utility definitions of regulation, load shaping and load factoring. Results from a storage system model are presented that differentiate appropriate storage system sizes for these applications.