Frequency Control Support in Low Inertia Power Grid by Energy Storage Systems: A Techno-Economic Analysis

Abstract

The road towards decarbonization and production of sustainable and cheap electricity relies on the use of renewable energy sources such as solar and wind. However, such converter-based plants do not contribute kinetic energy to the system, and so substitution of traditional plants with renewables causes the system kinetic energy to drop, making the grid more unstable and vulnerable to disturbances which in turn increases the use and dependability on frequency containment reserves. Hence the need for increased power requirement and higher ramp rates from the reserves would result in an exponential increase in cost for availing of such services. A solution to mitigate imbalances in grid system power could be found through the utilization of energy storage systems (ESS). The ESS can provide faster and higher power support while keeping the cost comparatively low at high power requirements. A novel research was conducted on a modified N ordic-32 Test system using PSS®E simulation software where various solar PV plants and wind turbines were placed according to Nordic development plans to simulate the future Nordic grid with different levels of renewable energy penetration (REP) and estimate the amount of frequency containment reserve for disturbance (FCR-D) required for N-1 contingency disturbance and compare the overall cost of FCR-D using traditional sources and ESS using Lithium-ion and Vanadium Redox flow b atteries. The results showed the performance of the ESS for frequency regulation was better compared to conventional hydro turbines, showing smaller initial system frequency dip and flexible power r amp-up r ates as required at different REP levels. The overall cost of FCR-D services was reduced by 40% or more when FCR-D services were provided by a combined contribution from traditional sources and ESS when compared to traditional sources alone.