A battery energy management strategy for UK enhanced frequency response

Abstract

Balancing the grid at 50 Hz requires managing many distributed generation sources against a varying load, which is becoming an increasingly challenging task due to the increased penetration of renewable energy sources such as wind and solar and loss of traditional generation which provide inertia to the system. In the UK, various frequency support services are available, which are developed to provide a real-time response to changes in the grid frequency. The National Grid (NG)the main distribution network operator in the UKhave introduced a new and fast service called the Enhanced Frequency Response (EFR), which requires a response time of under one second. A battery energy storage system (BESS) is a suitable candidate for delivering such service. Therefore, in this paper a control algorithm is developed to provide a charge/discharge power output with respect to deviations in the grid frequency and the ramp-rate limits imposed by the NG, whilst managing the state-of-charge (SOC) of the BESS for an optimised utilisation of the available stored energy. Simulation results on a 2 MW/1 MWh lithiumtitanate BESS are provided to verify the proposed algorithm based on the control of an experimentally validated battery model.

Scheduling of grid‐tied battery energy storage system participating in frequency response services and energy arbitrage

“…To overcome these issues, balancing markets have been introduced and utilised to ensure the security of grid frequency regulation with a minimal cost model based on the electricity market tendering schemes [11]. The National Grid Electricity Transmission (NGET), the main distribution network operator in the UK, has introduced various frequency response products, such as Firm Frequency Response (FFR) and a new fast frequency response, called Enhanced Frequency Response (EFR), with the aim of maintaining the system frequency within limits to 50 Hz under normal operation [12]- [13]. For providing such services to the grid, the BESS is well suited due to its ability to rapidly respond to import/export demands.…”

“…Using UK historical electricity pricing data [40], the proposed SOC management strategy selects the appropriate battery SOC profile to maximise the arbitrage revenue whilst delivering the EFR service. Detailed analysis of the EFR service design control algorithm and the NGET service requirements can be found in [12]- [13]. For the DFFR and SFFR services, considering the electricity price discrepancy during the day, the proposed arbitrage control algorithm selects the appropriate frequency balancing services considering the grid frequency conditions of the day and the time to maximize arbitrage.…”

Battery SOC management strategy for enhanced frequency response and day-ahead energy scheduling of BESS for energy arbitrage

“…Global electricity demand is forecasted to increase by 3.1% annually from 2010 to 2050 [1][2]. The UK electricity consumption in 2015 was 303 TWh [3].…”

“…Furthermore, ESS can increase power quality and reliability, meeting demand during peak hours, facilitating control of energy imbalance charges and reducing losses [7]. There are numerous ESS technologies such as fuel cells, compressed air, pumped hydro, hydrogen, flywheel, cryogenic, and superconducting magnetic storage technologies [1,5,9]. Development of improved battery technologies and decreasing costs make the application of Battery ESS (BESS) a favourable solution for grid application.…”

“…Large scale BESS can provide numerous market benefits such as frequency regulation, electricity arbitrage, ancillary services and reserve services [10,11,15]. BESSs having different battery chemistries have been installed around the world for power grid support [1].…”