Energy Storage Science and Technology ›› 2020, Vol. 9 ›› Issue (3): 869-877.doi: 10.19799/j.cnki.2095-4239.2019.0255

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Engineering application of flywheel energy storage in power system

TU Weichao1, LI Wenyan1(), ZHANG Qiang2, Jia'ao WANG3   

  1. 1.Research Center for Advanced Flywheel Energy Storage Technology of North China Electric Power University, Beijing 102206, China
    2.BC New Energy Tianjin Co. Ltd, Tianjin 300300, China
    3.Northern Alberta Institute of Technology, Edmonton T5G 2R1, Alberta, Canada
  • Received:2019-11-11 Revised:2020-02-07 Online:2020-05-05 Published:2020-05-11
  • Contact: Wenyan LI E-mail:liweny@126.com

Abstract:

The statistical data at the end of 2018 shows that the new energy power generation is the second largest power generation form in China, but the inherent randomness and volatility of the new energy itself have brought challenges to the stability of the power grid, and the contribution of the new energy units to the peak load regulation and frequency modulation of the power grid can be ignored. One of the ways to deal with this challenge is to build a certain scale of grid level flexible regulation resources represented by flywheel energy storage. The engineering value of flywheel energy storage is reflected by typical application scenarios such as frequency modulation auxiliary service market. By tracking the progress of flywheel energy storage project in recent years, this paper introduces the main subsystem of flywheel energy storage technology and the technical route of major companies and research institutions, and concludes that the engineering application of flywheel energy storage in power system mainly includes grid frequency modulation, renewable energy consumption and micro grid support. When applied to grid frequency modulation, flywheel changes its output according to the area control error of the grid. When applied to renewable energy consumption, flywheel facility has different control modes. In the power output smoothing control mode, the flywheel energy storage facility shall smooth the varying real power output from renewable energy on a continuous basis. By comparing the instantaneous real power output of renewable energy to the average real power output of renewable energy obtained over a field adjustable time period, the flywheel will adjust its power demands to ensure that the average real power output of renewable energy is equal to the sum of the instantaneous real power output of the flywheel and renewable energy. In the dynamic reactive power support control mode, the flywheel energy storage facility shall inject appropriate amount of reactive power at the grid so that the grid reactive power flow nullifies the grid voltage change as a result of average real power injection by renewable energy. The flywheel provide dynamic power support by operating the facility in variable power factor control mode. Reactive power absorption is a continuous function of two variables, one is grid voltage level and another is total real power output from renewable energy and the flywheel. The installation of flywheel energy storage device can make up for the uncertainty of renewable energy generation. However, compared with the power battery energy storage technology, the bottleneck restricting the large-scale application of flywheel energy storage technology lies in the high initial investment cost, and the development direction of grid level flywheel energy storage technology should be higher cost performance, so as to obtain the market share.

Key words: flywheel energy storage, engineering application, secondary frequency regulation, reactive power compensation

CLC Number: