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Techno-economic analysis of MJ class high temperature Superconducting Magnetic Energy Storage (SMES)systems applied to renewable power grids

Jiahui Zhu1, Chenghong Gu2,

Panpan Chen1Hongjie Zhang1 Jianwei Li2,

Huiming Zhang1, Ming Qiu1,

Weijia Yuan2 , lgnacio Hernando Gil2


1. China Electric Power Research Institute, Beijing 100192, China

2. Department of Electronic and Electrical Engineering, University of Bath,

United Kingdom


Abstract

High temperature Superconducting Magnetic Energy Storage (SMES) systems can exchange energy with substantial renewable power grids in a small period of time with very high efficiency. Because of this distinctive feature, they store the abundant wind power when the power network is congested and release the energy back to the system when there is no congestion. However, considering the cost and lifespan of SMES systems, there is an urgent demand to conduct a cost-benefit analysis to justify its role in smart grid development. This study explores application and performs economic analysis of a 5 MJ SMES in a practical renewable power system in China based on the PSCAD/EMTDC software. An optimal location of SMES in Zhangbei wind farm is presented using real power transmission parameters. The stabilities of the renewable power grid with and without SMES are discussed. In addition, a financial feasibility study is conducted by comparing the cost and the savings from wind power curtailment of deploying SMES and battery. The economic analysis tries to find the balance between SMES investment cost and wind farm operation cost by using real data over a calendar year. The technical analysis can help guide the optimal allocation of SMES for compensating power system instability with substantial wind power. Further, the economic analysis provides a useful indication of its practical application feasibility to fight the balance between cost and benefit.


Keywords

High temperature Superconducting Magnetic Energy Storage (SMES) system, Renewable energy, Smart grid, Allocation planning, Economic planning, Large-scale energy storage.


Introduction

  China is facing growing international pressures on the issues of climate change, greenhouse gas emission and limited energy resource because of its strong economic growth and the increasing demand for energy. It is important for China to speed up the utilization of renewable energy resource. As one of the most prospective sources of economical renewable energy, wind power can be used to solve the existing and potential environmental and energy shortage problems. In 2015, the additional wind power capacity of China is 30,753 MW which is 48.4% of the global scale and the total installed capacity has reached 33.4% worldwide [1-3]. Based on the accelerating growth of global wind power, Chinese Wind Energy Association (CWEA) thinks that the total installed capacity of China wind power will be 100 GW or more by the end of 2020 [4].

 

   However, we can find the variability of power output is a characteristic of wind energy, resulting in an adverse impact on the power system. Increasing the utilization of wind in power generation presents significant operational challenges in ensuring the grid security and power quality due to this inherent resource variability. In order to reduce the wind power impact over the power quality, high temperature SMES is applied to stabilize substantial power systems with integration of damping out low-frequency power oscillations, avoiding voltage sags and reducing the renewable curtailment. During rich wind period, some wind power has to be curtailed due to that the transmission network does not have sufficient transfer capacity or the receiving system cannot accommodate such amount of fluctuation power securely. SMES can store the abundant wind power when the network is congested and release it back to the system when there is no congestion. However, considering the cost and lifespan of SMES, there is an urgent demand to conduct a cost-beneficial analysis to justify its role in renewable energy generation.


   In this paper, an application planning of 5 MJ SMES is added in a practical renewable power system, Zhangbei wind farm. The operation of SMES is evaluated considering the wind turbine failure and the SMES location in Zhangbei wind farm power grid. In addition, a financial feasibility study is conducted by comparing the cost of deploying the SMES and BESS, and the savings from wind power curtailment. The economic analysis provides a useful indication of its practical application feasibility for compensating power system instability with substantial wind power.



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