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With the promotion of carbon peaking and carbon neutrality goals and the construction of renewable-dominated electric power systems, renewable energy will become the main power source of power systems in China. Therefore, ensuring frequency stability and system security will emerge as pivotal challenges in the future development process. Created by combining a Li-ion battery and a supercapacitor, a hybrid energy storage system (HESS), which possesses robust power regulation capabilities and rapid response capabilities, holds promise for supporting the frequency stability of power systems. In this context, the assessment of the economic viability of HESSs providing multitype frequency response services becomes a critical factor in their deployment and promotion. In this paper, an economic analysis approach for a Li-ion battery–supercapacitor HESS towards a multitype frequency response is presented. First, a multitype frequency response-oriented operational mode for the HESS is designed, outlining the roles and functions of the Li-ion battery and the supercapacitor in delivering distinct services. Moreover, building upon the analysis of the power trajectory of Li-ion batteries, a lifetime model for the HESS is proposed based on the rain-flow counting method. Furthermore, considering the competitive landscape for the HESS in the frequency regulation ancillary service market, a full lifecycle economic assessment model is proposed. Finally, case studies on actual power system frequency data and PJM market data are performed to verify the effectiveness of the proposed method, and the simulation results confirm that the HESS exhibits robust performance and a competitive advantage in providing multitype frequency response services. Additionally, it demonstrates commendable economic benefits, establishing its potential as a valuable contributor to frequency response services. [ABSTRACT FROM AUTHOR]

With the promotion of carbon peaking and carbon neutrality goals and the construction of renewable-dominated electric power systems, renewable energy will become the main power source of power systems in China. How to ensure the accommodation of renewable energy will also be the core issue in the future development process of renewable-dominated electric power systems. In this context, shared energy storage (SES), a novel business model combined with energy storage technologies and the sharing economy, has the potential to play an important role in renewable energy accommodation scenarios. This paper systematically organizes the application prospect, development status and key technologies of SES in the renewable energy accommodation scenario in the context of China, providing helpful references for the promotion of the business model. Firstly, a typical SES framework for renewable energy accommodation is described, and three basic forms of SES in this scenario are presented. Moreover, the application prospect of SES in the renewable energy accommodation scenario is quantitatively analyzed based on the renewable energy generation planning under the carbon peaking goal and the current guarantee mechanism of renewable energy accommodation. Furthermore, the rules for energy storage systems that provide the peak-regulation ancillary service in typical regions and provincial administrative regions in China are summarized, and the development status of SES in the renewable energy accommodation scenario is analyzed, combined with the actual market data. Finally, the key technologies to promote the further development of SES for renewable energy accommodation are presented. [ABSTRACT FROM AUTHOR]

Micro-grids have been developed for over two decades as building blocks for future smart grids. Micro-grids have appeared with the advantages such as control flexibility, easy connection of renewable resources, high efficiency and immunity to large area blackouts. Similar to other countries, development of micro-grids in China has gone through from the early stage of AC microgrids to the current varieties of AC, DC and hybrid AC/DC micro-girds based on their applications. Many technical problems have been solved and new problems are continuously appeared during the development process. This paper presents a past, today and future for development of micro-grids in China. The current status of micro-grids and renewable energy sources in China is presented first. The topologies of the micro-grids in China are then introduced and classified into three types. Different control techniques of the micro-grids are introduced. Finally, technical challenges and future prospect of micro-grids in China are discussed. [ABSTRACT FROM AUTHOR]

Offshore wind energy has been widely exploited as a promising renewable energy source in China in recent years. This renewable source's high curtailment rate due to strict wind energy penetration limits, however, remains a challenge of concern. Also, the difference between peak and valley loads of electric power systems continues to increase with economic and societal development. To address these issues, this study proposes a hybrid system composed of a high-capacity offshore wind farm coupled with a pumped hydrostorage (PHS) power system to absorb rejected wind power. The hydraulic energy stored by PHS system is expected to provide guaranteed energy during peak load demands on the main power grid. This study presents a multiobjective technoeconomic assessment model based on the principle of dynamic economy for optimizing the size of the PHS system. The conclusions can be summarized as follows: (1) the seasonal characteristics affect the utilization of wind energy; (2) PHS operating strategies have an influence on the PHS configuration, energy utilization, and economic benefit; (3) reducing the wind curtailment is the key to improve the system performance and economic feasibility; (4) the drop in water level has a negative effect on economic benefit and (5) provides clear guidance to set external financial parameters for a hybrid power station. The results show that a size-optimizing study is important in determining the system's economic feasibility and predicted performance. [ABSTRACT FROM AUTHOR]

Depletion of fossil fuel deposits is the main current issue related to the world's power generation. Renewable energy sources integrated with energy efficiency represent an effective solution. The electrification of end-use coupled with renewable power generation integration is considered as an important tool to achieve these tasks. However, the current electric power system does not currently have the suitable features to allow this change. Therefore, in the future, it has to allow two-way direction power flows, communication, and automated controls to fully manage the system and customers. The resulting system is defined as the smart grid. This article analyses the smart grid state of play within China, the US, and the EU, assessing the completion state of each smart grid technology and integrated asset. The analysis related to these countries presented here shows that the smart grid overall state of play in China, the US, and the EU are equal to 18%, 15%, and 13%, respectively, unveiling the need related to further efforts and investments in these countries for the full smart grid development. [ABSTRACT FROM AUTHOR]