Microgrid Schematic Structures and Project Examples

Microgrids represent a revolutionary step in the management and distribution of electricity, especially in the context of the new energy industry. These systems not only enhance the reliability and security of energy supply but also integrate various forms of renewable energy sources into the grid. A key component in the successful operation of microgrids is the application of electrochemical energy storage technology.

Industry Brief: Electrochemical Energy Storage Technology in Microgrids

According to Cheng Qiang from the New Energy Design Institute, the cumulative installed capacity of the global electrochemical energy storage market reached 9,520.5MW in 2019, marking a 43.7% increase compared to the previous year. While growth rates have shown signs of moderation, the market continues to develop in a structured and orderly manner. China, in particular, has shown a significant year-on-year increase of 59.4% in its cumulative installed capacity of electrochemical energy storage, highlighting the country's commitment to this technology.

Electrochemical energy storage systems serve as the backbone for various microgrid applications, whether in public buildings, residential complexes, factories, or distributed energy resources. These storage solutions are crucial for balancing the load and ensuring the smooth integration of renewable energy sources, like wind and solar, with the public grid.

Schematic Structures of Microgrids

Microgrids are composed of a complex network of energy sources, storage systems, and distribution mechanisms. The schematic structure of a microgrid often includes renewable energy generators (such as solar panels and wind turbines), energy storage systems (like batteries or flywheel storage), inverters, and power control systems (PCS). These components work in tandem to ensure that the energy produced is stored and distributed efficiently, reliably, and safely.

Energy Storage's Balancing Role

The energy storage system plays a pivotal role in maintaining the balance of the microgrid by absorbing excess energy during low demand periods and releasing it during peak demand times. This capability is essential for the overall flexible operation of the microgrid, ensuring that fluctuations in energy production from renewable sources do not impact the grid's stability.

Project Examples

International and Domestic Microgrid Projects

Some notable microgrid projects that incorporate energy storage systems include:

The Integrated Microgrid Test System in Zhejiang, China, which combines wind power, photovoltaic, a double-fed induction generator, diesel generator, and flywheel energy storage.

The Tianjin University Microgrid Test Bench, which uses an all-vanadium flow battery and flywheel energy storage alongside photovoltaics, wind power, and a proton exchange membrane fuel cell system.

The Santa Rita Prison Microgrid in San Francisco, powered by lithium batteries and including photovoltaics, fuel cells, and diesel generators.

The Milford Microgrid in the USA, which utilizes photovoltaic, a gas turbine, and a diesel generator.

South Korea's Microgrid Pilot Plant, which includes photovoltaic, wind power, wind-solar hybrid systems, and diesel generators.

These projects highlight the versatility and adaptability of microgrid systems to different environments and energy needs, demonstrating the feasibility and benefits of integrating storage technologies into such networks.

Case Study: An Island Microgrid Project

Islands often face unique challenges in terms of energy provision, with traditional solutions presenting issues such as environmental impact, high costs, and supply instability. A typical case study involves an island microgrid project that addresses these challenges through a combination of photovoltaic systems, energy storage, and diesel generators.

The project features off-grid and grid-connected microgrid architectures for different islands, with varying capacities of photovoltaic systems and energy storage solutions tailored to each location's needs. The benefits of such a project are multifaceted, promoting industry development, efficient clean energy use, low investment, and maintenance costs, as well as reliable electric energy supply.

Case Study: Microgrid in Lianyungang Village

In Lianyungang Village, a microgrid project was initiated to explore new energy service models. The project implemented an "integrated light, wind, and storage" energy system, achieving 100% user energy storage resource access. This comprehensive energy platform allows for diversified electricity consumption and supports emerging energy consumption forms such as smart homes and electric vehicles.

The project's microgrid system operates with an emphasis on green efficiency and smart electricity usage, with the added benefit of reducing energy costs through wind and solar charging and storage integration. It also facilitates vehicle-grid interaction through electric vehicle charging and discharging, as well as promoting local consumption through household energy storage.

Case Study: Highway Toll Station Microgrid Project

A 2019 project at a highway toll station implemented a microgrid system with 90kWp photovoltaic capacity and 65kWh energy storage. This project serves as a testament to the potential of integrated optical storage and highly integrated systems for promoting local consumption of photovoltaic power generation, even in small-scale, specific applications like toll stations.

Future Prospects

Looking ahead, the future of microgrids and electrochemical energy storage is promising, supported by policy initiatives and technological advancements. Renewable energy generation, particularly distributed generation and microgrids, is poised for rapid development, offering a practical means to harness renewable resources comprehensively and efficiently.

Technological Advancements and Policy Support

The integration of intermittent renewable energy sources into microgrids can lead to power quality challenges. However, advancements in energy storage technology stand as a crucial means to achieve energy balance and ensure the normal operation of microgrids. Continued research and development in key energy storage technologies, paired with robust policy frameworks, will be integral to the industry's growth.

Business Models and Market Development

As the sector evolves, there is an increasing need to explore economically and technically viable business models. These models should be supported by policies that encourage the application of energy storage technology and the development of microgrids. China's State Grid and Southern Power Grid have issued "Guiding Opinions on Promoting the Healthy and Orderly Development of Electrochemical Energy Storage," highlighting the strategic direction and supportive stance of major players in the industry.

Conclusion

Microgrid schematic structures and the integration of electrochemical energy storage technology are at the forefront of the new energy industry's evolution. Through innovative projects and supportive policies, microgrids are becoming increasingly vital in achieving energy sustainability, resilience, and efficiency. With a continued focus on technological innovation and market development, the potential for microgrids to revolutionize the energy landscape is immense.