At present, the development of commercial energy storage technology presents a diversified pattern, and there are many types of technologies. There are as many as a dozen mainstream technologies that have demonstration applications around the world. Each technology has its own advantages and limitations, and its future development depends on whether it can find the application field suitable for the characteristics of the technology and deliver it at a reasonable price. Therefore, the coexistence and common development of multiple technologies will become a future trend.
At present, various large-scale energy storage technologies are still in the initial stage of industrialization in the world. It is shown that some leading companies in their respective technical fields have emerged, and they already have molded products and large-scale production capacity, but the cost is relatively high. These companies are mainly committed to participating in more demonstration projects and beginning to explore the road to commercial operation.
Among the various large-scale energy storage technologies that have been practically applied or verified by third-party tests, pumped storage and compressed air technologies are relatively mature and suitable for energy storage systems above 100MW; sodium-sulfur batteries, all-vanadium flow batteries, lithium Ion batteries, advanced lead-acid batteries, and flywheel energy storage have begun to be used in MW-level applications; and in applications of 100 kilowatts and below, most energy storage technologies can meet the demand. In power tools and electronic products, lithium-ion batteries, nickel-metal hydride batteries, and supercapacitors are widely used.
On the whole, as one of the key technologies of the Energy Internet, there are three challenges in the development of large-scale commercial energy storage systems:
1. Economic challenges of commercial energy storage
Economy will become a key issue in the selection of various technical genres, and high cost is a common challenge that restricts the popularization and application of various energy storage technologies at present. Because different applications have different requirements for product performance, life, and reliability, and also have different specifications for key materials, there are cost constraints. The complexity of the manufacturing process will increase the difficulty of cost reduction.
In addition, low energy conversion efficiency will increase the user’s operating cost and reduce the customer’s use value. Key materials, manufacturing processes and energy conversion efficiency are common challenges faced by various technologies, but for specific application scenarios, various technologies face different challenges.
2. Application challenges of commercial energy storage
The application of large-scale energy storage systems in power transmission and distribution systems includes rational planning of energy storage power sources, flexible connection technology between energy storage systems and existing power grids, advanced control and regulation technologies, and the combination of energy storage systems and renewable energy, etc.
The power industry has high requirements for product reliability. Traditionally, it takes at least 5 years of on-site reliability testing and trials to pass the minimum standards for power users. However, the existing energy storage system has a short application time in the power system, which leads to the finalization of the product before mass production. The cycle is long; and the design maturity and reliability of energy storage products are directly related to a certain scale. This situation in the power industry makes commercial energy storage technology industrialization a long road.
3. Policy mechanism challenges for commercial energy storage
Policies targeting energy storage are difficult. Since power generation, power transmission, power distribution, and power consumption can all benefit from the application of energy storage, there is no clear conclusion on which party the policy will introduce. In addition, different application scenarios will bring great differences in the benefits of the above parties, and the economic value of commercial energy storage is difficult to calculate.