High proportion of renewable energy creates "energy storage heat"

"The power system is really hot about energy storage technology. I have attended four or five large-scale conferences this year, and it is estimated that there will be four or five in the second half of the year. Now the industry pays a lot of attention, and there is also a lot of investment attention." China Lai Xiaokang, director of the Institute of Electrical Engineering and New Materials of the Electric Power Research Institute, said at the 5th Global Distributed Energy and Energy Storage Summit held recently. Faced with the current phenomenon of "energy storage heat", Lai Xiaokang said that energy storage is indeed worthy of attention at present, but it is also necessary to realize that the energy storage industry has broken through the technical bottleneck and ushered in large-scale commercial applications. , but there is still a lot of work to be done in the future.

At this stage, energy storage is worth "hot"

In fact, the invention of energy storage technology has a history of more than 100 years, and it has not been applied on a large scale. In the 1970s, in conjunction with the operation of nuclear power plants and the dispatch of power grids, pumped hydro storage, a large-scale mechanical energy storage method, was developed and widely used. In addition, a large-scale energy storage technology has also been developed, namely compressed air energy storage, but so far only a small number of engineering projects. Experts say that the current "pursuit" of energy storage in the power system is worthy of attention around the world. So, why is it so hot during this period? The reporter learned from a number of industry experts that from the domestic situation, it is because the power system is now facing new challenges. So why didn't the power system need energy storage as urgently as it is now? Experts' point of view is that the "energy storage heat" is mainly due to the large number of renewable energy sources, and there is more demand. Lai Xiaokang said: "It turns out that our power system has been doing well without energy storage for more than 100 years. The load is random, but the power supply can follow, so we can survive without energy storage. The problem now is, I think the main problem is After the renewable energy is used as the main power source, the follow-up function of the power source is weakened, but a random quantity is added. If there is no energy storage at this time, the relationship between the loss balance of the power system will be broken, so if the power transmission and distribution in the power system With energy storage in all aspects, the power system will be more comfortable. If there is no energy storage in the case of a high proportion of renewable energy, it is difficult to imagine what the power system will be like." In recent years, my country's development has Energy storage has also gradually developed new trends, which are considered to be an important factor in fueling energy storage. For example, in June 2014, the "Energy Development Strategic Action Plan (2014~2020)" issued by the State Council clarified that large-capacity energy storage is one of the key innovation directions. Due to the abundance of renewable and clean energy such as wind energy and solar energy in China, my country's energy structure and environmental capacity require us to use renewable energy as much as possible. my country's development of renewable energy is full of motivation. In addition, my country is a big producer of renewable energy power generation equipment, has the ability to turn products into industries, and has a potential industrial chain. "Energy storage is in this industry chain. You have to produce a large number of wind turbines and photovoltaics, and use a large number of wind turbines and photovoltaics. Energy storage should be a part of the entire industry chain, so energy storage is indeed worthy of attention and deserves attention." Xiaokang said.

What are the functions of energy storage in renewable energy? In short, it is mainly reflected in access and consumption. In the transmission and consumption of large-scale centralized renewable energy power generation, the output of renewable energy power generation is smoothed, the forecast error of renewable energy power generation is reduced, the peak and frequency regulation capability of the system is improved, and the phenomenon of abandoned wind and light is reduced. In terms of promoting the flexible access and efficient utilization of distributed renewable energy power generation, the reliability of the distribution network should be improved, the power quality should be improved, peaks and valleys should be cut, and the access of distributed power sources should be supported.

So, what is the international situation of "energy storage heat"? Lai Xiaokang believes that the international energy storage is also developing rapidly around the development of renewable energy. "There are currently the most lithium-ion demonstration projects in the world, and the growth rate is the fastest. Therefore, I think the application field is mainly focused on renewable energy. In the selection of energy storage devices, the focus is on lithium-ion batteries. Of course, lead carbon There is also a place for battery energy storage in the energy storage grid, such as liquid flow.”

How to treat "energy storage heat" calmly

Lai Xiaokang believes that although energy storage is hot today, we need to see that no energy storage technology can cover all needs. Hu Xuehao, chief expert of the China Electric Power Research Institute, also agreed, "Although there are many types of energy storage technologies with different characteristics and performances, it can be said that there is no single technology that can cover various applications and meet various requirements. According to the time scale of the role of energy storage in the power system, energy storage technology is divided into: minutes below, minutes to hours, and hours above. Taking the energy storage section from minutes to hours as an example, what factors need to be considered when determining the quality of the device? Lai Xiaokang suggested the following: First, the application in the system must be scaled up, and the megawatt or even 100 megawatt level must be found. Too small will not play a big role in the power system, but also to ensure the safety of large-scale systems.

The second is to consider the technical level. The cycle life is 5000 times and above, and the efficiency is 80% and above.

The third is to consider the economy. When the power system is applied on a large scale, the energy storage device is not a necessity or must be chosen. It must be more economical than traditional devices and traditional technologies to deal with this problem.

Fourth, consider the form. What we need is batch and standardized production, and what we want is equipment, not engineering.

In addition, we hope that the unit cost of kilowatts and megawatts should not be too different. The characteristic of distributed energy promotion is that the scale benefit is not obvious. If the efficiency of energy storage devices can be improved at the 100-megawatt level and the cost can be reduced, it is not easy to use in distributed energy systems.

What we hope is that the multiplication factor of the kilowatt level used at home and the tens of megawatt level used in the demonstration project will be enough.

How to correctly view the current development stage of energy storage technology? Many experts have emphasized that economy is still the first. What needs to be seen is that some of the energy storage technologies currently mentioned are suitable for niche markets, but not necessarily suitable for scale. Lai Xiaokang believes that there is still a big gap between the current level of energy storage batteries and the expectation that they can be truly market-oriented. He reminds us to pay attention to several factors such as lifespan, efficiency, scale, safety, and cost. "These just show that energy storage is not something that can be achieved overnight. Therefore, despite the heat, we still think it is in the incubation period. In addition to pumped hydro storage, the global energy storage is only 840 megawatts, which is far from our needs. Although it is very hot, there is still a lot of work to be done in the future.” Here, experts reminded to cover the whole chain, recognize the shortcomings, and tackle key problems in a targeted manner. Relevant practitioners in my country should recognize their own shortcomings. One is the shortcomings in innovation, and the other is the shortcomings in high-end manufacturing. In addition, the goal of tackling key problems should be clear, and electric energy storage should focus on several possible elements such as long life, low cost, high safety, and high efficiency.