Can air also store electricity?

Author:Institute of Physics of the Ch Time:2022.06.22

Development of compressed air storage and application of compressed air storage

It is our dream, our mission,

It is also our responsibility.

Chen Haisheng · Researcher at the Institute of Engineering Thermal Physics of the Chinese Academy of Sciences

Gezhi Tao Tao 80 | April 23, 2022 Beijing

I am very glad to come to the Gezhi Tao forum. I am Chen Haisheng from the Institute of Engineering The Institute of Engineering of the Chinese Academy of Sciences. The topic I shared with you today is "The" Charging Treasure "on the grid".

Why is energy storage research so important?

Before talking about air charging treasure, let's talk about energy.

The first industrial revolution: the steam era (left)

Second Industrial Revolution: Electrical Age (Middle)

The Third Industrial Revolution: Electronic Information Age (right)

We all know that energy is the food of the industry, and every energy change is accompanied by an industrial revolution. The widespread use of coal has enabled humans to experience the era of steam; widespread use of oil and gas and electricity leads to human beings into the electrical era. Humans are now experiencing the third industrial revolution, which is what we usually call the era of electronic informatization. The main characteristic of its energy change is that renewable energy has gradually replaced stone energy sources and has become the main energy source.

In addition to close connection with industry, energy is also closely related to our daily life. my country's "dual carbon" goal strives to achieve carbon peaks by 2030 and carbon neutrality before 2060. Its main means is to increase the proportion of renewable energy to replace fossil energy. Our goal is: in 2025, the proportion of renewable energy power generation machines will exceed 50%, and the proportion of energy consumption of non -fossil energy in 2060 will reach 80%.

Wind power generation (left) and solar photovoltaic power generation (right)

Picture source: Xinhuanet

However, compared with renewable energy and fossil energy, there is a distinctive characteristic, or the disadvantage, that is, its uncontrollable -we usually talk about "eating by the sky". Specifically, intermittent, volatility and periodic. The so -called intermittentity refers to sometimes there are or sometimes no; the so -called volatility is sometimes unstable; and periodicity refers to the changes in time and season, such as during the day and at night, and periodic fluctuations. Essence

What are the consequences or effects of this irresistivated? Let's take a look at the operating mode of the traditional power system.

Through the grid scheduling, the load balance is achieved

After the traditional power system is sent out of the power plant, it can reach the user by losing and distributing. The load of the user end is uncontrollable, and the power generation side is controllable. The power system can control the power grid by controlling the power grid by controlling the power of the power supply side to achieve the purpose of achieving dynamic balance.

Through energy storage, the load balance is achieved

With the large -scale development of renewable energy sources, the power generation side and user side of the power system have a large amount of uncontrollable renewable energy sources, which has a great impact on the stable operation, control and security of the power grid, and even caused, and even causing it Many of the electricity that cannot be accessing the Internet is what we usually call the wind and light. So how to solve this problem? Fundamental energy storage is necessary to achieve balance.

It's like a water supply system: the water inlet pipe is unstable, and the water outlet pipe is also unstable. Then a pool is required to ensure the stable operation of the entire system. In the power system, the pool it needs is energy storage.

Ultimate scientific issue: What is the future of energy storage?

According to predictions, in the future, the proportion of energy storage capacity will reach 10%-15%in the power system mainly renewable energy. Because of the major strategic needs of energy storage, it is listed as one of the 125 ultimate scientific issues facing the "Science". At the same time, it is also the key support technology of the third industrial revolution and the strategic emerging industry of the country.

Upper (physical energy storage): pumping energy storage, compressed air storage, flywheel energy storage, heat storage and cold (chemical energy storage): lead -acid battery, lithium ion battery, sodium battery, liquid flow battery

At present, existing energy storage technology can be divided into two categories: one is physical energy storage, including pumping energy storage, compressed air, heat storage and flywheel, etc.; We often use lead -acid batteries, lithium batteries, sodium batteries and liquid flow batteries.

Different energy storage technologies have different performance characteristics. From the left figure, it can be seen that the storage time and power of different energy storage methods have their own applicable characteristics. At the same time, the demand for energy storage for the entire power grid can be seen from the right figure, which means that there are different performance requirements for energy storage.

If we put these two pictures together, we will find that different energy storage technologies have different application scenarios. The air charging treasure we mentioned today, that is, compressed air energy storage. It is a more suitable for large -scale and long -term energy storage technology in the upper right corner of this picture.

Why do I choose to compress the energy storage energy as my own research direction? The main thing is that compressed air storage has excellent performance. Its large scale, long life, and the cycle of energy storage are not limited, construction and operating costs are low. Secondly, the disciplines involved in the compressed energy storage mainly include power engineering and engineering thermal physics, which is exactly the mainstream discipline of the Institute of Engineering Thermal Physics. Moreover, compressor, expansion, heat storage and heat exchange, and engineering thermodynamics involved in the compressed energy storage energy, I have a corresponding research basis.

There is another reason. When I started researching compressed air energy storage in 2004, the country was basically in a blank state. Because the proportion of renewable energy at that time was very low, only zero. Many old gentlemen who care about me have also reminded me: "Go in 4 degrees of electricity, come out 3 degrees of electricity, Haisheng thinks about it, this research direction is right."

However, considering that since renewable energy is our development trend, energy storage will definitely have a big development prospect in the future, and I insist on it. Looking back now, being able to combine your research interests, work, and innovative directions with development prospects is really a kind of luck.

What are the problems with traditional compressed air storage energy?

Completed: 30%///////////

So what exactly is compressed air storage?

People are equivalent to compressors, balloons are equivalent to gas storage rooms, windmills are equivalent to expander

In fact, its basic principle is very simple, that is, when using the compressor to compress the air into high -voltage air when using the compressor, we are as blowing in the gas storage device, as shown in the balloon in the figure; During the peak, the high -voltage air was released to drive the expansion machine. Similar to the windmill of the windmill, we can drive the generator to generate electricity.

Our ancestors used before 1000

We do basic research first to read the literature first, and check what the predecessors did. We were surprised to find that our ancestors used compressed air storage 1,000 years ago. The Song Dynasty's "Zhu Ziyu" records the operation of our drums (Bài, a type of skin) for the ironmaking furnace. In fact, this is the earliest compressed air storage energy in the world, and it can drive with water. This is renewable energy and energy storage, which is the most cutting -edge and hottest research direction now!

The first compressed air storage technology patent

The first modern compressed air energy storage patent was applied in 1943 and was authorized in 1948.

German Huntorf Power Station: The first commercial operation of modern compressed air storage power stations

The first commercially operated modern compressed air storage power station was Germany the Huntorf Power Station in 1978. When using the electric trough, it is stored in the storage cave through the compressor; when the electricity is used, the high -voltage air is released and the high -voltage and high -temperature air generated by the fuel combustion drive the expansion machine to generate electricity together. From its completion to the present, the Huntorf Power Station has been running for more than 40 years. It still has good results, very stable, and strong reliability.

However, this traditional compressed air storage has found problems during the promotion: first, it depends on geographical conditions; second, it depends on fossil fuel; third, the system's efficiency is relatively low.

There are three main reasons. One is that the compression heat generated by air during compression is not recovered. We have this feeling in our lives: when the cylinder is gossip with a cylinder, the cylinder will heat up. This is compression heat, and the traditional air energy storage system does not recover compressed heat. Secondly, the energy storage density of air is relatively low, so large -scale gas storage devices are required. Third, the system processes such as compression and expansion are independent of each other, making its overall efficiency is not high.

Advanced compressed air storage overall idea

So, how to solve these problems? Our overall idea is to solve these three problems by compressed heat recovery, high pressure of gas or liquefied high -density storage, as well as high -efficiency processes and coupling matching.

Specifically, in the process of air compression, we switch and recycled the compressor's compressor through the heat exchanger, and then stored in the heat storage device. During the power generation, the expander recovers calories through the heat storage device to get rid of the dependence on fossil fuel.

Secondly, through the pressure container spherical tank or liquid dharma jar and other gas storage devices to get rid of the dependence on geographical conditions. Finally, the efficiency of a single process is improved by efficient compression and expansion, heat release, and heating. At the same time, in the process of compression and expansion, heat storage and heat release, try to match the parameters of these two systems as possible, that is, the red line and green line in the upper right picture are close, so that its loss is more loser more Small and more efficient.

Based on these three technologies, we have designed advanced compressed air storage. Its working principle is to compress the air and store the air in the gas storage device during the electricity period, and recover its compressed heat at the same time; release the high -voltage air when the power consumption is used to recover the storage heat, and finally achieve the high temperature and high pressure with high temperature and high pressure. The air -driven swelling machine is generated.

From theory to design and manufacturing

Completed: 50%///////////

The above is just the idea of advanced compression of air energy storage. If you want to turn this idea into a prototype or prototype, there are many challenges: First of all, our theoretical analysis is often a single discipline, and the prototype is often multi -disciplinary; Second, theoretical analysis can be made in practice as long as the theory is feasible, and the prototype must be manufactured in practice.

Take the expansion machine as an example. We first carried out basic research on aerodynamic dynamics, studied the detailed streaming vortex structure, secondary flow and leakage flow, and obtained its loss mechanism on this basis and obtained the corresponding relationship.

Pneumatic design (left), strength design (middle), structural design (right)

Then, we applied the results of basic research into the design software, and carried out pneumatic design, strength design and structural design to complete its component design.

Component processing

On the basis of component design, we will process, assemble, and test the components, and finally form the assembly system of the expander.

Total assembly integration

This is our system of 10MW (Muwa) swelling machine. The entire system has more than 4,000 components, of which 40%are universal and 60%are non -standard parts. Since we are the first related research, these non -standard parts need to be designed, processed and manufactured independently.

In this way, we have realized the entire leap from mechanism research to part design, to sample machine integration.

From 1 kilowatt to 100 MW.

Completed: 60%///////////

However, in order to achieve compressed air storage applications, it is necessary to change from the components of the laboratory, the laboratory prototype to the project demonstration, which brings more challenges.

First of all, its complexity must be transformed from the level of the component level to the system level; second, it is necessary to realize the transformation from the operating machine in the laboratory to the engineering demonstration, or the change of each time As long as it can be created in the room, it is necessary to consider the use of engineering demonstrations, that is, its economy, and to achieve this third change.

In order to realize the transformation from laboratory prototypes to engineering demonstration, we have adopted a strategy of gradually enlarging and steadily improved. We walked from one victory to another.

1KW compressed air energy storage system

In 2010, Zhongguancun, 5㎡

This is a 1 -kilowatt compressed air energy storage system built in Zhongguancun in 2010. It mainly conducts conceptual verification and system analysis. Its area is 15 square meters.

15KW compressed air energy storage system

In 2011, Zhongguancun, 70㎡

On this basis, we completed the 15 -kilowatt compressed air storage system in Zhongguancun in 2011. The main development of basic research and design is carried out. We can see that it covers an area of about 70 square meters.

1.5MW Advanced Compressed Air Storage Energy Demonstration System

In 2013, Langfang, Hebei, 400㎡

With the support of my country's 863 project and other projects, in 2013, we built the first international set of 1.5 MW advanced compressed air energy storage projects in Langfang, Hebei. Essence

10MW Advanced compressed air storage energy demonstration system

In 2016, Guizhou Bijie, 1500㎡

In 2016, with the support of the National 973 project, the National Development and Reform Commission, and the National Energy Administration, we built the first international set of 10 MW advanced compressed air energy storage system in Bijie, Guizhou, with system efficiency of 60.2%.

From the above video, we can see that this 10 MW system includes devices such as multi -stage compressor, compressed motor, heat storage, heat exchanger, generator, expander and other devices. It also includes the control system, auxiliary system, electrical control system, and the entire central control room. The system has now run for more than 4,000 hours.

100MW Advanced compressed air storage energy demonstration system

In 2021, Zhangjiakou, Hebei, 6000㎡

On this basis, at the end of 2021, we built the first 100 MW advanced compressed air energy storage system in Zhangjiakou, Hebei. This is a bird's -eye view of the entire demonstration project.

Main factory (left) Central Control Room (right)

This is the main factory building and central control room that has been completed.

Many touching stories emerged during the entire construction process. Zhangjiakou is a well -known wind farm far away, mainly because of the wind in this place, and our entire construction is in winter. The minimum temperature in Zhangjiakou can reach minus 25 degrees in winter, but due to the large wind, the physical temperature can reach minus 40 degrees.

We see that the photo on the left is inside the plant, snow at the door, and the right side is the process of working overtime at night. Since we often move the equipment and have no time to close the factory door, the snow is blowing in, and the conditions at that time were still very difficult. Under such difficult conditions, in the winter of 2021, more than 20 people in our team had a business trip in Zhangjiakou for more than 90 days. It was really touching, and it did reflect the mission of science and technology workers and their feelings.

This photo is 10:46 pm on December 31, 2021. After the entire project was successfully connected to the grid to send electricity, everyone took a group photo. This lady in the middle of the "C position" is our test engineer Fu Wenxiu. She is also a mother of more than 1 year old. Everyone kindly calls her Xiu Xiu.

In order to realize our on -time grid, grab the grid to send power and power debugging by the end of 2021, and she insisted on working for 103 days, so when everyone celebrated the group photo, she resolutely asked her to stand in the middle. After I came back, I asked her: Xiu Xiu, hard work? She said: It is really heavy and stressed, but the moment I realized the grid -connected telegram, I was really excited. This sense of happiness and accomplishment was not what ordinary people could understand.

"Long March" about compressing air storage

Completed: 80%///////////

Compared to 10 MW, the efficiency of 100 MW systems will increase by 10%, an increase of a magnitude (10 times), and the cost will decrease by 30%. Its performance indicators are better than the compressed air energy storage system of the same scale.

Now there have been six demonstration projects for compressed air storage capacity, and there are more than 20 sets of construction and planning.

In the future, we need to do three things well: first, the promotion and application of existing technology; the other is the larger -scale system development, such as 300 MW systems; the third is to continuously develop new compressed air energy storage technology and continuously improve Efficiency and other performance.

It is believed that with the large -scale development of renewable energy and energy storage technology, renewable energy will experience renewable energy subsidies, renewable energy parity, and then renewable energy+energy storage and affordable. Only when renewable energy + energy storage achieves parity, the era of renewable energy of human beings will really come.

From 1934 to 1936, the Chinese Workers and Peasants Red Army experienced a long march of 25,000 miles, which was a major turning point for the victory of the Chinese revolution. Then this picture shows the Long March of our team on compressing the energy storage of air. Over the past 18 years, our team has always adhered to the ideal, concentration, persistence, and innovation policy. Whether it is technical or funding, we have always adhered to and worked hard, and realized that from basic research to key technologies to integrated demonstrations to then re -to -integrated demonstration to then re -to -integrated demonstration. The leap of industrialization has also achieved a leap from a kilowatt -meter to MW level to a hundred MW. Whether it is the dissertation, patent, or system performance indicators, we have reached the international leading level. Recently, our 100 MW compressed air storage energy has also realized industrialization through technology.

It is our dream, our mission, and our responsibility for the development of compressed air storage and application of compressed air storage.

Finally, I would like to thank my team. All the jobs did it. I just made a report on behalf of them. It is my luck to be able to advance with a group of like -minded people.