Carbon dioxide energy storage is a new type of long-term energy storage technology. According to public information, currently three companies, Energy Dome, Boruiding Energy, and Bairang New Energy, are at the forefront globally.
1. Energy Dome, Italy
As its company name “Dome” describes, the most significant feature of the Energy Dome carbon dioxide energy storage system is the use of huge air bags to store carbon dioxide gas at close to normal temperature and pressure.
In the vision of Energy Dome CEO Claudio Spadacini, these dome-shaped structures will become a symbol of the transition to clean energy, “just like windmills and solar panels.”
Efficient, low-cost, flexible, durable, and reliable, Energy Dome said that its carbon dioxide energy storage system will achieve a cost of electricity of 50-60 US dollars/MWh (340-410 yuan/MWh) in the next few years, which will be more than twice lower than lithium-ion batteries; at the same time, Energy Dome carbon dioxide storage The energy system efficiency can reach 75-80%.
One year after Energy Dome’s first 2.5MW/4MWh commercial demonstration carbon dioxide energy storage project was put into operation, at the end of 2023, Energy Dome announced that it would deploy the first long-duration energy storage project with a duration of 10 hours in Italy. The scale of the project It is 20MW/200MWh and is expected to be put into commercial operation in the third quarter of 2024. Clik here to get more about Top 10 high capacity battery cell.
According to Energy Dome, the capital expenditure required for the project will be less than 50% of the capital expenditure for a 4-hour lithium-ion energy storage project.
2. Bairang New Energy
Bairang New Energy, founded in 2021, uses gas-liquid interconversion and two-state synergy energy storage technology. Its basic principle is to use excess electricity to compress carbon dioxide gas at normal temperature and pressure into liquid during the low period of electricity consumption, and then compress it. The thermal energy generated during the process is stored; Here are more about balcony solar storage system.
During peak power consumption periods, the stored thermal energy is used to heat liquid carbon dioxide to a gaseous state and drive the turbine to generate electricity.
Bairang New Energy said that its gas-liquid interconversion carbon dioxide energy storage technology has a full-cycle cost of electricity as low as 0.15 yuan/KWh, which is obviously economical; at the same time, the system design of decoupling the system power unit and capacity unit means that when the power is determined.
Under the premise, increasing the energy storage time only requires expanding the system capacity unit. Therefore, the longer the energy storage time, the lower the unit cost of the carbon dioxide energy storage system.
Due to the closed cycle, Bairang New Energy’s carbon dioxide energy storage system is not affected by conditions such as external temperature and geographical environment, and has good universal applicability. The units and related equipment are all constructed above ground, so the engineering difficulty is low and the construction is fast.
The storage and release of electric energy is realized through the physical phase change of carbon dioxide. When the phase change temperature and pressure are determined, there is no time limit for the phase change of carbon dioxide in the gas-liquid interconversion carbon dioxide energy storage system.
The unit equipment is a rotating machine, and the operating principle is the same as that of thermal power. The unit is similar and can perform work uninterrupted. The maximum single cycle of system operation can be up to 24 hours, the single charge and discharge time can be more than 23 hours, and the system’s equivalent time utilization coefficient can be close to 100%.
The Wuhu Conch 10MW/80MWh carbon dioxide energy storage project that will be connected to the grid for power generation at the end of 2023 adopts Bairang New Energy’s gas-liquid interconversion carbon dioxide energy storage technology. Combined with the process characteristics of cement production, it uses the waste heat of cement kilns to improve energy storage efficiency and convert cement into.
The carbon dioxide emitted during the production process is compressed to a high-pressure state and stored in a high-pressure gas storage tank. The compressed carbon dioxide is then released through a release valve to drive the turbine to rotate and generate electricity.
The system is deeply coupled with the CCUS capture production line of Conch Cement, and uses the carbon dioxide captured on the cement production line for the energy storage system to achieve the temporary storage of carbon dioxide, which not only reduces the cost of the energy storage system but also reduces the cost of carbon storage, achieving Carbon dioxide capture and recycling.
At the same time, by making full use of the heat of the flue gas below 110°C generated during the cement production process, the waste heat is converted into electricity and supplied to production, which can enable the company to save about 1,565 tons of standard coal per year; the systematic use of low-grade waste heat cracks the The problem of insufficient utilization of low-grade waste heat in cement plants.
3.Borui Dingneng
Recently, Zhang Zhentao, chief scientist of Boruiding Energy, introduced in an interview with ESPlaza Long-term Energy Storage Network, “Boruiding Energy uses matrix carbon dioxide energy storage technology. Here are more about top bess manufacturers.
The high-pressure side carbon dioxide can be stored in a supercritical state or high-pressure liquid form and expands. The rear and low-pressure sides can be stored in gaseous or liquid form.
Therefore, compared with other carbon dioxide energy storage technology routes, Boruiding Energy’s carbon dioxide energy storage combinations are more diverse and can flexibly meet different scenarios.”
Different from the companies currently engaged in the research and development of carbon dioxide energy storage technology around the world, Borui Dingneng is the only company controlled by Chinese people and the only domestic research and industry integrated team in this technology field, Zhang Zhentao added.
Borui Dingneng’s new carbon dioxide energy storage is based on the principles of forward Brayton cycle and reverse Carnot cycle. It liquefies carbon dioxide and stores it at low pressure, and drives the expander to generate electricity through boosted gasification. This technology has the characteristics of high cycle efficiency, low construction difficulty, long operating life (30 to 50 years), low system cost, compatible with CCUS technology, and not restricted by geographical conditions.
In addition, in terms of application scenarios, Boruiding Energy’s carbon dioxide energy storage technology can conform to the technological trend of CCUS and realize the “turning waste into treasure” of carbon dioxide, which is also of high value for energy conservation and carbon reduction.
According to Yue Yunkai, co-founder/CEO of Borui Dingneng, Borui Dingneng has mastered key technologies such as carbon dioxide energy storage thermal process and automatic control, especially high-pressure ratio/wide operating conditions transcritical CO2 compression technology, low exergy Borui Ding
Energy has achieved breakthroughs in high-load heat exchange/storage technology, wide operating conditions and high-speed CO2 turbine expansion technology, as well as timely response and system intelligent control technology based on energy storage and release action scheduling.
In terms of product development, Boruiding Energy’s self-developed carbon dioxide energy storage system can achieve an energy storage efficiency of up to 75%, can achieve a service life of more than 30 years, and the cost of electricity is as low as about 0.15 yuan/KWh.
In August 2023, the country’s first 100-kilowatt liquid carbon dioxide energy storage demonstration and verification project will be completed; in October, the joint debugging and testing of the project system will be completed; in December, the project will be filed for the world’s first 100MW/400MWh carbon dioxide energy storage commercial power station…
Although Boruidingneng, founded in 2022, started late, it is making a name for itself in the carbon dioxide energy storage market with its continuous technology iteration capabilities.
4. Core equipment
The carbon dioxide energy storage system mainly consists of high and low pressure storage tanks, compressors, turbines and heat and cold storage units.
Compared with air, carbon dioxide has a larger molecular weight, so the turbine and compressor will be smaller. After mass production, the amount of raw materials used can be reduced and the cost reduced.
As a key equipment in the carbon dioxide energy storage stage, the performance of the compressor directly affects the conversion efficiency of the system. According to the different ways of compressing the working fluid, compressors can usually be divided into two categories: positive displacement compressors and turbine compressors.
According to the different ways of changing the working volume of positive displacement compressors, they can be divided into two categories: reciprocating compressors and rotary compressors. Among them, piston compressors are the most widely used reciprocating compressors; rotary compressors include screw compressors, scroll compressors, sliding vane compressors and rolling rotor compressors.
Turbine compressors can be divided into centrifugal compressors and axial flow compressors based on the different directions of gas flow.
Due to the large pressure on the high-pressure side of carbon dioxide energy storage systems, rotary compressors are usually not suitable for carbon dioxide energy storage systems. Due to flow restrictions, piston compressors are usually suitable for small-flow carbon dioxide energy storage systems, and turbine compressors are usually suitable for large-scale carbon dioxide energy storage systems.
For carbon dioxide piston compressors, manufacturers currently occupying important markets in the world mainly include Italian Dorin Compressor Company, Frascold Compressor Company, Refcomp Compressor Company, and German Bizer Refrigeration Technology Co., Ltd.
In terms of carbon dioxide turbine compressors, centrifugal compressor manufacturers mainly include Danfoss, Mitsubishi Heavy Industries, Atlas Copco and other companies; there are relatively few axial flow compressor manufacturers. The current major manufacturers include MAN Energy Solutions in Germany and Howden in the UK. Here are more information about photovoltaic energy storage.
5. Summary
To sum up, the commercial promotion of carbon dioxide energy storage has promising prospects. However, the carbon dioxide energy storage system also has some shortcomings.
First of all, basic innovation research on carbon dioxide energy storage needs to be in-depth. There is insufficient theoretical research on the core technology system of carbon dioxide energy storage systems, and there is a lack of complete top-level design and bottom-level support.
There are still many key technologies that need to be overcome in carbon dioxide energy storage in terms of thermodynamic cycle construction theory, system dynamic operation control strategy, key equipment development and high-performance material selection. At the same time, there is also certain practical pressure in equipment processing and manufacturing, system application, etc.
Due to the unique properties of carbon dioxide such as low viscosity, high density, and low critical point, there are also some potential problems when the compressor in the carbon dioxide energy storage system is working.
But as Energy Dome expects on its official website: “CO2 Battery, the only viable alternative for long-duration energy storage.” In the future, with the expansion of market share and continued technology iteration and upgrade, the carbon dioxide energy storage system will become more and more expensive, both in terms of cost and cost.
Both performance and performance will be improved. Carbon dioxide energy storage, which is currently a bit “niche”, is also expected to become an important development direction for long-term energy storage technologies.
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