Successful Workshop for Leading the ‘Carnot Battery’, the Future of Energy Storage

To address the variability of renewable energy sources such as solar and wind, the Korea Institute of Energy Research (KIER) has joined forces with industry, academia, and government to lead in the development of the future energy storage technology known as the “Carnot Battery.”

On May 17th (Friday), the Korea Institute of Energy Research (KIER) held a workshop at its main headquarters in Daejeon with experts from industry, academia, research, and government to discuss the technology, policy status, and development direction of the Carnot Battery in relation to energy storage and heat pumps.

Solar and wind energy are crucial for achieving future carbon neutrality. However, their output varies depending on weather conditions, emphasizing the importance of storage technologies to store renewable power for later use. Currently, lithium-based storage devices account for 99% of domestic distribution, but they are not suitable for long-duration, large-capacity storage due to high costs, short lifespan, and safety issues. To manage renewable energy power in the hundreds of megawatts (MW), there is a requirement for more cost-effective and reliable long-duration storage technologies.
<sup>* Renewable Energy Generation Targets: The goal is to achieve a renewable energy generation share of 28.9% by 2036, with new facility capacity expected to reach 80GW by 2036 (according to the 10th Basic Plan for Electricity Supply and Demand, January 2023, Ministry of Trade, Industry, and Energy).
* Long-Duration Storage Device Outlook: Approximately 22.6GW of long-duration storage devices will be needed by 2036 (according to the 10th Basic Plan for Electricity Supply and Demand, January 2023, Ministry of Trade, Industry, and Energy).</sup>

This is why Carnot Battery technology is gaining attention. The Carnot Battery utilizes electric heaters or heat pumps to transform renewable electricity into high-temperature thermal energy (over 600°C), which is subsequently stored in thermal media like stone, sand, or metal. The stored energy can be converted back into electricity when needed. Although currently in the early stages of development, it is expected to store large amounts of power for over 10 hours while maintaining low operating costs comparable to pumped hydro storage. As a result, active research is being conducted worldwide.
^{* Advanced countries like the United States and Germany are also conducting research at the demo/pilot plant level. The world’s leading example is Germany’s Siemens-Gamesa, which has developed a 5.4MW/130MWh Carnot Battery system.}

Another benefit of Carnot Batteries is their capability to repurpose coal-fired power plants that are being decommissioned due to reduced levels of particulate matter and greenhouse gas emissions. By simply replacing the boiler system of a coal-fired power plant with a thermal storage system, it can be converted into a Carnot Battery. Instead of coal, the system uses renewable electricity to generate and store heat in the thermal media, enabling power production without the need to change the rest of the existing infrastructure.
^{* Out of the total 58 coal-fired power plants, 28 are scheduled to be decommissioned (according to the 10th Basic Plan for Electricity Supply and Demand, January 2023, Ministry of Trade, Industry, and Energy).}

The Carnot Battery workshop was attended by over 70 experts from industry, academia, research institutions, and government, including the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and Korea Electric Power Corporation (KEPCO). During the workshop, KIER introduced the low-cost, high-temperature thermal storage media technology, a key component of the Carnot Battery, and presented a vision for applying thermal storage systems to decommissioned power plants.

The Korea Institute of Energy Technology Evaluation and Planning (KETEP), the organization responsible for overseeing research and development, explained the current status of new project planning related to the Carnot Battery. Research institutions, including KIER, shared their research and development efforts on high-temperature thermal storage and heat pumps for the Carnot Battery, as well as updates on international collaborative research.

In the subsequent industry presentations, Doosan Enerbility discussed “Applications of Long-Duration Thermal Energy Storage Systems and Plans for Developing High-Temperature Thermal Storage Media.” MAN Energy Solutions (MAN-ES), a Swiss energy company, presented “New Business Cases for Carnot Batteries Utilizing Heat Pumps.” The Korea Advanced Institute of Science and Technology (KAIST) shared the “Development Status of Carnot Batteries by Startups” and introduced academic trends in the field.

Dr. Junhyun Cho of KIER, who organized the workshop, stated, “The workshop was a productive event where domestic research institutions and companies gathered to discuss the activation of Carnot Battery research in Korea and future roadmaps. We hope that through the cooperation and consolidation of capabilities among related organizations in this globally early-stage field, Korea can achieve technological superiority as a first mover in Carnot Battery technology.“

Meanwhile, Dr.Junhyun Cho is participating as a Korean representative in the Carnot Battery International Collaborative Research Program launched by the International Energy Agency (IEA). He is contributing to setting global technology, new business, and policy directions by conveying Korea’s perspectives in these areas.