KENTECH Develops New Concept Energy Storage Technology Without Compressors

Jihyun Hwang, Professor at Korea Energy Engineering University.

An innovative technology that enables high-efficiency energy storage without the need for a compressor by utilizing the cryogenic properties of liquefied hydrogen (LH2) has been developed in South Korea.

Korea Energy Engineering University (KENTECH, Acting President Park Jin-ho) announced on the 23rd that the research team led by Professor Jihyun Hwang has developed a new concept integrated energy storage system, which includes: an LH2 cryogenic system, a nitrogen refrigerant system, a liquid air energy storage system, and a system that links power generation. This system is considered to be far superior in terms of efficiency and economic feasibility compared to conventional energy production and storage systems that utilize LNG cryogenics.

The new concept integrated energy storage system developed by the research team is designed to divide operation into On-peak periods, when electricity demand is high, and Off-peak periods, when energy consumption is relatively low, similar to the existing LNG cryogenic concept. The key difference is that, during On-peak periods, the system utilizes LH2 cryogenics, which is much colder than LNG cryogenics. This enables the implementation of an optimal system capable of generating electricity for 8 to 12 hours a day, and all of the LH2 used is vaporized and supplied to consumers. It is expected that this technology can be applied to future liquefied hydrogen import terminals worldwide, allowing for additional energy to be stored efficiently.

New Concept Energy Storage System Utilizing LH2 Cryogenics and Nitrogen Refrigerant.

The most groundbreaking aspect developed by the research team is the optimal energy storage system concept for Off-peak periods. By using LH2 cryogenics to liquefy air instead of conventional LNG cryogenics, the system eliminates the need for air compressors that were previously essential. This maximizes energy efficiency and can greatly improve economic feasibility.

In addition, by incorporating the nitrogen refrigerant system concept into the air liquefaction system, the team further maximized efficiency and developed a new concept liquid air energy storage system that does not require any compressors at all.

The new concept liquid air system utilizing LH2 cryogenics is expected to become a model for large-scale energy storage systems that can address the intermittency of renewable electricity production in future green hydrogen production.

In this study, the team developed a new concept liquid air energy storage system and evaluated its potential as a future technology through Energy, Exergy, and Techno-Economic analyses, including Net Present Value (NPV), Internal Rate of Return (IRR), and Payback Period (PBP).

This system offers the advantage of significantly reducing maintenance issues by eliminating the need for air compressors, and it is expected to be applicable to green hydrogen energy islands through commercialization.

Professor Jihyun Hwang, corresponding author of the study at KENTECH, stated, "The Green Hydrogen Energy Island project for the offshore wind farm development in Sinan, Jeollanam-do, is drawing global attention, but the intermittency of renewable energy remains a major challenge. Although various technologies such as batteries are being considered as alternatives, there is still a lack of clear solutions for large-scale, high-efficiency ESS (Energy Storage System) technology. In this context, the new concept energy storage system utilizing LH2 cryogenics developed in this study will serve as a powerful alternative."