Liquid air energy storage (LAES) could be a cost-effective long-term energy storage solution, according to a new study by an international research team from the Massachusetts Institute of Technology (MIT) and the Norwegian University of Science and Technology (NTNU). The study suggests that LAES can provide a reliable method for storing and releasing electricity as needed.

How liquid air storage works

The LAES process involves three stages: charging, storing, and discharging. During charging, ambient air is cleaned, dried, and liquified using electricity. This liquid air is stored in insulated tanks at low temperatures and atmospheric pressure. When electricity demand increases, the liquid air is pressurized, heated, and vaporized, driving a turbine to generate electricity.

The study claims that this process is clean, using only ambient air and electricity, and can be implemented at multiple locations, including near industrial sites that can exchange waste heat to improve efficiency. The technology uses commercially available components and does not rely on rare or expensive materials.

Economic viability

The researchers investigated LAES’ economic viability in future power grids by calculating its net present value (NPV) to determine whether the project will generate more profits than its costs over its lifetime. This value accounts for LAES’ long-term financial feasibility by considering revenues, capital expenditures, and operational costs, all of which are discounted at a 7% rate.

To achieve this, the researchers developed a model to stimulate LAES performance within projected energy markets, utilizing comprehensive pricing data from the National Renewable Energy Laboratory (NREL). Using this model, they analyzed various decarbonization scenarios provided by the NREL across 18 U.S. regions.

The model considered capital expenditures, operating costs, and revenue from the purchase and sale of electricity.

The researchers found that a 100 MW LAES system would only be economically viable if 100% decarbonization is achieved by 2035. Even then, profitability was limited to certain southern states, such as Texas and Florida, where energy market conditions favored LAES technology. The model showed that LAES would be financially sustainable only in scenarios where demand for stored energy was high, particularly in markets with ideal pricing structures.

The researchers also conducted a sensitivity analysis on storage capacity, comparing weekly versus monthly storage durations. Their analysis indicated that weekly storage offered greater economic efficiency, as monthly storage incurred unnecessary costs for excess capacity.

The research emphasizes the crucial role of aggressive decarbonization policies and specific regional market conditions in determining the economic viability of LEAS as a vital component of future sustainable energy grids.

Improving NPV

The research team explored two key factors to enhance LAES’ economic competitiveness: energy efficiency improvements and the implementation of financial incentives.

The report states that while advancements in energy efficiency yielded limited NPV improvements under realistic market conditions, introducing capital expenditure subsidies, ranging from 40% to 60%, enhanced economic viability across all realistic scenarios.

Additionally, integrating LAES with existing power projects and industrial facilities could reduce costs and improve efficiency to make it a more attractive investment for energy providers.

Cost Comparison

The levelized storage cost for LAES was approximately $60/MWh, regardless of the decarbonization scenario.

The report claims that LAES is approximately one-third the cost of lithium-ion battery storage and half of that of pumped hydro.

This cost advantage can position LAES as a viable option for grid-scale energy storage in the future. Furthermore, LAES does not degrade over time like lithium-ion batteries, ensuring consistent performance throughout its operational life.

The research also found that the location of the LAES system affects its costs, further highlighting the importance of regional analysis.

Last January, MIT researchers designed a new lithium-ion battery, which includes a cathode based on organic materials instead of metals such as cobalt or nickel.