Learn how liquid air energy storage works. A simple guide to LAES technology, the cryogenic process, and how it compares to batteries and CAES.
What if you could turn air into a liquid, store it in a giant thermos, and use it later to make electricity? That is exactly what liquid air energy storage (LAES) does. It sounds like science fiction, but it is real technology. The first commercial plant opened in the UK in 2018. LAES could be a key piece of the clean energy puzzle.
LAES is a way to store energy by turning air into a liquid.
Here is the big picture. Renewable energy sources like wind and solar do not produce power all the time. Sometimes there is extra electricity. Sometimes there is not enough. LAES lets us save the extra for later.
The process uses something called cryogenics. That is the science of super-cold temperatures. Air turns into a liquid at -196 degrees Celsius. That is colder than the surface of Pluto. At that temperature, air becomes a pale blue liquid that takes up 700 times less space than it does as a gas.
The process happens in three stages.
Stage 1: Liquefaction. Extra electricity runs a big cooling system. The system cleans the air by removing water vapor and carbon dioxide. Then it cools the remaining nitrogen and oxygen until they become liquid. The liquid air is stored in large, well-insulated tanks. These look like giant thermos bottles.
Stage 2: Storage. The liquid air stays in the tanks at very low pressure. Unlike CAES, which needs high pressure underground, LAES tanks sit above ground. They can be built almost anywhere.
Stage 3: Power generation. When electricity is needed, the liquid air is pumped into a heat exchanger. It warms up and rapidly turns back into gas. It expands by about 700 times. That expanding gas rushes through a turbine. The turbine spins a generator. Electricity flows out.
LAES has some important advantages over other storage methods.
Location flexibility. CAES needs underground salt caverns or porous rock formations. Those are not available everywhere. LAES tanks can be built on any flat ground. A LAES plant can go almost anywhere.
No rare materials. Batteries use lithium, cobalt, and nickel. These materials are expensive and have supply chain issues. LAES uses only air. Air is free and available everywhere.
Long lifespan. A LAES plant can operate for 30-40 years with proper maintenance. The components are simple and durable. There are no toxic chemicals to degrade over time.
Scalability. LAES plants can be built at almost any size. Small units could power a building. Large plants could support the electricity grid.
Have you ever seen frost form on a cold winter morning? That is water vapor in the air turning into ice. Now imagine making the air itself so cold that it turns into a liquid.
Think of LAES like freezing leftover soup. When you have too much soup, you put it in the freezer. Later, when you are hungry, you take it out and heat it up. LAES does the same thing with air. It freezes extra air into liquid. When we need power, we warm it up.
The expanding air is like opening a shaken soda bottle. All the gas rushes out at once. That rush can spin a turbine and make electricity.
LAES efficiency depends heavily on the liquefaction process. Standard LAES achieves a round-trip efficiency of about 50-60%. That means for every 100 kWh of electricity used to liquefy the air, you get 50-60 kWh back.
The main energy loss happens during liquefaction. Cooling air to -196 degrees Celsius takes a lot of energy. Improvements in liquefaction technology could boost LAES efficiency to 70% or higher.
One promising approach is using waste heat. The LAES plant in Pilsworth pairs with a nearby biomass plant. The biomass plant produces waste heat. That heat is used to warm the expanding air, improving overall efficiency. This concept is called waste heat integration.
Another approach is cold energy recycling. When liquid air warms up, it absorbs heat and creates cold. That cold can be captured and used to pre-cool the incoming air for the next liquefaction cycle. This reduces the energy needed for cooling and improves overall efficiency.
LAES energy density is about 50-100 kWh per cubic meter of liquid air. That is much higher than CAES (2-6 kWh per cubic meter) but lower than lithium-ion batteries (200-500 kWh per cubic meter). However, the tanks are cheap compared to batteries, making LAES cost-effective for long-duration storage.
Pilsworth LAES Plant, UK. The world’s first commercial LAES plant. Built in 2018 by Highview Power. It stores 15 MWh of energy and delivers 5 MW of power for about 3 hours. It uses waste heat from a nearby biomass plant. The total cost was about $12 million.
Carousel LAES Plant, UK. A larger plant announced in 2020. It plans to store 50 MWh with 15 MW of power. It will use waste heat from a waste treatment facility.
Planned projects in the US. Highview Power has announced plans for a 50 MW / 400 MWh LAES plant in Vermont and a 200 MW / 800 MWh plant in Texas. Neither has been built yet.
Common misconceptions:
Discussion questions:
Last updated: June 15, 2026
What temperature does air need to reach to become liquid?
When liquid air warms up, how much does it expand?
What color is liquid air?
What is the main advantage of LAES over CAES?
What industrial process can make LAES more efficient?
Answers: C: -196 degrees Celsius, B: 700 times, C: Pale blue, B: It can be built anywhere, not just above caverns, B: Using waste heat from other processes
What is liquid air energy storage?
Liquid air energy storage (LAES) cools air to -196 degrees Celsius until it becomes liquid, stores it in insulated tanks, and later warms it to generate electricity.
How efficient is LAES?
LAES is about 50-60% efficient. That is lower than batteries but the technology keeps improving.
What is liquid air?
Liquid air is air that has been cooled to very low temperatures until it turns into a pale blue liquid. It is mostly liquid nitrogen and liquid oxygen.
How does LAES compare to CAES?
LAES does not need underground caverns, so it can be built anywhere. But it is slightly less efficient than modern CAES. LAES tanks sit above ground.
Where is the first LAES plant?
The first commercial LAES plant opened in Pilsworth, UK in 2018. It uses waste heat from a nearby biomass plant to improve efficiency.
