Liquid air, the source of clean energy that was neglected for almost 50 years and that in 2026 will have its first commercial plant in the world

While some turn to large-scale lithium batteries and others to pumped hydroelectric plants, a small but growing industry is convinced there is an even better solution: batteries that use air.

Near the town of Carrington in northwest England, the foundations are being laid for the world’s first commercial liquid air energy storage facility.

The complex will become a collection of industrial machinery and several large storage tanks, filled with compressed air and cooled to a liquid, using surplus renewable energy to meet demand.

The stored energy can be released later when demand exceeds supply.

If the project is successful, others will follow suit. Its promoters, the company Highview Power, They are confident that liquid air energy storage will help countries replace fossil fuels with clean renewable energy, although for now the technology remains expensive.

However, as the need to store clean energy grows, they are betting the balance will tip in favor of liquid air.

The problem of intermittency

The transition to renewable energy is essential for the world to reduce greenhouse gas emissions and avoid the worst impacts of climate change. However, this poses challenges for power grids.

Power plants that burn fossil fuels such as coal and gas They can be turned on and off practically at willoffering a predictable electricity supply that adjusts to demand.

Instead, renewable energies are intermittent. This means that sometimes they don’t generate enough electricity, which carries the risk of power outages, and other times there is an excess—such as on windy days—something that could damage the grid.

An important part of the solution is to store excess energy so it can be released when needed. This helps ensure reliable supply and minimizes the risk of damage to the network.

As the use of renewable energy has increased, it has become increasingly important to develop grid-scale storage capacity, says Shaylin Cetegen, a chemical engineer at the Massachusetts Institute of Technology (MIT) who studies energy storage systems.

For decades, the main form of energy storage has been pumped hydroelectricity. Surplus electricity is used to pump water uphill, where it is stored behind a dam.

When power is needed, water flows through turbines, generating electricity. In 2021, the world had 160 gigawatts of pumped hydroelectric capacity.

More recently, as demand for energy storage has increased, large-scale battery storage systems have been built.

This process is developing rapidly and is accelerating. According to the International Energy Agency, andGrid-scale battery storage grew from 1 GW in 2013 to more than 85 GW in 2023, with more than 40 GW added in 2023 alone.

Liquid air energy storage, on the other hand, is a relatively new technology. The basic idea has been around since 1977, but received little attention until this century.

The liquid air solution

The process works in three stages. First, air is taken from the environment and cleaned. Second, the air is repeatedly compressed until it reaches a very high pressure. Third, it is cooled to liquefying by a multichannel heat exchanger: a device with multiple channels and tubes that transport substances at different temperatures, allowing controlled heat transfer between them.

“The energy we get from the grid powers this charging process,” explains Cetegen.

When the grid needs additional power, liquefied air is used. It is removed from storage and evaporates, returning to its gaseous state. It is then used to drive turbines, generating electricity for the grid. The air is then released back into the atmosphere.

There are some clever energy saving techniques during the process. For example, gases at high pressure heat up, so the compression of air generates heat.

This heat can be used to help recover the liquid state of the air in the second part of the process. “Without these thermal recovery cycles, The efficiency of the process is around 50%, but by implementing them, we can exceed 60%, approaching 70%”, says Cetegen.

The challenge is to deploy sufficient liquid air energy storage to significantly accelerate the ecological transition.

A network-scale interim solution

The new Manchester plant is the world’s first commercial-scale initiative. It is being built by Highview Power, a company that has been developing energy storage systems using liquid air for 20 years.

It follows in the wake of a pilot plant in the nearby town of Pilsbury. The Carrington plant will be able to store 300 megawatt-hours of electricity, enough to cover a brief power outage for up to 480,000 homes.

It will come into operation in two phases, explains CEO Richard Butland.

In August 2026, the turbine is scheduled to begin operation. This will not generate electricity, but will help stabilize the electrical grid.

According to Butland, currently power grid operators sometimes resort to commissioning gas plants to stabilize the grid. “This represents an enormous cost for the system,” he says. By offering an alternative method of stabilization, “we can prevent them from doing that.”

The liquid air energy storage system is expected to begin operations in 2027. Highview intends to make a profit by selling electricity to the grid when it is needed most.

That is, although energy storage is an essential technology, its economic viability is complex, says Cetegen.

In a study published in March, she and her colleagues evaluated the feasibility of liquid air energy storage in 18 regions of the United States.

They compared eight different decarbonization scenarios, with different levels of renewable energy adoption. In all cases, they estimated the profitability that a project could obtain through the purchase and sale of electricity over a period of 40 years.

Florida and Texas

In the most ambitious decarbonization scenario, energy storage using liquid air It proved viable in Florida and Texas, but not anywhere else.

“We do not observe any economically viable systems in the other decarbonization scenarios,” says Cetegen.

Although this could be misinterpreted as “a negative result,” Cetegen emphasizes that it does not mean that energy storage using liquid air is a bad idea.

To begin with, his methods were deliberately conservative, and his study revealed that Other forms of energy storage, such as pumped hydroelectricity and batteries, were even less economically viable.

More specifically, the main problem was that the storage facilities did not generate much profit in their early years, because there was not enough renewable energy in the US electricity grid to drive price volatility.

“The system was not used much in the early years [del modelo]”, he states.

Cetegen highlights one last argument in favor of energy storage using liquid air: its low cost.

Energy storage technologies are typically evaluated using an indicator called “levelized cost of storage,” which estimates the cost of each unit of energy stored over the life of the project.

For liquid air, this cost can be as low as $45 per megawatt-hour, compared to $120 for pumped hydroelectric storage and $175 for lithium-ion batteries.

“While none of these storage methods are currently economically viable without political support, liquid air energy storage stands out as a particularly cost-effective option for large-scale storage.”, says Cetegen.

Ultimately, Butland predicts that power grids will rely on a combination of storage technologies. Pumped hydro storage is extremely efficient and works for decades, but is location dependent as it requires a water supply.

On the other hand, batteries are highly efficient and can be placed anywhere, but must be replaced after about 10 years. Liquid air has the advantage of being able to store energy for longer than batteries, with minimal losses.

As a country begins the transition to green energy, its electrical grid needs to be remodeled to adapt. “We are rebuilding all networks globally, based on the next generation,” says Butland. And that could well involve a lot of energy storage using liquid air.