Liquid air might transform the way we store and use energy

Over the last 30 years, the UK has made huge progress in its decarbonisation efforts. According to British energy regulator Ofgem, overall emissions have fallen by 40 per cent since 1990 – more than any other advanced economy. What’s more, we’ve got to the stage where almost half of our electricity comes from renewable or low-carbon sources.

While this is undeniably great progress, it’s simply not enough.

In 2019, the UK government declared a global climate and environmental emergency. This led to parliament making a historic commitment to achieve net-zero greenhouse gas emissions by 2050 – this means achieving a balance between the amount of greenhouse gas emissions produced and what is removed from the atmosphere.

To this end, late last year the UK government set out its Ten Point Plan for a Green Industrial Revolution. “We will turn the UK into the world’s number one centre for green technology and finance, laying the foundations for decades of economic growth by delivering net-zero emissions in a way that creates jobs and allows us to carry on living our lives,” said UK Prime Minister Boris Johnson in the policy paper.

“The UK was the first major economy to embrace a legal obligation to achieve net-zero carbon emissions by 2050. I will establish Task Force Net Zero to take forward this national priority, and through next year’s COP26 Summit, we will urge countries and companies around the world to join us in delivering net zero globally.”

However, meeting the 2050 goals will be no easy feat. According to Ofgem’s 2020 Decarbonisation Action Plan, the way we heat homes and our transport still needs to transform dramatically if we are to get anywhere close to where we need to be. Today, only 5 per cent of energy used to heat our homes is from low-carbon sources and our use of electric vehicles may need to grow from 230,000 today, to 39 million by 2050. “To meet the challenge of net zero, therefore, we must now go further and faster, especially in decarbonising transport, heating and our industrial use of energy,” the action plan states.

This change will not only depend on the growth of renewable energy sources such as wind and tidal power and the take-up of electric vehicles and heat pumps, it will also depend on the creation of a system that can adequately and reliably supply energy when consumers need it. It is a simple fact that the two biggest sources of renewable energy – wind and solar power – are ‘variable’. Therefore, being able to store this energy effectively is crucial.

This is a significant challenge, especially when you consider the latest projections by the EIA, which suggest world energy consumption is likely to grow by nearly 50 per cent by 2050. Indeed, a report by the Energy Research Partnership says, “current storage models alone are not robust enough to meet the economies of scale needed for future energy demands and generation scenarios”.

It’s easy to see why this is the case. While traditional electrochemical solutions such as batteries can store energy when it is not needed and release it to the grid when demand is high, they are far from an ideal solution for renewable energy, which is intermittent and may need to be stored for an extended period of time.

“While batteries are ideal for reacting to instantaneous demands for storage, they are just too expensive for storing large quantities of energy over longer time periods such as weeks and months,” explains Robert Morgan, professor in the Sir Harry Ricardo Laboratories within the Advanced Engineering Centre at Brighton University.

However, a breakthrough innovation by a British company called Highview Power offers a solution to the problem. Over the past 15 years, the firm has developed a proprietary cryogenic energy storage system called the CRYOBattery that can cool solar or wind energy into a liquid state. This can then be kept in insulated storage tanks for weeks at a time. When the liquid air is allowed to warm and turn itself back into a gas, it expands so quickly that its power can spin a turbine that puts green energy back into the grid.

The CRYOBattery is scalable up to multiple gigawatts of energy storage and can be located anywhere. “This scale is one of the key benefits of the technology,” explains Jonathan Radcliffe, a reader in energy systems and policy, leading an interdisciplinary research team at the University of Birmingham. “Increasing the amount of energy stored is achieved by having more storage vessels that hold liquid air, which is relatively inexpensive. The expensive parts of the system are the liquefaction unit and turbine generator that are related to the power generated or demanded. For batteries, to double the amount of energy stored, you need to double the number of batteries, which is incredibly costly.”

Radcliffe says it is this “decoupling” of energy and power that sets liquid air technologies apart from batteries. “A further benefit is that it can be integrated with other industrial processes, where there are sources of heat or cold. For example, at their five-megawatt demo plant, Highview used excess heat from power generation to increase the output from storage,” he explains.

The system is equivalent in performance to, and could potentially replace, a fossil fuel power station – and is incredibly cost-effective too. “The novelty of the technology is thermal energy is stored as low-grade heat and cold, as well as in a cryogenic fluid,” says Morgan. “This improves the efficiency of the process.

“What’s more, the technology has favourable capital cost characteristics, which mean it gets cheaper as it’s scaled. This is not the case with batteries which do not get that much cheaper at large scale. The technology also uses components already used in other industries at scale so there is a good, well-supported supply chain for equipment and maintenance.”

Javier Cavada, Highview Power’s CEO, is incredibly passionate about his firm’s technology. “Renewables are not only the cleanest and cheapest way to store energy today, but they are also the smartest,” he explains. “However, a move to renewables means that wind and solar energy need to consistently cover all services 24 hours a day, seven days a week. Current storage systems are not enough to facilitate this, but our solution is a gamechanger. It uses liquid air to deliver anything from four hours to four weeks of energy. It is clean – nothing goes in but air, and even cleaner air comes out. It’s also safe, freely-locatable, and is roughly half the cost of lithium-ion batteries for long-duration storage applications.”

Recognising the potential of the innovation, the UK Department for Business, Energy & Industrial Strategy awarded Highview Power a £10m grant to build a 50-megawatt (with a minimum of 250 megawatt hours) liquid air energy storage facility in Greater Manchester. Construction began late last year, and it is likely to be fully operational by 2023. It is expected to be the largest energy storage system in Europe, outside of pumped hydro schemes, which require a mountain reservoir to store water.

“This revolutionary new CRYOBattery facility will form a key part of our push towards net zero, bringing greater flexibility to Britain’s electricity grid and creating green collar jobs in Greater Manchester,” said the UK’s Energy and Clean Growth Minister Kwasi Kwarteng in an official statement. “Projects like these will help us realise the full value of our world-class renewables, ensuring homes and businesses can still be powered by green energy, even when the sun is not shining and the wind not blowing.”

Highview Power will operate the facility in partnership with Carlton Power, a UK independent power station developer. The facility will use existing substation and transmission infrastructure, with its income derived from several markets, including arbitrage, grid balancing, the capacity market, and ancillary services such as frequency response and voltage support. The Trafford Power site at Manchester was developed by Carlton Power to be the first project consented in Europe as being fully Carbon Capture Ready. Its proximity to its designated carbon storage field make the site one of the most economically viable sites in the UK for conversion to carbon capture and storage.

“Our facility will deliver much-needed clean, reliable and cost-efficient long-duration energy storage to the National Grid,” says Cavada. “The CRYOBattery will help the UK to integrate renewable energy and stabilise the regional electrical grid to ensure future energy security during blackouts and other disruptions.”

In recognition of his efforts, Cavada was recently invited by the UK Prime Minister Boris Johnson to the unveiling of the Ten Point Plan for a Green Industrial Revolution - a key target of which is the creation of up to 250,000 British jobs, of which 50,000 will be in important industrial areas where Highview Power is developing plants based on its technology.

“It was an honour to join Boris Johnson and to be a part of the UK’s commitment and technological ambition to make net-zero goals a reality,” Cavada says. “Assets like Highview Power plants are vital to the transition to net zero, creating highly skilled jobs and enabling integration of renewables on a massive scale. These assets do require the grid to provide stability in their revenues, as it was provided years back to onshore wind and in the coming years is being provided to offshore wind. We are thrilled to make innovative energy storage a reality and be part of this green revolution.”

It is hoped that Highview Power’s technology will give the UK far greater flexibility in helping meet the country’s electricity needs from the grid. In fact, when it is up and running, it’s expected that it could be used to power as many as 200,000 homes for five hours a day.

“This is just the start,” Cavada says. “At Highview Power we have truly global ambitions.”

Cavada’s vision is already taking shape. Sumitomo Heavy Industries, a technology leader in environmental and power technologies, recently made a $46m investment into Highview to help it expand its projects globally.

As a result of this investment, great progress is being made in the US – where the energy storage market is expected to surge over 700 per cent to nearly $5.4bn by 2024, driven mostly by utility-scale projects, according to analyst firm Wood Mackenzie Power & Renewables.

Here, Highview has joined forces with Encore Renewable Energy, a developer of renewable energy generation and storage projects, to unveil plans to develop the first long-duration, liquid air energy storage system in the US. This facility will be a minimum of 50 megawatts, provide in excess of eight hours of storage (400 megawatt hours) and will be in northern Vermont.

In a press release, Salvatore Minopoli, vice president of Highview Power USA, said the company has strategically sought partners in the US that are renewable energy market leaders with experience in developing large-scale projects. “With their expertise in community-scale solar PV systems, traditional battery storage applications and solutions for the redevelopment of under-utilised properties, Encore Renewable Energy is a perfect partner for us as we continue expanding our technology in the United States,” he said.

The project is the first of many utility-scale, liquid air energy storage projects that Highview plans to develop across America to help scale-up renewable energy deployment. The Vermont facility will also contribute to resolving the longstanding energy transmission challenges surrounding the state’s Sheffield-Highgate Export Interface.

“Vermont is a largely rural area, and output from existing renewable energy plants often exceeds electric demand,” explains Cavada. “What’s more, the capacity of the electrical transmission lines leading out of the area is not enough to deliver the excess power without putting the reliable operation of the electrical grid at risk.”

Highview Power’s technology offers a unique, cost-effective solution for these problems. “It will allow for fewer curtailments and provide important energy-balancing services for Vermont’s rapidly evolving modern grid,” Cavada says.

Highview has also recently entered into a joint venture agreement with Energía Latina S.A.-Enlasa, the largest backup power generation provider in Chile, to co-develop giga-scale cryogenic energy storage projects in Chile and other Latin American markets.

The joint venture, named Highview Enlasa, will help to open Latin American energy markets to baseload renewable energy potential. Chile has one of the best solar irradiations of the world and deployment of solar power together with the national decarbonisation strategy require long-duration energy storage to provide the needed energy balance to achieve a sustainable grid. Other Latin America markets have similar initiatives, and a CRYOBattery plant in Chile will serve as a great business case for the region.

“We are excited to work with Enlasa to bring Highview’s technology to Chile,” Cavada explains. “Together, our two companies can harness the growing deployment of renewables in Chile and across Latin America and bring renewable baseload power to the region, all without the geographic constraints associated with other energy storage technologies.”

Ultimately, it’s clear that Highview – along with its partners – is set to transform the way we store and use energy – and in a big way. Cavada couldn’t be more excited about this future. “It’s early days, but our technology is available and ready to make a difference,” he concludes. “A sense of urgency from global markets is currently our only challenge, and fossil fuels are our only competitor. Over the next two years we expect to be transforming energy storage the world over, in continental Europe, the US, Latin America and Australia. I can’t wait to see what we can achieve.”