Energy
Storage technology

GE Taps Into The Coolest Energy Storage Technology Around

Burgess COMMENTARY

Peter Burgess

GE Taps Into The Coolest Energy Storage Technology Around

The development of energy storage technology is going to be one of the defining features of the 21st century’s energy landscape. It will allow nations to decarbonise their economies by integrating renewable energy into their grids, reduce peak power demand and make all forms of power generation more efficient.

It is going to be a huge market and it is going to render the utilities business unrecognisable within a few decades.

Up to now, battery technology has been grabbing the headlines, even though 99% of the world’s energy storage capacity is currently in the form of pumped hydro-electric power. There is a good reason for this – thanks to the spread of electric vehicles, the amount of battery capacity is increasing rapidly and costs are starting to come down, making the technology increasingly viable.

Meanwhile, most of the places that are suited to pumped hydro already have it, new facilities are not cheap and there are geographical limitations to where you can put them – more than three quarters of Europe’s pumped storage capacity sits in just eight countries.

But batteries are far from being the only new energy storage technology out there and one of the more obscure and unlikely initiatives has just received a massive vote of confidence from GE.

A tiny UK company called Highview Power stores energy by using cheap, off-peak energy to cool air to -196°C using a conventional industrial refrigeration plant, turning 700 litres of ambient air into a litre of “liquid air” that can be stored in a simple insulated tank. When you need the energy, you simply open the tap, the liquid air turns back into a gas, expands in volume, drives a turbine and creates electricity. If you add heat when you release the gas, you make the process more efficient.

Highview says liquid air energy storage (LAES) has advantages over other emerging storage technologies in that it uses well-established technologies and doesn’t require any inputs such as the lithium that batteries need – the most exotic material involved in the process is stainless steel, the company says, while the extra heat can come from the process of cooling the air or from the waste heat of other industrial processes, including power stations. It is not geographically constrained like pumped hydro, it is long-lasting unlike many battery technologies and there is an existing global industrial gases infrastructure it can tap into. And unlike for a gas such as hydrogen, the storage tanks do not have to be specially reinforced or highly pressurised.

Energy storage technologies allow you to get the most out of renewable energy resources such as wind, which often produces more power than is needed at night that at the moment just goes to waste. But they can also make conventional plant more efficient, too, while captured waste heat can be used to provide heat and hot water for homes and offices. According to the International Energy Agency, “to support electricity sector decarbonisation, an estimated 310 GW of additional grid-connected electricity storage capacity would be needed in the United States, Europe, China and India. Significant thermal energy storage and off-grid electricity storage potential also exists.”

The upper reservoir (Llyn Stwlan) and dam of t...
A pumped storage hydro-electric plant in Wales. It can generate 360MW of electricity within a minute of the need arising. But there are few new sites available for pumped hydro. (Photo credit: Wikipedia)

Highview recently won an £8 million grant from the UK Department of Energy and Climate Change to build a 5MW demonstration plant at a landfill gas facility in southern England. Now the company has signed a global licensing and technology collaboration agreement with GE’s Oil and Gas unit. The companies will explore opportunities to integrate Highview’s technology in peaker power plants using GE gas turbines and gas engines.

Peaker power plants, as the name implies, are used only at times of peak demand. Because they have to stop and start as required, they are far less efficient than baseload plants that produce power all the time – and, like all fossil fuel power plants, they produce a lot of waste heat. Highview’s technology will help GE’s peaker plants in two ways – by releasing the stored energy it will make them able to respond more quickly to demand surges, cutting start-up times from 10-20 minutes to between 2 and 5 minutes. “It’s like a turbo-charged ramp-up time because our system provides power while the peaker plant warms up,” says Matthew Barnett, head of business development at Highview.

LAES will also make the peaker plants more efficient, allowing the plants to produce more power for the same amount of fuel because the Highview unit will be able to produce power alongside the peaker plant, using the gas-fuelled plant’s waste heat in its own processes. “It will work a bit like a hybrid car, where you have a smaller engine alongside an electric motor,” Barnett adds.

And there is no reason why liquid air storage can’t be retrofitted on non-peaker power stations to make them more efficient too, opening up the potential of huge markets in China and India.

It’s not GE’s first foray into energy storage – the company is also using battery storage alongside some of its wind turbines that enable the turbines to store power if the wind speed increases quickly and the grid cannot absorb all the power produced. The turbines can then use this stored power to continue providing energy when the wind is not blowing, to smooth variations in power and provide frequency regulation.

But Barnett isn’t worried that Highview’s LAES technology will lose out to batteries – or to other options such as ultracapacitors and flywheels. “There is space for all the different technologies – they often work on different time-scales. There could even be hybrid projects where you see liquid air alongside batteries or flywheels.”

With both Germany and Japan having introduced support schemes for energy storage, as have both New York and California, one thing is for certain – energy storage as a central part of the power system is coming your way – and it’s closer than you think.