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8 June 2018

Liquid Air storage plants arrive to challenge batteries

Highview Power has partnered waste management firm Viridor to build what they believe is the first Liquid Air Energy Storage (LAES) plant in the world – near Bury, at the Pilsworth landfill gas site. Highview, with backing from GE, used £8m of government funding in the joint project, through the Energy Innovation Program, and the results look rather promising.

KiWi Power has already announced that it will be using the 5 MW (15 mWh) LAES plant to provide ancillary services to the wider grid – feeding in power when there is a shortage in return for payments, and also storing power when there is a surplus. These ancillary services and storage capacity are key to integrating more renewable sources of energy into the grid. KiWi believes it can power around 5000 homes for three hours, using the LAES plant.

The LAES system works by cooling (not compressing, that would be CAES) air into liquid form, storing this liquid, and then converting the liquid back to gas to drive a turbine – which then generates electricity. When electricity prices are low, the plant will cool air to fill its storage reserves. This stored energy can then be converted to electricity when prices are higher.

Its main benefits over batteries, the pair claim, are its lack of a need for rare earth metals like lithium or other chemicals, and its longer lifespan, which is estimated at 30-40 years, compared to a grid-scale battery’s 10-year life cycle. LAES plants could also be installed pretty much anywhere – something that CAES can’t manage because of its need for very large storage spaces, such as depleted mines.

LAES is more energy intensive than CAES, but it will make the argument that it can be more environmentally friendly than battery technologies, because of the materials and chemicals used in their construction. Highview adds that at the plant’s end-of-life, because of its mostly steel construction, it can be much more easily recycled than a battery system. As with most emerging grid technologies, it’s a game of swings and roundabouts, when it comes to deciding which ones to embrace.

Of course, a great deal of data is needed to power these ancillary services, collected from the grid infrastructure as well as the homes that are demanding electricity. Metering and edge-computing are going to be in high demand, as countries begin to embrace such smart gird technologies, and this is a huge opportunity for service providers to pursue.

As the Bury plant is part of a landfill site, it is also tasked with converting waste landfill gases into electricity. High View Power CEO Gareth Brett said “the plant is the only largescale, true long-duration locatable energy storage technology available today, at acceptable cost.”

Viridor’s managing director for energy, Richard Pennells, added “the innovative LAES technology that has been developed through the Highview Power project could play an important role in supporting UK growth in low carbon, renewable energy sources, and in maintaining the security of the UK’s electricity supply.”

Highview is hoping that the Bury system drums up interest for its LAES technology. It estimates that 60% of the global energy storage market comprises long-duration grid-connected storage, and that our LAES technology is ready to meet 45% of this 60%.

It added that utilities have been interested in the project, and are now using the data from it to “confirm their expectations.” Brett added that it is in negotiations to build plants 10x the size of Bury – bringing it up to the scale of the Tesla battery that has made so many headlines. Highview believes that 100+ MW projects are possible too.