Dive Brief:

• Highview Power in partnership with British recycling and waste disposal company Viridor has brought online what it calls the world’s first grid-scale liquid air energy storage (LAES) plant.

• The 5 MW, 15 MWh demonstration plant at the Pilsworth landfill gas site in Bury near Manchester received support from the U.K. government's Department for Business, Energy and Industrial Strategy (BEIS), which supplied $10.7 million in funding.

• Demand response aggregator KiWi Power will draw energy from the LAES plant to power about 5,000 average-sized homes for around three hours.

Dive Insight:

LAES is one of the technologies attempting to stretch out the duration of energy storage systems. LAES technology is similar to compressed air energy storage (CAES) except that it cools air to -169 degrees Celsius to turn it into a liquid.

As with CAES, LAES arbitrages the differences between electricity prices at times of high and low demand. Using low cost power, the technologies use pumps to compress and store air under pressure. When energy prices are higher, the air is released and fed into a conventional turbine to produce electric power.

LAES' advantage is that, unlike CAES, it is not dependent on geography. CAES requires large storage caverns, such as depleted salt mines, to store air. LAES stores energy in insulated tanks.

While that solves the location problem, it introduces other issues. In particular, the liquefaction process adds to the already inefficient thermal air cycles, Tim Grejtak, energy storage analyst at Lux Research, told Utility Dive via email. It takes more energy to liquefy the air than it does to just compress it and store it.

Grejtak also said it is important to note that the Pilsworth plant is a pilot project to evaluate LAES technology, and “three hours of storage isn't a suitable duration for a system that is likely very inefficient.” Longer durations typically make better use of poor efficiency technologies, he said. Nonetheless, he noted the importance of developing an efficient and cost effective long-duration storage technology.

The Pilsworth plant is designed to demonstrate how LAES can provide several reserve, grid balancing and regulation services. But Highview sees even greater opportunities. The company says LAES technology can scale to hundreds of megawatts and could easily store enough electricity to power a town like Bury (around 100,000 homes) for many days.

"The market opportunity for LAES is considerable. We estimate that 60% of the global energy storage market comprises long-duration, grid connected storage and that our LAES technology is ready to meet almost half of this," Highview Power CEO Gareth Brett, said in a statement.