In the deserts of the United Arab Emirates a sprawling clean energy project, stretching across an area roughly the size of 12,600 football fields, will play host to a breakthrough allowing solar energy to power the equivalent of half a million homes through the night. The Gulf state has been steadily combining 5.2GW of solar power capacity with 19GWh of battery storage to create the largest battery scheme in the world.
Meanwhile, about 7,500 miles away, at the US’s National Renewable Energy Laboratory facility in Colorado, researchers and engineers are making some of the smallest batteries the world has ever seen. A fraction of the size of the grid-scale lithium-ion batteries used to store renewable energy, they have been designed to power electronic tags that will track the 3in-long (about 7.5cm) young from salmon and eel species.
Unlike lithium-ion batteries, which have a finite number of charge/discharge cycles, many of these alternative battery technologies can be used indefinitely and recycled when the units reach the end of their 20-year service life.
Already developers are turning to a large range of materials to store renewable electricity when it is available and use it to power everything from wearable technology to heating networks, factories and missiles.
Here are some of the energy storage innovations raising eyebrows:
Liquid air
Late last year, on the site of a former coal plant in Trafford, the former mayor of Greater Manchester marked the start of construction on a long-awaited energy storage project that could usher in the “re‑industrialisation” of the county. In simple terms the Carrington project, developed by the British startup Highview Power, aims to capture renewable energy when it’s abundant and store it as liquid air. In theory, a “cryobattery” can store energy for hours, days or even weeks.
Molten salt
While in Manchester energy is being stored at sub-zero temperatures, in the Nevada desert the opposite approach has been taken. Here, 10,000 solar panes generate electricity for the Crescent Dunes scheme, which for the past 10 years has harnessed the sun’s power to heat a reservoir of potassium and sodium nitrate to 560C.
Sand
Much like renewable electricity can be stored by heating salt, clean energy can be stored in sand. In the small town of Pornainen in southern Finland, thousands of tonnes of sand help store energy used to heat schools, libraries and town halls. This should allow the district to end the use of oil in its local heating network completely and reduce the use of wood chips by about 60%. The sand battery uses about 2,000 tonnes of crushed soapstone to store clean energy in the form of heat to provide 1MW of thermal power and a storage capacity of 100MWh.
Sweat tech
In Japan, researchers at the Tokyo University of Science are investigating how human sweat could be a viable energy source to power wearable technologies.