Molten salt and human sweat: the weird batteries that could store renewable energy

The Crescent Dunes project in the Nevada desert harnesses the sun’s power to heat a reservoir of potassium and sodium nitrate to 560C. Photograph: UCG/Universal Images Group/Getty Images View image in fullscreen The Crescent Dunes project in the Nevada desert harnesses the sun’s power to heat a reservoir of potassium and sodium nitrate to 560C. Photograph: UCG/Universal Images Group/Getty Images Molten salt and human sweat: the weird batteries that could store renewable energy From Nevada to Manchester, developers are trialling innovative solutions to clean energy’s biggest challenge 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. As traditional lithium-ion batteries push boundaries in size and scale, alternative battery types could provide the same vital role in harnessing low-carbon energy – but without the scramble for critical minerals such as lithium, cobalt and nickel that have raised concerns for environmental protection and vulnerable communities . View image in fullscreen The Polar Night ‘sand battery’ in Pornainen, Finland, can cover almost a month of the small town’s heating demands in summer and nearly a week’s in winter, cutting oil use by storing energy as heat. Photograph: Polar Night Energy 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. Andy Burnham said the development of the Trafford green cluster, which includes the Carrington “liquid air” cryobattery, could mean “this decade is the most exciting since the Victorian period for Greater Manchester”