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Finnish researchers have installed the world's first fully working "sand battery" which can store green power for months at a time. The developers say this could solve the problem of year-round supply, a major issue for green energy. Using low-grade sand, the device heat made from cheap electricity from solar or wind. The sand stores the heat at around 500C, can then warm homes in winter when energy is more expensive. Because of climate change and now thanks to the rapidly rising price of fossil fuels, there's a surge of investment in new renewable energy production.
But new solar panels and wind turbines can be quickly added to national grids, these extra sources also present huge challenges. , most batteries are made with lithium and are expensive with a large, physical footprint, and can only cope with a limited amount of excess power. One of the big challenges now is whether the technology can be scaled up to really make a difference - and will the developers be able to use it to get electricity out heat? The efficiency falls dramatically when the sand is used to just return power to the electricity grid.