Battery technology is seemingly the easy solution to the storage solution, but developers of gravity-based ‘virtual batteries’ are starting to make noise that is hard to ignore. Innovative start-ups such as Energy Vault and the UK’s Gravitricity, have developed methods of storing energy as gravitational potential. Using winch systems to lift high mass blocks with excess electricity, power can be generated in times of high demand by simply releasing the block, allowing it to spin a turbine as it falls. Edinburgh-based Gravitricity, aims to use redundant mine shafts, with a 3,000-ton weight, the equivalent of about 21 blue whales, to produce a system with a LCOE of under half the price of lithium-ion batteries. Early reports have suggested that a…