To have and to hold

摘要

IT SOUNDS SIMPLE: lift heavy blocks with a crane, then capture the power generated from dropping them. This is not an experiment designed by a ten-year-old, but the premise of Energy Vault, which has raised $uom from SoftBank, a big Japanese tech investor. The idea has competition. A cluster of billionaires including Bill Gates, Jack Ma, Ray Dalio and SoftBank's Masayoshi Son are backing other schemes to capture power. A firm incubated at Alphabet, Google's parent company, wants to store electricity in molten salt. Such plans hint at one of the power business's hardest tasks. Generating clean power is now relatively straightforward. Storing it is far trickier.