Wind and solar energy will supply almost 50% of the world’s electric power generation by 2050, Bloomberg New Energy Finance forecasts in its annual long-term analysis of the global electricity system released June 19. Precipitous declines in cost and increasingly cheaper batteries to store and discharge power will drive the trend. Coal, which now supplies 38% of world electricity, will supply 11% at midcentury, the report says. Global investment in new power generation through 2050 will total $11.5 trillion: 73% will go to wind and solar and 13% to other zero-carbon technologies such as hydro and nuclear. Natural-gas-fired power stations will shift from baseload to backup for renewable power resources.