California’s brutal five-year drought did more than lead to water shortages and dead lawns. It increased electricity bills statewide by $2.45 billion and boosted levels of smog and greenhouse gases, according to a new study released Wednesday. Why? A big drop-off in hydroelectric power. With little rain or snow between 2012 and 2016, cheap, clean power from dozens of large dams around California was scarce, and cities and utilities had to use more electricity from natural-gas-fired power plants, which is more expensive and pollutes more.