New Jersey’s last two coal-fired power plants are set to shut down, a key step in the state’s goal to get all of its electricity from carbon-free sources by 2050. Exelon Corp.’s Atlantic City Electric utility said that buying out existing power-purchase agreements and shuttering the Logan and Chambers plants would save customers as much as $30 million. The state’s Board of Public Utilities has unanimously approved the proposal. New Jersey’s biggest utility, Public Service Enterprise Group Inc., exited coal power in May 2021 and expects to reach net-zero by 2030. The two coal plants had deals to sell power that ran until 2024, but Atlantic City has notified grid operators that they will be deactivated by May 31.