General Motors Co. Chief Executive Mary Barra is pressing Washington for an expansion of electric-vehicle tax credits, a plea that would help the company and rivals like Tesla Inc. sell battery-powered cars in an era of cheap gasoline and skepticism about alternative vehicles . A handful of auto makers face the expiration of $7,500 income-tax credit that has applied to hundreds of thousands of electric-vehicle purchases since the Obama administration established the offer. GM has used the incentive to bring the tab of its electric Chevrolet Bolt to under $30,000. GM is expanding production of the Bolt, but it will soon hit a sales cap that triggers the gradual expiration of the incentive for individual car companies that have sold 200,000 electric cars since the credit’s inception in 2009. Ms. Barra will call for an “expanded” tax credit at the CERAWeek conference in Houston on Wednesday, based on a […]