Dallas Morning News: The chairman of the Public Utility Commission is worried that federal climate-change legislation could pummel the Texas economy, and he asked the company that operates the state’s electric grid to study the matter. Chairman Barry Smitherman sent a letter to Bob Kahn, CEO of the Electric Reliability Council of Texas, asking him to look at the impact of greenhouse gas regulations on electricity prices. Burning coal and natural gas to make electricity emits carbon dioxide, which is …