SPRINGFIELD — Western Massachusetts Electric Co. has announced plans to install three charging stations for plug-in electric cars as its parent company studies the future of rechargeable vehicles. Charging equipment has been installed at the company's headquarters in Springfield and at the Courtyard Marriott Hotel in Hadley. A third location is planned for Pittsfield. WMECO President Peter Clarks says the company wants to better understand consumer charging patterns and preferences. He says soaring gasoline prices and efforts to reduce greenhouse gas emissions make it clear the electric vehicles are a key component of the future of transportation.