Construction has started on a 19-turbine wind farm in Western Massachusetts that when finished will generate enough electricity to power 6,000 homes. The Hoosac Wind Power Project on two hilltops in the towns of Monroe and Florida is being built by Iberdrola Renewables. Iberdrola officials said the 340-foot-tall turbines will offset about 100 million pounds of carbon dioxide per year when they go online in December, the equivalent of the annual emissions produced by 9,400 cars. The Recorder of Greenfield reported that the project is expected to generate $257,000 in annual payments in lieu of taxes for the host communities for the next 20 years.