Minnesota Power began offering a green energy option to its residential and small commercial customers last month. The utility is buying half the output from three wind turbines at Great River Energy's Chandler Hills Wind Farm on Buffalo Ridge (Windpower Monthly, May 2001). The program, called WindSense, charges customers $2.50 a month for 100 kWh blocks of green electricity, up to a 20-block maximum. The charge is because wind power costs more than its coal and hydro generation, the utility says. Customers must sign up for at least the first year. "We don't know how many customers will subscribe to WindSense, but we think it's important to offer a renewable energy choice," says Minnesota Power's Patrick Mullen. "Customer response to the program will help Minnesota Power determine if additional wind generation should be purchased." Minnesota Power serves 144,000 customers in Minnesota and Wisconsin.