Boston utility NStar has agreed to pay a starting price for power from the Cape Wind project that is substantially above the cost of conventional energy and will slightly increase the average customer’s monthly bill beginning the first year the offshore wind farm generates electricity, according to a 15-year contract filed with state regulators Friday.
The price, 18.7 cents per kilowatt hour, is the same as what National Grid agreed to pay when it signed a contract in 2010 to purchase half the power generated by Cape Wind. NStar’s deal is to purchase 27.5 percent of the wind farm’s total output. Since the Cape Wind power represents only about 2 percent of the energy distributed by NStar, it is expected to have a moderate impact on the average customer’s bill, $1.08 a month. Customers in the Boston area pay about $86 a month.