Monhegan Island is getting a $420,000 federal grant to upgrade its power system. The Department of Agriculture grant will fund a 13-kilowatt solar power system, a new 40-kilowatt generator and a new switching system that will allow the Monhegan Plantation Power District to switch between different power sources and incorporate renewable energy sources like solar or wind power. U.S. Rep. Chellie Pingree says Monhegan residents pay about 70 cents per kilowatt hour, more than four times the average mainland rate and among the 20 highest rates in the country. She says the grant will improve the reliability and efficiency of the island’s power grid. Monhegan is about 10 miles off the coast and is a summer haven for artists. It has a year-round population of about 70.