An Energy Expo will be held Sept. 23 at Plymouth North High School. The event is free and open to the public from 1 to 5 p.m. Attendees can check out the new high school building at 41 Obery St., sign up to receive a free home energy audit, learn about energy-saving discounts and rebates, and enter a raffle to win a bicycle, Kindle, and other prizes. There will also be vendors, a free bicycle clinic, and guest speakers including state representatives Thomas J. Calter and Vinny deMacedo. The Energy Expo is sponsored by the town’s Energy Committee, Plymouth public schools, Plymouth League of Women Voters, and Habitat for Humanity of Greater Plymouth.