CONCORD, N.H. — The state commission that regulates utilities has released a report card on four power companies’ responses to a freak 2011 snowstorm, giving Public Service of New Hampshire low marks but calling Unitil Energy Systems a ‘‘model.’’

The New Hampshire Public Utilities Commission released the 60-page report this week on utilities’ preparation and restoration efforts with the storm, which put more than 300,000 homes and businesses in the dark.