In a move seen as a major setback for a pilot offshore wind project under development by the University of Maine, state regulators voted Tuesday to reconsider the contract terms by which Central Maine Power agreed to purchase electricity from the project. The Public Utilities Commission voted in 2014 to allow the UMaine Aqua Ventus project to negotiate a price at which CMP would buy electricity generated by the wind turbines, to be located off the island of Monhegan.