Request for Proposals for delivery of all-requirements retail electric power supply to approximately 1,400 municipal electric accounts located on Cape Cod and Martha's Vineyard representing approximately 75,000 MWh of annual retail sales. The all-requirements retail electric power supply includes electrical energy, capacity, ancillary services, renewable energy resources as mandated by Massachusetts General Law c. 25A, §§11F, 11F 1/2 and Clean Energy Standard requirements (310 C.M.R. §7.75), and transmission and distribution losses. The supplier will be responsible for all load and supply scheduling, network and transmission service scheduling, ISO New England and New England Power Pool communications, customer billing coordination with local distribution companies, customer complaint handling, EDI arrangement, and all other services necessary for competitive supply to end-use customers. Bidders may propose contract delivery periods ranging from a minimum of one (1) year to a maximum of three (3) years. Price offers must be fixed annually with no seasonal, time-of-day, variable, or indexed pricing permitted. The RFP also invites optional proposals for supporting renewable energy beyond state-mandated requirements through procurement and retirement of additional Massachusetts Class 1 Renewable Energy Attributes (MA Class 1 RECs). Bidders may propose an adder to the fixed price for each 1% of Participants' retail sales met with additional MA Class 1 RECs. All-requirements retail power supply for all Participant accounts will commence with the July 2019 meter read dates. The selected bidder must execute a Municipal Competitive Electric Supply Agreement (MCESA) as supplied or amended.