Maine RECs, new RFP

[Gwgan]

Maine has increased the timetable of required renewable resources and now has a new RFP which even mentions storage: MPUC: 2020 Request for Proposals for the Sale of Energy or Renewable Energy Credits from Qualifying Renewable Resources
Still no solar carve-out so it is a limited market. There is an alternative compliance payment rate for $50/MWh for unmet quotas which seems to me to be a cap on price.
Anyone here familiar with ISO-NE generators? What distinguishes Class I from Class IA? It sounds like a very specific reference:

Class IA resource" means a Class I resource other than a Class I resource that for at least 2 years was not operated or was not recognized by the New England independent system operator as a capacity resource and, after September 1, 2005, resumed operation or was recognized by the New England independent system operator as a capacity resource.