Renewable Portfolio Standard

The Massachusetts Renewable Portfolio Standard (RPS) is designed to diversify the state's electricity supply portfolio, stabilize rates, increase energy security, improve environmental quality, and invigorate the clean energy industry.
The RPS was established as part of the 1997 utility restructuring act and was refined by the 2008 Green Communities Act.  The state’s Department of Energy Resources (DOER) is responsible for issuing and implementing the RPS regulations (225 CMR 14.00 and 225 CMR 15.00).

The RPS promotes the deployment of clean energy technologies in a couple of ways.

First, it requires all retail suppliers licensed in Massachusetts to buy renewable energy certificates (RECs) produced by generating facilities that meet certain criteria. For each megawatt-hour of green electricity produced by these facilities, a REC is generated. Licensed suppliers must hold RPS-eligible RECs equivalent to a fixed percentage of the electricity that they sell to consumers each year, in megawatt-hours.

Second, it creates a new revenue stream for facilities meeting RPS criteria. Facility owners can sell both electricity and RECs, either directly to consumers or to other suppliers.

The state's RPS rises annually, as shown in the table below. By increasing the demand for RECs from new facilities, the RPS leads to an increase in energy generated by wind, solar, hydro, bioenergy, and other qualified facilities.  The RPS also creates demand for RECs from certain existing facilities, thereby helping to ensure their continued operation.  (The distinction between new and existing facilities is defined by whether the facility entered into commercial operation after or before December 31, 1997.  Incremental generation rates above pre-1998 levels may qualify as new generation in some cases.)

Compliance Year	Minimum Percentage of New Renewable Generation (Class I)	Minimum Percentage of Existing Renewable Generation (Class II)	Minimum Percentage of Waste Energy Generation (Class II Waste)
2003	1.0	-
2004	1.5	-
2005	2.0	-
2006	2.5	-
2007	3.0	-
2008	3.5	-
2009	4.0	3.6	3.5
2010 and beyond	+1% annually	3.6	3.5

 

Qualifying Forms of "Renewable" Generation

The DOER determines whether renewable energy facilities qualify for RPS eligibility. A qualified generating unit must meet the following criteria:
•  It must produce electricity from one of the following sources, fuels, or technologies:

• Solar photovoltaic or solar thermal electric energy
• Wind energy
• Ocean thermal, wave, or tidal energy
• Landfill methane gas, provided that the fuel is directly supplied to the generating unit rather than conveyed through conventional delivery networks for natural gas
• Low-emissions, advanced biomass power conversion technologies using an "eligible biomass fuel"
• Fuel cells using an "eligible renewable fuel"
• Hydroelectric
• Marine or hydrokinetic energy
• Geothermal energy

Eligible biomass fuels are defined as follows: "Fuel sources including brush, stumps, lumber ends and trimmings, wood pallets, bark, wood chips, shavings, slash and other clean wood that are not mixed with other unsorted solid wastes; by-products or waste from animals or agricultural crops; food or vegetative material; energy crops; algae; organic refuse-derived fuel; anaerobic digester gas and other biogases that are derived from such resources; and neat ‘eligible liquid biofuel’ that is derived from such fuel sources."  “Eligible liquid biofuel” is further defined as a liquid fuel “that is derived from eligible biomass fuel and that yields at least a 50 percent reduction in lifecycle greenhouse gas emissions relative to average lifecycle greenhouse gas emissions for petroleum distillate fuel…; or that is derived from waste feedstocks consisting of previously used or discarded…material resulting from…food service activities…Waste feedstock shall include, but not be limited to, waste vegetable oils, waste animal fats, substances derived from wastewater and the treatment of wastewater, or grease trap waste…”

Generating units that co-fire or blend both eligible and ineligible types of fuels-either for startup or as a means of keeping output consistent-may also qualify. If the ineligible fuel is used only to cold-start a unit that otherwise solely runs on a renewable fuel, then it is acceptable. Otherwise, the amount of total electrical output that qualifies for RECs will be proportionate to the net heat content of the eligible fuel as compared to all fuel consumed in the time period.  Emissions requirements also apply.

For fuel cells, eligible renewable fuel includes eligible biomass fuel and landfill methane gas; hydrogen is an eligible renewable fuel only when derived by methods detailed in the regulations.

Hydroelectric facilities must have a nameplate capacity no greater than 25 megawatts for Class I, and no greater than 5 megawatts for Class II. They may not involve any dam or water diversion structure constructed after December 31, 1997, or pumped storage of water.  Facilities must meet site-specific standards that address healthy river flows, water quality standards, fish passage and protection measures and mitigation and enhancement opportunities in the impacted watershed. Facilities can demonstrate compliance with these standards by achieving certification by the Low Impact Hydropower Institute, a non-profit organization that has established criteria for “low impact” hydroelectric facilities and implements the certification process. 

•  Generating units connected directly to the grid may be located anywhere within the control region of ISO-New England (ISO-NE), the independent system operator for the New England electricity marketplace. Grid-tied units outside of the ISO-NE control area may qualify, but their output must be verifiable by ISO-NE. Off-grid units may qualify, but only if they are located in Massachusetts. Other behind-the-meter (customer-owned) units must be located within the ISO-NE control area.

•  The electrical output of the generating unit must be verifiable by ISO-NE unless it qualifies as a small generating unit. A small unit must be able to verify its output in a manner satisfactory to the DOER, and it also must verify that its RECs are not being sold or used to satisfy RPS requirements outside of Massachusetts.