The Massachusetts Department of Public Utilities (DPU) adopted amended net metering rules in July 2009 (see final order). These DPU rules were ordered in accordance with the MA Green Communities Act passed in July 2008.  In August 2009, the DPU issued its model net metering tariff and directed the utilities to file compliance tariffs, which are currently filed and under consideration (the DPU has given notice of a suspension of the effective date until December 2009 to provide ample time for public hearings on the filed tariffs - it is possible that the tariffs will go into effect prior to Dec 2009).    
 
The state's investor-owned utilities must offer net metering. Municipal utilities are not obligated to offer net metering, but they may do so voluntarily. The aggregate capacity of net metering is limited to 1% of each utility’s peak load.  For the purpose of calculating the aggregate capacity, the capacity of a net-metered solar facility is 80% of the facility’s DC rating at standard test conditions (STC) and the capacity of a net-metered wind facility is the name plate capacity. The DPU has directed the utilities to report the aggregate capacity of net metered facilities on a regular basis.   
 
In Massachusetts, there are several categories of net metering facilities. "Class I" facilities are defined as systems up to 60 kW in capacity. "Class II" facilities are generally defined as systems greater than 60 kW and up to one megawatt (MW) in capacity that generate electricity from agricultural products, solar energy or wind energy. "Class III” facilities are generally defined as systems greater than 1 MW and up to 2 MW in capacity that generate electricity from agricultural products, solar energy or wind energy. Massachusetts also allows “neighborhood net metering” for neighborhood-based Class I, II or III facilities that are owned by (or serve the energy needs of) a group of 10 or more residential customers in a single neighborhood and served by a single utility. The neighborhood facility may also serve additional customers (including commercial) as long as the base requirements are met. All net-metered facilities must be behind a customer’s meter, but only a minimal amount of load located on-site is required.  
 

	Size of Facility
Class I	< 60 kW
Class II	> 60 kW; < 1 MW*
Class III	> 1 MW; < 2 MW*
* For municipalities and government entities, size applies on a per-unit basis, rather than per facility.

The treatment of customer net excess generation (NEG) varies by facility class and customer type. In all cases, the NEG is monetized and Net Metering Credits are calculated based on the excess kilowatt hours (kWh) produced. In summary, value of the Net Metering Credits at the end of a billing period is slightly less than the utility’s full retail rate for Class I solar and wind facilities, Class II facilities, and Class III facilities used by government customers as they would receive credit for the default service, distribution, transmission, and transition charge (kilowatt hour, kWh). Net Metering Credits for Class III facilities and neighborhood facilities that are used by customers other than government entities differs only in that they do not receive credit for the distribution component. Class II and Class III customers are required to install revenue-grade meters to measure kWh output.  

 

 

Credit Calculation		Units	Class I	Class I- Wind, PV, Ag.	Class II	Class III	Neighborhood Net Metering
	Customer Charge	$/month
Delivery	Distribution Charge	¢/kWh		ü	ü	*
	Transmission Charge	¢/kWh		ü	ü	ü	ü
	Transition Charge	¢/kWh		ü	ü	ü	ü
	System Benefit Charge
	DSM (EE)	¢/kWh
	RE	¢/kWh
Supply	Basic Service	¢/kWh		ü	ü	ü	ü
Generation	Average Monthly Clearing Price at the ISO-NE	¢/kWh	ü
	* Only applies to class III municipalities and governmental entities

Credits may be carried forward to the next month indefinitely, and credits from net metering facilities may be transferred to another customer of the same utility as long as they are within the same service territory and ISO-NE load zone. Utilities may choose to pay for the net metering credits for Class III facilities rather than allocating the credits. If a neighborhood facility has NEG at the end of a billing period, the credits are awarded to designated neighborhood customers. The amount of NEG attributed to each such customer is determined by the allocation provided by the neighborhood net metering facility.   
 
Third-party owned systems may be net metered. Utilities are not granted the renewable energy credits or environmental attributes generated by a net metered facility.  
 
Customers apply for net metering by completing the interconnection application and the utility's accompanying net meteinrg tariff (known as "Schedule Z" in the model net metering tariff). See the MA DG and Interconnection Main Page for links to the utility interconnection tariffs.