Effective August 3, 2012, the net metering provision as approved by the Massachusetts DPU limits net metering to 3% of a utility's historical peak load for private customers and 3% for public entities. National Grid's historical peak load of 5,131 MWs occurred on August 2, 2006 in its Massachusetts Electric territory; making each 3% limit equal to 153.93MW.
Note: The private limit also includes those public entities whose generator rating is less than 60kW. Neither limit includes projects that qualify as exempt Class I Net Metering Facilities (see 220 CMR 18.07(5)).
The aggregate capacities of Net Metering projects that fall under these caps (as of December 1, 2013) are as follows:
||Net Metering Service
*In order to receive Net Metering Services, all interconnection projects that do not qualify for the Simplified interconnection process (i.e. all projects over 15kW single-phase or over 25kW three-phase) must apply for and receive a cap allocation through MassACA
Note: As a result of Massachusetts DPU ruling 11-11-A (issued 10/25/2012), a new Massachusetts System of Assurance (MassACA) has been implemented by the DPU to monitor the available cap allocations and determine eligibility for Net Metering with regard to the private and public caps.
Net Metering Eligibility:
Subject to the limitations provided by the DPU (summarized in the separate list below), customers are eligible to receive new Net Metering Services if their distributed generation facilities are:
- Class I Facilities - Up to 60 kW(AC) in aggregate generation capacity
- Class II Facilities (for wind, solar, anaerobic digesters, and agricultural facilities)
- Private Facilities - Up to 1,000 kW(AC) in aggregate generation capacity
- Public Facilities - Up to 2,000 kW(AC) in aggregate generation capacity
- Class III Facilities (for wind, solar, anaerobic digesters, and agricultural facilities)
- Private Facilities - Up to 2,000 kW(AC) in aggregate generation capacity
- Public Facilities - Up to 10,000 kW(AC) in aggregate generation capacity
The DPU limitations to Net Metering Services include (but are not necessarily limited to):
Note: Distributed generation facilities, which are not eligible for Net Metering Services, may alternatively register as Qualifying Facilities in order to sell excess power to National Grid at wholesale rates. (Refer to the section about Qualifying Facilities below.)
Net Metering Purpose:
- DPU 11-11-A (issued 5/7/2012) requires that as of April 24, 2013 all host customers must receive a cap allocation through the Massachusetts System of Assurance for Net Metering Eligibility (MassACA) prior to being issued a new Net Metering Service.
- DPU 11-11-C (issued 8/24/2012) generally prohibits “gaming” of the rules and regulations that permit customers to receive Net Metering Services through the use of multiple meters. Therefore:
- Net Metering Services may only be provided to a host customer (up to the aggregate limits described above) through a single meter, at a single interconnection point, per each single legal parcel of land.
- As a corollary, Net Metering Services cannot be offered to a customer through a new, separate electrical service (or meter) if an existing service is already available on the same parcel of land.
Intermittent generators, such as solar- and wind-based generators, only produce electricity when their energy source is available (e.g. when the sun shines or the wind blows). Conversely, when their energy source is not available, intermittent generators do not produce power (and may even consume small amounts of electricity for their power electronics).
With distributed generation (DG), intermittent generators are often connected behind the same utility meter as customer loads (e.g. HVAC, consumer electronics, lights) that can be turned off and on based on the needs of the customer. As a result, on-site electric power production does not necessarily match on-site electric power consumption (also known as the customer ‘load’ or ‘demand’) on a moment-to-moment basis.
Therefore, sometimes DG customers are importing power from the grid (consuming more power than they are generating on-site), and other times DG customers are exporting power to the grid (generating more power than they are consuming on-site). In Massachusetts, net metering allows these DG customers to financially balance out the total amount of energy imported with the total amount of energy exported over the course of a billing period (typically about a month). Then, the customer is only billed (or credited) for the net difference between these two amounts.
Net Metering in Practice:
In most cases, National Grid simply reads the retail meter at the beginning and end of the billing period to determine the net energy import or export (in kWh) for the billing period.
Calculating Net Metering Credits (NMC):
- If the DG customer is a net importer (using more energy on-site than it generates) during the billing period, then National Grid will simply bill the DG customer for the net energy use (in kWh) during the billing period (which has already been reduced due to the on-site generation).
- If the DG customer is a net exporter (generating more energy on-site than it uses) during the billing period, then National Grid will: (1) bill the DG customer for zero kWh of energy usage and (2) credit the DG customer for the net energy exported to the grid during the billing period in the form of Net Metering Credits (NMC). Refer to the “Calculating Net Metering Credits” and “Allocating Net Metering Credits” sections below for more details.
- In all cases, DG customers will still be responsible to pay for any demand charge (measured in kW) and/or customer charges associated with the account. These charges will not be credited back to DG customers.
DISCLAIMER: The calculation of Net Metering Credits (NMC) in Massachusetts is determined based on the DPU 1177 “Net Metering Provision”
in section 1.01 and section 1.06. Please refer to this ruling for an official explanation of how to calculate NMC. However, for your convenience, National Grid has summarized how it calculates NMC based on the “Class” of the Net Metering Facility as defined by the DPU.
Based on the Facility Type, each billing period National Grid calculates a DG host customer’s NMC by adding up the applicable charges (in $/kWh) for the host customer’s account (see the table below) and multiplying that number by the net exported energy (in kWh). The result is that the DG customer’s bill is credited its NMC as a dollar-value credit. Refer to the “Allocating Net Metering Credits” section below for more details.
Applicable Charges for Distributed Generation Facilities
*Other types of generators with an aggregate capacity of >60kW are not eligible to receive Net Metering Services. These generators must be registered as Qualifying Facilities. (Refer to the section about Qualifying Facilities below.)
**Distribution Charge refers to the Distribution Energy Charge (billed in $/kWh), not the Distribution Demand Charge (billed in $/kW) applied under some rate classes.
||Class I,Class II and Class III
| Distribution Charge**
| Basic Service Charge
|Avg. Monthly ISO Clearing Price
Generally, the dollar-values of these charges can be found on the most recent electric bill for the host account. However, more information about rates and prices can be found using the following links:
Note: Customers are always responsible for the customer charge and any demand related charges, even if they are a net exporter during a billing month.
Allocating Net Metering Credits (NMC):
Once the Net Metering Credits (NMC) have been calculated as a dollar-value on a host customer’s account each billing period (see above), the DG system owner can allocate NMC to other National Grid electric billing accounts using the Schedule Z
Any NMC allocated to other accounts will accrue as a dollar-value credit on the other accounts’ bills during the next available billing period. Any NMC that are not allocated to other accounts will accrue on the host account as a dollar-value credit. Generally, unused NMC will accrue on accounts indefinitely (or until they are used). In other words, customers with Net Metering Services should NOT expect to receive a check or payment as compensation for accrued NMC.
*Generally, the Schedule Z allows National Grid’s Massachusetts Electric customers to allocate NMC to any National Grid (Massachusetts Electric) electric account within the same New England ISO load zone
(Western & Central MA; Boston & Northeastern MA; or Southeastern MA). However, National Grid’s Nantucket Electric customers may only allocate NMC to other electric accounts in the Nantucket Electric service territory. Also, generation capacity interconnected as a “Public” Net Metering Facility may only allocate NMC to other electric accounts in the name of a DPU-certified Public Entity.
Note: After the system owner is first offered the Authorization to Interconnect for the Net Metered Facility, the NMC may not be applied to the host account (where the net meter is located) until the following billing period. If the host account is transferring NMC to other accounts, the non-host account(s) may need to wait for an additional billing period (beyond the delay for the host account) before the NMC are applied to the non-host account(s).
First Bill Walk Through
Please review our First Bill Walk Through
presentation as a guide to understand your net metering bill.
Qualifying Facilities (for FERC):
Qualifying Facilities have several options for metering and billing. For a description of qualifying facilities please see the Electric-Qualifying Facilities
webpage on the Federal Energy Regulatory Commission's website.
For more information about the options for Qualifying Facilities, view our Rates Tariff
(pdf) and refer to “Qualifying Facility Power Purchase Rate P” (the second to last item in the document).
Contact E-mail: Distributed.Generation@us.ngrid.com
Please refer to the Interconnection Documents
webpage for a list of all relevant Net Metering documents.
Links noted by "(pdf)" are in PDF format and support Adobe Acrobat 5.0 and later. Download Adobe Reader, free software to view and print PDF files.