Subject to the limitations provided by the RI PUC (summarized in the list below), customers are eligible to receive new Net Metering Services if their distributed generation facilities:
Use an eligible resource (refer to R.I.G.L. Chapter 39-26-5 for official requirements):
Are sized to not exceed:
3 year average on-site load
5MW AC aggregate generating capacity
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.)
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 Rhode Island, 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.
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.
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.
The calculation of Net Metering Credits (NMC) in Rhode Island is determined based on the RI PUC No. 2075 Net Metering Provision. Please refer to this ruling for an official explanation of how to calculate NMC. An excerpt from this provision is provided below:
"Renewable Net Metering Credit" shall mean a credit that applies to an Eligible Net Metering System up to one hundred percent (100%) of the Renewable Self-generator's usage at the Eligible Net Metering System Site over the applicable billing period. This credit shall be equal to the total kilowatt-hours of electricity generated and consumed on-site during the billing period multiplied by the sum of the:
Standard offer Service kilowatt-hour charge for the rate class applicable to the net metering customer;
Distribution kilowatt-hour charge;
Transmission kilowatt-hour charge; and
Transition kilowatt-hour charge.
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.
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 B form.
Only net metering systems that are at an "Eligible Net Metering System Site" as defined in the RI PUC No. 2075 Net Metering Provision are eligible to allocate credits. Please refer to this ruling for an official explanation of eligibility (summarized in the list below). The net metering system must:
Include an eligible generating facility (see above).
Be located in the same geographical location, such that:
The net metering system is located on part of a campus, complex, or farm with contiguous sites; OR
The net metering system is owned or operated on behalf of a municipality or multi-municipal collaborative through a municipal net metering financing arrangement.
Be used to allocate NMC only to accounts of the same customer of record. (Generally, names on accounts may not be changed for the purpose of allocating credits.)
This does not apply if the net metering system is part of a multi-municipal collaborative.
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. Customers with Net Metering Services should NOT expect to receive a check or payment as compensation for accrued NMC.
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).
Please review our First Bill Walk Through presentation as a guide to understand your net metering bill.
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, please review the Massachusetts DPU QF website , and then 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@nationalgrid.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.