Net Metering
The net-metering provision as approved by the MA DPU limits net-metering to 1% of a utility's historical peak load for private customers There are regulations being promulgated to expand the net-metering cap to allow 2% for municipalities. Once in place, the amount of projects that would fall under these caps would be as follows:
National Grid’s historical peak load of 40.8 MWs occurred on July, 22, 2011 in Nantucket Electric territory; making the 1% limit 408 KWs and the 2% limit 816 KWs.
As of January 6, 2012 in Nantucket, there are 21.06 KWs with net-metering service under the 1% limit and 100 KWs with net-metering service under the 2% limit.
There are 12 KWs with net metering applications in the process of being interconnected under the 1% limit and of those 12 KWs have returned the Schedule Z.
There are 900 KWs with net metering applications in the process of being interconnected under the 2% limit and of those 0 KWs have returned their Schedule Z.
Who is eligible: Customers with generating facilities up to 60 KW in aggregate capacity are eligible. Wind, solar and agricultural facilities up to 2,000 KW in aggregate capacity are also eligible.
Who is NOT eligible: All other generating facilities not described above are ineligible for net metering. Non-solar, non-wind, and non-agricultural facilities over 60 kW are not eligible for net metering. Those facilities which are ineligible may be able to sell excess power to National Grid at wholesale rates if they can meet the requirements of a Qualifying Facility.
What is net metering: Solar and wind based systems are intermittent generators which only produce electricity when a source of energy is present (e.g. when the sun is shining for solar and wind blowing for wind). When a source of energy is not present the generator does not produce power and may even use electricity for power electronics. Customer loads vary over time (e.g. lights, HVAC, plug loads, etc).
Customers who have a solar photovoltaic systems and/or wind turbine systems will draw power from the electric grid when their generation does not meet the energy needs of the facility loads. These same customers may send power to the grid at times when their electric generation exceeds the energy needs of the facility. Net metering allows the customer to net out the energy drawn from the grid with energy sent to the grid over a billing period (billing month). For most small customers (residential and small business), National Grid simply reads the retail meter at the beginning and end of the billing month to determine the net use or export.
At the end of a billing month, if a customer has used more energy than they have sent out to the grid (i.e. their meter reading went up during the billing month), they will only have to pay energy related charges for the net energy used during the billing month. They used all the energy produced by their generator during the billing month, and this reduced the energy they had to purchase from the utility. If the customer has sent more energy to the grid than was drawn from the grid during the billing month (i.e. their meter reading went down during the billing month), then the customer is a net exporter during that billing period. When a customer is a net exporter during a billing period, they are billed for zero kilo-watt hour usage and a renewable generation credit will be applied to the account.
The credit is determined by multiplying the net export kWH times the sum of the eligible charges. There are 3 sets of eligible charges that may be applied and vary by classification. The classifications and net metering calculations are listed under the M.D.P.U. No 1177 Net Metering Provision section 1.01 and section 1.06. The determinants are provided below for your reference:
Class I Net Metering Facility means a plant or equipment that is used to produce, manufacture, or otherwise generate electricity and that is not a transmission facility and that has a design capacity of 60 kilowatts or less.
Class II Net Metering Facility means an Agricultural Net Metering Facility, Solar Net Metering Facility, or Wind Net Metering Facility with a generating capacity of more than 60 kilowatts but less than or equal to one megawatt; provided, however, that a Class II Net Metering Facility owned or operated by a Customer which is a municipality or other governmental entity may have a generating capacity of more than 60 kilowatts but less than or equal to one megawatt per unit.
Class III Net Metering Facility means an Agricultural Net Metering Facility, Solar Net Metering Facility, or Wind Net Metering Facility with a generating capacity of more than one megawatt but less than or equal to two megawatts; provided, however, that a Class III Net Metering Facility owned or operated by a Customer which is a municipality or other governmental entity may have a generating capacity of more than one megawatt but less than or equal to two megawatts per unit.
Calculation of Net Metering Credits
Qualifying Facilities have several options on 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 on the options for Qualifying Facilities, view our Rates Tariff (pdf)—Qualifying Facility Power Purchase Rate P. Please see the Qualifying Facility Power Purchase Rate P for more information on the options for such a facility. To find the tariff, click on the following link and navigate down on the bookmarks to the second to last item titled "Qualifying Facility Power Purchase Rate P. Tariff Document (pdf)
Interconnection Information
Contact E-mail:
Distributed.Generation@us.ngrid.com
National Grid’s historical peak load of 40.8 MWs occurred on July, 22, 2011 in Nantucket Electric territory; making the 1% limit 408 KWs and the 2% limit 816 KWs.
As of January 6, 2012 in Nantucket, there are 21.06 KWs with net-metering service under the 1% limit and 100 KWs with net-metering service under the 2% limit.
There are 12 KWs with net metering applications in the process of being interconnected under the 1% limit and of those 12 KWs have returned the Schedule Z.
There are 900 KWs with net metering applications in the process of being interconnected under the 2% limit and of those 0 KWs have returned their Schedule Z.
Who is eligible: Customers with generating facilities up to 60 KW in aggregate capacity are eligible. Wind, solar and agricultural facilities up to 2,000 KW in aggregate capacity are also eligible.
Who is NOT eligible: All other generating facilities not described above are ineligible for net metering. Non-solar, non-wind, and non-agricultural facilities over 60 kW are not eligible for net metering. Those facilities which are ineligible may be able to sell excess power to National Grid at wholesale rates if they can meet the requirements of a Qualifying Facility.
What is net metering: Solar and wind based systems are intermittent generators which only produce electricity when a source of energy is present (e.g. when the sun is shining for solar and wind blowing for wind). When a source of energy is not present the generator does not produce power and may even use electricity for power electronics. Customer loads vary over time (e.g. lights, HVAC, plug loads, etc).
Customers who have a solar photovoltaic systems and/or wind turbine systems will draw power from the electric grid when their generation does not meet the energy needs of the facility loads. These same customers may send power to the grid at times when their electric generation exceeds the energy needs of the facility. Net metering allows the customer to net out the energy drawn from the grid with energy sent to the grid over a billing period (billing month). For most small customers (residential and small business), National Grid simply reads the retail meter at the beginning and end of the billing month to determine the net use or export.
At the end of a billing month, if a customer has used more energy than they have sent out to the grid (i.e. their meter reading went up during the billing month), they will only have to pay energy related charges for the net energy used during the billing month. They used all the energy produced by their generator during the billing month, and this reduced the energy they had to purchase from the utility. If the customer has sent more energy to the grid than was drawn from the grid during the billing month (i.e. their meter reading went down during the billing month), then the customer is a net exporter during that billing period. When a customer is a net exporter during a billing period, they are billed for zero kilo-watt hour usage and a renewable generation credit will be applied to the account.
The credit is determined by multiplying the net export kWH times the sum of the eligible charges. There are 3 sets of eligible charges that may be applied and vary by classification. The classifications and net metering calculations are listed under the M.D.P.U. No 1177 Net Metering Provision section 1.01 and section 1.06. The determinants are provided below for your reference:
Class I Net Metering Facility means a plant or equipment that is used to produce, manufacture, or otherwise generate electricity and that is not a transmission facility and that has a design capacity of 60 kilowatts or less.
Class II Net Metering Facility means an Agricultural Net Metering Facility, Solar Net Metering Facility, or Wind Net Metering Facility with a generating capacity of more than 60 kilowatts but less than or equal to one megawatt; provided, however, that a Class II Net Metering Facility owned or operated by a Customer which is a municipality or other governmental entity may have a generating capacity of more than 60 kilowatts but less than or equal to one megawatt per unit.
Class III Net Metering Facility means an Agricultural Net Metering Facility, Solar Net Metering Facility, or Wind Net Metering Facility with a generating capacity of more than one megawatt but less than or equal to two megawatts; provided, however, that a Class III Net Metering Facility owned or operated by a Customer which is a municipality or other governmental entity may have a generating capacity of more than one megawatt but less than or equal to two megawatts per unit.
Calculation of Net Metering Credits
- For a Class I Wind Net Metering Facility, Class I Solar Net Metering Facility, Class I Agricultural Net Metering Facility, Class II Net Metering Facility, and Class III Net Metering Facility where the Host Customer is a municipality or other governmental entity, the Company shall calculate for each Billing Period a Net Metering Credit equal to the product of the excess kWh, by time-of-use if applicable; and sum of the following Distribution Company charges applicable to the rate class under which the Host Customer takes service:
- The basic service kWh charge
- The distribution kWh charge
- The transmission kWh charge
- The transition kWh charge
- For a Class I Net Metering Facility other than a Class I Wind Net Metering Facility, Class I Agricultural Net Metering Facility, or a Class I Solar Net Metering Facility, the Distribution Company shall calculate a Net Metering Credit for each Billing Period as the product of the excess kWh, by time-of-use if applicable; and average monthly clearing price at the ISO-NE.
- For a Neighborhood Net Metering Facility or a Class III Net Metering Facility where the Host customer is not a municipality or governmental entity, the Distribution Company shall calculate a Net Metering Credit for each Billing Period as the product of the excess kWh, by time-of-use if applicable; and sum of the following Distribution Company charges applicable to the rate class under which the Host Customer takes service:
- The basic service kWh charge
- The transmission kWh charge
- The transition kWh charge
- Net Metering Tariff
- Interconnection Standards
- Schedule Z
Note:-Note:- Help information regarding highlighted input fields is available at the bottom of the window in the status bar!
Qualifying Facilities have several options on 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 on the options for Qualifying Facilities, view our Rates Tariff (pdf)—Qualifying Facility Power Purchase Rate P. Please see the Qualifying Facility Power Purchase Rate P for more information on the options for such a facility. To find the tariff, click on the following link and navigate down on the bookmarks to the second to last item titled "Qualifying Facility Power Purchase Rate P. Tariff Document (pdf)
Interconnection Information
Contact E-mail:
Distributed.Generation@us.ngrid.com
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.
