SREC II – Production Metering Requirements
1. ACCURACY REQUIREMENTS
Metering equipment must meet the accuracy requirements of ISO New England Operating Procedure
No. 18 or any successor thereto or the Small Generator Metering Protocol specifications (below) per
NEPOOL GIS Rule 2.5(j).
Minimum Accuracy Requirements
Only "revenue grade" (also called "revenue quality") meters tested and certified to ANSI C-12
standards are allowed. Minimum accuracy and other requirements, based on nameplate capacity, are
as follows:
Nameplate
Capacity (DC)
Minimum Meter
Accuracy
(all values are +/-)
Up to 10 kW, using nonautomated reporting
2%
(ANSI C-12.1-2008 )
Meters used as part of a
Data Acquisition System
(“DAS”) must meet the
"Greater than 10 kW and
up to 1 MW" nameplate
capacity requirements
below.
Greater than 10 kW and
up to 1 MW
Greater than 1 MW
1%
(ANSI C12.16 or better)
0.5%
(ANSI C12.20-2010
Other Requirements
Electromechanical meters may be used. Refurbished meters, if
retested and certified, may be used. Allowable configurations for
meters are :

Single-phase 120 volt - Form 1S, Class 100

Single-phase 240 volt - Form 2S, Class 200

Three-phase 120 - 480 volt - Form 14- 16S, Class 200
Only new solid state meters are allowed. Current transformers
(“CTs”) must conform to the 0.6% (ANSI/IEEE C57.13-2008) accuracy
class, or the meter must be tested using the CT and certified to meet
the minimum accuracy requirement.
Only new meters are allowed. CTs must conform to the 0.3%
(ANSI/IEEE C57.13-2008) accuracy class.
Version 2.0 April 24, 2015 2015
2. METER TESTING AND CALIBRATION
Meters shall be tested, and as needed calibrated or replaced, in accordance with Table 2 below.
Meter Testing Requirements
Category (kW
– DC)
Up to10 kW
Minimum Frequency
None
Greater than
10 kW and up
to 500 kW.
As required by DAS
Vendor requirements
and best practices
Greater than
500 kW
least once every two
years per NEPOOL OP18
Other Requirements
MassCEC at its discretion may require testing or
replacement of a meter associated with unreasonable
energy production reports.
DAS Vendors are required to demonstrate energy reports
to the PTS are within +/- 1% of the meter registry for an
individual system. MassCEC at its discretion may require
testing or replacement of meter associated with
unreasonable energy logged by the meter registry.
Only new meters are allowed. CTs must conform to the
0.3% (ANSI/IEEE C57.13-2008) accuracy class.
3. THE SOLAR METER PLACEMENT
The solar PV production meter may be installed at any point between the AC output of an inverter and
the point of interconnection with the electric grid.
As an alternative, energy reported from a utility owned net-meter installed on the utility side of the
electric service may be used in lieu of a solar production meter where:
1) the output from a solar PV inverter is interconnected on the utility side of the electric service
2) as long as the PV array is the only generator or energy storage system behind the utility net
meter.
4. TREATMENT OF PARASITIC LOAD
Per the Renewable Energy Portfolio Standard (RPS) 225 Code of Massachusetts Regulations (CMR)
14.02, energy consumed by parasitic load, which is not otherwise accounted for by the solar PV
production meter, must be excluded from reported generation values.
For the purposes of SREC II metering requirements, unaccounted for parasitic load is defined as the tare
loss associated with nighttime energy consumption by an inverter. Tare loss of less than or equal to the
levels listed below (as reported by the inverter manufacturer) is deemed to be de minimis and is not
required to be excluded from the meter reading. When bi-directional (net) meters are used to report
production the value reported shall be the “delivered” energy, not the “net” energy.
Inverter Rated Output
(AC)
10 kW or less
Tare Loss de minimis Level
(Watts)
30
Greater than 10 kW up to 100 kW
330
Greater than 100 kW up to 1 MW
3,330
Greater Than 1 MW
8,200
If the tare losses of an individual inverter exceed the de minimis levels contact MassCEC for further
guidance on reporting.
5. MULTIPLE INVERTER SYSTEMS
Multiple inverter systems which combine output power from the multiple inverters before
interconnecting to the gird, and which are registered in the PTS as a single PV system, shall have only
one meter that measures the combined energy output.
6. METER LABELING
PV system meters shall have weather resistant labeling that clearly associates the meter with the PV
system. For example “PV Production Meter.”
7. METER START
All new and refurbished meters shall be set at 000000 or 999999 at time of shipment to the installer to
ensure accurate and consistent “start” readings for every system.
8. METER WARRANTY
A meter warranty of not less than one year is required on all new and refurbished meters.