GMP - Green Mountain Power (VT)

Vermont Utility Interconnection & net metering rules

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Tariffs and interconnection rules move often. If something here is out of date or missing, tell us and we'll fix it.

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Net Metering AllowedYes
NEM TypeMonthly
Supply Side Taps AllowedNo
Line Taps AllowedYes
Load Taps AllowedYes
AC Disconnect RequiredYes

Net metering & export

Net Metering Allowed
Yes
NEM Type
Monthly
TOU Utility
Yes
Post Solar Billing Method
Export Rate
Net Excess Generation Notes

Current blended rate for excess credit is $.15417

Rebates Offered
No
Deregulated
No
Allows Standby
Yes

Interconnection & taps

Approval Req To Install
Yes
Supply Side Taps Allowed
No
Line Taps Allowed
Yes
Load Taps Allowed
Yes
Tap Criteria


Automatic Transformer Upgrade Size
0
Meter Aggregation Allowed
Yes

System size & offset

System Size Restrictions
0
System Size Restriction Type
No Restrictions
System Size Battery Included
No
System Size Includes Existing Systems
No
Offset Type
No Restrictions
Offset Value
0
Offset Calculation Period
0
Industry Standard Watts Sqft
2
System Offset Notes

Ground Mount systems cannot exceed 25kW AC

Metering & disconnect

Production Meter Required
Yes
Production Meter Position
Inv-PM-Disco-POI
Production Meter Labeling
Production Meter
AC Disconnect Required
Yes
AC Disconnect Labeling
Visible Lockable Labeled Disconnect
Allowed Meter Adapter
Tesla Backup Switch,ConnectDER

Plans & docs

Site Plan Reqs

For PV arrays, include the anticipated location of central inverters and GSU Transformer(s). For rotating machines, include floorplans of the generator building. GMP may need seven feet of unobstructed wall space inside generator buildings for a control and communications cabinet. Although not required on the application site plan, required conduits paths should be detailed prior to the start of construction.


All Ground mounted projects OVER 25 kW AC require significant impact and environmental studies to be completed by /HO at HO's expense.

SLD Reqs
  • Existing system must be shown on Site Plan and Line Diagram
  • Projects over 150 KW in size require the One-Line Diagrams to be signed and stamped by a licensed Electrical Engineer (PE).
  • GMP accepts PE licenses issued by the states other than Vermont but not foreign issued licenses. If a one-line is revised after the application is submitted, the applicant is responsible to provide GMP an updated PE stamped copy.
  • One-lines must include wire specifications for customer owned primary including approximate lengths. Customer one-lines should show facilities up to the point of common coupling (PCC) which is typically one of the following: a. Primary riser when transformation is customer owned b. Secondary meter when transformation is GMP owned
  • The nameplate rating of the generator should be stated, not the de-rate anticipated by fuel source or genset limitations. GMP expects generators to operate at or near unity power factor unless otherwise agreed upon. The kVA base rating listed in Section 3, not the nameplate kW, could determine whether GMP requests the 5.100 or 5.500 application and applicants should check with GMP if unsure of which application form to use. For rotating machines if the generator specification sheets list multiple models, highlight the ratings applicable to the planned unit. For inverters list the aggregate nameplate kW AC rating

Install Reqs

A manual disconnect switch is required for all facilities rated above 150kW AC. A manual disconnect switch is not required for inverter interfaced facilities rated 150kW or less but is still a requirement for rotating generation rated 150kW or less.

Net Metering disconnect is required for all inverter-based system regardless of output capacity.

Where required, the switch is to be a utility accessible, lockable, load break rated, visible break disconnect switch with safe working clearances as determined by GMP safety standards. The disconnect switch must be located between the area EPS and the DR Unit and capable of interrupting the generator and/or load current.

Placards
  • The DR Customer is responsible to affix a weatherproof, permanent label to the switch labeled “GENERATOR DISCONNECT SWITCH”. If the disconnect switch is not located within 40 feet line of sight from the Company revenue meter the DR Customer is responsible to post a weatherproof map at the meter. The map must be a site plan clearly identifying the disconnect switch location.
  • Main Service Meter Label: Net Metering 
  • AC Disconnect Label: Solar (or PV) Disconnect 
  • Solar Rate Meter (PV meter) label: "GROSS GENERATION METER *Bottom Terminals Energized"
  • Battery Meter, if applicable Label: Battery Meter 
  • Battery AC Disconnect, if applicable Label: Battery Disconnect 
  • Example document saved to files below named "GMP Socket Labeling"
Meter Num Req SLD 3LD
No
ESID Num Req SLD 3LD
No
Site Plan Notes

Existing system must be shown on Site Plan and Line Diagram

Electrical Diagram Notes

Existing system must be shown on Site Plan and Line Diagram

Website
link
Phone
(802) 770-3399
Compiled from public records, 2026. Tariffs and interconnection rules change; verify with GMP - Green Mountain Power (VT) before you rely on this. The useful move: if an installer says you need a main panel upgrade, ask how these tap and interconnection policies were considered first.