Interconnection Standards

Last updated: July 28, 2020

Program Overview

Implementing Sector:State
Category:Regulatory Policy
Incentive Type:Interconnection
Web Site:
Eligible Renewable/Other Technologies:Solar Photovoltaics, Wind (All), Hydroelectric, Wind (Small)
Applicable Utilities:Investor-owned utilities and cooperatives
System Capacity Limit:10 MW
Standard Agreement:No
Insurance Requirements:Not addressed
External Disconnect Switch:Required
Net Metering Required:No


Name:Mont. Code § 69-8-601 et seq.
Date Enacted:1999
Name:Administrative Rules of Montana 38.5.84
Effective Date:8/13/2010


Interconnection Standards

In July 2010, the Montana Public Service Commission (PSC) adopted interconnection rules, effective August 13, 2010.  These rules apply to all-electric utilities under the PSC's jurisdiction, including investor-owned utilities and co-ops.  Small generators or systems up to 10 megawatts (MW) located on the land of utility customers within good standing are allowed to interconnect.  While there is no statewide standard interconnection agreement, the largest investor-owned utility in Montana, NorthWestern, does have a standard interconnection agreement for net-metered systems.  The use of certain equipment may qualify a facility for an expedited interconnection review.


Until August 2010, Montana had interconnection guidelines dictated by the net metering legislation, enacted in 1999.  These guidelines required interconnected facilities to comply with all national safety, equipment, and power-quality standards established by the National Electrical Code (NEC), the Institute of Electrical and Electronics Engineers (IEEE), the National Electrical Safety Code (NESC) and Underwriters Laboratories (UL). Net metering applies to systems up to 50 kilowatts (kW) in a capacity that generate electricity using hydropower, wind, or solar energy. The law does not set a limit on the aggregate capacity of systems interconnected to each utility's distribution system.

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