Interconnection guidelines - Great River Energy

What interconnecting parties need to know

If you are interconnecting to Great River Energy’s transmission system (generation developer, load or other transmission owner), you are required to follow our interconnection guidelines. Depending on your request type you may need to:

  • Use “good engineering practices,” as specified by North American Electric Reliability Corporation (NERC)
  • Fund a system impact study
  • Fund a facilities study

Federal Energy Regulatory Commission (FERC) rules require electric utilities to treat all electric transmission users in a comparable manner, including other utilities and non-utility users of the transmission system, such as generation developers or large loads.

Midcontinent Independent System Operator (MISO) supervises the connection of new generation facilities and use of the transmission network. MISO reviews proposed connections to determine if they meet established criteria. Generation developers seeking interconnection to the transmission system must go through the MISO interconnection process.

Entities seeking to interconnect to Great River Energy’s transmission system are required to go through our interconnection process.

Two studies must be completed

Before any new interconnection point can be connected to the transmission system, two separate studies must be completed. Great River Energy performs the studies for transmission interconnection requests. MISO performs the studies for generation interconnection requests.

  • System Impact Study to evaluate the impact of a proposed interconnection on the transmission system.
  • Facilities Study to evaluate the facilities, network modifications and upgrades to the transmission system and estimate the costs and construction timeline to accommodate the transmission interconnection.

The interconnecting party is responsible for:

  • The cost of these studies
  • Following the Great River Energy or MISO study process
  • Making the study results available to the public, if required

System Impact Study

The System Impact Study (SIS) report contains information about the proposed interconnection and how it is used. The report is important both for the protection of the party connecting to the electric system as well as the other transmission users.

The SIS will determine if the transmission system has adequate load serving capability and the major components required to interconnect with the Great River Energy transmission system. The SIS may include, but not be limited to:  power flow analysis, fault study, stability study (if required), transient switching analysis, reliability requirements and impact to other customers on the Great River Energy transmission system. During the analysis, additional details of the proposed facility may be required and will be requested from the interconnecting party as necessary.

Facilities Study

The Facilities Study will determine (a) any transmission system upgrades needed to accommodate the transmission interconnection request, (b) the estimated costs of any transmission system upgrades, and (c) an estimated date that the transmission system upgrades will be completed and ready for in-service. During the analysis, additional details of the proposed point of interconnection may be required and will be requested as necessary.

Existing Transmission Interconnection Modification form

This process exists for modification(s) by a third party to existing Great River Energy equipment or changes to an existing interconnection.  Requests will be analyzed to guarantee the proposed system changes do not result in negative impacts to grid reliability.

Great River Energy reserves the right to request that the interconnection customer submit a new interconnection request and also to perform a System Impact Study and a Facilities Study depending on the specifics of the modification requested.

Great River Energy requires a minimum of two years advance notice prior to the project in-service date. This allows Great River Energy time to complete the various studies, execute agreements, obtain project approval, allocate resources, procure project materials, and construct the required transmission facilities for the interconnection. For projects with fewer than two years advance notice, Great River Energy cannot guarantee the interconnecting party will meet its requested in-service date, but Great River Energy will expedite the process as much as possible.

How to start the process

If you need to connect to Great River Energy’s transmission system, please e-mail:

Generators seeking to interconnect should contact MISO and follow their interconnection process.