Generator Interconnection Cost Analysis in the Midcontinent Independent System Operator (MISO) territory

Publication Type

Policy Brief

Date Published




Electric transmission system operators (ISOs, RTOs, or utilities) require new large generators seeking to connect to the grid to undergo a series of impact studies before they can be built. This process establishes what new transmission equipment or upgrades may be needed before a project can connect to the system and assigns the costs of that equipment. Berkeley Lab has collected interconnection cost data from interconnection studies for the Midcontinent Independent System Operator (MISO), representing nearly 50% of all projects requesting interconnection from 2010 to 2020. Project-level cost summary data are available for download on this page.

We find:

  • Average interconnection costs have grown as the number of interconnection requests have escalated
  • Projects that have completed all required interconnection studies have the lowest cost compared to applicants still actively working through the interconnection process or those that have withdrawn.
  • Broader network upgrade costs are the primary driver of recent cost increase.
  • Potential interconnection costs for wind, storage, and solar are larger than for natural gas
  • Larger generators have greater interconnection costs in absolute terms, but economies of scale exist on a per kW basis.
  • Interconnection costs vary by location

Berkeley Lab will publish a series of short analytical papers of generator interconnection costs to the transmission system for MISO, PJM, SPP, ISO-NE and NYISO, which you can find at

Year of Publication



A brief overview of this study can be viewed here


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