Generator Interconnection Costs to the Transmission System - Summary Briefing

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Berkeley Lab has published a series of briefs analyzing interconnection cost trends across five U.S. wholesale electricity markets. The series employs extensive data collection (2500+ project-level interconnection cost estimates) and analysis for MISO, PJM, SPP, NYISO, and ISO-NE. The data provides developers, regulators, policymakers, and other stakeholders with critical insights about interconnection cost data that are often difficult and inefficient for the public to obtain. This presentation offers a summary of the analyses followed by key results for each market. We find:

  • Interconnection queues have exploded over the past years, resulting in lengthy study processes with high applicant withdrawal rates.
  • Interconnection cost estimates are not available as pre-request information but require a lengthy interconnection study process. Final cost estimates remain difficult to collect.
  • Interconnection costs have grown substantially over time in all studied regions.
  • 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the lowest cost compared to applicants still actively working through the interconnection process or those that have withdrawn.
  • Upgrade requirements of the broader transmission system are the primary cost driver.
  • Many projects facing high interconnection costs withdraw from the queue.
  • Renewables and storage projects have higher interconnection costs than natural gas power plants.
  • Larger generators have greater interconnection costs in absolute terms, but economies of scale can exist on a per kW basis.
  • Interconnection costs vary by location

This work was funded, in part, under the U.S. Department of Energy’s Interconnection Innovation e-Xchange (i2X)

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A brief overview of this study can be viewed here

A webinar recorded on June 29, 2023 discussing this research can be viewed here


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