Sign in Subscribe
Public utilities

Wisconsin Public Service Commission Updates Regulatory Framework for Firm Capacity Calculations

Strategic Insights

— 2 min read

The Public Service Commission of Wisconsin has released a regulatory update regarding the Firm Capacity - DLOL input file for the PLEXOS modeling. The update clarifies the methodology used by Wisconsin Electric Power Company and Wisconsin Public Service Corporation to calculate Firm Capacity, which includes the use of DLOL class-level accreditation values. The companies have provided detailed explanations and calculations in supplemental attachments, including an excel spreadsheet showing how DLOL class-level accreditation values are used to calculate Firm Capacity for all existing, candidate, and generic units that use class-level accreditation values.

Key Takeaways:

  • The Public Service Commission of Wisconsin has issued a regulatory update regarding the Firm Capacity - DLOL input file for the PLEXOS modeling.
  • The update clarifies the methodology used by Wisconsin Electric Power Company and Wisconsin Public Service Corporation to calculate Firm Capacity, which includes the use of DLOL class-level accreditation values.
  • The companies have provided detailed explanations and calculations in supplemental attachments, including an excel spreadsheet showing how DLOL class-level accreditation values are used to calculate Firm Capacity for all existing, candidate, and generic units that use class-level accreditation values.
  • The calculation of thermal resource SAC for planning years 2023-2027 is computed using MISO Tariff Schedule 53 and equals: ISACunit * Ratio UCAP/ISACSeason.
  • For planning years 2028 forward, MISO will compute thermal resource SAC using Schedule 53a or DLOL SAC, with the DLOL SAC calculation defined as: SACDLOL = Resource Class-Level UCAP * (Resource ISAC / Resource Class-level ISAC).
  • The companies have utilized information provided by MISO to better understand how DLOL will be applied, which has evolved over time, making it difficult to utilize in long-term planning.
  • The companies have provided a significant number of modeling sensitivities in its analyses to account for this uncertainty.

Statistics:

  • The calculation of thermal resource SAC for planning years 2023-2027 is computed using MISO Tariff Schedule 53.
  • The calculation of thermal resource SAC for planning years 2028 forward will be computed using Schedule 53a or DLOL SAC.
  • The DLOL SAC calculation is defined as: SACDLOL = Resource Class-Level UCAP * (Resource ISAC / Resource Class-level ISAC).
  • Renewable units, i.e. wind, solar, and hydro ISAC values, are equal to their ICAP values.
  • Battery facilities' ISAC values are equal to their ICAP values times 0.95, an internal assumption/placeholder.
  • Generic natural gas fueled units ISAC values incorporate a 0.97 adjustment factor compared to their ICAP value, an internal assumption/placeholder.
  • Generic natural gas fueled units DLOL values include an individual adjustment factor of 1.10, i.e. 10% improvement.
  • Existing natural gas fueled units that are either relatively new (Weston RICE) or have firm fuel (PWGS and Fox Energy) incorporate a 1.05 individual adjustment factor (5%) for their seasonal DLOL capacity values.

Sources:

  • PSCW-AMG-4.10 (WEPCO and WPSC)
  • Confidential attachments provided by Wisconsin Electric Power Company and Wisconsin Public Service Corporation
  • MISO Tariff Schedule 53
  • Schedule 53a
  • PSC Ref No. 543400 (filed in response to PSCW data request WK-1.2 in docket 5-EI-2025)
  • Docket No. 5-BS-280
  • PLEXOS modeling
  • Schedule 53a Section VI H

Read more