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MISO Prepares for FERC Order 881

Written by John Harmon, MISO Senior Operations Director

FERC Order 881, a directive issued by the Federal Energy Regulatory Commission (FERC) in December 2021, is reshaping the landscape of electric transmission. In response, MISO is actively working to comply with the Order alongside industry stakeholders. This order introduces new regulations aimed at enhancing the accuracy and transparency of electric transmission facility ratings used by transmission providers, such as MISO.

The Order requires that transmission providers take into account the natural cooling and heating effects of weather (Ambient Adjusted Ratings or AAR) to enhance available transmission capacity, which could alleviate transmission congestion. Additionally, the Order introduces several transparency measures that promote and enhance sharing of the Transmission Owner rating methodology and AAR data on password protected websites.

Compliance with Order 881 is a large effort, prompting MISO to take strategic action. Here is what MISO is doing to align with this mandate:

  • Internally, MISO has established cross-functional project teams and initiated an Order 881 program to ensure organizational alignment.
  • Externally, MISO has partnered with Transmission Owners within its footprint to help facilitate their compliance efforts through various initiatives:
    • Hosting regular workshops to foster discussions on solutions and progress.
    • Establishing a value-added weather information service that provides real-time and forecasted ambient conditions throughout the MISO footprint to Transmission Owners so they can use this information to calculate their facility AARs.
    • Providing regular communications to highlight key workshop outcomes and align preparation steps to meet compliance requirements.
  • MISO has also partnered with key vendors and the Linux Foundation to establish an open and freely available defacto standard to aid in the common and interoperable exchange of ratings data.

As solution development progresses, MISO will expand stakeholder engagement activities. In the first quarter of 2025, MISO will conduct system testing, including integration testing with Transmission Owners. Through these collaborative efforts, MISO is committed to achieving compliance with FERC Order 881 while fostering transparency and reliability within the electric transmission sector.

Additional information on FERC Order 881: Understanding the Requirements of FERC Order 881 – Midwest Reliability Organization (


John Harmon, Senior Operations Director, Midcontinent Independent System Operator

John Harmon is Senior Operations Director responsible for MISO’s Reliability Coordination function and real-time operations engineers, including outage coordination. He has held numerous leadership positions during his 16-year career at MISO, which includes operator training and compliance program implementation as well as oversight of MISO’s market functions which includes operations forecasting, unit commitment, day-ahead market, and MISO’s Financial Transmission Rights market. John has also served in various project management roles within MISO for new market product implementation and new member integration.

Prior to MISO, he was an electrical engineer at an independent engineering firm supporting electric utilities in the Midwest. John has a B.S. in Electrical Engineering from Rose-Hulman Institute of Technology.

In addition, John is a member of MRO’s Reliability Advisory Council.


MRO is committed to providing non-binding guidance to industry stakeholders on important industry topics. Subject matter experts from MRO’s organizational groups have authored some of the articles in this publication, and the opinion and views expressed in these articles are those of the author(s) and do not necessarily represent the opinions and views of MRO.