FERC Order 881: The Countdown for Compliance is Here

FERC 881 enhances transmission line rating and reporting using real-time weather intelligence.

With less than a year until the Federal Energy Regulatory Commission (FERC) 881 mandate goes into effect, many of the nearly 9,000 electric utilities in the United States are still grappling with implementation. The groundbreaking order, issued in 2021, aims to enhance the efficiency and reliability of the U.S. electric grid by improving transmission line rating and reporting using real-time weather intelligence.

 

How Weather Impacts Line Rating

Multiple weather parameters affect transmission lines – from capacity to mechanical stress and direct damage. Temperature conditions and wind are two significant factors that affect transmission capacity.

Lines can carry more current in cooler conditions because cooler temperatures help dissipate heat generated by the electrical current. Conversely, hot conditions limit the ability to dissipate heat, increasing the risk of overheating, sagging, and potential damage to the lines.

Other weather factors include rain and wind, which cool transmission lines, and solar irradiance, which can increase the temperature of the transmission lines.

 

What is FERC 881?

FERC 881 addresses the continuing influence of weather on transmission line capacity. Most U.S. utilities still rely on static line rating. The calculations are based on conservative estimates of worst-case weather conditions and do not adjust in real-time to actual weather conditions. This results in underutilization of transmission capacity.

The new regulation requires electric utilities to use ambient line rating, which adjusts the transmission line’s capacity based on real-time or near-real-time ambient temperature.

There are multiple advantages to FERC 881, including better dynamic and responsive line capacity management, improved grid reliability and renewable energy integration
Specifically, FERC 881 requires:

• Ambient-Adjusted Ratings (AARs): Transmission providers must use AARs for evaluating near-term transmission service requests (within 10 days) and for day-ahead and real-time markets.
• Seasonal Line Ratings: For longer-term service requests, providers must use seasonal line ratings that consider historical weather data.
• Hourly Updates: Regional transmission organizations and independent system operators must establish systems allowing transmission owners to update line ratings at least hourly.
• Emergency Ratings: Unique emergency ratings must be used for contingency analysis in operations and post-contingency simulations.
• Transparency: Transmission owners must share their line ratings and methodologies with providers and market monitors, maintaining this information in an accessible database.

There are multiple advantages to implementing the new regulation, including better dynamic and responsive line capacity management, improved grid reliability and renewable energy integration, but it represents a significant shift in data modernization and implementation. This is why with less than a year to go into effect, many utilities have not acted on, or fully implemented the new line rating system.

 

FERC 881 Is the First Step in Advanced Line Rating Regulation

Utility companies have reported an increase in available transmission capacity of up to 15% using ambient line rating.
Ambient Line Rating is a positive step toward more efficient line capacity. Utility companies, like Heimdall Power Inc., have reported an increase in available transmission capacity of up to 15%. But the calculations still leave out several significant weather factors, including wind -related measurements and cloud cover. Which is why before FERC 881 is enacted, the Federal Energy Regulatory Commission proposed potential requirements for the more advanced calculation, dynamic line rating.

DLRs are updated at 15-minute intervals with integrated real-time data such as ambient air temperatures, wind speed, cloud cover, solar heating intensity, precipitation, and line tension or sag.

The additional data has the potential to increase a line’s power-carrying capacity by up to 44% according to a 2019 Department of Energy report.

How DTN Weather Intelligence Supports FERC 881 Compliance and Beyond

For the electric utility industry, efficiently transitioning from static to ambient, and potentially dynamic line ratings, demands a weather intelligence provider that has deep expertise in the industry.

DTN delivers both of these capabilities with data solutions that offer:

• Comprehensive Weather Data: Historical, current, and hourly forecast data up to 15 days, aiding in compliance and further analysis, including Dynamic Line Rating (DLR) applications.
• Real-Time Integration: Reliable, up-to-date weather forecasts essential for precise AAR & DLR calculations.
• Scalable and Reliable: Utilizes advanced cloud technology for continuous data availability and validation.
• Regulatory Compliance: Supports FERC 881 requirement for hourly AAR updates.
• Accuracy: High-resolution, up-to-date weather data for accurate line rating adjustments.
• Ease of Integration: Simple API and data feed interfaces allow for seamless and cost-efficient integration with existing utility systems.

FERC Order 881 is just one piece of the evolving landscape of the modern electric grid.  While the implementation process may pose near-term challenges for utilities, the long-term benefits for both the grid and customers are substantial. DTN weather data solutions can help electric utilities efficiently transition to FERC 881 and DLR with a comprehensive suite of stable and scalable API and data feed products that deliver accurate and reliable weather insights. To learn more visit DTN.