The devastating impact of Winter Storm Uri in February 2021 has fundamentally changed the way the electricity industry approaches preparing for cold weather. This unprecedented event, which caused the largest controlled load reduction in U.S. history, exposed critical vulnerabilities in the Bulk Electric System (BES) and catalyzed sweeping regulatory changes that renewable energy facilities now must navigate.
The storm affected generator owners and operators, transmission owners and operators, balancing authorities and reliability coordinators in multiple regions. The comprehensive response from FERC and NERC resulted in new standards to increase the availability of generating facilities during extreme weather events while improving the reliability of the transmission grid. For renewable energy facilities, these standards present unique challenges and compliance obligations that require careful attention.
Regulatory framework
Operational requirements
The first regulatory response came through Project 2019-06, which added critical requirements to the EOP-011-2 reliability standard. Generator owners must now determine cold weather operating limitations, establish comprehensive cold weather preparedness plans, maintain these plans, and provide training to operations and maintenance personnel. The amendments to IRO-010 and TOP-003 establish requirements for sharing cold weather operating constraints between transmission owners, balancing authorities and reliability coordinators. These revisions became effective on April 1, 2023.
Project 2021-07: Network operation in extremely cold weather
Building on the initial response, Project 2021-07 focused on “Extreme Cold Weather Network Operations, Preparedness, and Coordination.” This project emerged from FERC and NERC’s comprehensive joint report on the February 2021 cold weather outages, which provided twelve key recommendations for industry-wide improvements. Nine of these recommendations were incorporated into the NERC standards through a Standards Authorization Request (SAR), with a special Standards Drafting Team formed in February 2022.
Emergency operations
The revision of EOP-011-2 created EOP-011-3, which removed the obligations of the generator owner and generator operator and transferred them to the new EOP-012-1 standard. Importantly, EOP-011-3 has changed the requirements to ensure that designated manual load shedding minimizes overlap with critical load and Under Frequency Load Shedding (UFLS)/Under Voltage Load Shedding (UVLS) circuits. The standard also requires provisions to determine the reliability effects due to cold and extreme weather conditions.
Extremely cold weather
This new standard represents the most important compliance obligation for sustainable energy supplies. EOP-012-1 establishes design and operating parameters for generating units to account for low temperatures, taking into account the effects and potential operational impact of wind and precipitation factors – factors that are particularly relevant for wind and solar installations.
The standard introduces three new defined terms that clarify, down to the component level, the applicable unit elements and prescribed temperature calculations that generator operators must protect. For sustainable installations, this means understanding how inverters, panels, turbine components and control systems respond to extreme cold.
One of the key additions in EOP-012-1 is the requirement for corrective action plans (CAPs) after each cold weather generation reliability event. This obligation requires generator owners to conduct documented analyzes following applicable cold weather events, with formal CAP creation, tracking, and disposition.
As an evolution of extreme cold weather preparedness plans, the standard, EOP-012-2, builds on EOP-012-1 by clarifying its applicability and individual requirements while incorporating improvements driven by FERC. An important addition to the standard is clarifications on generator owners’ obligations to calculate the extreme cold weather temperature for each generating unit location, identify relevant cold weather data, and review these calculations every five years. They must also enforce existing provisions in EOP-011-1, which requires generator owners to develop cold weather preparedness plans and provide annual training. The revised standard clarifies which production units are subject to winter operations requirements. In addition, it introduces timelines for completing corrective action plans and addresses the communication of generator limitation statements in cold weather.
For renewable facilities, this requirement presents unique challenges. The technical rationale for implementing freeze protection measures varies considerably between different generation technologies and geographic locations. A wind farm in North Dakota faces different winterization needs than a solar facility in Texas. Generator owners should understand how these requirements apply to their specific fleet composition and individual power plants.
Phase 2 recommendations
The ongoing Phase 2 implementation focuses on several critical areas that will further shape cold weather preparedness requirements. One of the main focuses concerns the development of new or revised mandatory reliability standards for weatherproofing of generators and transmissions. These standards will establish requirements for the inspection and maintenance of freeze protection measures before and during the winter seasons, along with funding mechanisms to support weatherization efforts across the industry.
Natural gas infrastructure coordination is another critical part of the Phase 2 recommendations. The interconnected nature of gas and electric systems became painfully apparent during Winter Storm Uri, leading to demands for better winterization of natural gas infrastructure, especially production and delivery systems. Enhanced coordination between the natural gas and electricity industries during emergencies is now mandatory, with better identification and communication of risks associated with gas supply contracts and their potential impact on firm load shedding decisions. This coordination is particularly relevant for renewable facilities with backup generation capabilities.
Planning and operational improvements are the third pillar of Phase 2 recommendations. More extreme weather scenarios must now be taken into account when calculating winter reserve margins, recognizing that historical patterns may not adequately predict future conditions. Load shedding protocols should be revised to ensure that critical infrastructure, including gas facilities that support electricity generation, is protected during extreme events. Additionally, improved coordination of manual and automatic shutdown procedures among reliability coordinators will help prevent cascading failures during widespread cold weather emergencies.
Renewable energy facilities face specific challenges in cold weather that require a tailored approach:
Wind generation
- Blade icing and its impact on production
- Turbine shutdowns at low temperatures
- Winterizing nacelle components and control systems
- Cold weather lubrication requirements
Solar energy generation
- Snow accumulation on panels reduces output
- Inverter performance in extreme cold
- Temperature management of the battery energy storage system (BESS).
- Fewer hours of daylight during winter storms
Hybrid facilities
- Coordination between multi-generational technologies
- Energy storage performance in cold weather
- Complex operational decision making during extreme events
New regulations
During the Arctic cold snap of January 2025, the U.S. power grid showed remarkable resilience, with renewable energy playing a critical role in maintaining reliability. Grid operators in regions such as PJM, ERCOT and SPP reported uninterrupted service despite record-breaking demand and freezing temperatures. Wind and solar power generation, supported by improved forecasting and integration protocols, have contributed significantly to meeting peak loads. These successes were underpinned by cold weather operational standards introduced after Winter Storm Uri, which mandated better preparedness, freeze protection and cross-sector coordination, allowing renewable energy to function reliably even under extreme conditions.
The event marked a turning point in the way renewable energy is viewed during winter emergencies. FERC and NERC’s post-Uri reforms, including standards EOP-011-3, EOP-012-1, and subsequent revisions to the current EOP-011-4 and EOP-012-3, required generators (renewable and conventional) to implement cold weather preparedness plans and provide annual training. As a result, wind turbines were better equipped to deal with icing risks, and solar facilities improved their energy yield prediction. The January 2025 performance showed how far-sighted regulatory insight and technological adjustments can ensure that renewable energy sources can reliably contribute to the stability of the electricity grid, even in the most severe weather conditions.
Oscar Vite is Compliance & Risk Engineer for Radian Generation at expertise in energy infrastructure and regulatory standards. He has contributed to winterization strategies for power generation and supports NERC compliance in various operating environments.
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