Extreme Cold Weather Standards in the US: What They Signal for Renewable and Storage Operators

Why Winter Storm Uri changed the rules

Winter Storm Uri in February 2021 marked a turning point for the US power sector. The event triggered the largest controlled firm load shed in US history and exposed how poorly many assets were prepared for extreme cold.

In response, US regulators FERC and NERC launched a multi-year effort to close cold-weather gaps across the Bulk Electric System. New standards now define how generators – including wind, solar, and hybrid plants – must plan, operate, and report for extreme winter conditions.

What the new NERC cold weather standards require

The initial regulatory changes came through Project 2019-06, which updated Reliability Standard EOP-011-2. Generator Owners must now:

• determine cold weather operational limits for each unit,

• develop and maintain cold weather preparedness plans, and

• train operations and maintenance personnel on those plans.

Revisions to standards IRO-010 and TOP-003 added requirements to share these cold-weather limitations with Transmission Owners, Balancing Authorities, and Reliability Coordinators. These measures became effective in April 2023.

Project 2021-07 then went further, addressing “Extreme Cold Weather Grid Operations, Preparedness, and Coordination.” It translated key recommendations from a joint FERC–NERC report on Uri into new and revised standards.

A central outcome is EOP-012-1, which focuses specifically on extreme cold weather. It:

• sets design and operating parameters for generating units at low temperatures,

• introduces new defined terms to make clear which components must be protected, and

• requires documented Corrective Action Plans (CAPs) whenever a Generation Cold Weather Reliability Event occurs.

The follow-on standard EOP-012-2 clarifies applicability and strengthens obligations. Generator Owners must calculate an Extreme Cold Weather Temperature for each unit location, identify relevant cold-weather data, review these assumptions at least every five years, and maintain training and preparedness plans. It also adds timelines for completing CAPs and improves rules around communicating cold-weather constraints to grid operators.

Phase-2 work is now looking at additional standards for:

• generator and transmission weatherization and inspection of freeze protection systems,

• tighter coordination with natural gas infrastructure, and

• improved planning practices, including more conservative winter reserve margins and refined load-shedding protocols that better protect critical infrastructure.

Technology-specific challenges for wind, solar, and hybrids

Different technologies face very different cold-weather risks:

• Wind: blade icing, low-temperature shutdowns, nacelle and control system winterization, and lubrication at low temperatures.

• Solar: snow and ice covering modules, inverter performance in extreme cold, battery energy storage temperature management, and reduced winter daylight during storms.

• Hybrid plants: more complex operational decisions, coordinating multiple generation types and storage while responding to fast-changing weather and grid conditions.

For operators, the key takeaway is that “one-size-fits-all winterization” does not work. Each asset type and location needs its own freeze-protection strategy.

Lessons from the January 2025 Arctic cold snap

A more recent stress test came during the January 2025 Arctic cold snap, when regions like PJM, ERCOT, and SPP faced record demand and sub-zero temperatures. This time, the US grid performed far better: renewable generation helped maintain reliability, supported by improved forecasting, cold-weather operational standards, and better coordination.

This episode shows that when generators follow the new standards – from winterization to training and emergency coordination – wind and solar can be dependable contributors, even under extreme winter conditions.

BasenPower commentary: what this means for storage and hybrid projects

From BasenPower’s perspective, the US experience around Uri and the newer Arctic cold snap carries three important messages for renewable and storage asset owners globally:

1. Cold weather readiness is now a core design requirement, not an afterthought
   For wind, solar, and especially BESS, low-temperature performance has to be engineered from day one. That means appropriate insulation and heating for battery containers, robust BMS algorithms for charging and discharging at low temperatures, and clear procedures for storm preparation and post-event inspection.

2. Compliance and reliability go hand in hand
   The NERC standards discussed in the article are written for the US Bulk Electric System, but the underlying ideas travel well: know the temperature limits of each unit, create written plans, train people, and document corrective actions after each event. Even in markets without formal cold-weather standards, adopting similar practices can reduce forced outages and protect investments.

3. Hybrid thinking is essential
   As more projects combine PV, wind, and storage, the cold-weather strategy must cover the interactions between them: how the storage system supports the plant during low-irradiance periods, how control systems prioritize load during constrained conditions, and how backup generation and grid support services are coordinated in emergencies.

Practical questions for asset owners and developers

For owners, developers, and lenders evaluating projects in cold climates, this article suggests a simple checklist:

• Have we defined a realistic extreme cold design temperature for each site?

• Do our contracts specify winterization measures for inverters, transformers, switchgear, and BESS?

• Is there a documented cold-weather preparedness plan, including training, drills, and CAPs after events?

• How will we monitor and log BESS performance during cold spells to support both compliance and continuous improvement?

As the US experience shows, extreme cold does not have to be a show-stopper for renewables and storage – but it does require disciplined planning, investment in protection systems, and a willingness to treat winter as a core engineering problem rather than an occasional inconvenience.

News reference: pv magazine / pv magazine USA, “Extreme cold weather preparedness for renewable energy facilities,” December 11–12, 2025.