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Protecting Power Plants in Extreme Weather Events

By David Butz, Senior Consulting Engineer, and Jason Neville, Engineering Manager and Consultant

In recent years, many people around the world have been experiencing record-setting hot and cold temperatures. These events, apart from being life threatening, significantly strain electrical infrastructure and can cause inoperable utility equipment and power outages. Power outages can cause disruptions to day-to-day life for the public, and cause utilities to lose revenue and face potential penalties.

In two articles published in 2023 for POWER, we discussed how to plan for and mitigate the effects of both hot and cold weather events to maintain power plant readiness and reliable operation. In this blog, we have highlighted some of the key points from those articles. 

Weather Readiness Assessment

To meet our customers’ requests to maximize plant availability during hot and cold weather operations, TG Advisors has developed a “Weather Readiness Assessment” that accomplishes three goals through data analysis, plant maintenance records, engineering calculations, and expert experience. The assessment:

  • Addresses regulatory requests (typically maximum and minimum ambient temperature capability and/or wind chill capability).
  • Identifies equipment limitations and opportunities for improved robustness.
  • Reviews a plant’s weather preparation and action plan, and provides feedback for improvement.

TG Advisors’ process includes a plant walkdown and interview with key personnel to review equipment condition and plant configuration, and identify site-specific needs. 

Heat Risks

Output reduction during hot weather should be expected and accounted for. For plants with gas turbines as the prime mover, hot weather adversely impacts heat rate and output due to the lower air density of hot air entering the compressor. Another common source of problems during hot weather operation is failure of cooling systems. Bearing metal temperatures need to be maintained below limits and typical plant configurations utilize fin-fan coolers to reduce the temperature of lube oil once it exits the bearings. Degradation of the lube oil coolers may only be apparent on hot day operation when the system is stressed.

Water and Wind Risks

Water is a major freeze risk, and any equipment that uses water needs to be protected. Systems and equipment not needed during cold weather operation should be removed from service and the water drained to ensure the equipment is not damaged during a freeze event. Water wash systems, inlet chillers, or wet compression systems are examples of equipment that can be removed from service and drained if weather forecasts indicate cold weather approaching; this will allow winterization efforts to focus on items needed for plant operation during a cold weather event. Wind on its own cannot cause freezing. The ambient temperature must be below freezing for water to freeze. At temperatures below freezing, wind can rapidly increase the freeze rate by increasing convection, or the rate at which heat is removed from a pipe or other water source. Wind effects can be negated by proper wind breaks and/or insulation.

An Effective Weather Plan

A written hot or cold weather plan should be treated as a living document – one that ensures an appropriate plan is in place for operating plants during hot and cold weather events. Regular updates are a critical part of risk mitigation because equipment failure modes can change with age, weather patterns can shift, plant operational modes and configurations can change, along with plant personnel. What worked in the past will not necessarily be sufficient in the future. A good hot or cold weather plan should include:

  • A list of hot and cold weather-critical equipment
  • A list of weatherization supplies and equipment
  • Responsible parties and contact information
  • Staffing requirements
  • Plan implementation details, including criteria (calendar date vs. temperature specific)
  • Checklists
    • Preparation
    • In-action
    • Post-action/corrective-action
  • Revision control
  • Documentation of historical minimum and maximum temperatures
  • Training requirements

Hot and cold weather events will continue to occur more frequently than ever before. The regulatory requests for documenting hot and cold weather temperature capability are here to stay and may become more detailed. Preparation and planning are therefore critical for plants to remain operational during these events. Please reach out to us at dbutz@entrustsol.com or Jason.neville@entrustsol.com to talk to us about how we can help your site maximize availability during both the hot and cold weather seasons. 

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