Extreme Weather for Utilities
Regardless of varying opinions of the causes of our increasingly severe weather cycles, the effects are indisputable. According to an article in MarketScale, weather-related power outages in the U.S. have increased 67% since 2000. These weather events include hurricanes, tornadoes, fire, floods, ice storms, and other acts of nature.
For the operating horizons of the high voltage electric power grid, the effects are being assessed, incorporated, and mitigated every day. Whether it is a record-setting heat spell or an unanticipated artic vortex plunging temperatures to record lows, the reliability of the grid is expected to remain constant.
Unfortunately, due to long lifetimes, electricity systems are likely to be exposed more frequently to more extreme climate conditions than those for which they were designed. They may not operate as intended under these more extreme conditions, according to a report from the Department of Energy. The same report indicates extreme weather is the leading cause of electric power outages, especially more significant events.
The tools employed to preserve reliability are in the process of being modified not only in response to increasingly common severe weather events but also to accommodate and maximize new additions to the fleet of generators. In addition, power companies need to ensure the safety of their workers operating in these weather conditions.
Hot Weather Realities
Record-setting high temperatures are now commonplace in forecasts both near and long term. In traditionally hotter regions, increased heat equals increased demand for power. Intermittent interruptions go from annoying inconveniences to life-threatening situations. Maintaining sufficient operating reserves and careful planning of maintenance outages become critical tasks.
According to the World Meteorological Organization, there is a 66% likelihood that the annual average near-surface global temperature between 2023 and 2027 will be more than 1.5°C (34.7°F) above pre-industrial levels for at least one year. There is a 98% likelihood that at least one of the next five years, and the five-year period as a whole, will be the warmest on record.
So far, reserves have generally proven sufficient, and skilled operators have managed the system well. Increased attention will continue to be placed on effective communication between transmission operators and generators. The NERC reliability standards will continue to address and modify expectations for communication.
Cold Weather Considerations
Revisions to NERC standards are underway that will affect the planning criteria of Balancing Authorities and Transmission Operators, and the operating characteristics of generators in severe cold weather. Initial steps are underway to modify requirements for communicating generator capabilities in cold weather. Additional proposed requirements address modifications or retrofits to generators and gas transmission systems to substantiate capacity in extreme cold weather. Identifying effective modifications and cost recovery for implementing changes remains challenging.
Human Performance and Safety
Higher stress on the Bulk Electric System (BES) equals higher stress on the people who operate the system. Reliability risks associated with unplanned outages increase as we operate closer to the limits of system capacity. No matter how effective the modifications to operating procedures and practices turn out to be, the critical path to continued reliability runs through the people who plan, operate, and maintain the BES.
Severe weather effects on equipment are well documented and are being addressed in the measures described above. Accounting for effects on personnel are less well known as the system is operated closer to the margins where threats to reliability escalate. Stress is definitely a factor. Reliability expectations increase in an environment of potential service interruptions. Line crews are immersed in the consequences of severe weather, both heat and cold, and must be vigilant to this threat to their own safety.
In addition to protecting the grid, power companies must also make sure their workers, especially those required to work outside, follow best practices for the weather they’re facing.
In a summer heat wave, organizations should make sure their workers:
- Drink water every 15 minutes, even if they’re not thirsty
- Rest in the shade to cool down
- Wear a hat and light-colored clothing
- Learn the signs of heat illness and what to do in an emergency
- Keep an eye on fellow workers
- Ease into it – they need to get used to the heat
During cold weather, workers should:
- Wear at least three layers of clothing including a hat or hood and insulated boots
- Keep a change of dry clothing in case their work clothes get wet
- Take frequent breaks and consume warm, high-calorie food and complex carbohydrates
- Drink plenty of liquids (it’s easy to become dehydrated in cold weather too!)
- Shield work areas to reduce wind chill
- Perform heavy work during the warmer part of the day
- Avoid fatigue since energy is needed to keep muscles warm
Workers should be prepared when working outside during extreme weather.