Utility-caused wildfires are a subsection of human-caused wildfires that are directly ignited by utilities, usually power lines. They are unplanned ignitions that can cause wild burns.[1] Hotter and drier weather as a result of climate change has been liked to lower moisture content in vegetation, which, along with high tree mortality has created ideal wildfire conditions.[2] Ignition often occurs when power lines come in contact with vegetation, whether elevated or on the ground.[1]
Throughout the world, utilities, especially overhead power lines, have caused wildfires.[3] In 2023, downed power lines sparked fires in Lahaina, Hawaii.[4] In February 2024, on the Texas Panhandle, a decayed utility pole fell on dry grass and sparked the largest wildfire in state history.[5] The 2018 California Camp Fire, the largest and most deadly fire in California state history, was caused by a single faulty clip on an overhead power line.[6][7] In the notorious 2009 'Black Saturday' fires in Victoria, Australia fires sparked by power lines killed 159 people and caused more than $4 Billion (AUS) dollars in damages.[8] In Greece, on August 11th, a wooden electricity pillar with a loose cable held with a clothes hanger, sparked a fire that killed one woman and burned over 10,000 hectares.[9]
Electric companies are investigating solutions such as burying power lines, installing sensors, and using software to monitor cables and automatically shut them off.[10] In 2023 wildfire mitigation plans, Californian utility companies proposed over $9 billion to mitigate factors that cause wildfires.[11]
Industry critics claim that the industry is not doing enough to mitigate these disasters.[10]
Causes
editUtility-cased wildfires can be started by a variety of factors.
Downed lines
editThe vast majority of transmission lines, over 70%, in the United States are outdated, and are near 25 years old.[12] The average age for power transformers that power over 90% of the country is 40 years old.[13] Power lines, whether old or new, are susceptible to storm damage, and, in 30% of cases, the power line does not automatically shut off.[14] This can happen when the fallen line draws too little electric current to activate a fuse or circuit breaker.[14] These high-impedance faults (HiZ) can cause high-energy, high-temperature arcing that can cause ignition.[14]
Contact with vegetation and foreign objects
editVegetation contact, and contact with foreign objects, such as trees, are leading causes of wildfires.[1] In California, these factors were responsible for 35%, and 18%, respectively, of utility-related fires larger than 10 acres.[1] Strong winds have been known to exacerbate these problems.[1] Live wires can ignite dry vegetation and fuels, and fallen trees can result in downed lines.[14]
Conductor slap
editPower lines are traditionally designed with significant clearance between conductors, this prevents them from contacting under normal operating conditions.[15] Under poor conditions, line conductors can slap against one another; this causes high energy arcing, and, occasionally, small bits of molten metal (generally aluminum) are ejected.[16] These ejected pieces of molten aluminum can ignite wildfires.[14]
Component failure
editMany components, such as switches, transformers and insulators, contain thousands of complex circuits and parts.[17] While often able to effectively provide service for decades, they do eventually fail.[14] Occasionally, before complete failures, there is electric arcing and sparks that are too small to be detected by fail-safe sensors.[14] These sparks and electric arcs can result in the ignition of vegetation or foreign objects.[14]
References
edit- ^ a b c d e "REDUCING UTILITY-RELATED WILDFIRE RISK" (PDF). energysafety.ca.gov. Public Utilities Commission and Boston Consulting Group. December 2020. Archived from the original (PDF) on 2022-02-24. Retrieved 18 October 2024.
- ^ Park Williams, A.; Allen, Craig D.; Macalady, Alison K.; Griffin, Daniel; Woodhouse, Connie A.; Meko, David M.; Swetnam, Thomas W.; Rauscher, Sara A.; Seager, Richard; Grissino-Mayer, Henri D.; Dean, Jeffrey S.; Cook, Edward R.; Gangodagamage, Chandana; Cai, Michael; McDowell, Nate G. (March 2023). "Temperature as a potent driver of regional forest drought stress and tree mortality". Nature Climate Change. 3 (3): 292–297. doi:10.1038/nclimate1693. ISSN 1758-6798.
- ^ Boxall, Bettina (5 January 2020). "Human-caused ignitions spark California's worst wildfires but get little state focus". San Diego Union-Tribune. Archived from the original on 19 June 2023.
- ^ "Deadly Maui wildfire was sparked by downed power lines, investigation finds". Yahoo News. 2024-10-03. Retrieved 2024-10-06.
- ^ "Decayed power pole sparked the largest wildfire in state history, Texas House committee confirms". Marfa Public Radio, radio for a wide range. 2024-05-02. Retrieved 2024-10-06.
- ^ Zimmerman, Jeffrey. November 2018 Camp Fire. National Oceanic and Atmospheric Administration, Jan. 2020, https://www.weather.gov/media/publications/assessments/sa1162SignedReport.pdf.
- ^ Derbeken • •, Jaxon Van (2019-12-06). "New Images of PG&E Hooks on Camp Fire Power Line Released". NBC Bay Area. Retrieved 2024-10-06.
- ^ "How an Australian State Fought Back Against Grid-Sparked Wildfires - IEEE Spectrum". spectrum.ieee.org. Retrieved 2024-10-06.
- ^ Souliotis, Yannis; Maltezou, Renee (15 August 2024). "Faulty power cable may have caused Greece's worst wildfire this year, sources say".
- ^ a b Penn, Ivan (22 March 2024). "Utility-Caused Wildfires Are Becoming a National Problem". The New York Times.
- ^ Warner, Cody; Callaway, Duncan; Fowlie, Meredith (February 2024). "Risk-Cost Tradeoffs in Power Sector Wildfire Prevention" (PDF). Energy Institute at Haas.
- ^ U.S. Department of Energy. Quadrennial Energy Review Energy Transmission, Storage, and Distribution Infrastructure. 2015.
- ^ Tompkins, Al (2022-12-27). "When will we update our power grid?". Poynter. Retrieved 2024-10-03.
- ^ a b c d e f g h "How Do Power Lines Cause Wildfires?". Texas Wildfire Mitigation Project. 2014-02-13. Retrieved 2024-10-06.
- ^ "Power Line Safety". International Sign Association. Retrieved 2024-10-07.
- ^ Short, Tom (10 October 2024). "Conductor Slap" (PDF). Electric Power Research Institute.
- ^ "Transformers: Explaining the basics". CALCO. 10 October 2024.