Low-Energy Fridays: Turn Down (the Power) for What?
Last month, customers of Public Service Company of Colorado (PSCo) joined the world of public safety power shut-offs when PSCo turned off power to areas around Denver and Boulder. The need to “de-energize” the electric lines going through this area of PSCo’s service territory was due to a combination of dry weather and high winds coming off the Rocky Mountains.
Under such circumstances, a number of factors can cause electric power lines to start a fire. For example, during high winds, the power line can sway and come in contact with another power line, a communications line, or a tree. This can create an arc, which is when an electrical current discharges, or “arcs,” across a gap between the power line carrying the current and a tree or another line creating sparks, light, and an explosion. A fire can also start if high winds knock down an energized power line. In either case, sparks from the power line can fly and ignite dry brush or other vegetation, causing a fire.
PSCo wasn’t just being paranoid. Fires caused by power lines have done a lot of damage in recent years. In California, electric utility infrastructure (some of it nearly 100 years old) has caused a series of major fires. In 2019, one of the state’s major utilities, Pacific Gas & Electric Company (PG&E), filed for bankruptcy due to the fines and penalties accumulated from wildfires in 2017 and 2018—including a $13.5 billion settlement related to one fire that killed 84 people.
Last year, Maui County sued Hawaiian Electric Company (HECO) claiming their power lines were responsible for a fire that destroyed the town of Lahaina. More recently, Xcel Energy (PSCo’s parent company) has also been the focus of investigations into their utility equipment causing fires. This February, Southwestern Public Service (also owned by Xcel Energy) acknowledged that its equipment likely caused a fire that consumed more than 1 million acres across the Texas Panhandle. A cloud of suspicion surrounds PSCo itself as the potential source of one small fire that merged with another to cause 2021’s devastating Marshall Fire.
It is against this backdrop that electric utilities are looking for ways to avoid being the source of fires. An electric utility may be subject to significant fines, damages, and other penalties if found liable for causing a fire. To avoid such fines, electric utilities are turning to planned shutoff programs. This means that under certain conditions—typically high winds and dry weather—the utility will de-energize a transmission line or one or more substations to ensure that no electricity is flowing through those areas where a spark can ignite a fire. While this may mitigate the risk of a utility starting a fire, there are trade-offs—namely, power outages for people served by those lines.
Customers bear the brunt of these programs in multiple ways. First, infrastructure costs (and sometimes replacement or repair costs for damaged equipment) are recovered through electricity rates. Then, to avoid fires, they may lose power for hours or days. That’s why it’s important for the utility to have a communications plan and be transparent with their actions. One issue with PSCo’s shutoffs was the limited amount of communication and information between it and their customers, including the city of Boulder, which lost power to its wastewater treatment facility. Rules put in place by the California Public Utilities Commission detail the circumstances under which electricity may be shut off and require its utilities to provide advanced notice to customers about the potential for shutoffs. Such rules are not in place in Colorado—yet.
Given the inconveniences of pre-emptive shutoffs, why not just bury all these transmission and distribution lines underground? Well, it’s expensive. PG&E is planning to bury 10,000 miles of distribution lines at a cost of over $20 billion. As one of the largest electric utilities in the United States, PG&E serves around 16 million people across 70,000 square miles with 107,000 miles of distribution lines and 18,500 miles of transmission lines. That comes out to around $2 million per mile.
Electric infrastructure crosses all types of environments including forests, deserts, mountains, and plains. Some of those lines were in place long before anyone lived around them; however, the electric grid is being asked to do a lot more than it has in the past—and our reliance on it is growing. When implemented with advance and transparent customer notice, preemptive shutoffs can help a utility avoid longer outages, fires, and other damage to their infrastructure and the environment. Alternatives like undergrounding may not be feasible in some cases.
New technologies, such as grid-enhancing technologies and better utilization of distributed energy resources, including microgrids, may give utilities a more robust understanding of what is occurring on the system and keep power on at the local level. Until then, proactively managing risks and being open and transparent with customers is necessary as the grid—and our reliance on it—evolves.