Riding the storm: Increasing resiliency for extreme weather events

From the wildfires in Australia and tropical storms in the Caribbean to drought and flooding in the United States, no corner of the globe was immune to extreme weather events in 2019 — and no corner expects to be in the future. 

While system hardening plans are nothing new for utilities, some public power utilities are taking a fresh look at how their infrastructure can be increasingly resilient in the face of increased frequency of some natural disasters.

Resilient Design

The Fort Pierce Utilities Authority — a public power utility providing electric, water, wastewater, natural gas and internet services on Florida’s east coast — is one year into its 10-year system hardening plan. The plan serves as a guide for protecting its infrastructure from extreme weather, which includes almost yearly hurricanes and tropical storms, as well as daily spring thunderstorms.

Though the utility has always taken measures to protect against extreme weather, Paul Jakubczak, PE, FPUA’s director of electric and gas systems, said the conversation is changing.

“It’s more important now because electricity is no longer a luxury — it’s a necessity. In Florida, people use 26% more electricity than the national average, primarily because of air conditioning use.”

The utility gathered data from its outage management system, reviewed outage reports and collected institutional knowledge from field workers to create its system hardening plan. The plan was presented to the utility’s board of directors and approved through its capital improvement budgeting process.

A major component of the plan is inspecting all poles and replacing them if needed. FPUA conducts inspections on a five-year cycle, more quickly than the Public Service Commission’s recommended eight-year cycle.

The utility is working on replacing all wood feeder poles with concrete or ductile iron utility poles, which carry a 70-year life expectancy compared to the 40-year life expectancy for wood.

Pole replacement also is a component of the system hardening plan created by the Guam Power Authority, which serves approximately 52,000 customers on the Pacific island. Having a plan to prepare for extreme weather is key for Guam, which is located in “Typhoon Alley,” a region notorious for being in the path of almost every storm headed toward Asia, according to John M. Benavente, PE, GPA’s general manager. As a result, it regularly deals with typhoons (known as hurricanes in the Atlantic) that exceed a Category 5 rating.

“GPA has to resort to the solutions or fixes we’ve implemented for economic and sustainability reasons. Our customers include the U.S. military and federal government installations, which account for approximately 20% of our load,” Benavente said. “National and homeland defense are of paramount importance, and, therefore, GPA continues to improve the system to ensure a reliable and sustainable energy environment.”

GPA also is preparing to protect itself from rising sea level storm surges and tsunamis. In 2017, scientists visited GPA with concerns that a tsunami may hit the island in the next few decades.

Pole replacement helps prepare for increasing storms and weather events, but it’s nothing new to the utility. GPA began replacing all wooden poles with spun concrete poles in the 1980s. It regularly replaces poles and uses concrete poles for all new line extension projects. Today, 90% of its more than 36,000 poles are concrete.

GPA also is working on moving to a hybrid system consisting of a primary distribution line that’s an overhead concrete pole and a secondary system that’s underground. Energy from the transformers mounted on concrete poles serves customers through an underground line connected to their homes and businesses.

“This hybrid system eliminates the aerial secondary line typically attached to customer homes through a weather head on their roofs. During a typhoon on Guam, this secondary line system typically gets damaged the most, and storm recovery then takes a substantial amount of time.”

The utility recently converted an additional 500 customers to the secondary underground system. Approximately 20% of GPA's distribution system serves customers with underground lines. “In the last storm, once the main primary lines were repaired, those 500 customers were immediately restored.”

GPA plans on installing underground systems on most of the island in the next 25 years, which should mitigate much of the damage from future typhoons.

Moving systems from overhead to underground is not without complications. This process requires trenching, so GPA works with the Guam State Historic Preservation Office and other local government agencies for permits and clearances.

To fund this and other projects, GPA issued long-term bonds. “We don’t have the ratepayers of today paying for the entire investment, which would last for decades,” Benavente said. “Furthermore, additional funds generated as required by bond indentures in the form of debt service coverages are used on capital improvement projects.”

Rethinking Old Ways

In addition to burying power lines to protect against future typhoons, GPA recently signed a contract with the Korea Electric Power Corp. to build a 198-megawatt baseload power plant, which is scheduled to go online in October 2022.

The new plant will be located 300 feet above sea level, which will protect generators and equipment from tsunamis and storm surges. Previously, GPA constructed all conventional baseload generating plants at or near sea level to take advantage of seawater for cooling.

Instead, the new Ukudu plant will be located close to the Guam Waterworks Authority’s Northern Wastewater Treatment Plant, which will allow GPA to repurpose approximately 3 million gallons of sewer water to treat and use for cooling the steam turbine part of the combined-cycle units — without any impact to Guam’s water aquifer. Working with the wastewater treatment plant will also reduce the sewage waste that currently flows into the ocean.

Siting the power plant adjacent to the wastewater facility will also increase reliability, as it is a large power load demand area and most of its transmission lines are underground. In addition, the plant will hold adequate water resources, as well as 30 days of fuel oil capability, in case a tsunami cuts out fuel supplies to the new plant.

The Ukudu power plant will be constructed by an independent power producer under a build-operate-transfer contract. The contract includes an option for the tranfer of ownership to GPA in either 25 or 30 years.

Managing Environmental Conditions

As part of its system hardening plan, FPUA focuses on vegetation management and performs a four-year growth cut back every three years. This is particularly important in Florida, because its continuously warm and moist climate allows for year-round vegetation growth.

With so much of its infrastructure located close to the ocean, the utility also must mitigate damage from salt spray.

“As the ocean air blows in, salt is deposited on insulators, which cakes up if you don’t get a good rain,” Jakubczak said. “When you get the first dewy morning or a light misty rain, electricity travels across insulators and could cause an outage.”

This became a problem during Hurricane Matthew, a Category 4 hurricane that hit Florida in 2016. During the hurricane, a substation tripped off twice because of this salt spray, which required the utility to use the fire department to spray the insulators with water to remove the salt build up. Since then, the utility has purchased pressure washers for its two substations sited near the Atlantic Ocean. FPUA is also installing higher-class insulators. Though it has a 13.2-kilovolt system, it installed 23- and 35-kv insulators to increase the distance between the energized conductors and the pole or cross arms which they are mounted on.

Two years ago, the utility did a system study that indicated problematic substation breaker operations, including fuses not blowing when they encountered a fault. As a result, the utility changed its distribution fuse protection philosophy and began using a fuse blow philosophy that helped with restoration times and decreased breaker operations. FPUA also installed trip savers, which maintain customers’ power if there’s a momentary outage, such as from a tree branch touching a wire.

In the six years Jakubczak has been with the utility, he has noticed the frequency of storms increase.

“They talked about hurricanes not making landfall in Florida for over 10 years,  but that all changed in 2016 with Hurricane Matthew. Since then, hurricanes seem to be coming one after another. Fort Pierce was in the line of  fire for Hurricane Dorian before it stalled over the Bahamas. If it hadn’t, we would have been right in the bullseye, and we would have had a lot of customers without power,” Jakubczak said. “Since I’ve been here, some of the system hardening techniques that we have implemented have decreased the number of outages. We are seeing both the reliability numbers and the customer benefits improving.”

Identifying Priorities

After a storm, FPUA now restores power 24 to 36 hours more quickly than nearby utilities. Eighty-six percent of FPUA customers lost power during Hurricane Irma, a Category 4 hurricane that struck Florida in 2017 and affected all public power utilities in the state, but the utility took only four days to restore power with the help of out-of-state mutual aid crews.

To determine where to focus its efforts, FPUA relies on data from reporting mechanisms to prioritize worst-performing areas that need pole upgrades or lines buried. It keeps a close eye on critical community infrastructure such as hospitals and water and wastewater treatment plants.

FPUA is deploying advanced metering infrastructure, which will provide additional data that can be reviewed to determine whether the utility is spending money on improvements in the best possible way.

Jakubczak recommends utilities participate in the American Public Power Association’s Reliable Public Power Provider program as a way to begin creating a system hardening plan. As part of the program application, utilities are asked questions about how they track and manage reliability, and whether they have a capital improvement plan to address these metrics.

“Just thinking about [system reliability] makes you think about how you track outages. Is it based on customers calling? Is it based on animal or tree issues, or system location, or age?” Jakubczak said. “Once you start thinking about those scenarios, you create a plan and a budget and then work on an implementation strategy. Each utility has a unique approach to how they want to keep the lights on — we are all a little different.”

Incorporating Community Feedback

For customer-owned utilities, communication is a vital part of system hardening efforts. Twice a month, FPUA holds board meetings, which are televised and available on its website. FPUA also posts information related to storms and storm preparation for customers on social media outlets such as Facebook and is working on making its online outage maps more interactive.

GPA holds outreach meetings in villages and at the utility headquarters. The working sessions and monthly meetings of the Guam Consolidated Commission on Utilities — a five-member board of commissioners elected to serve both GPA and GWA — are open to the public, live-streamed and recorded. It mails a monthly newsletter to customers with billing statements, and it sends out media statements, public service announcements, and paid advertising as necessary.

“GPA strives to foster cooperation on all fronts, is committed to transparency of its operations to our island community, and has always reached out to inform the ratepayers and public on various matters,” Benavente said. “GPA is owned by the ratepayers and has a successful track record of achieving community support of its efforts.”