Burying power lines isn’t the only way to weatherproof the grid
Scientists are working with power companies on fresh tools so that weather-induced power outages don’t last so long
At the Electric Power Research Institute (EPRI), a think tank for the private energy sector, researchers use an array of pulleys, slings and heavy machinery to drop hefty wooden beams across electrical transmission lines.
The controlled tests are designed to simulate what happens to electric systems when destructive storms sweep through, leaving hundreds of thousands of people without power in catastrophes like Hurricane Ida, which ripped through the South and sparked extreme flooding along the East Coast.
The idea at EPRI’s outdoor research lab in rural Massachusetts is to find ways to get power lines to fail gracefully, an intervention that if it can’t prevent the toppling of energy systems might at least make it possible to restore the energy systems quickly.
“You design structures that are self-sacrificing,” said Andrew Phillips, vice president of transmission and distribution infrastructure at EPRI. “They fail, but they fail in a place you want them to fail.”
With forecasters predicting that climate change will increase the frequency and intensity of storms as warmer air gathers up more moisture that will be released as torrential downpours, finding a way to weatherproof utility systems has taken on new urgency. Ida left more than 1 million power customers without electricity when it roared past New Orleans and through Mississippi last weekend.
By Friday, less than a quarter of customers served by Louisiana’s largest utility that lost power had it back on. Entergy estimated that power would be restored in New Orleans and its surrounding suburbs by Wednesday, 10 days after the storm made landfall. That is a long time in the humid heat of late summer, even for healthy people, and can be life-threatening for those with medical conditions and the elderly.
Burying power lines is still the most common weatherproofing technique for electrical systems. But building subterranean grids is expensive — North Carolina rejected the idea 20 years ago when estimates suggested such a project would cost billions of dollars and take decades to complete — and such systems are still vulnerable to flooding. So now many power companies are pioneering technology aimed at making their systems resilient in extreme weather, rather than immune.
The idea is it may not be possible to prevent a Category 4 storm with 150 mph winds from toppling a 400-foot transmission tower as Ida did in Louisiana, but it may be possible to get the grid back up quickly after such a crippling weather event.
As disasters linked to climate change become more common, energy companies have begun implementing these strategies and building extra-sturdy power lines that can withstand winds and flooding.
“There’s nothing you can do to completely protect the grid from damage. Anything you do, you’re left with vulnerabilities,” said Ted Kury, director of energy studies at the University of Florida.
Success against weather events, Kury said, should be measured by how swiftly power is restored since preventing outages from happening is nearly impossible.
Repairing downed power poles is the most time-consuming fix after a natural disaster, energy analysts say. One possible solution is to allow cables to drop at the first sign of trouble, which prevents a domino effect where a tree falls on a line, topples a nearby pole and then multiple poles are dragged down as the power line continues to collapse. Designing the line to fail at controlled points would minimize the force pulling on the pole and perhaps keep the first one from toppling over.
“Now, instead of taking 36 hours to fix a pole, it can take you two or three hours,” EPRI’s Phillips said.
While photos of downed power lines in the wake of Ida suggest not much has changed in the approach to and impact of storms, recovery times show that the strategy may be working. After Hurricane Wilma battered South Florida in 2005, Florida Power & Light began updating its system to include hulking 55-foot concrete support beams for power lines, underground wires, automated power switches and other intelligent devices.
When Hurricane Irma struck the area in 2017, power was restored to customers within days; it had taken several weeks after Wilma.
Another solution sweeping across the country over the past decade are so-called smart metering systems, electronic devices that report energy consumption to suppliers and customers in real time. That allows service providers to pinpoint the source of an outage as it happens. Before smart meters, operators learned of outages through customer phone calls or inspection crews, which meant that small interruptions could grow large before a provider was aware.
While some cities have had them since 2009, other places, like Palo Alto, Calif., are poised to install them starting next year to give residents real-time data on energy usage.
More recently, companies are interspersing larger electrical systems with microgrids, which can generate power locally when cut off from a regional power-generating station. They can keep fire stations and hospitals powered during wildfires and prolonged electricity outages.
San Francisco, for example, is designing a microgrid with Pacific Gas & Electric “to help meet the resilience needs of disadvantaged and vulnerable communities.” This comes after PG&E cut power to customers several times in the region last year to reduce the risk that downed lines and other equipment would ignite a fire during bouts of dry weather and strong winds.
The primary reason tools like these aren’t widespread is cost, experts say. A typical overhead power line already costs $100,000 per mile to string; placing that cable underground can cost more than 10 times as much.
Updating electricity infrastructure is a big undertaking that requires a balancing act involving innovation, costs and public interest, experts say. Wealthy cities and neighborhoods can pay to hide unsightly power lines underground, but statewide efforts are tougher to get off the ground.
After a 2002 snowstorm rocked North Carolina, leaving 2 million homes without electricity, the state studied how much it would cost to run lines underground. A task force determined it would take 25 years to build and cost $41 billion. That would have meant doubling people’s electricity bills, so the state decided not to push forward.
“Once you realize a solution is possible, it’s just the first step in a long road toward making it happen,” said Richard Sedano, CEO at the Regulatory Assistance Project, a nonprofit focused on clean energy.
And alternatives to running high-voltage lines underground are necessary since there’s no one-size-fits-all approach to strengthening power grids.
Buried power lines are insulated from wind, ice and tree damage, but they aren’t completely weatherproof, experts note. When Hurricane Irma hit Florida, 18 percent of underground power lines experienced an outage. Underground lines are also more vulnerable to flooding, which makes problems harder to locate and repair, the experts say.
Salt water may cause further complications since underground wires are more susceptible to corrosive storm surges.
“Everybody’s ‘best grid’ is going to look different,” Kury said. “If you’re in an area prone to flooding, a policy putting everything underground doesn’t make a lot of sense.”