Granite Geek: Ice storms can take down power lines but electric wildfires can take out communities
|Published: 09-25-2023 4:47 PM
It says something about New Hampshire’s climate that the annual sustainability report from our largest electric utility discusses ice storms, tornadoes, floods and even microbursts, but doesn’t mention wildfires
It says something else that this may change.
“We look at what has happened in California and Maui. It’s definitely something we talk about,” said Doug Foley, Eversource’s president of New Hampshire electric operations, during a recent discussion we had about the rising wildfire risk in a changing climate.
New Hampshire’s damp, cool climate has protected us from big wildfires since we stopped clear-cutting mountainsides and igniting the debris with sparks from lumber trains a century ago. But now that the greenhouse effect has taken hold and equally damp and cool Quebec and Nova Scotia are burning up, we have to take the risk seriously.
Since live power lines touching trees or brush have helped cause some of the disastrous fires erupting around the world, I talked to Foley recently to see how Eversource was rethinking its approach to street-level distribution lines and cross-country transmission systems. Unitil, Liberty, New Hampshire Co-Op and all other electricity suppliers in New England are having similar conversations.
He walked me through a bunch of changes. Many have been in development or have been rolled out for some time prompted by other factors – pretty much everything in electricity production and transmission is changing these days – but many deal with the wildfire threat.
Some moves are pretty straightforward. For example, Foley said the company is changing the way cut brush is dealt with when trimming trees in a transmission right of way, placing it in ways that are less likely to act as fuel loads if a fire does start. That’s part of “vegetation management,” the industry term for dealing with trees near their lines, which has been a headache for the electric grid since Edison’s days.
They’re also working with different guidewires, different types of cross-arms, larger insulators and “vice-top” insulators that should be less likely to break apart in storms.
Here’s another change that has a New Hampshire twist. It involves Hendrix Wire and Cable in Milford, now part of Marmon Utility, which is one of those companies that is unknown to the public but famous within the industry. You have seen thousands of their signature products without realizing it: the Hendrix Cable Spacer, which clamps onto as many as four of the wires or cables strung between utility poles, organizing them in a way that allows more of them to share the valuable commodity of pole space. (Its shape has always reminded me of the thunderbird of Native American folklore.)
Hendrix also makes what it calls Tree Wire, a coated version of the power lines that run along the top of street-side distribution poles. Those power lines are traditionally exposed to the elements for cost and weight reasons – insulation is expensive and heavy – which makes it more likely a fire will start if a limb or branch lands on them while they’re still live.
Eversource is rolling out Tree Wire throughout its three New England states. “It’s not insulated enough for worker safety or the public, but it’s insulated against brush contact,” said Foley.
Another change to streetside poles is changing switching equipment that uses oils to provide insulation and cooling. The oils can be flammable, adding to the fuel load once a blaze begins. The industry is moving to alternatives that use a vacuum instead.
As for the poles themselves, Eversource has an ongoing project to replace wooden poles with metal in the high-voltage transmission lines, and replace many streetside poles with taller, stronger wooden poles. This change was spurred by storms and cars knocking down poles (which happens more than you’d think) but will also reduce the chance of a fallen wire igniting dry brush.
Then there’s the techier stuff, like smart switches that will be able to differentiate between a high-impedance fault at a transformer when a tree limb contacts a live wire, and an inrush current when a heavy load is switched on. The first requires power to be shut off but the second doesn’t. Differentiating between them might prevent a fire from starting.
Similarly, Eversource has a program in which trucks drive around public ways looking at circuits and connections with infrared cameras that can spot arcing, a sign of potential failure, before it’s visible to the eye.
“It’s kind of like a Google Streetview setup. On top there’s a technician operating a camera. They can drive along at a pretty good speed, documenting it,” he said. Similar infrared spotting is done with helicopters and drones.
Above all of this is a rethinking. Avoiding disaster has always been central to the job of electricity production. The addition of wildfire risk adds a big complication: Possibly turning off power in some areas where drought and high wind have made it very dangerous to have current running through lines. System operators at the Manchester control center can shut off power to particular areas if needed, Foley said.
“We have a lot of conversations in regard to our all-hazards plan: Should we have a public safety shutoff as part of our safety plan,” said Foley. “If you shut off areas of the grid, you’re going to impact hospitals, water treatment, traffic lights, and the list goes on – so one needs to think about that.
And we’ve got to communicate, among ourselves, emergency teams, fire chief, and also with the public. … Communication is key. If people don’t know what’s going on, it’s very hard for them.”
There is yet another complication and that’s money.
As a regulated utility, Eversource can get ratepayers to cover these costs as part of the “transmission and distribution” portion of our monthly electric bill – the portion we can’t avoid by going to an independent electricity supplier – as long as the state Public Utility Commission agrees. Not a few people are suspicious that utilities are sticking unnecessary costs on this part of the bill under the umbrella of improving reliability, to make up for losing business just selling electricity in a deregulated world.
So there’s a lot of debate about what’s necessary, what’s superfluous, what’s a ripoff, what’s a deal. With everything changing at the same time, that’s a complicated debate to have.
Consider it another way that the changing climate is making life more difficult. As if we needed another.]]>