Clear Trees? Or Bury Power Lines?

Thomas MacMIllan PhotoIn the wake of power outages caused by storm-toppled trees, United Illuminating suggested cutting back all greenery around power lines. Others have suggested another solution: Placing all power lines underground, out of harm’s way.

That’s an option—if you’re willing to pay for it, and wait.

Putting overhead power lines underground offers a number of advantages: Fewer power outages, more room for street trees to flourish, and a more aesthetically pleasing cityscape.

“Undergrounding” also has some drawbacks: Power outages, when they happen, are harder to fix, and it’s very expensive to put all the power lines below ground.

It can cost a million dollars per mile to put lines underground. That would mean it could cost over $700 million to bury New Haven’s overhead power lines.

Putting electricity lines underground is just prohibitively expensive, said Joseph Thomas, United Illuminating (UI) vice-president of electric system operations.

Others disagree. Some cities are going ahead with burying projects, despite the expense. Anaheim, California, and Concord, Massachusetts, are in the midst of overhead-to-underground conversions.

Their solution to the high cost? Do it slowly. Really slowly.

Concord, with a population less than 15 percent of New Haven’s, started burying power lines in the early ‘90s, and won’t be done until about 2065.

Since 1990, Anaheim has spent $185 million to put its power lines underground, paid for by a 4 percent surcharge on the monthly electricity bills.

Read on for a deeper look into the challenges and opportunities involved in burying power lines.

What kind of power lines do we have now?

For both overhead or underground, power lines come in three varieties. “Transmission” lines carry high voltages from generation stations to electrical substations. Primary “distribution” lines take the power, at lower voltages, from there to transformers. Secondary distribution lines then take the power directly to customers.

New Haven already has a fair amount of underground electricity infrastructure, mostly downtown. Here’s the breakdown in New Haven, according to United Illuminating (UI) spokesman Ed Crowder: 

Transmission: 8.73 miles
Primary distribution: 233 miles
Secondary distribution: 503 miles
Total: 745 miles

Transmission: 68 miles
Primary distribution: 181 miles
Secondary distribution: 68 miles
Total: 317 miles

What’s the deal with overhead power lines? Are they good or bad?

Among the pros: It’s a relatively straightforward system; it’s all out in the open and accessible for repair. The system is also easily modified and rerouted.

But, as with many systems, its advantages can also be disadvantages. The lines are accessible, but vulnerable. They’re all out in the open, but they’re not very attractive.

Overhead power lines are most vulnerable during storms, which can knock down branches or full trees that hit power lines and cause outages. During 2011’s Hurricane Irene, for instance, some parts of Connecticut went without power for more than a week.

Irene was the first of three huge storms that have pummeled the state in recent years. It was followed by Hurricane Sandy in 2012, and Winter Storm Nemo in 2013, each of which led to more power outages.

As a result, United Illuminating started looking at more aggressive tree trimming plans, to the dismay of some ratepayers in New Haven. As long as power lines are overhead, cities will have to balance the needs of the power grid with the needs of street trees.

Overhead power lines seem problematic. What do underground systems look like?

They look fairly invisible, since the power lines are hidden away underground. Take a look at the blocks around the Green, where all power lines are below ground.

Burying can be as simple as digging a ditch, taking the lines off the poles and laying them in the ground. That’s called “direct buried” power lines. The better, and more expensive, way to do it is to install a conduit system, so that the wires are protected underground.

Underground power lines don’t conflict with tree canopies, and they’re not vulnerable to storm-toppled branches, which means a more attractive and reliable power system.

Sounds great. Let’s go underground!

Hold on—underground power lines aren’t perfect either. As with overhead lines, their advantages are accompanied by downsides. Here are a few:

• Tucking electricity cables out of sight also means it is harder to locate and fix problems when they happen. The power may go out less frequently, but when it does, it takes a longer time to fix. Thomas, the UI vice-president, said repair times can be four to six times longer with underground outages.

• While underground power lines are safe from trees, they’re more vulnerable to flooding. Thomas said underground cables might not be appropriate for coastal areas, for that reason.

• Remember that utility poles carry not just power lines, but phone lines, too. Those lines don’t matter for power outages, obviously. But if aesthetics are your concern, then you’ll have to bury them, too.

• Underground power lines might save tree canopies, but their installation can have an impact on tree roots. In order to avoid hitting tree roots, the power lines would have to be buried under the middle of the street, a significant and costly undertaking.

• In fact, the biggest drawback to “undergrounding” is the cost. It can cost a million dollars or more per mile to put power lines underground. Underground power lines also have to be thicker and more expensive than overheads. United Illuminating determined that it would cost $6 billion to put all its lines in Connecticut underground.

The city has about 750 miles of overhead power lines, which could mean a $750 million pricetag if it all were to go underground.

That expense would ultimately land on ratepayers’ monthly bills. Individual customers would have to pay to install new underground connections from their properties to the grid. That might cost about $6,000 for the average customer, said Thomas.

Oh. Forget it, then. Let’s just stick with overhead lines.

Well, wait. At least a couple of towns have figured out how to work around these problems.

Concord, Massachusetts, for example, is about halfway done with the task of burying its power lines, funded by a small surcharge on monthly electricity bills. Concord started the job in the early 1990s and will be done by about 2065, said David Wood, head of the town-run municipal company.

“It’s a very slow process. It’s a very expensive process,” Wood said.

He said customers pay a 1.5 percent surcharge on their power bills, which generates about $400,000 annually. Wood said Concord has to let the money accrue over a few years before it can afford to bury another section of power lines. Wood said Concord cuts some costs by combining power line burial with water and sewer work.

Concord does have power outages occasionally, but they can be quickly repaired, even underground, Wood said. That’s because his staff are trained specifically for work on underground lines: “Our guys are very efficient.”

A failed cable can be pulled out and replaced in about six hours, Wood said. “Unless you have a conduit failure, which isn’t likely, you don’t have to dig up the ground.”

City of Anaheim PhotosBut Concord is tiny compared to New Haven. Tell me about Anaheim.

Anaheim, a city with more than twice the population and area of New Haven, began its underground conversion at about the same time as Concord. Like Concord, it also owns its municipal power company.

Anaheim’s plan is financed by a 4 percent surcharge on monthly power bills. The city has so far spent $185 million on the project.

Dukku Lee, Anaheim’s general manager of public utilities, said the work is costing about $4 million per mile. He called the higher price “reflective of the cost of living and everything else here in southern California. Costs tend to be a little higher than other areas.”

Lee said Anaheim isn’t aiming to eliminate every last overhead power line in the city. It’s focusing on the “major arterials,” which offer the “biggest benefits,” he said. It’s the difference between working on a water main that serves thousands and an offshoot pipe that serves dozens, Lee said.

Anaheim is now about 60 percent done with the conversion of its major arterials, Lee said.

The city has a rebate program to help homeowners who want to bury the power lines from overhead lines to their houses.

Lee said outage repair times for the city’s underground system can be as little as three or four hours.

I noticed you said both Anaheim and Concord have their own power companies. Coincidence?

Good catch. Yes, both Concord and Anaheim have municipally operated electric companies, which probably helps streamline the undergrounding process.

Lee said that because Anaheim’s power utility is run as a municipal not-to-profit, Anaheim residents pay 10 percent less than their counterparts in surrounding towns, even after the 4 percent surcharge for the line-burying project.

If New Haven were to decide to bury power lines, it might need to do it as part of a regional effort, which could be complicated by tensions between the city and the suburbs.

“The starkly higher cost for underground transmission has tended to diminish support for this option when the burden of payment is realized,” PURA Chair Arthur House wrote in a Jan. 30 letter to state Sen. Martin Looney, who asked about burying power lines. “In addition, we have found that lower income ratepayers often resist the prospect of aggressively more costly electricity bills to pay for buried power lines in suburbs.”

Even spread out over decades, Anaheim and Concord are still shelling out a lot to bury their lines. Is it worth it?

Hard to say. Aesthetics aside, the calculation may come down to what you think the weather will be like for the next century.

Thomas, the UI vice-president, pointed out that before Irene, Connecticut went about 25 years without suffering a major storm. If the state is going to see another 25-year stretch like that, then it’s probably not worth it to pay millions to put the lines underground. Others argue that in an age of climate change, it’s not accident that we have seen three devastating storms in three years.

As it is, both UI and the states Public Utilities Regulatory Authority (PURA) have concluded that the numbers just don’t make sense. To prevent power outages, PURA’s strategy focuses not on burying power lines but on three other things, according to spokesman Dennis Schain: First, “hardening” the existing system, making it stronger and better at withstanding severe weather. Second,  a “realistic approach” to trimming trees. And third, “distributed generation,” so that power doesn’t have to be transmitted so far.

This last focus includes the creation of “microgrids,” which UI’s Thomas described as small generation and distribution systems connecting essential municipal buildings, including hospitals. A microgrid would be a “parallel system,” fueled by natural gas, for instance, that could take over if the main grid goes down.

Huh. There really doesn’t seem to be an easy answer to all this. Got any other ideas?

Actually, yes. Here’s one last thought:

All these measures to protect power lines might not be as necessary as people think. Connecticut’s forest may already be adapting to more and more powerful storms, so that future storms will lead to fewer downed trees and fallen limbs.

That theory belongs to Chris Ozyck, an urban forester with New Haven’s Urban Resources Initiative. He said that because Connecticut had gone for decades before Irene without a major storm, lots of trees and limbs were primed to fall when the hurricane hit. But each successive storm has cleared out more dead or weak trees and limbs, leading to less damage with each succeeding storm, Ozyck said.

“Trees get pruned by mother nature,” Ozyck said. “We have sort of a resilient forest now after it’s been tested. I personally feel like we have time.”

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posted by: DanP on February 7, 2014  3:41pm

We have lived in Beaver Hills for decades and love the trees.  UI has never in 38 years trimmed the trees in front of our house next to the power lines. They must do that routine maintenance before they choose to butcher viciously all the trees. Where have they been?  we have submitted request, and had our own tree company do some of that work.
No need to destroy our nice neighborhood.  UI, do your routine maintenance in advance of the future storms..

posted by: Rob Smuts on February 7, 2014  3:50pm

Plenty of cities in California who don’t have their own utility also are in the midst of long-term under grounding projects. Same idea - a surcharge, sometimes topped up by a levy a neighborhood or business district will vote on itself will accrue for a few years, then they will do a couple miles (often coordinated with other work or paving that needs to happen). That approach would require state enabling legislation for both the surcharge and for the district levy.

Another, harder (politically) piece that would make the financials better would be for the city to have a municipal utility to own the new underground lines. You’d want to contract back with UI for everything, but have state legislation exempting the municipally owned lines from the various congestion and other fees tacked to the bill, which would go a long way to covering the costs. The fight would be from UI, which would be leery of losing ownership of the lines even if they made as much or more with the contract to manage them, and the concern about reducing the base of people paying those congestion and other funds (meaning everyone else would need to cover those who would stop paying). My argument would be that denser, built-out communities like New Haven have been subsidizing everyone else for a hundred years on our utility bills, but that is a little subjective (Fairfield County, which is responsible for the congestion that prompted the charge might argue that their income taxes more than make up for it). A more salable argument might just be the very small amount of customers involved.

All of this is mainly a state-level debate.

posted by: cp06 on February 7, 2014  3:55pm

New Haven should have municipal-produced power which will be much cheaper than the ridiculous rates we pay now.  We should take advantage of new technology and have GREEN (or at least greener) municipal power AND bury the lines. This can be done. Can we find the will and leadership to do it?

posted by: P Christopher Ozyck on February 7, 2014  5:22pm

Good article Tom . In my personal opinion…  Cost for under grounding would be reflected in higher rates over a good many years.  Higher rates would incentivize conservation by users. The country is in an energy boon that should reduce cost to produce electricity and increase economy.  If this is a trend of progressive cities banking on thier future - should not we begin sooner when it’s relatively cheaper to lock in contracts before economy heats up again.  Inflation also has a potential to reduce the relative cost.  What I think is most compelling is to combine electric burial with routing fibre optic lines.

As for the trees… Yes our Forrest was pruned by Mother Nature and is more resilient. But there remains a great many hazardous ( to powerlines) trees that need removal and many more that need pruning.  If we had a regular pruning regime ,we would not be in this situation.  Many healthy trees will need to be pruned to reduce weight/ wind loads and this needs to be done and supervised people with the overall trees health safety in mind. 

Ultimately U.I. will need to work with each municipality to manage the urban forest.  From a management standpoint, undergrounding may be easier- especially in development dense communities.

posted by: concernedcitizenNewHaven on February 7, 2014  5:31pm

All of those profits over the years could have buried all these power lines. But no. Pad the stockholders’ wallets. Screw the trees.

posted by: Jonathan Hopkins on February 7, 2014  6:08pm

Excellent article.

Would like to know more about Anaheim’s tax rebate for property owners that choose to bury lines - that seems like an important piece of this discussion that demands more investigation.

Rob Smuts also makes great points about ownership, which would be required if we do end up deciding to bury lines.

One thing is very clear, however, we do not want this to happen:

posted by: new havener on February 7, 2014  9:12pm

burying the lines is a herculean task, when you consider, gas, water, sewer, and in many areas electrical & communications main cabling is already underground…stop & consider how to snake around all that to place new wires, conduits,junction splices, and transformers(which almost always have to be above ground), additionally digging, while not knocking the above-mentioned services out, must be done done half by machine and half by shovel. point being it’s incredibly dangerous, time-consuming, and costly.

now, the dreamers in all of say ‘this can be done’ or ‘this should be done’, but the fact is this won’t get done. as much as the liberals in all of us say this will create jobs, stabilize the power, and save the urban/suburban trees, the conservatives in all of us will not have the financial stomach for the cost. at minimum, crews to do this, irrespective of the material needed, will be at least 8, plus two cops, for road work, and 2 to 4 men, plus a cop, to wire up to the house, then each home-owner will need their own electrician to connect the new and disconnect the old, and UI will need to return at a later date to remove the aerial wire to the house. Only when a whole street is complete, could the poles be removed, and that’s if the cable-tv and phone-wires are buried as well.
it won’t happen in our lifetime. but we can dream.

posted by: Bradley on February 7, 2014  9:58pm

Rob, a couple of clarifications. The congestion charges are attributable to congestion on the transmission system. The congestion occurred in southwest CT, which in this context is everything south of I-84 and west of I-91, I.e., including New Haven. The transmission system is federally-regulated. Exempting New Haven from the charges would require action by the Federal Energy Regulatory Commission or Congress, not the state. Conversely, municipal utilities are already exempt from the state-mandated conservation and renewable energy charges on electric bills, so no state action would be required in this area if New Haven became a munie.

I am agnostic on municipal utilities. But there are reasons why none have been created in Connecticut for nearly a century and very few in the country as a whole during this period. Economically, the cost of acquiring a utility network by purchase or eminent domain or creating a new system are huge. Politically, I suspect few elected officials would want to take on the responsibility of responding to constituents when the lights went out or rates went up.

posted by: BeaverhillTom on February 7, 2014  11:30pm

It is a shame that as New Haven grew alleys were not zoned into expanding residential areas. Cities with alleys have a corridor to run power, cable, and phone lines. Also, sanitation has access to your trash and you do not keep rodent-attracting trash bins right next to your house six days a week.

posted by: robn on February 8, 2014  10:28am

UI can forget their current trimming plan. It’s dead on arrival and any attempt to push it forward will meet fierce resistance.

Our two options are..

1) keep things the way they are. Chris Ozyck isn’t stating a theory about large weather events pruning trees, he’s stating a scientific fact and this points to fewer outages in the near future (as we’ve clearly seem in this past ice storm…UI had far fewer outages than they expected because their expectation is built upon a faulty premise that our trees are in a constant state of care)

2) bury the lines. In my opinion not necessary but there are three distinct advantages. Two advantages already stated are lower Maintenence and aesthetics. One overlooked advantage is data.  The technology exists to push data through electrical systems but the roadblock is the transformers on top of poles (which could be replaced with appropriate tech in the burial scenario))New Haven could lease bandwidth to ISPs for Internet, VOIP and streaming video. We could be the highest bandwidth city in the US

posted by: poetbum on February 8, 2014  7:21pm

Our first priorities should be making energy production cheaper, safer, and greener.  Burying the lines has nothing to do with production, as far as I can tell.  It might make some neighborhoods prettier and help us avoid the rare blackout, but certainly it’s not worth spending serious money on.  A ‘smart grid’, on the other hand, would be a great thing to have.

posted by: Bradley on February 9, 2014  7:20am

Robn, after talking with Chris Ozyck and Christy Hass ( the city tree warden), I believe there is at least one other option.  UI could expand its trimming program over historical levels to address dead and dying trees in its easement (its current plan allows it to cut healthy trees in or near the easement as well). But, UI would have to plant replacement trees of comparable caliber (if it takes down a 12-inch diameter tree, it would have to plant four 3-inch trees). This is already city policy when someone takes down a healthy street tree.

posted by: offerathought on February 10, 2014  7:45am

Could all public utilities be placed beneath the sidewalks rather than buried under streets - constructing a series of tunnels the lids being of reenforced cast concrete which may cantilever open for repairs. Gas lines, water lines, electric & phone.

posted by: robn on February 10, 2014  1:10pm


Your noting part of the problem, not a solution;  UI would love to remove large gauge trees and replace them with smaller caliber dwarfs that will never reach the size or magnificence that we are luckily accustomed to in New Haven, and that provide true sun and wind sheltering. Look at streets where this is happened. It creates a ridiculous cartoon of a streetscape.

posted by: HewNaven on February 10, 2014  1:20pm

It is a shame that as New Haven grew alleys were not zoned into expanding residential areas. Cities with alleys have a corridor to run power, cable, and phone lines. Also, sanitation has access to your trash and you do not keep rodent-attracting trash bins right next to your house six days a week.

In the Chatham Square section of Fair Haven there are several alleys that are still perfectly viable (e.g. Peck Alley, Pine Alley, Clinton Place, Park Place, Wilcox Place). I’m not sure if there are alleys in other parts of New Haven, or why they have them in this neighborhood.

posted by: Ali on February 10, 2014  2:19pm

Thank you, Robn for the following (and also Jonathan Hopkins who mentioned this in an earlier comment)

UI would love to remove large gauge trees and replace them with smaller caliber dwarfs that will never reach the size or magnificence ... Look at streets where this is happened. It creates a ridiculous cartoon of a streetscape.

I cringe every time I seem some mish-mash of small, flowering trees being planted as “street trees”.

posted by: reptile on February 10, 2014  4:34pm

I’ve lived in East Rock for 6 years in my current apartment, and prior to that, lived in a house in East Rock for ~20 years. In my current apartment we’ve lost power once in the 6 years—and that was because of some bonehead stealing copper in the power station - . Prior to that, I can count on a single hand the number of times we lost power for more than a flicker. On the other hand, my friends in Branford, Guilford, Vernon all seem to lose power with every single storm.

UI is doing a great job of keeping the power reliably up without trimming the trees excessively. Please look at East Rock as an example of what you’re doing right - without needing to take down the trees that make our neighborhood feel like a real place to want to live.

posted by: LosVaz on February 10, 2014  5:43pm

I can see it now.  Somehow PURA is convinced that under-grounding is the way to go.  UI or CL&P ask for a rate increase to do the deed and the local yokels come out against it asking for the utilities to take it out of executive salaries, as if that would cover it.  Or the prudent decision is to do maintenance trim of trees and another “storm of the century” comes 5 years after the last storm of the century.  The same yokels would scream bloody heck that UI didn’t trim enough and stopped trimming to pad its profits and pay more to execs.  UI, nor CL&P cannot win.  Darn if they do and darn if they don’t.

posted by: everloved on February 11, 2014  6:12pm

I don’t know why it weirded me out that power lines were being buried many years ago in new fancy neighborhoods.  Maybe because they were new and fancy or that there is a permanancy to it.  But I love trees much more.  How about mandatory solar power.  Of course ui would hate that.  It makes me feel weird that all houses are corporate outposts.  Then there is the extensive water and sewage department.  Imagine that underworld.  I am sure there is a way to utilize them for power avenues but it sounds like the job will cost as much as possible.

posted by: ElmKaren on February 12, 2014  11:32am

Great reporting!

The problem isn’t that trees are being “trimmed”—it’s that they are being butchered and mangled in ways that all but ensure that they will die in a few years—perhaps taking some power lines and cars along with them.

Aside from the better resilience to storms, buried lines are also significantly more aesthetically pleasing—which would raise our property values. I’d pay the $1-2 a month more on my electricity bill if that were the case.


posted by: Bradley on February 12, 2014  11:33am

Robn, you misunderstand my point. I don’t think healthy trees should be removed - we would agree on the benefits that mature shade trees provide. Dead and dying trees, on the other hand, do pose a real threat to utility lines as well as nearby properties. When UI removes those trees, it should plant replacement trees. In many cases, it will make more sense to plant a shade tree on the other side of the street rather than an ornamental tree under the line.

Reptile, I have lived in East Rock for a little longer than you and have had a similar experience. Part of the reason outages in the city are (normally) brief is that UI has a sensible policy of prioritizing repairs to maximize the number of customers restored, which benefits more densely settled areas.