Why don't we go underground?

Moving power lines underground can help avoid danger during storms. However, undergrounding the power grid also has its own problems.

The first message to be transmitted over Samuel Morse’s telegraph line was the question, “What hath God wrought?”, sent from Washington, D.C. to Baltimore, Maryland via a system of wires suspended above houses and poles. wood. Suspension telegraph lines were soon replaced by Alexander Graham Bell telephone wires, and an ever-expanding electrical network connected communities. However, they are not a popular choice. At first, people complained about the telephone poles, because they said it was ugly and unreasonable. Today, people say they’re risky.

Each year, hurricanes, blizzards, and a host of other weather phenomena destroy ground-based utilities. Heavy snow and ice can break ropes. More commonly, violent winds toppled power poles, or uprooted neighboring trees, tore down wires.

The cost of power failure is enormous . Multiple analyzes show that even an hour of outage can cost commercial and industrial facilities tens of thousands of dollars, and outages often last for more than a day. In specific industries such as museums, power outages can also affect the environment in which valuable antiques are preserved. And as we witnessed in the aftermath of Hurricane Maria in Puerto Rico, damaged power grids can claim lives.

That’s why many people argue about “underground” , the process of moving from an elevated location to a protected underground tunnel. Proponents say doing so will help keep the grid secure even in stormy places like south Florida. But Ted Kury, director of energy research at the University of Florida’s Center for Public Utilities Research, says there’s no rush. Undergrounding could reduce storm-related blackouts in some places. But these tunnels bring their own problems and also costs .

Why don't we go underground?
This photo from the archives of the National Oceanic and Atmospheric Administration (USA) shows the impact of ice and snow on telephone poles.

There are two methods used to remove poles and bring them underground. The cheapest method is called open digging, which is how companies dig deep into the ground, put wires in, and then fill in the trenches. In this way, traffic and movement of people will be affected (even if only temporarily).

Many cities choose this method instead of directional drilling . Similar to an old oil and gas drilling technique, directional drilling is a less invasive but more expensive option. From a fixed point, a pipeline is brought underground for miles without affecting street activities.

With both ways, there still have to be certain changes to the lines before bringing them to the ground, the most important is the problem of heat dissipation . In essence, wires are very hot because they are the means of carrying electricity. Outdoors, this heat can dissipate, but deep in the ground that is not possible. That’s why underground wires are wrapped in plastic and surrounded with a layer of oil to keep things from getting too hot.

That sounds so simple, anyone with an excavator can do it! Depending on the density of the local population and the topography, undergrounding can cost billions of dollars . According to Kury, many localities have outlined the costs of undergrounding and have come to the conclusion that it is not “worth the money”. In North Carolina, for example, the process of undergrounding lasted about 25 years and caused electricity prices to increase by 125%. Most lines are still suspended. Even Washington, DC with the decision to partially underground electric wires, is expected to cost 1 billion dollars.

That’s not the only cost. Repairing underground systems is often more expensive than repairing overhead systems. “When the power goes out, there are two obstacles to fixing the line,” Kury said . “One, identify the fault, and then fix the line” . While smart grid technology makes it easier to identify faults and pinpoint where outages are on the system, repairing underground systems often requires digging, which is more difficult. if the ground freezes in a blizzard.

Ultimately , no system can be protected in all situations. During Hurricane Sandy, which made landfall in the northeast of the United States in 2012, underground electrical equipment flooded and aboveground power poles toppled. “It’s nearly impossible to protect the grid from damage,” Kury said.

Localities that do not want to invest in large underground projects may have other options. In recent years, many cities have replaced old wooden poles with frames made of durable metal. The ropes can help anchor the poles to the ground. At the same time, Kury says that vegetation management is very important. Pruning, watering, and helping plants resist pests can keep them healthy and better able to withstand storms. Also, quickly remove weak trees to avoid the risk that they could destroy neighboring power lines during high winds.

Many companies are also looking to methods of using drones. Commercial drones can help reduce response times for customer calls. In some places, data from drones is used to share the latest information with technicians and customers on everything from the height of lines to the function of drains in the water. Town. And in a difficult situation, drones can assist in aerial reconnaissance in locations that have been hit by storms that are inaccessible.

The smart grid has also helped to overcome the problems that arise. During recent storms, Kury said, Florida’s electricity suppliers have chosen to close substations at risk of flooding and reroute energy. The hope is that proactive decisions like these will allow grid power to be restored more quickly and reduce the potential for system-wide hazards.

In short, “There is no one-size-fits-all option”. Each city must make decisions that are right for its inhabitants, while accepting the fact that no system can function perfectly when confronted with natural phenomena.