Why Aren’t All Powerlines Underground?

It was a stormy Saturday night. I was deep into an online game—headphones on, fully locked in—when suddenly everything went dark. The screen froze, the lights flickered out, and my Wi-Fi vanished mid-match. Total blackout.

Sitting there in the silence, I couldn’t help but wonder: why is our power grid still so fragile? Why aren’t all power lines buried underground to stop this from happening? That night really made me realize how much we rely on electricity—and how frustrating it is when it goes out. So, I started digging into the reasons behind it.

What I found surprised me: burying power lines isn’t as simple as it sounds. The high installation and maintenance costs, technical challenges like heat dissipation and voltage limits, longer and pricier repairs, plus complex environmental factors—all these explain why overhead lines still dominate in many places.

If you’ve ever looked up at those tall poles and wondered why they’re still there, stick with me—there’s a lot more to this story than meets the eye.

Why Are Underground Power Lines So Expensive?

Ever wonder why burying power lines costs so much? It’s not just a little pricier—it’s a major investment.

Underground power lines are much more expensive to install and maintain than overhead lines. For local distribution lines, costs can be 4 to 14 times higher, reaching $1.16 million per mile underground, compared to $448,800 for overhead. For high-voltage transmission lines, the gap is even wider: underground systems can reach $5 million per mile, while overhead lines typically range from $500,000 to $1 million.

What Drives the Cost?

Let’s talk numbers. For distribution lines—the ones that bring power to homes—burying them costs about $1.16 million per mile, while overhead lines run around $448,800. That’s roughly 2.6 times more.

It gets steeper with high-voltage transmission lines, which move electricity across long distances. Underground lines can cost up to $5 million per mile, while overhead versions fall between $500,000 and $1 million. That’s 3 to 6 times more.

For homeowners, it’s no different. Burying lines to a house costs $10 to $25 per foot, while overhead is $5 to $15. For a typical 250-foot run, that’s $2,500 to $6,250 for underground, versus $1,250 to $3,750 for overhead. In many cases, going underground can get really expensive—sometimes adding millions, even if it’s just a few miles. That’s why many builders stick with overhead lines to keep costs down.

Why So Pricey?

So, why is undergrounding so pricey? It starts with installation. Burying lines requires digging trenches, which means using heavy machinery, hiring skilled crews, and a lot of time. The cables themselves are more expensive too—they need special insulation to handle the underground environment, unlike overhead lines that use simpler, air-cooled designs.

Then there’s maintenance. When an overhead line fails, you can spot the issue quickly—maybe a fallen tree branch or a damaged pole. But underground problems are hidden. Finding the fault can take days, requiring specialized equipment to pinpoint the problem. Then you have to dig just to reach it. Repairs can cost up to 10 times more than fixing overhead lines.

How This Affects You

These high costs don’t just affect utility companies—they affect customers too. A study by the North Carolina Natural Disaster Preparedness Task Force found that undergrounding could double or triple electric bills. That’s a tough sell when people are already concerned about rising costs. In my experience, utilities are always trying to balance reliability with affordability—and overhead lines are often the more budget-friendly choice.

Balancing Cost and Benefits

The high cost of underground lines means tough decisions have to be made. Utilities have to weigh the upfront price tag against long-term benefits like fewer outages and a cleaner look. But when money is tight and customers don’t want their bills going up, overhead lines usually come out on top. In the end, it’s not just about cost—it’s about what makes sense for the community.

What Technical Challenges Do Underground Power Systems Face?

Technical issues can make underground lines a headache. Many engineers scratch their heads over these challenges. It’s not just about digging a trench.

Underground cables can get hot because soil traps heat, which can damage their insulation. They are also limited to around 66 kV voltage, while overhead lines can carry 400 kV or more, making them better for long-distance transmission.

Heat Dissipation Problems

One big problem is heat. Overhead lines are cooled by the air around them, but underground cables are surrounded by soil, which keeps the heat trapped. If this heat isn’t managed properly, it can damage the cable’s insulation and cause failures.

Engineers often need to carefully design cooling systems for underground lines—similar to building a radiator for a cable—to prevent overheating and protect insulation. Special designs or materials can help, but they add to the cost and complexity.

Voltage Limitations

Voltage is another limitation. Underground cables generally operate at a maximum of about 66 kV. Overhead lines, on the other hand, can handle 400 kV or more, making them the preferred choice for long-distance, high-voltage transmission. This is why you see those massive overhead lines stretching across the countryside. Burying very high-voltage lines would require different, often impractical technology.

Capacitive Loading Issues

Another challenge is something called capacitive loading. Underground AC cables have higher capacitance, which means they store more electrical charge, creating reactive power that needs to be managed with extra equipment.

I remember an engineer explaining it to me like trying to keep a water pipe from overflowing—you need additional systems to control the flow, which adds cost and complexity. For example, a 138 kV underground cable had 70 amps of charging current with no load over just 8 miles.

Real-World Impact

These technical limits aren’t just in textbook. They limit where underground lines can be used. They work well for local city distribution but aren’t usually suitable for long-distance, high-voltage transmission. Many projects that aimed to bury lines had to rely on overhead systems because of these voltage and technical challenges. It just goes to show—building the power grid isn’t only about money. The tech has to make sense too.

Underground vs Overhead: Which Is More Reliable?

Power outages are frustrating, and underground lines seem like the perfect answer. But I’ve learned reliability isn’t black-and-white. Both systems have pros and cons.

Underground lines experience 78% fewer outages and are 94.3% less likely to fail during storms, with 69% less downtime. However, when failures do happen, repairs take 51.5% longer and cost up to 10 times more than overhead lines.

Fewer Outages, But Slower Repairs

Underground lines perfom well when it comes to preventing outages. They’re protected from common causes like wind, ice, and falling trees, which account for 24-30% of outages across the country.

Data shows underground lines have 78% fewer outages and are 94.3% less likely to fail during storms, with 69% less total downtime. That’s huge in storm-prone areas. During major storms like hurricanes, underground lines have been shown to maintain power while overhead lines can remain out of service for days.

But when underground lines do fail, it’s a different story. Repairs take 51.5% longer because faults are harder to locate and crews often need to dig to reach the cable. This makes the whole process time-consuming and expensive, sometimes up to 10 times the cost of fixing overhead lines.

Different Types of Risk

Each system has its weak spots. Overhead lines are exposed to weather—lightning strikes cause 6-8% of outages, and wind or ice can bring down poles. Underground lines are less affected by weather but facing more risks from flooding, earthquakes, or accidental damage during construction. I once heard about a crew accidentally cutting an underground cable while digging for a new pipeline—it took days to restore power.

Finding the Right Fit

In the end, it’s all about trade-offs. Underground lines offer more reliable service, but when issues happen, they’re harder to fix. Overhead lines are more exposed, but easier and cheaper to repair. Utilities often decide based on local conditions—underground systems make more sense in dense urban areas, while overhead lines remain practical for rural regions.

Power Lines: Balancing Environment and Appearance

Overhead lines can be visually intrusive and pose risks to wildlife, but undergrounding isn’t perfect either. The debate often goes beyond appearance—it’s also about safety, ecosystems, and long-term impact.

Overhead lines are estimated to kill up to 175 million birds annually through collisions and electrocution(Related Reading: Why Don’t Birds Get Electrocuted in Powerlines), and have been linked to wildfires, such as California’s 2018 Camp Fire. Underground lines eliminate these risks but require land disturbance for trenching.

Wildlife and Fire Risks

Overhead lines pose serious risks to wildlife. Studies suggest that up to 175 million birds annually die from collisions or electrocution, especially large species like eagles and hawks. Overhead lines have also been implicated in major wildfires—think of the 2018 Camp Fire in California, the deadliest in state history, caused by a faulty overhead line. In wildfire-prone regions, such incidents often prompt calls for moving lines underground to reduce future risks.

Visual Upsides of Going Underground

Underground lines offer a clear looking advantage. Without poles and wires, streetscapes appear cleaner, and views remain unobstructed—an especially important factor in residential developments and scenic areas.

Many urban planners and developers consider undergrounding a premium feature. However, installing underground lines requires trenching, which can temporarily disturb landscapes and habitats.

Environmental Trade-Offs

While underground lines reduce collision and fire risks, digging trenches isn’t environmentally neutral. It disturbs soil, vegetation, and sometimes wildlife habitats. However, once installed, underground lines have a smaller long-term footprint compared to overhead lines, which require ongoing maintenance of corridors that break up habitats. It’s a trade-off between short-term disruption and long-term ecological stability.

Community Perspectives

Communities often push for underground lines for both appearance and environmental safety. But high costs and technical issues can limit feasibility.

In many cases, communities must weigh the benefits of a cleaner skyline and reduced fire risk against the significant financial investment. These environmental and aesthetic factors are part of a broader conversation about what kind of infrastructure makes the most sense for a given region.

Power Line Infrastructure Around the World

You know, one thing I’ve noticed in the electrical industry is how differently countries manage their power lines. It’s not just about putting lines above or below ground—it’s about balancing cost, reliability, and looks in ways that fit each country’s unique situation.

For example, European countries like the Netherlands, Belgium, and the UK have way more underground lines—often between 60% and 100%—while the US has less than 20%. This comes down to history, cost, and geography.

Why Europe Leads the Way

Let’s start with Europe, where underground power lines are far more common. The Netherlands is the gold standard, with 100% of its distribution lines buried. Belgium and the UK are close behind, at 85% and 81%, respectively. Germany has about 70% of its low-voltage lines and 60% of its medium-voltage lines underground. Even countries like Denmark (59%), Italy (35%), and France (32%) have large shares underground. Sweden has been particularly proactive, adding about 200 km (124 miles) of underground lines every year since 2007, contributing to around 40% of all power lines in Europe being underground.

Why is Europe so far ahead? It’s mainly about population density and land constraints. In densely packed cities, overhead lines clutter the skyline and take up valuable space, so undergrounding makes sense for looking and practicality. Plus, many European countries have invested heavily in modernizing their grids, often with government support or incentives. Underground lines aren’t just about keeping the power on—they’re also about making cities look cleaner and more modern.

Why the US Is Behind

You might be wondering why the US isn’t keeping up. It’s not that they don’t care—it’s a mix of history, economics, and geography. The US power grid was built in the mid-20th century when the focus was on electrifying vast areas as cheaply and quickly as possible. Overhead lines were the obvious choice back then, and with over 600,000 miles of transmission lines already in place, switching to underground would be a huge and costly project, as we have done the math in the chapter before.

Geography also plays a role. The US has vast open spaces, unlike Europe’s compact cities, so overhead lines don’t block views or take up precious land. Plus, overhead lines can handle higher voltages. These factors make overhead lines more practical for long-distance transmission across rural areas.

What Can We Learn?

What can we learn from this? Underground lines work best where looks and reliability matter most, like Europe’s urban centers. But it’s not one-size-fits-all. The US might add more underground lines in high-risk or high-visibility areas, like coastal towns or city centers. In fact, some coastal communities choose underground lines after big storms to avoid long outages—even if it costs more. The key is picking the right solution for each place.

The Future for Power Line Infrastructure

The future of power line is exciting but full of unknowns. After years in the industry, I’m still curious about where we’re headed. So, will underground lines become the new norm? With emerging technologies like advanced insulation and smart grids, along with policy and investment trends, we may see more underground projects, especially in cities and storm-prone areas.

Emerging Technologies

Technology could be a game-changer for underground lines. One big issue right now is heat dissipation—buried cables trap heat, which can damage insulation. New materials, like advanced polymers or even superconducting cables, could allow for higher voltage transmission underground, which is currently limited to 66 kV compared to 400 kV for overhead lines. These innovations could make undergrounding more feasible for long-distance transmission.

Smart grid technology is another area to watch. Sensors and monitoring systems could make fault detection faster and more precise, reducing repair times and costs. I’ve heard of pilot projects where utilities are testing these systems to make underground lines more manageable. For example, some cities are experimenting with underground microgrids that can operate independently during outages, powered by local renewable sources like solar.

Policy and Investment Trends

Policy is starting to shift toward grid resilience, especially with climate change bringing more extreme weather. Governments and utilities are prioritizing infrastructure that can withstand storms, floods, and wildfires. Underground lines, with their 94.3% lower failure rate during storms, are an attractive option for high-risk areas. Incentives or subsidies could make undergrounding more affordable, particularly in urban centers or coastal regions.

Investment plays a big role too. As renewables like solar and wind grows, the grid needs to adapt to handle distributed energy. Underground lines could play a role in urban areas where space is tight, supporting smart cities with electric vehicles and smart homes. A Santee Cooper article shows that 64% of their distribution lines are already underground, a clear sign of the trend.

Regional Variations

The future won’t look the same everywhere. In urban areas, the demand for aesthetics and reliability might lead to more undergrounding. In rural areas, where cost is a bigger concern, overhead lines will likely remain dominant. Some experts have proposed hybrid systems, where urban centers use underground lines while rural areas stick with overhead ones. It’s a practical way to balance cost and benefit.

At industry conferences, experts often outline a vision for underground networks in smart cities: a seamless, resilient grid capable of supporting modern technologies. It’s a promising idea, but one that still faces technical and financial challenges.

Balancing Act

The future of power line infrastructure will be about finding the right balance. While underground systems offer clear benefits, their high costs and technical challenges mean overhead lines will continue to play a key part of the grid, especially in rural areas. As technology and priorities shift, we might see more undergrounding in strategic locations. Still, this transition will be gradual rather than sweeping.

As technologies advance and priorities shift, undergrounding is likely to expand in targeted, high-impact areas. Still, this transition will be gradual rather than sweeping.

Conclusion

So, why aren’t all power lines underground? It’s a complex question with no simple answer. From my perspective, it’s about balancing costs, technical feasibility, reliability, and environmental impacts.

Underground lines offer fewer outages and better aesthetics, but high installation and repair costs, along with technical challenges, keep overhead lines as the go-to for many areas. Europe’s high undergrounding rates show what’s possible, but the US’s vast geography and existing infrastructure make a full shift unlikely.

Looking ahead, new technologies and policies could tip the scales toward more underground lines, especially in cities and storm-prone regions. For now, the grid reflects a practical compromise, shaped by history and economics.