The first solar road was installed in 2016 by engineers in Normandy, who were glowing with the type of excitement that typically accompanies innovative technology. Roads that silently collected sunlight as automobiles drove by overhead were the project’s remarkably futuristic promise. It was called Wattway. The concept briefly had the feel of something taken from science fiction and modified for everyday use.
But the road ahead was anything but level. The panels started to fracture within the first year. Their surface was covered with dirt, their energy output fell short of expectations, and they had to deal with maintenance problems that came much too soon. The idea of solar roadways persisted, nevertheless. It was only a diversion.
| Feature | Details |
|---|---|
| Concept | Embedding solar photovoltaic panels directly into road surfaces |
| Early Pilots | Wattway (France), SolaRoad (Netherlands), Solar Roadways (USA) |
| Intended Benefits | Generate power, heat roads, charge EVs, light up traffic lines |
| Main Challenges | High costs, low energy efficiency, maintenance difficulties |
| Current Use | Limited to niche applications like bike paths, parking lots, and signage |
| Expert Consensus | Currently impractical at scale; more effective solutions exist |
Solar highways still have symbolic value. They are clearly appealing. Why not turn the vast amount of area that roads already take up into something useful? Public roadways are everyone’s property, unlike rooftop panels, which need ownership, authorization, and planning. At least in principle, the idea seems especially democratic and unquestionably effective.
SolaRoad, a solar cycling route in the Netherlands, briefly achieved success. For a period, it powered street lights and made headlines throughout the world. However, the glass layers deteriorated over time, and energy production drastically decreased, just as its French cousin. The panels were not directly illuminated by the sun. Tire muck and grime took care of the rest.
Innovation has not been halted by these obstacles. There are still engineers who think solar surfaces can be used for certain purposes. Road markers can be programmed by integrating LED lights into the panels. In colder climates, heating elements could melt snow, making winter driving much safer. The most intriguing possibility is that electric cars may eventually be able to be wirelessly charged while they are in motion.
The technology is still quite cutting edge. However, the cost of putting it into practice remains high. Solar highways are frequently 10–20 times more expensive per kilowatt of electricity produced than rooftop solar or large-scale solar farms. Just that number raises serious questions about the concept, particularly in an industry where efficiency is crucial.
Additionally, there is a significant efficiency issue. Conventional solar panels can absorb the most energy throughout the day since they are angled toward the sun. In contrast, road-based panels are flat and shadowed by trees, automobiles, and even dust that tires kick up. Performance is greatly decreased by these conditions, often by 40% or more.
I questioned a project lead at an energy research lab in Boston about the continued interest in solar highways. They were “more about imagination than implementation,” he stated with a smirk. That reaction persisted. It clarified the concept’s emotional appeal in addition to its tenacity. Our infrastructure should be able to do more, multitask, adapt, and feel as forward-thinking as the vehicles that use it.
I recall strolling down a pedestrian walkway in Seoul that was illuminated by the sun. It attracted attention even though it wasn’t generating much power. Using energy that had been captured earlier in the day, gentle lights led walkers beneath trees at night. In a technical sense, modest. rich in symbolism. Even small-scale solar feels very significant in times like that.
Some businesses are completely reimagining the solar-road strategy by utilizing neighboring technology. Newer designs include installing panels along guardrails or sound barriers—places that don’t see as much physical wear and can be directed toward the sun—instead of embedding them into asphalt. These modifications are much more useful, but they lack the same dramatic appeal.
Municipalities are lowering their goals in the interim. Pilot initiatives that were formerly praised have either ended or changed to passive demonstrations. The same concept, however simplified, is now used by a few small municipalities to power signage or crosswalk lights using solar panels.
The story is changing as a result of deliberate testing. The idea of solar highways as a main source of power has changed. Rather, they are seen as auxiliary elements that can improve energy resilience in specific ways, particularly in areas where land-based or rooftop solar is impractical.
Every watt counts when it comes to the urgency of climate change. Cost, however, also does. Durability is also important. There is still a clear conflict between what is creative and what works. While ground-mounted solar farms are producing electricity at more affordable rates, rooftop solar is still growing quickly. In contrast, solar highways focus more on posing new issues than they do on addressing the current energy crisis.
What can we learn about multifunctionality from infrastructure? Are roads going to be more than just surfaces? Does visibility influence policy or even behavior?
Cities can continue to experiment—safely, economically, and visibly—by incorporating solar features into low-impact areas like bike lanes or parking lots. These studies offer data, but they may not feed the grid in large quantities. Additionally, they convey intent, which has a silent power of its own in public infrastructure.
For many engineers, installing photovoltaic glass on highways is not the end aim. It’s to draw lessons from previous endeavors and use them in other contexts. After all, the destination need not be the road. It might be a lab. A testing field. An emblem.
Public enthusiasm has diminished, but not completely disappeared, in recent years. The technology is still in use today. It is merely changing its course, becoming more intelligent, compact, and practical.
Therefore, the concept of solar roadways is still remarkably alive even though we may not yet be able to drive on highways that beam electricity into our batteries. Under our feet, it is softly and steadily changing.