Solar Highways: What’s it all about?

Solar Highways: What’s it all about?

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Using solar technology, roadways, parking lots, sidewalks, driveways, bike paths, and even outdoor recreational areas are replaced or upgraded. This way, these surfaces and areas are able to power a neighborhood.

What is a Solar Highway?

As the introduction to this informative yet entertaining YouTube video by Michael Naphan states, they’re “solar freaking roadways”.

Unlike concrete and tarmac surfaces, they aren’t likely to crack or develop potholes that take forever to repair. That’s because they’re coated with a tempered glass material developed especially for the project. This new tempered glass technology has been put through rigorous testing to ensure it meets the necessary impact, load, and traction regulations.

If a unit is damaged or starts malfunctioning, rather than tearing up a whole section of the road, you simply replace the problematic unit.

Instead of having what Naphan refers to as “useless asphalt and concrete”, solar highways generate electric power – and essentially pay for themselves. By harvesting solar energy, these solar freaking highways perpetually generate capital.

Solar Roadways – The Journey

Solar Roadways

Scott Brusaw and his wife Julie met in California when they were growing up, and are now based in Sandpoint, Idaho.

Julie has always had a lot of concern for environmental issues. As Scott testifies in their Indiegogo YouTube video, Julie got the idea for Solar Roadways while they were working in their garden.

At first, Scott was skeptical of the notion because solar panels are notoriously fragile.

But the idea nagged at him, and a week later he began working on a design for a structurally sound casing. Thanks to an Indiegogo funding campaign, Scott – who has an M.S. in Electrical Engineering – was able to develop the tempered glass technology.

The journey has enjoyed considerable recognition. In 2009 and 2010, Solar Roadways became finalists in the IEEE Ace Awards. Solar Roadways also won GE’s Ecomagination Challenge “Powering the Grid” (2010) and “Powering the Home” (2011).

In 2013, Google featured the company in their Moonshots. Later that same year, the World Technology Award for Energy also saw Solar Roadways as a finalist.

Popular Science listed Solar Roadways as one of the 100 Greatest Inventions of the Year 2014. Furthermore, the company has also enjoyed three funding phases from the US Federal Highway Administration and the US Department of Transportation.


Ideally, for solar panels to operate optimally, they need to be placed at an angle. This isn’t possible when working with road surfaces, of course.

However, during one of their testing phases, Solar Roadways found that the horizontal solar highways generated more power on overcast days than their angled counterparts.

Working with some complex mathematical equations, Solar Roadways have been able to estimate the amount of power their solar highways will be able to generate in a year. The full specifications can be found here, but we’ll give you the breakdown.


In the US, there are approximately 32,868.61 square miles that could potentially be covered. At an efficiency rate of 18.5%, this area could hypothetically generate about 15.73 billion kilowatts an hour. With four hours of peak sunlight a day, this translates to roughly 22,966 billion kilowatts a year.

However, because solar highways can’t be angled to achieve this optimal power generation, you need to subtract 31% efficiency. Furthermore, the 0.5-inch glass covering reduces efficiency by another 11.12%.

All told we’re looking at an optimal 14,085 billion kilowatts a year in the US. That’s way more than the 3,741 billion kilowatts used in 2009.

Clean Energy

The first major attraction point for solar highways is their use as a source of clean energy. Theoretically, if enough solar highways are installed, everyone would be able to drive an electric car that would be recharged by the same roads they’re traveling.

That means less air pollution from the carbon exhaust emissions of gas and diesel vehicles. Not to mention we won’t be burning fossil fuels and wreaking havoc on the environment to harvest them to fuel our cars. Cleaner air, happier environment, a whole array of health benefits.

According to the Solar Roadways site, approximately 50% of all greenhouse gas emissions are from the burning of fossil fuels. By replacing fossil fuel sources with solar freaking highways and generating up to 14,085 billion kilowatts a year in the US alone, these emissions could theoretically be eliminated.


Another 25% of the current greenhouse gas emissions are reportedly from our vehicles. Theoretically, solar highways won’t only be able to provide energy for electric car recharging points, but to actually charge the EVs while they’re driving.

If it’s possible to replace all cars on the road with EVs and rely exclusively on solar energy from these solar highways, the technology could theoretically reduce greenhouse gas emissions by 75%.


Solar Roadways have not as of yet laid any solar highways, focusing their phase testing on driveways and sidewalks predominantly. They are hoping to begin building their first solar highways in 2017 or 2018.

The French, however, have already laid the world’s first solar highway ever – in Tourouvre au Perche (Normandy). Although only 0.6 miles long (about 1km), the photovoltaic cells amount to 2,800 square meters.

Colas, an Anglo-French construction company, is responsible for building the solar highway. Their hope is that, at the very least, it will be able to power Tourouvre au Perche’s street lights.

The solar highway technology Colas used to build their 1km test strip is called Wattway, the company’s own invention. Five years in the making, Colas has already tested the technology in car parks.

One major drawback to the development and implementation of solar highways has been the incredibly high cost involved.


Colas sought to tackle this issue by using smaller, rectangular panels rather than the hexagonal design pioneered by Solar Roadways. Their thinner model, just a few millimeters thick, can be laid on top of existing surfaces. This reduces construction expenses significantly.

Even so, the single-lane 0.6-mile solar highway cost a whopping €5 million (over $5.8 million). A double-lane of the same length would cost double that.

Bonus Points

Another major benefit of solar highways, as marketed by Solar Roadways, is their ability to produce their own heat. This may seem like something of a side issue, but when you consider the implications, it’s actually quite genius.

By emitting their own heat, solar highways do away with the age-old issue of snow and ice on roads during the cold winter months.

The solar panels used in Solar Roadways’ design incorporate power elements. These are used to keep the surface a few degrees above freezing temperature. This way, snow and ice are immediately melted.


There are a few major perks as a result.

Snow and ice on our roads and driveways have been known to cause accidents, traffic delays, and injuries. The usual solution is to salt roads and sidewalks, but the salt has been known to corrode cars’ undercarriages.

Not to mention the amount of tax money spent on snow removal vehicles, right?

Furthermore, unlike asphalt and concrete, there’s no need to keep repainting road lines after they’ve faded from years of exposure. Solar Roadways’ design incorporates a series of LED lights, which can be programmed for any display. Warning signs, parking lot configurations – you name it, you can display it.

Even better, the intelligent panels detect pressure. If a tree has fallen across the road, or boulders in mountainous areas, the communication between panels will be able to display LED warnings to alert drivers in advance.

The Solar Roadways design also incorporates a power channel on the side. Here, power lines and even high-speed internet cables can be stored and tap into solar energy as necessary.

This negates the need for telephone poles and power cable towers, which can cause considerable damage after and even during a storm. No more live wires thrashing about on the road when one of these structures gets blown over.

A second channel is used to capture the melted snow and ice, as well as stormwater. Stormwater has been known to contribute as much as 50% to water pollution, an issue solved by the Solar Roadways design.

These stormwater channels will direct the runoff to treatment facilities instead of allowing it to pollute the soil, lakes, and oceans. In some cases, the water may even be treated in the channel itself!

Engineering Flaws?

Not all the news out there on solar highways is good news, unfortunately. The solar highways have been dubbed a “solar freaking failure” by many engineers.

Researchers have estimated that there’s actually a 60% loss in the amount of energy a solar highway would be able to capture. Furthermore, the LED lights used in the design aren’t nearly visible enough during the day – which could turn it into a safety hazard.

With a little bit of math, you’re looking at capturing 40% of the 18.5% solar energy current solar panels are able to capture. That’s 7.4% – of which only 20% can be used for the LED lights, rendering them virtually invisible during the day.

The cost of covering the amount of space required to produce the optimal 14,085 billion kilowatts a year in the US currently amounts to around $20 trillion. In other words, about ten times higher than the federal budget.


And then there’s the issue of the solar highway having caught alight shortly after the first major Solar Roadways test.

At the end of the day, there’s a lot of work that still needs to be done before solar freaking highways will be a truly feasible project. But we’re excited to see all the kinks worked out and the technology implemented in the future!

If you enjoyed this article and like all things solar then you should check out these other articles! One is all about solar security lights around your home, and the second one is about solar path lights around your yard.

Everything You Should Know About Solar Highways

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