Future Of Driving

The World's First Solar Road Explains Why We Don't Have Solar Roads

Excited for the August 21 eclipse? Visit our Eclipse 2017 page to explore the science, history, and myths of the event. The Curiosity team will be viewing the eclipse alongside NASA in Carbondale, Illinois. Follow us on Facebook for live videos, trivia, and interviews on the big day.

It seems like a no-brainer: we have solar panels. We have millions of miles of road. Why not cover those roads with solar panels and fix our energy problems for good? Well, France just tried that. Turns out that solar roads aren't the miracle you'd think they are.

Related: Green Roofs Are Basically Roof Yards

Wattway By The Numbers

The new test road, called Wattway, makes up a single lane that stretches 1 kilometer (0.6 miles) through the village of Tourouvre-au-Perche in France's Normandy region. Over its two-year test period, it's expected to be used by roughly 2,000 motorists daily. The cutting-edge roadway cost €5 million, or roughly $5.4 million in U.S. currency. So what about its energy-generation stats? It's covered in 2,880 photovoltaic panels, which are projected to produce 280 megawatt hours (MWh) of energy each year and an electrical output of 767 kilowatt hours (kWh) per day. How much electricity is that, you ask? It's enough to power...wait for it...the streetlights.

Related: ReGen Villages Are Off-Grid Settlements That Are Totally Self-Reliant

You might be surprised to learn that Wattway's big claim to fame is how inexpensive it is compared to alternative plans. Each panel is extra thin and designed to be installed on top of roads that already exist, so it saves money in construction costs. Still, that €5 million price tag is just for the initial cost—it doesn't include future maintenance, and how well the solar panels will withstand the pounding of thousands of cars each day is an open question.

Why Solar Roadways Aren't Worth The Effort

According to Ars Technica, "their questionable efficiency is one of the main reasons that more solar roads aren't currently being built." The efficiency of Wattway's solar cells is purportedly 15 percent, which sounds low until you realize that most rooftop solar panels only hit about 20 percent.

Related: Earth Overshoot Day Came Earlier Than Ever In 2016

But, Ars Technica continues, "that doesn't take into account the fact that the solar panels are flat on the ground, rather than angled towards the sun's trajectory, significantly reducing efficiency at higher latitudes. Heavy traffic could also block sunlight; as could snow, mud, and perhaps standing water after rain." Add to that the exorbitant cost and the questionable amount of maintenance, and you start to wonder if solar roadways are more trouble than they're worth.

Is there something you're curious about? Send us a note or email us at editors (at) curiosity.com. And follow Curiosity on Facebook, Instagram and Twitter.

Watch And Learn: Our Favorite Videos About Solar Energy

Can Streets Become Giant Solar Panels?

Weigh the pros and cons of solar roadways.

The Future Of Solar Energy Is Tiny Technology

Our best bet for solar energy may be on the nanoscale.

Solar Energy Explained

Here's how we get electricity from the sun.

If you liked this you'll love our podcast! Check it out on iTunes, Stitcher, Google Play Music, SoundCloud, search 'curiosity' on your favorite podcast app or add the RSS Feed URL.