The Future, Optimism and Solar Roadways

Jonathan Strickland

Artist's rendition of downtown Sandpoint, Idaho - Home of Solar Roadways |

Here at Fw:Thinking, we take an optimistic view of the future. Humans have achieved some remarkable things in our relatively brief history. From designing basic machines to creating a worldwide information network, we've done pretty well. But being optimistic doesn't mean we don't acknowledge challenges and obstacles. In fact, only by admitting there are hurdles to overcome can we really expect to get to the future we want.

That's why I wanted to blog about the Solar Roadways project. You may have seen the video that helped the project go viral by proclaiming the future is solar "freakin'" roadways. Perhaps you even contributed to the campaign. It's a great video and a compelling idea: Replace the road system with solar panels and turn thousands of square miles of space into a giant solar farm.

According to Scott Brusaw, the electrical engineer behind the project, such a system could provide three times more energy than what we currently consume. Electricity from the road system could go back into the power grid. On top of that, embedded LEDs in the panels would allow us to create dynamic road systems that adjust lanes and alert drivers to oncoming hazards like an animal crossing the road. It's pretty phenomenal.

That's not all -- the roads could also have embedded heating elements to keep snow or ice from forming on the roads. This would be important because you couldn't run a snow plow over solar panels -- they'd destroy the glass protecting everything. Can you imagine roads that remain snow free even during a blizzard? Don't answer that yet, we have more to say about it.

I love the idea. The dynamic roads are cool, giving us options we wouldn't normally have. Using the same tech on walkways, parking lots or recreational areas is also a neat concept. But now we need to look at the challenges that face such a project. To ignore these challenges is to doom the whole thing.

First, there's the enormous scale involved. According to their own estimates, all the paved surfaces in the United States take up about 25,000 square miles (about 64,750 square kilometers). How long would it take to replace all of that? And how is replacing even accomplished? Most of what I've seen from Solar Roadways is focused on the technology (understandably) but not on the implementation.

I assume first we would need to dig up existing roads before laying down the panels. The Solar Roadways plan includes a stormwater channel and a cable corridor, both of which would need to be installed alongside the roads. The panels would need to be wired together and then connected by some means to power cables that feed back into the grid. That's a lot of work! On the bright side, it would mean lots of jobs for people -- as far as I know, there's no automated means to lay these solar panels together. But I imagine the project would take decades to complete.

Plus, the United States doesn't have a unified power grid that mirrors our roadways. We'd need to get that electricity to the grid somehow, which would require extra infrastructure to conduct the power where it needs to go. And this would need to be a two-way connection because you'd occasionally need to send power back to the roads.

Why is that? Well, if you want to use LEDs to create lanes and other displays on the road itself at night, you'll need power. Without the sun, you'll have to draw power from elsewhere. I assume the solar roadways will also have some form of rechargeable batteries which will fill up during sunlight hours and discharge when the sun isn't out. But if there's a long stretch of days without sunlight, particularly in the winter when the roads also have to heat up to keep snow and ice off of them, we'll have to route power to the roads.

That means pouring electricity back into our road system. And because we don't have that unified smart grid, that power will have to come from whatever region is connected to the road system. As for the heated roads, melting ice takes energy. And if the snow or ice storm is fierce enough, it's going to take a good deal of energy. It could be that the energy you need to heat a stretch of road ends up being more expensive than traditional snow and ice removal methods (snow plows, salt trucks and the like).

Then there's the expense of the panels themselves. We don't know how much an individual panel is going to cost yet. It's impossible to compare the costs of asphalt roads and solar panels until we have a final price tag for the panels. But even if the solar panels cost the same as laying an asphalt road, you're still talking about paying for an entire country's road system to be dug up and repaved.

Next, you've got maintenance. The folks at Solar Roadways say that maintenance is pretty easy -- the solar panels can all talk to each other and when one stops working the surrounding panels send out a distress signal. An engineer can go to the specific malfunctioning panel, pop it out and replace it within 10 minutes. That sounds amazing!

But what about maintaining the surface of the panels themselves? They are made from tempered glass, which is shatter and scratch resistant. But roads take a lot of abuse -- not just from heavy cars but from grit and dirt that gets rubbed onto them every day. What's going to keep the panels clean and free from scratches, which would impact the solar panels' efficiency?

And while the surface of the panels can withstand tremendous forces, what happens to the delicate stuff beneath the glass? Forces don't stop just at the surface of an object -- they transfer through. Plus, wheels will hit one side of the panel first before crossing over to the other side. Could repeated actions cause the road bed underneath to become uneven, resulting in uneven tiles? Think of how bumpy that would be!

It probably sounds like I'm totally dismissing the solar roadway idea. I'm not -- I just have a lot of concerns. It's possible that the team has answers for some or all of these concerns, though many of the responses I've read haven't spelled out specific strategies on how to approach these problems. I would love to see this proposal become a reality. I'm skeptical not because I "hate" the idea but because I want to see it work. To do that, we can't ignore all the very real challenges.