Solar Roadways

I’ve made the casual comment on social media that solar roadways are a bad idea. It’s a terrible idea, and I wanted explain a few reasons why. It’s a really cool idea and I understand why people are excited. That’s all well and good, but when you start to look at the problem objectively without the hype, it starts to fall apart. This of course, coming from a guy who is planning to live on Mars.

If you don’t know what I’m talking about, there is a mom and pop company that is looking to replace the current road system with solar panels. The idea being that the roads are empty space, and we could have them doing work for us. To get yourself into full hype mode, read 7 REASONS WHY SOLAR ROADWAYS ARE F!#%ING AWESOME and watch the video below.

I want to call bullshit on a few of their features.

  • LED LIGHTS! If you were to make road lines with lights, it would be hard to see in the day and way too bright at night. Try looking at your cellphone in direct sunlight, how well does that work? We don’t change road configurations often enough to make this even remotely useful. One of the only times that lanes change is for traffic control or construction. We can use signs for traffic control like we do now and the panels wouldn’t be hooked up during construction. “But they are solar! They could run on their own during construction!” Live power and construction is a big no-no. That’s not a good idea.
  • NO MORE SNOW! So much bullshit on this one. There is no way, and I mean absolutely no way that the solar panel make enough power to melt ice. Solar panels are taking the energy from the sun, converting it to electricity, then converting it back to heat. The sun is the original source. If the sun can’t melt the ice, there is no way that power from the sun will melt the ice.  Black roads absorb heat more efficiently than a solar panel and a heating element can make it, therefor blacktop should be able to melt ice more efficiently than the Solar Roadway. Sure, you can melt ice with heaters, people do it all the time, but it will take power, the road cannot generate the power needed to melt ice with solar power.
  • UNDERGROUND CABLES! Putting rainwater a runoff channel right next to a power cable channel is a bad, bad idea. We put our high voltage lines in the air for a very good reason; the Earth is the other conductor, and if power cables touch the ground, they short out and things blow up. Solar power is DC, and all our power lines are AC. To convert we need to install step up transformers all along the trench.  They put these behind fences for a reason, they are fucking dangerous.
  • THEY ARE MADE WITH RECYCLED MATERIAL! Asphalt roads are 99% recycled. This is a buzzword argument.

Lets take a rational look at this. For these roads to be worth exchanging for our current system, they will have to perform better or cheaper. To make the solar panels worth the cost of installation they will have to make more energy than it takes to make, install and maintain them. I want these panels to meet these two criteria:

  1. The surface they are planning to use must be better than the surface we are currently using.
  2. We have to be able to use the power these panels produce.

I want to know, why replace our roads with glass that have solar panels under them, instead of just making more solar power plants?

Here is the claim made by Solar Roadways:

Everyone naturally pictures sliding out of control on a smooth piece of wet glass! Actually, one of our many technical specs is that it be textured to the point that it provides at least the traction that current asphalt roads offer – even in the rain. We hesitate to even call it glass, as it is far from a traditional window pane, but glass is what it is, so glass is what we must call it.

We sent samples of textured glass to a university civil engineering lab for traction testing. We started off being able to stop a car going 40 mph on a wet surface in the required distance. We designed a more and more aggressive surface pattern until we got a call form the lab one day: we’d torn the boot off of the British Pendulum Testing apparatus! We backed off a little and ended up with a texture that can stop a vehicle going 80 mph in the required distance.

I’m calling sacks of bullshit on this. If the material was so great, Solar Roadways should be trying to sell the road surface on it’s own merits without solar. Road construction is a complicated engineering effort and a few lab tests does not warrant the replacement of the entire roadway system. The US roadway system cost $425 billion (2006 dollars) and you can bet Solar Roadways will cost a lot more than asphalt.

For that kind of money, why don’t we build an orbital elevator, fusion power plant or travel to another star. Or, why not spend billions of dollars and build solar farms to make electricity?

And that brings me to the second point, We are putting solar panels in the road, at a 0 degree tilt, under dirt, grime and vehicles that block the sun. I can’t think of a worst place to put them. Before we start that, why don’t we put solar power on every roof? For panels to be effective they need to be angled at the sun, clean and have an unobstructed view of the sun. For best results they should track the sun. None of these things are possible if they are flat on the ground with things on top of them. The idea sounds cool, but the benefits of the Solar Roadway can all be met cheaper and better by just building solar power plants where they can be at their most efficient.