A Dutch company is about to unveil the world's first-ever bike path built entirely of solar panels. It's about 230 feet long — you can traverse it in few seconds of pedaling.

It seems pretty neat at first. But there's also a good argument that this is a really inefficient way to generate solar power:

The bike path, built by SolaRoad, "is made up of rows of crystalline silicon solar cells, encased within concrete and covered with a translucent layer of tempered glass." It will open to the public on November 12.

The glass that overlays the panels has to be tough enough to withstand the thousands of cyclists who will ride on the path every day:

But is this even practical? The bike path will cost roughly $3.7 million and, when it's fully built out to 330 feet in 2016, will generate enough electricity to power… three households. Not very cost-effective. (That's more than 1,000 times costlier than the price of rooftop solar electricity in the United States.)

Of course, one big hope for solar bike paths — much like with the Solar Roadways project being tested in Idaho — is that they might be able to scale up and provide a lot of electricity in the future. After all, we have all this open space on our roads and bike paths. Why not put it to use?

Unfortunately, there are some big drawbacks here. For one, solar panels sitting underneath roads and bike paths can get covered in dirt and mud and ice and snow, reducing their effectiveness. SolaRoad is hoping to address this by tilting the panels slightly and giving them a non-adhesive coating, so that the rain washes the dirt off. It remains to be seen how effective this is.

A better approach would be to put solar roofs over the bike paths

Another big problem is that these panels aren't tilted toward the sun, the way rooftop photovoltaic panels are. According to The Guardian, that means they're expected to produce 30 percent less electricity than conventional panels.

Over at Renewables International, Craig Morris argues that the panels will probably perform much, much worse than that once you factor in shading, ice in the winter, and the rough surface needed to prevent bicyclists from slipping. He's sour on the whole idea: "Here's hoping news about how terrible the idea is gets around fast so that the project is not copied elsewhere."

Indeed, if you really wanted a solar-powered bike path, Morris notes, there might be an easier alternative. You could install roofs above parts of the bike paths and then install solar panels on the roofs. Less dirt. You can angle the panels. More electricity with less hassle. (Plus it would shield cyclists from the frequent rain, although it would be less pleasant on sunny days.)

That said, even if solar roads and bike paths are unlikely to generate a ton of electricity for household consumption, they might have more modest uses. Which is why the technology may still be worth testing.

Over at TreeHugger, Lloyd Alter points to one Dutch company's vision for solar roads: "Sensors gathering information about traffic circulation can help improve traffic management, or even allow automatic vehicle guidance. Other possible functions are variable road markings, ‘tag-along' LED-lights and heating in winter. And eventually, a system for wireless energy."

It may be unlikely that solar roads will ever be practical enough to power electric cars zipping up and down the highway. But smaller sensors or road de-icing systems? That's not quite as far-fetched.

-- Should we cover all our roads with solar panels?

-- Is there a free-market solution to global warming?

-- Solar power is contagious: Installing panels on your roofs often means your neighbors will too

Will you support Vox’s explanatory journalism?

Millions turn to Vox to understand what’s happening in the news. Our mission has never been more vital than it is in this moment: to empower through understanding. Financial contributions from our readers are a critical part of supporting our resource-intensive work and help us keep our journalism free for all. Please consider making a contribution to Vox today.

Understand how policy impacts people. Delivered Fridays.

Check your inbox for a welcome email.