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Generating power while facilitating travel at the same time, solar highways could be the roads of the future. We essentially have the technical know-how to make them, so why aren’t solar highways being rolled out around the developed world?
It turns out there are two big reasons: cost and red tape.
One of the biggest commercial efforts to pave roads with solar panels comes from Solar Roadways, an Idaho start-up founded by the husband-and-wife team of Scott and Julie Brusaw. The Solar Roadways system is based on durable hexagonal glass plates that hold solar cells, electronics and LEDs. Advocates point out that a Solar Roadway panel would simply would be replaced if it fails, unlike asphalt roads, which must be patched and/or repaved.
Are Solar Highways Impractical?
Naysayers of the technology have said solar highways are impractical. An article on the blog Extreme Tech calculated that covering all the roadways in American with solar panels would cost $56 trillion.
However, unlike the asphalt system, a Solar Roadway pays for itself through the generation of electricity.
Scott Brusaw, an electrical engineer, pointed out to Popular Mechanics
The technology behind Solar Roadways is feasible, according to experts, but does have certain limitations. For example, the performance of the solar panels decreases if they become grimy. To overcome this problem, Solar Roadways has proposed the use of self-cleaning glass, which uses chemically-engineered materials to keep dirt and water from sticking. However, this could make for a slippery road surface.
To make an asphalt road comparable to a Solar Road, you have to add a power generation plant (and the coal or radioactive material to run it), a power distribution network, snow removal, line repainting, pothole repair, etc. And then, you've only made them equal in costs.
Putting technology issues to one side, Solar Roadways and similar efforts also have to deal with the fragmented network of local, state, and federal governments in the US that all have a say in the rollout of new road technologies. To change how America builds its roadways would call for a Herculean feat of bureaucratic lifting.
Assuming the technological promise is as it appears, I think it might have a shot. And here's why: it's readily deployable at a small scale.
Jonathan Levine, professor of urban planning at the University of Michigan
Challenges Faced in Solar Highways
A single, small US town could install technology similar to what Solar Roadways is proposing, which would not call for linking roads from several jurisdictions and all the legal issues that comes with that. In fact, functioning solar highways in other parts of the world underscore how regulatory issues are getting in the way of the technology being adopted.
In China, where the one-party system facilitates rapid government action, officials recently announced a 1-kilometer stretch of solar highway. According to state media, the road consists of three layers: transparent concrete at the surface, solar panels in the middle and insulation on the bottom.
Project designer and transportation engineering expert Zhang Hongchao told state media that the highway could handle 10 times more strain than a normal asphalt road and could produce 1 million kWH of electricity each year. However, it could be a while before the project can increase in size, he pointed out, as the road cost around 3,000 yuan ($458) per square meter, appreciably higher than conventional roads.
In France, a small town actually did open the world’s first solar highway back in 2016. That 1-kilometer stretch of road cost €5 million ($6.3 million) to construct.
A solar powered cycling path opening in the Netherlands in 2014. It has generated 3,000 kWh of electricity, however, the cost of building the path could have covered 520,000 kWh.