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Comment by danpat | Hacker News Reader

The creators were answering questions on Reddit here:

http://www.reddit.com/r/IAmA/comments/1042mm/solar_roadways_...

The summary seems to be "we've got this awesome idea, and lots of money, now we're going to try to see if it will work."

The engineering consensus seems to be that it won't, or at best, will have extremely limited applications. Everybody would be far better off putting high-efficiency solar panels on rooftops than low-efficiency ones on the ground where they'll get dirty and broken.

Reading their literature, there seems to be a great big gap where any kind of decent engineering analysis would be.

While I can see the appeal of the idea, unicorns and hyperspace drives would also be pretty cool. I have my doubts.

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Note: this AMA is over a year old and many of the issues they were having could be outdated by now. They might have resolved some of the concerns with the technology from a year ago.

The engineering consensus or the naysayers consensus? It's all too easy to tear apart ideas on the Internet, which is a shame.

Engineering consensus. The math doesn't pass the smell test, not without some incredible materials breakthroughs.

They've got an expensive trough through which to run power, cable and fiber that I wager all by itself costs more than paving a traditional road.

Also ask yourself the question: If there was demand for putting more utility wires underground wouldn't they already be simply burying them which is much less expensive?

> I wager all by itself costs more than paving a traditional road.

Compared to a single road paving, the hi-tech road is more expensive but this road is supposed to be more durable than traditional paved roads. That means you need to compare the cost of several road pavings to get a more accurate comparison.

The hi-tech road is supposed to be installed once for several decades, where paved roads are re-paved every few years. This increases the cost of the traditional paved road.

Also, these hi-tech roads are supposed to subsidize their cost with energy creation.

> If there was demand for putting more utility wires underground wouldn't they already be simply burying them which is much less expensive?

Burying power lines is expensive. On its own, too expensive but combined with this project, it could be fiscally sound.

The key word is "supposed". If glass tiles were a good choice for road surfaces, I'd expect we'd have seen them in use by now. If it's just economics that have stopped glass tile use in roadways, I'm still dubious that the energy production from these units will come close to offsetting the additional expense.

This is what R&D is for.

The first part of R&D is research, implying "research if this is even possible". The point people are making it's far from clear that this will work, so it's silly to assume that it will work a priori given the obvious engineering challenges.

Humans have been researching and developing road surfaces for a few millennia now. It's going to be very expensive to find plausible materials that haven't already been tried.

Especially clear ones.

> If glass tiles were a good choice for road surfaces, I'd expect we'd have seen them in use by now.

These types of attitudes don't help push forward innovation.

paved roads are re-paved every few years

This is not my experience. I've lived near a secondary arterial road for nearly 9 years, and have never seen repaving done on it. It's still in fine condition.

In my limited understanding, the frequency of required maintenance depends heavily on weather conditions, and also on the size of vehicles who commonly travel on the road. Trucks cause orders of magnitude more wear on roads than cars do.

Weather conditions it is, then. It doesn't snow here, though it rains a lot. But if snow is a problem, then a solar road makes much less sense anyway.

I live in Michigan and the roads are repaved what seems like every other year. After each winter, there are potholes the size of craters on the moon. Very dangerous when everyone is swerving into incoming traffic and slamming on breaks to avoid them.

> The hi-tech road is supposed to be installed once for several decades, where paved roads are re-paved every few years.

We're comparing the cost of solar panels to the cost of pouring some shit onto the ground... I'd assume that difference is far more than tenfold?

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