Roads take up space, cost money to build and maintain. If you build it next to the road the road need twice the amount of space and still require the space, construction and material for the actually road. If you build it above the road you get all the issue of overhead roof on a road (trees that fall on it, wind, height limitation).
In addition to saving money by not actually building a normal road, the idea in most of solar roads projects is that it combines the work of putting internet and power cables into the ground.
That it currently do not work economically is the issue that the article showcase. Maybe it will never work and it always will be cheaper to simply build the road with current construction methods, put internet/power cables under it, buy large lands (farming land?) and construct regular solar parks.
Other concept of combining solar panels and building materials that is argued as more cost effective are roofs on houses. Same concept as solar road, ie that you get a roof and a solar panel in one without spending the work and material for both, but I have no idea if the economics is better than solar parks or if it is cheaper to just build normal roofs and go the route of getting land and building solar parks separately.
It's more than that. We simply don't live in a world where physics is in favor for doing this.
Many people have done more than back of the envelope calculations to show this simply was a non starter.
Those (people who took money to build ) push this idea are either ignorant at best and dishonest at worst.
It only makes sense to start thinking about sidewalks once you've covered all the roofs, which are way better in every sense.
So the sidewalk would need to be just as strong as the road.
https://www.semanticscholar.org/paper/The-higher-the-heel-th...
Shows less than 30 N/cm^2 (40 PSI) for women in heels - and higher heels result in lower heel pressure. Forefoot pressure is higher, despite the larger surface area.
I don't think the study invalidates parents claim, if anything it more it less supports it.
Also I have seen high hees being abused by walking mostly on the heel.
https://en.solaroad.nl/wp-content/uploads/sites/2/prf1-ENG-S...
Why can't they just work on something that makes sense?
It just does not make sense.
Under the road is literally the only option, and it's a terrible option at that. Rooftops - or better yet, former farm fields- are always going to be cheaper and more efficient.
The rest still stands, of course. If you absolutely do want to put solar panels in the same place as cars, starting with parking lots is clearly a better idea. Fewer problems with high speed collisions, the electricity is generated closer to where it's needed, and people will be thankful for having parking in the shade. (Still more expensive than putting panels on a roof or field of course.)
https://www.cbs58.com/news/truck-wedged-under-bridge-shuts-d...
Reason? Solar cells keep getting cheaper and cheaper. That makes the costs of scaffolding to hold the cells take a larger and larger share of installation costs. In the limit where cells are essentially free, putting cells everywhere there is some large horizontal area will make sense.
Now, of course, we may not get close enough to that limit for this to make sense, cells may be too fragile for mounting in a road, there may be plenty of more profitable places to put solar cells, etc, etc, but that isn’t guaranteed, and we can’t tell without experimenting.
Further road surfaces need to be transparent for solar to work, handle high loads, channel water off the surface, and provide lots of friction in a wide rang of weather conditions. It’s an extremely difficult problem, but solving it without massive reduction in panel costs is kind of pointless.
If solar cells become essentially free, we _could_ get there.
Also ”ground based installation is really cheap.” doesn’t matter. Putting cells in roads _may_ become even cheaper, even though the cells themselves would produce a lot less power per square meter.
”it’s an extremely difficult problem, but solving it without massive reduction in panel costs is kind of pointless.”
I didn’t claim it was easy or that it was efficient now. I just pointed out that reduction in panel costs can lead to a situation where using them in suboptimal settings can be economically viable, if installation costs are lower for that suboptimal setup.
And massive reduction in panel price has been the norm for decades. https://en.wikipedia.org/wiki/Swanson%27s_law:
”Swanson's law is the observation that the price of solar photovoltaic modules tends to drop 20 percent for every doubling of cumulative shipped volume. At present rates, costs go down 75% about every 10 years.”
(1) of course, if Americans start having flying cars, road surfaces may become a thing of the past.
So many things are wrong with using solar road surfaces that it’s hard to make them look viable even if the panels cost nothing. Because that means electricity is worth very little, and you still need to integrate them into the road surface which costs money.
Going down that road leads to solar power satellites, not solar roadways.
1. Solar roadways is a terrible idea that will never be a good idea. It is strictly worse than building a roof over the road and putting solar panels on that.
2. Roughly half the renewable energy on earth comes from decaying isotopes and half comes from sunlight. If humans want more than that, they'll basically need to get it from sunlight not hitting the earth i.e. solar power satellites. That is a road that we'll eventually go down, but not for quite some time.
Solar roads has the distinct advantage over covering all the roads in that it's not an eye sore and fits more seamlessly in the scenario we figure out the engineering.
There's this idea in economics called opportunity cost. The simple version is that if we fund bad ideas that can't possibly be good, we lose out on the good ideas we could have funded but didn't.
This is the reason you don't heat your house by burning paper money. You'd rather have rent and groceries and heat instead of really economically inefficient heat.
I'm going to bet they said that after the check cleared.