4 ms·

I think putting a roof on streets (on a relatively light aluminium/carbon fiber scaffold) for the panels is less outlandish than trying to fix "solar roads" by

I think putting a roof on streets (on a relatively light aluminium/carbon fiber scaffold) for the panels is less outlandish than trying to fix "solar roads" by adding maintenance vehicles (or solar roads themselves, really). It keeps away rain (which improves driving), doesn't expose the panels to the weight of tractors, has similar safety properties (the panels need to react quickly on any accident related impact and isolate affected circuits to avoid electrocuting passengers), and if slanted, is somewhat self-cleaning in wind or rain. I agree though that it's nice that somebody did a field test. That idea sprang up again and again and it helps to have some real world data: people anticipated the cracking issue, but who argued against solar roads because of leaves killing the efficiency?

WalterBright 7y ago
> but who argued against solar roads because of leaves killing the efficiency? I had my concrete driveway pressure washed recently. It looked really good for about a week. Then leaves fell on it, and the leaves stained it brown again. All the engineers had to do was look at flat concrete.
- pgeorgi 7y ago
  concrete is a permeable material, solar panels not so much. If you coat your driveway with a resin cover, the stains will probably disappear every time it rains. But nevertheless, it wasn't a talking point before - of course, with enough observation you can think of all possible failure modes beforehand. Sometimes it's easier to just try things out.
  - modriano 7y ago
    But anyone who has read a book about designing a home solar system can tell you that all of the literature tells you that you have to pick the location of your panels carefully so they aren't occluded by trees over part of the year because the power losses due to occlusion are significant and can make a system non-viable and non-economic. From the book I read [0] (although mine is the 2015 edition), not planning for obstacles is the #1 reason solar power system designs fail. I'm not sure why they didn't hire an experienced engineer for this multi-million Euro project. [0] https://www.amazon.com/Solar-Electricity-Handbook-installing-photovoltaic/dp/1907670718 https://www.amazon.com/Solar-Electricity-Handbook-installing...
    - pgeorgi 7y ago
      > because the power losses due to occlusion are significant and can make a system non-viable and non-economic That depends on how large the individual cells are and how they're wired up. There are panels that have a pass-through if they're occluded too much to avoid them limiting the output of other cells. It's possible that these panels had compensation mechanisms built-in. > I'm not sure why they didn't hire an experienced engineer for this multi-million Euro project. This isn't a few amateurs getting a construction grant and slapping the cheapest off-the-shelf panels they could find onto the pavement. The panels were built by a French company called Wattway, a subsidiary of Colas, a large French street construction corporation. The parent company also did the construction work of actually putting these things on the street. Apparently the "Institut National de l'Energie Solaire" was involved in this project as well, which is a public research facility (co-run by a university and the CEA, which has a budget of more than 5 billion Euros, and has a staff of 19k employees and 1200 grad + post-grad students). That "solar road" might have been part of a research grant for all kinds of PV developments and they had to deliver it as a demonstration. That would also explain to me why they give up so easily. From the article: "Wattway [...] told Le Monde that it would not be going to market."
  - WalterBright 7y ago
    Or they could have just left a square meter outside on the ground for a few months to see how it did. It would have saved millions of dollars.

WalterBright 7y ago

> but who argued against solar roads because of leaves killing the efficiency? I had my concrete driveway pressure washed recently. It looked really good for about a week. Then leaves fell on it, and the leaves stained it brown again. All the engineers had to do was look at flat concrete.

pgeorgi 7y ago
concrete is a permeable material, solar panels not so much. If you coat your driveway with a resin cover, the stains will probably disappear every time it rains. But nevertheless, it wasn't a talking point before - of course, with enough observation you can think of all possible failure modes beforehand. Sometimes it's easier to just try things out.
- modriano 7y ago
  But anyone who has read a book about designing a home solar system can tell you that all of the literature tells you that you have to pick the location of your panels carefully so they aren't occluded by trees over part of the year because the power losses due to occlusion are significant and can make a system non-viable and non-economic. From the book I read [0] (although mine is the 2015 edition), not planning for obstacles is the #1 reason solar power system designs fail. I'm not sure why they didn't hire an experienced engineer for this multi-million Euro project. [0] https://www.amazon.com/Solar-Electricity-Handbook-installing-photovoltaic/dp/1907670718 https://www.amazon.com/Solar-Electricity-Handbook-installing...
  - pgeorgi 7y ago
    > because the power losses due to occlusion are significant and can make a system non-viable and non-economic That depends on how large the individual cells are and how they're wired up. There are panels that have a pass-through if they're occluded too much to avoid them limiting the output of other cells. It's possible that these panels had compensation mechanisms built-in. > I'm not sure why they didn't hire an experienced engineer for this multi-million Euro project. This isn't a few amateurs getting a construction grant and slapping the cheapest off-the-shelf panels they could find onto the pavement. The panels were built by a French company called Wattway, a subsidiary of Colas, a large French street construction corporation. The parent company also did the construction work of actually putting these things on the street. Apparently the "Institut National de l'Energie Solaire" was involved in this project as well, which is a public research facility (co-run by a university and the CEA, which has a budget of more than 5 billion Euros, and has a staff of 19k employees and 1200 grad + post-grad students). That "solar road" might have been part of a research grant for all kinds of PV developments and they had to deliver it as a demonstration. That would also explain to me why they give up so easily. From the article: "Wattway [...] told Le Monde that it would not be going to market."
- WalterBright 7y ago
  Or they could have just left a square meter outside on the ground for a few months to see how it did. It would have saved millions of dollars.