2 ms·

'Solar roads' are uniformely a miserable idea. They are eco-theatre. You want solar, put it in an uninhabited ground-level unobstructed serviceable cheap locat

'Solar roads' are uniformely a miserable idea. They are eco-theatre. You want solar, put it in an uninhabited ground-level unobstructed serviceable cheap location near the grid outside of town. Because, wires can transmit electricity anywhere it's needed. Elaborate structures for solar cost more than the panels these days. Never build them. At most, tilt them to the local lattitude. If tempted to do more, instead buy more panels. Power per dollar works out better.

jacquesm 3y ago
Yes, definitely. In the early 00's I put up an elaborate system with two axis trackers, it was very nice but fragile, not nearly as sturdy as a regular rack would have been and the extra money spent on the trackers would have been better spent on more panels, even at the prices back then. So today this is a complete no brainer (assuming you have the space, but tracking panels use more space than stationary ones so even then it probably won't work to your advantage).
- JoeAltmaier 3y ago
  This! Even so my local utility is putting in tracking solar projects. Got to be eco-theatre as well. And they track over the day! not over the year. Here the sun varies 42 to 78 degrees to the south, but the panels are flat overhead (90 deg). Again, all that mechanism for so little gain.
  - cesarb 3y ago
    > This! Even so my local utility is putting in tracking solar projects. Got to be eco-theatre as well. They probably did the math, and at that location, the ROI for a single-axis tracker was better than the ROI for fixed panels. > And they track over the day! not over the year. This probably means it's a single-axis tracker, which points east in the sunrise and west in the sunset. To track over the year it would need a second (north-south) axis, but the ROI for that probably wasn't better than a single-axis tracker. > Again, all that mechanism for so little gain. A single-axis tracker isn't that complicated (and a single axis with a single motor can move a whole row of panels at once), so even if the gain is small, it can be more than enough to pay for the mechanism.
    - bryanlarsen 3y ago
      A single-axis tracker isn't expensive, but solar panels have gotten very cheap. They've gotten so cheap that this Texas company claims that it's cheaper to buy more panels and lay them on the ground rather than using a rack to get them at a better angle. https://electrek.co/2022/12/12/texas-solar-farm-flat-on-the-ground/ https://electrek.co/2022/12/12/texas-solar-farm-flat-on-the-...
    - JoeAltmaier 3y ago
      The single axis could have been used to tilt toward the sun, instead of always year-round being tilted away from the sun (straight overhead). Got to be a bigger benefit than catching some oblique early morning or late evening rays. Missing out on the core of the power-generating day (11 to 1) by being pointed in the wrong direction is gotta be suicide to efficiency.
    - jacquesm 3y ago
      > They probably did the math, and at that location, the ROI for a single-axis tracker was better than the ROI for fixed panels. They probably didn't do the math. If they had they would have installed fixed panels. Panels are so dirt cheap that you'd have to come out more than 60% ahead on the cost of the tracker and that's never ever going to happen. Just add more panels. I have 50 of them now in some pretty bad orientations, ~ 100 KWh on a good day and if I had half that many on trackers it wouldn't even come close. And on bad days the only thing that you want in a solar installation is surface area. Peak performance isn't interesting at all, and tracking at best gives you 20 to 25% more power at the price of the tracking mechanism being much more bulky than panels, panels shading each other when used with trackers so you'll use your space far less efficiently, fragility and finally complexity. Don't use trackers.
ta1243 3y ago
Putting solar on the ground uses land. Land is valuable. This method adds no land use. It also provides a roof for the users of the path. Solar above car parks is great too -- it provides shade, means you don't get wet getting out of the car, and it provides energy.
- JoeAltmaier 3y ago
  Way overestimating the cost of rural land. You want a roof, build a roof. You want solar, build a solar farm. You should no more put solar over other structures than grow radishes up there. It's a terrible idea from every point of view (except eco-theatre).
  - usrusr 3y ago
    That kind of frontier attitude "if we need more land we'll just build a longer road into the desert" won't fly anywhere within a thousand kilometers from where that bike path roof is built.
pjc50 3y ago
Yeah, the solar road is a bad idea. The solar roof or solar car park, on the other hand, is a more appealing idea. Many places are running out of "cheap" locations, that's why housing is so expensive. > wires can transmit electricity anywhere it's needed. Well .. yes, if you build the wires. A surprising amount of projects are getting held up on grid connection grounds. Whereas embedding the panels near urban demand reduces that problem.
kibwen 3y ago
The "solar roadways" nonsense from a few years ago was about putting solar panels in the road surface itself, which is a terrible idea for many reasons. Putting solar panels above the road is only a bad idea if the cost is prohibitive relative to putting them elsewhere.

jacquesm 3y ago

Yes, definitely. In the early 00's I put up an elaborate system with two axis trackers, it was very nice but fragile, not nearly as sturdy as a regular rack would have been and the extra money spent on the trackers would have been better spent on more panels, even at the prices back then. So today this is a complete no brainer (assuming you have the space, but tracking panels use more space than stationary ones so even then it probably won't work to your advantage).

JoeAltmaier 3y ago
This! Even so my local utility is putting in tracking solar projects. Got to be eco-theatre as well. And they track over the day! not over the year. Here the sun varies 42 to 78 degrees to the south, but the panels are flat overhead (90 deg). Again, all that mechanism for so little gain.
- cesarb 3y ago
  > This! Even so my local utility is putting in tracking solar projects. Got to be eco-theatre as well. They probably did the math, and at that location, the ROI for a single-axis tracker was better than the ROI for fixed panels. > And they track over the day! not over the year. This probably means it's a single-axis tracker, which points east in the sunrise and west in the sunset. To track over the year it would need a second (north-south) axis, but the ROI for that probably wasn't better than a single-axis tracker. > Again, all that mechanism for so little gain. A single-axis tracker isn't that complicated (and a single axis with a single motor can move a whole row of panels at once), so even if the gain is small, it can be more than enough to pay for the mechanism.
  - bryanlarsen 3y ago
    A single-axis tracker isn't expensive, but solar panels have gotten very cheap. They've gotten so cheap that this Texas company claims that it's cheaper to buy more panels and lay them on the ground rather than using a rack to get them at a better angle. https://electrek.co/2022/12/12/texas-solar-farm-flat-on-the-ground/ https://electrek.co/2022/12/12/texas-solar-farm-flat-on-the-...
  - JoeAltmaier 3y ago
    The single axis could have been used to tilt toward the sun, instead of always year-round being tilted away from the sun (straight overhead). Got to be a bigger benefit than catching some oblique early morning or late evening rays. Missing out on the core of the power-generating day (11 to 1) by being pointed in the wrong direction is gotta be suicide to efficiency.
  - jacquesm 3y ago
    > They probably did the math, and at that location, the ROI for a single-axis tracker was better than the ROI for fixed panels. They probably didn't do the math. If they had they would have installed fixed panels. Panels are so dirt cheap that you'd have to come out more than 60% ahead on the cost of the tracker and that's never ever going to happen. Just add more panels. I have 50 of them now in some pretty bad orientations, ~ 100 KWh on a good day and if I had half that many on trackers it wouldn't even come close. And on bad days the only thing that you want in a solar installation is surface area. Peak performance isn't interesting at all, and tracking at best gives you 20 to 25% more power at the price of the tracking mechanism being much more bulky than panels, panels shading each other when used with trackers so you'll use your space far less efficiently, fragility and finally complexity. Don't use trackers.

ta1243 3y ago

Putting solar on the ground uses land. Land is valuable. This method adds no land use. It also provides a roof for the users of the path. Solar above car parks is great too -- it provides shade, means you don't get wet getting out of the car, and it provides energy.

JoeAltmaier 3y ago
Way overestimating the cost of rural land. You want a roof, build a roof. You want solar, build a solar farm. You should no more put solar over other structures than grow radishes up there. It's a terrible idea from every point of view (except eco-theatre).
- usrusr 3y ago
  That kind of frontier attitude "if we need more land we'll just build a longer road into the desert" won't fly anywhere within a thousand kilometers from where that bike path roof is built.

pjc50 3y ago

Yeah, the solar road is a bad idea. The solar roof or solar car park, on the other hand, is a more appealing idea. Many places are running out of "cheap" locations, that's why housing is so expensive. > wires can transmit electricity anywhere it's needed. Well .. yes, if you build the wires. A surprising amount of projects are getting held up on grid connection grounds. Whereas embedding the panels near urban demand reduces that problem.

kibwen 3y ago

The "solar roadways" nonsense from a few years ago was about putting solar panels in the road surface itself, which is a terrible idea for many reasons. Putting solar panels above the road is only a bad idea if the cost is prohibitive relative to putting them elsewhere.