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> one would think it would be cheaper to build on already-developed lots, since no earth-moving and other infrastructure work is required Nope - trenching thro

> one would think it would be cheaper to build on already-developed lots, since no earth-moving and other infrastructure work is required Nope - trenching through a concrete or blacktop parking lot is much more work than running conduit on undeveloped land. Also, you’ve got to shut down your parking lot for a few weeks to do the work. It makes sense to do when building a new parking lot, in fact I see that kinda frequently these days, but retrofitting one seems like a lot of work

lostapathy 4y ago
Why dig trenches? Run the wiring in the overhead canopy.
- extra88 4y ago
  Maybe, but underground wires avoids problems caused by storms or people driving into structures.
  - pjerem 4y ago
    People driving into structures is already a solved issue in any covered parking, solar or not. We know how to build structures on steel poles that does not fall apart when people accidentally hit them with their car. You can even add steel bumpers around the poles like in any covered parking lot.
  - MayeulC 4y ago
    Make the wires run through newly created speed bumps. It's a parking lot, and limiting speed should secure the panels even more.
extra88 4y ago
You don’t have to do the whole lot at once, it could be done one segment at a time. And many lots are underutilized most of the time, built to accommodate the need at peak times of year.
- zdragnar 4y ago
  That means really inefficient scheduling of the different teams involved in making such a project happen. It'll drive up the cost significantly to have them start and stop multiple times, perhaps to the point of making it entirely uneconomical. Labor is already the largest cost of solar projects, after all
  - Teever 4y ago
    Comments like this bug me. If America had this kind of attitude during world war two it never would have supplied the world with the machines needed to win the war. Not only is this easier than previous mobilization against existential threats but we have better technologies for communicating and computing than ever before. If the logistical problem of coordinating underpaid illegal undocumented workers to shift between the walmart parking lot and home depot parking lot with surplus workers going and banging out a few McDonald's and Denny's restaurants is too much I gotta say we're fucked man.
    - ncmncm 4y ago
      It is just concern trolling.
  - ncmncm 4y ago
    None of that is true. They can do one or two rows at a time without blocking use of the rest of the lot, and without stopping and starting. Labor is most commonly a tiny fraction of the cost of a solar installation, home rooftop excepted.
    - zdragnar 4y ago
      You need to break up the asphalt for trenches, dig down and set cement foundation for the solar frames, run electrical, repave and install the panels themselves. Oh, and once the fresh asphalt is cured, repaint the lines. You are much better off doing an entire parking lot at once, or maybe half at a time, than you are doing multiple sections, as that work isn't all done be the same people.
dehrmann 4y ago
One reason I'm not confident in solar is there are a lot of small-scale installations, but fewer large ones. If the economics of it are so great, you'd think economies of scale and better locations would make it more cost effective than small installations. My theory about what's going on is there are tax breaks for small scale operators that make it marginally profitable on paper.
- nrp 4y ago
  In the US, 70% of solar power is generated at utility-scale plants: https://www.eia.gov/energyexplained/solar/where-solar-is-found.php https://www.eia.gov/energyexplained/solar/where-solar-is-fou...
  - mark-r 4y ago
    That makes sense; power utilities have lots of money, and they're going to build new plants to provide power, that's their job. As solar power becomes cheaper relative to other options and has intangible benefits too, it will increasingly become the power plant of choice. I'm not sure the efficiencies of small vs. large solar even enter into the calculus. The transmission lines are a known part of the picture and largely already exist.
- glogla 4y ago
  There's a lot of large scale installations, see https://en.m.wikipedia.org/wiki/List_of_photovoltaic_power_stations https://en.m.wikipedia.org/wiki/List_of_photovoltaic_power_s...
- ZeroGravitas 4y ago
  Small scale costs slightly more due to economies of scale, but it also distributes the power sources and so cuts transmission costs and adds redundancy. Overall, as PV panel prices continue to trend downwards, we'll see less big installation in sunny places (which originally were the only ones that made financial sense) to more, smaller installs as other costs come to dominate the equations.
- jcims 4y ago
dotancohen 4y ago
I just did an installation on my roof. We have very high winds in my area, so I went with a provider that already did a few dozen roofs in my area. I was surprised to see that the frames are not bolted to the roof, rather, they are bolted to concrete blocks which sit on pads on the roof. Each 300W solar panel feels like it weighs no more than 5 kilograms, the bolted aluminium frames look very easy to scale inexpensively. There are no trenches, rather, DC conduits run the length of the panels. I confidently hang out with my 7 year old under the solar panels for a good half hour.
- nonrandomstring 4y ago
  > We have very high winds in my area Here's a point that worries me slightly. With climate change comes more turbulent weather, and increased winds everywhere. Surely the first casualties of a gale or hurricane are panels. The bigger the area, the more vulnerable the installation.
  - ncmncm 4y ago
    Oddly enough, existing standards take weather extremes into account. Nice concern troll.
    - nonrandomstring 4y ago
      > concern troll That's a little rude and uncalled for isn't it?
      - lovemenot 4y ago
        It was a little rude, certainly. Whether uncalled-for or not depends on your intent. Only you are in a position to know for sure. My own feeling was that the comment was mostly deserved. Objections and problems raised against proposed solutions to critical issues, just left for someone else to solve feels disingenuous. Whether not it actually is. Maybe, next time try to solve your own objections and we won't get the drama.
      - 4y ago
KaiserPro 4y ago
> Nope - trenching through a concrete or blacktop parking lot is much more work than running conduit on undeveloped land. that is true, but on the flipside you can avoid a lot of the trenching by putting the conduits in the structure of the canopy. The other important thing to note is that large buildings tend to have large substations near by, so the actual amount of trenching required is a lot less. However it does require a lump of capital to do, and it only makes sense really for the corporation that owns the land to do it.
vladvasiliu 4y ago
> Also, you’ve got to shut down your parking lot for a few weeks to do the work. Would you have to shut down the whole parking lot for roof work? It's anecdotal, but most parking lots I've seen around LA seemed to have an open top floor which was mostly empty since people presumably prefer their cars to be shaded. I know I specifically didn't want to leave my motorbike on the top floor for this specific reason. So adding solar panels, which would add shape, would basically increase the parking lot floor.
- PopAlongKid 4y ago
  > parking lots I've seen around LA seemed to have an open top floor That would more commonly be called a parking garage or structure, a parking lot as referred to in the article is just an open, paved area of ground. I suspect the construction issues for the top floor of a parking structure are different from those of ground-level installation with no existing vertical structure. Also, by their very nature, parking garages most likely have significantly less square footage on the top floor than a parking lot for the same number of vehicles.
rufus-overhead 4y ago
I worked at this New Jersey facility when the parking lot solar was installed. The parking availability was only minimally impacted. Base pylons were installed over a period of about a month. That involved condoning off a small section of the lot while a crew cut a four foot square through the asphalt then used an powered auger to quickly excavate for the concrete pour. As I recall the crew completed a couple of those per day. The final installation of mounting structure, panels and electrical connections was done over a number of weekends. There was no trenching involved. As I recall the construction went surprisingly fast. I spoke with one of the building maintenance supervisors a couple of months after completion. He stated they were extremely happy with the power savings and return on investment. https://www.google.com/maps/@40.8458928,-74.0970349,3a,75y,123.16h,93.55t/data=!3m6!1e1!3m4!1syS7khdWVzQeQccFP5S7Sww!2e0!7i16384!8i8192 https://www.google.com/maps/@40.8458928,-74.0970349,3a,75y,1... * edited out reference to surviving hurricane. Can't recall exact year this went up.

lostapathy 4y ago

Why dig trenches? Run the wiring in the overhead canopy.

extra88 4y ago
Maybe, but underground wires avoids problems caused by storms or people driving into structures.
- pjerem 4y ago
  People driving into structures is already a solved issue in any covered parking, solar or not. We know how to build structures on steel poles that does not fall apart when people accidentally hit them with their car. You can even add steel bumpers around the poles like in any covered parking lot.
- MayeulC 4y ago
  Make the wires run through newly created speed bumps. It's a parking lot, and limiting speed should secure the panels even more.

extra88 4y ago

You don’t have to do the whole lot at once, it could be done one segment at a time. And many lots are underutilized most of the time, built to accommodate the need at peak times of year.

zdragnar 4y ago
That means really inefficient scheduling of the different teams involved in making such a project happen. It'll drive up the cost significantly to have them start and stop multiple times, perhaps to the point of making it entirely uneconomical. Labor is already the largest cost of solar projects, after all
- Teever 4y ago
  Comments like this bug me. If America had this kind of attitude during world war two it never would have supplied the world with the machines needed to win the war. Not only is this easier than previous mobilization against existential threats but we have better technologies for communicating and computing than ever before. If the logistical problem of coordinating underpaid illegal undocumented workers to shift between the walmart parking lot and home depot parking lot with surplus workers going and banging out a few McDonald's and Denny's restaurants is too much I gotta say we're fucked man.
  - ncmncm 4y ago
    It is just concern trolling.
- ncmncm 4y ago
  None of that is true. They can do one or two rows at a time without blocking use of the rest of the lot, and without stopping and starting. Labor is most commonly a tiny fraction of the cost of a solar installation, home rooftop excepted.
  - zdragnar 4y ago
    You need to break up the asphalt for trenches, dig down and set cement foundation for the solar frames, run electrical, repave and install the panels themselves. Oh, and once the fresh asphalt is cured, repaint the lines. You are much better off doing an entire parking lot at once, or maybe half at a time, than you are doing multiple sections, as that work isn't all done be the same people.

dehrmann 4y ago

One reason I'm not confident in solar is there are a lot of small-scale installations, but fewer large ones. If the economics of it are so great, you'd think economies of scale and better locations would make it more cost effective than small installations. My theory about what's going on is there are tax breaks for small scale operators that make it marginally profitable on paper.

nrp 4y ago
In the US, 70% of solar power is generated at utility-scale plants: https://www.eia.gov/energyexplained/solar/where-solar-is-found.php https://www.eia.gov/energyexplained/solar/where-solar-is-fou...
- mark-r 4y ago
  That makes sense; power utilities have lots of money, and they're going to build new plants to provide power, that's their job. As solar power becomes cheaper relative to other options and has intangible benefits too, it will increasingly become the power plant of choice. I'm not sure the efficiencies of small vs. large solar even enter into the calculus. The transmission lines are a known part of the picture and largely already exist.
glogla 4y ago
There's a lot of large scale installations, see https://en.m.wikipedia.org/wiki/List_of_photovoltaic_power_stations https://en.m.wikipedia.org/wiki/List_of_photovoltaic_power_s...
ZeroGravitas 4y ago
Small scale costs slightly more due to economies of scale, but it also distributes the power sources and so cuts transmission costs and adds redundancy. Overall, as PV panel prices continue to trend downwards, we'll see less big installation in sunny places (which originally were the only ones that made financial sense) to more, smaller installs as other costs come to dominate the equations.
jcims 4y ago

dotancohen 4y ago

I just did an installation on my roof. We have very high winds in my area, so I went with a provider that already did a few dozen roofs in my area. I was surprised to see that the frames are not bolted to the roof, rather, they are bolted to concrete blocks which sit on pads on the roof. Each 300W solar panel feels like it weighs no more than 5 kilograms, the bolted aluminium frames look very easy to scale inexpensively. There are no trenches, rather, DC conduits run the length of the panels. I confidently hang out with my 7 year old under the solar panels for a good half hour.

nonrandomstring 4y ago
> We have very high winds in my area Here's a point that worries me slightly. With climate change comes more turbulent weather, and increased winds everywhere. Surely the first casualties of a gale or hurricane are panels. The bigger the area, the more vulnerable the installation.
- ncmncm 4y ago
  Oddly enough, existing standards take weather extremes into account. Nice concern troll.
  - nonrandomstring 4y ago
    > concern troll That's a little rude and uncalled for isn't it?
    - lovemenot 4y ago
      It was a little rude, certainly. Whether uncalled-for or not depends on your intent. Only you are in a position to know for sure. My own feeling was that the comment was mostly deserved. Objections and problems raised against proposed solutions to critical issues, just left for someone else to solve feels disingenuous. Whether not it actually is. Maybe, next time try to solve your own objections and we won't get the drama.
    - 4y ago

KaiserPro 4y ago

> Nope - trenching through a concrete or blacktop parking lot is much more work than running conduit on undeveloped land. that is true, but on the flipside you can avoid a lot of the trenching by putting the conduits in the structure of the canopy. The other important thing to note is that large buildings tend to have large substations near by, so the actual amount of trenching required is a lot less. However it does require a lump of capital to do, and it only makes sense really for the corporation that owns the land to do it.

vladvasiliu 4y ago

> Also, you’ve got to shut down your parking lot for a few weeks to do the work. Would you have to shut down the whole parking lot for roof work? It's anecdotal, but most parking lots I've seen around LA seemed to have an open top floor which was mostly empty since people presumably prefer their cars to be shaded. I know I specifically didn't want to leave my motorbike on the top floor for this specific reason. So adding solar panels, which would add shape, would basically increase the parking lot floor.

PopAlongKid 4y ago
> parking lots I've seen around LA seemed to have an open top floor That would more commonly be called a parking garage or structure, a parking lot as referred to in the article is just an open, paved area of ground. I suspect the construction issues for the top floor of a parking structure are different from those of ground-level installation with no existing vertical structure. Also, by their very nature, parking garages most likely have significantly less square footage on the top floor than a parking lot for the same number of vehicles.

rufus-overhead 4y ago

I worked at this New Jersey facility when the parking lot solar was installed. The parking availability was only minimally impacted. Base pylons were installed over a period of about a month. That involved condoning off a small section of the lot while a crew cut a four foot square through the asphalt then used an powered auger to quickly excavate for the concrete pour. As I recall the crew completed a couple of those per day. The final installation of mounting structure, panels and electrical connections was done over a number of weekends. There was no trenching involved. As I recall the construction went surprisingly fast. I spoke with one of the building maintenance supervisors a couple of months after completion. He stated they were extremely happy with the power savings and return on investment. https://www.google.com/maps/@40.8458928,-74.0970349,3a,75y,123.16h,93.55t/data=!3m6!1e1!3m4!1syS7khdWVzQeQccFP5S7Sww!2e0!7i16384!8i8192 https://www.google.com/maps/@40.8458928,-74.0970349,3a,75y,1... * edited out reference to surviving hurricane. Can't recall exact year this went up.