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Comment by btbuildem | Hacker News Reader

For a layperson, this seems like such a no-brainer: you're basically upgrading open parking lots to car ports. Drivers should love that, no?

The lobbying angle explains A LOT. Of course, it's entrenched players clinging on to their profits. Oh well.

The cost argument is interesting.. one would think it would be cheaper to build on already-developed lots, since no earth-moving and other infrastructure work is required -- but it looks like the structures must conform to a higher standard. Nobody cares if a panel topples in some remote field, but it one falls on someone's car, bad press and lawsuits.

I certainly hope things move forward and we see more solar over the desolate landscape of the endless parking lots in North America. If anything, the promise "free" power to the lot owners could tip the scales.

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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 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

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

Maybe, but underground wires avoids problems caused by storms or people driving into structures.

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.

Make the wires run through newly created speed bumps. It's a parking lot, and limiting speed should secure the panels even more.

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.

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

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.

It is just concern trolling.

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.

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.

No, you don't need trenches. No, you don't need to repave. Or repaint lines.

Construction is mainly making post holes and placing and truing posts, and pouring concrete. Concrete can be poured at day's end. Electricals can go in last, after framing for the whole lot is up, also a row or two at a time. Wiring does not need to be trenched; it is out of the weather at the ceiling, and more accessible for service.

It is always easy to think of a dumb way to do anything. Admittedly, some people habitually stop there. Some contractors, even.

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.

In the US, 70% of solar power is generated at utility-scale plants: https://www.eia.gov/energyexplained/solar/where-solar-is-fou...

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.

There's a lot of large scale installations, see https://en.m.wikipedia.org/wiki/List_of_photovoltaic_power_s...

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.

This must be passing a tipping point. I live in a very nondescript part of Ohio and there are about 12,000 acres of land incorporated into three different solar farms proposed, approved or under construction within 20 miles of my home.

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.

> 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.

Oddly enough, existing standards take weather extremes into account.

Nice concern troll.

> concern troll

That's a little rude and uncalled for isn't it?

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.

It does seem strangely rude.

It struck me as rude. But I also understand that too much time on HN (in particular) and I can get a little put off by some of the cynicism I see in the comments.

Is the cynicism concern trolling? I'm not sure. Certainly there are people "with agendas" that would toss cynical remarks into a discussion thread like they were thought-grenades.

But the more erudite leanings of HN also attracts a kind of skepticism from people who want to post as naysayers because it suggests they have already perceived the issue, saw its failings, and have moved on ... intellectually.

I hate to even post the above because I'm pointing too many fingers and don't wish to put anyone on the defensive. (There are other reasons I am sure someone would post a contrarian comment.) I wanted to explain though why I don't immediately jump to "concern troll" when I see a negative comment put forth on a story about a very progressive idea.

It is rude to troll. Solar panels have been going up on roofs for probably longer than you have been alive. Do you post "concerns" about weather for every single other thing mentioned that is outside? Wind turbines? Cars?

> Surely the first casualties of a gale or hurricane are panels.

Actually, windmills.

Seriously, I asked my electrical inspector why there are so few domestic-y scale windmills in my part of New Mexico, where for several months a year we have raging wind every day. "Nobody builds one that can last more than a year or so out here".

The panels, on the other hand, are just fine.

Nearby, in windy and desolate Colorado, SunEdison has three big arrays, each with a different mounting technology:

1) fixed-tilt, seasonally-adjustable, flat-panel PV

2) single-axis-tracking, flat-panel PV

3) dual-axis-tracking, concentrator photovoltaics

> fixed-tilt, seasonally-adjustable, flat-panel PV

What is adjusted for the season? The angle of the panels? I would imagine that one would have to be very close to the equator for this to be worthwhile.

You can retilt those two, three, or four times per year.

Tilting for summer achieves maybe 70% of the power of an automated tracker. In the winter it’s much closer. I suspect in snowy places that the extra weight could overload the automated mechanism. In winter, tracking and fixed achieve nearly the same.

If you were retilting for summer at 25 degrees latitude, you’d tilt slightly away from the equator.

> 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.

> 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.

> 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.

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,1...

* edited out reference to surviving hurricane. Can't recall exact year this went up.

Most of the issue is around the funding model of developments.

Basically, the owners of these things are usually syndicated and are in the business of harvesting money from taxes via accelerated depreciation. Having an asset that is producing money breaks the business model… they want to lose money on paper for the first few years.

Usually when I see these types of things they are local businesses, banks or other entities that actually own their own property, or leaseholders making their own improvements to save opex. A few Targets near me have solar roofs, for example.

Currently, commercial solar installations can be depreciated 100% in the first year, which is a pretty strong tax incentive for developers. This is scheduled to reduce to 20% for systems placed in service after 2022. I haven’t looked at the new energy bill so not sure if it would extend the current treatment.

In crowded city centers, i doubt wind would be fast enough to topple panels.

Even so, the frames are sturdy enough to hold the panels against strong winds.

Crowded city centres have more wind due to the Venturi Effect, not less.

Generally there are no huge parking lots in crowded city centers (or, if there were, they would be shaded by the highrise buildings producing the Venturi effect, so no good for solar panels), so the problem would take care of itself. But anyway, I don't think engineering a roof over a parking lot so it can support a solar panel and not fall over is an unsolvable problem.

I agree but the OP is the one who brought up crowded city centres like that was relevant to the amount of wind. I don't understand what relationship they were trying to suggest there.

In the case of Edison Electrical Institute, your own utility might pay dues to them —- to lobby against your interests as a consumer. I think utilities are not required to report trade association dues on your bill.

No one is talking about the grid connection and batteries though. You will need batteries somewhere because demand and supply don't match.

Then there is servicing the solar. And engineering/architecture bespoke to each case. I can see how a large solar farm might make all that more efficient.

Put it this way, home solar is not always a no-brainer, financially, and that doesn't usually involve building a structure, just attaching them to a roof.

Home solar is strictly more expensive than utility solar.

If your area allows you to opt into power from a solar farm, and pay the solar farm's rates, jump on it.

Why is car park solar not more expensive then?

Say you have 1000 car parks, 1000 plans you need to send to local governments, 1000 architectural plans to deal with, and son on.

Some of the things will scale but a lot wont.

if you own 1000 parking lots you already did that, if you pulled a permit to repave them you've done it again.

Repave is a different thing to build. You are changing the landscape. NIMBYists can have a say, for example.

Also who said one person owns 1000 lots. I am saying there are 1000 separate lots we want to solarize, vs. a plant. If they are owned by different people, then you need a business to market, educate and sell this to them etc. Which is another layer.

For commercial installations, demand and supply often match very well. They're not trying to get off grid but reduce bills. Whereas many homes with working parents and school age children are using power after sunset, for offices and shopping centres, they're running something like air-conditioning while the sun's up.

Where I live, home solar pays for itself in 4-5 years; for our office building, it was 3-4 years.

Solar panels must also be maintained.

Even a canopy without electronics on it, or a lot without a canopy on it, must be maintained to some degree. And parking lots are often mandated, with a specified capacity, for every use.

Now that we're in an era where cities are moving toward eliminating cars from the road, reducing parking lot acreage, and easing those aforementioned mandates. So, as a business, we'll want to calculate the tradeoffs of installation and maintenance, as well as the understanding that we're less able or willing to demolish a productive solar array when I need to build something else in its stead.

Installing solar arrays over a parking lot may essentially lock-in that desolate acreage while the value of the land underneath them begins to ramp up.

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