Parking and rooftop ensure the structural protection of your cabling, while at the same time optimizing the positioning of your servicing ports. Slightly elevated rooftop solar can also significantly reduce the a/c bill of a structure (especially smaller houses in sunny environments) and parking helps protect the paint of cars.

Wind kicks up dust, dust clings to panel, no rain for months on end, panels get covered up and scratched. Turns out there’s issues to using these spaces, and you need additional hardware (and thus have additional failure modes) to mitigate them.

I think solar panels done right could actually help a desert though. Providing shade can allow some plants to thrive but most solar developers aren’t thinking about the ecology of a region.

I feel like sacrificing the deserts to save the rainforests is a trade worth making - but is such a trade even possible, or is it not that simple?

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/201...

There are important deserts and there are important grasslands and important forests. It seems a valid point that not all ecosystems are of equal importance.

Well that's a point of view that's never steered us wrong.

The only way we've done it is by eliminating everything in our path. We've been excellent at justifying eliminating entire ecosystems - when will we stop?

Probably right before we've justified eliminating entire countries of people with the weapons of death we've developed by extracting every last resource for the ground by digging it up.

Solar cells need a heat sink to keep them cool or else the efficiency sucks.

Deserts tend to be cold at night.

Capture heat during the day as a byproduct of using the solar panels, and use it at night for heating homes? Maybe I'm being too optimistic, usually things that improve efficiency don't actually work for some reason.

Further it's dangerous. Installation, maintenance become a headache and a risk.

Then, so many rooftops are not in optimal 'viewing locations'. Shaded by trees; shaded by neighboring buildings especially in a city.

It seems natural to a non-engineer to 'make electricity where you need it'. But rooftops don't scale with need, not at all. An apartment building on a lot with 3 stories or 30, same rooftop area. Terrible economics.

And electricity is fungible! Make it over there; use it over here. Almost free. Certainly cheaper than struggling to mount something delicate in the hardest place you can find.

A friend of mine lives off grid in Mexico, and he got double duty out of his solar array by making it a big carport and workshop area. So yeah that totally works.

But, if you're going to invest $X in solar, it's better to spend it on utility scale stuff than even commercial versions of covering parking lots. This is because the utility scale operation better amortizes the equipment needed to tie into the grid, as well as operationally will keep the panels clean and working at peak efficiency.

Add in covered parking lots and distributed batteries (dedicated batteries, cars, etc.) and I bet that we would reduce the need for building even more high voltage lines across the countryside.

We should be looking for ways to generate and store electricity close to where it is needed where we have already destroyed nature.

You can’t simply put solar on a roof

Do you mean that you can't meet 100% of your demands, or it can't be done for some other reason?

You could reduce, but not eliminate, the demand for purchased energy. Would that be unacceptable? Is there not a net metering programme there?

For me the big deal is usually demonstrating payback. I'm in British Columbia and my solar experience is only with single family homes; on and off grid.

There was no big cost analysis with off grid homes. You need power, or you don't. It's just another category in the budget and the cost decisions are about balancing desires and cost.

With grid-connected homes, we don't even try to sell it now. Nearly all our customers have mortgages to pay for their new house and factoring in the interest paid makes it much less attractive.

A few years ago, low interest rates and high energy costs made it an easier sale. If you were in the position of having money in the bank, you could get a better return on that money by upgrading your home to save energy. Of course it could only scale as large as the cost of improvements.

Even then, a lot of homeowners didn't intend to own the home long enough to realize the returns, and I don't think small solar systems improve resale value. The feeling in the office is that if you're planning to resell, the money is better spent on the kitchen.

I think the parent was saying the solar was too heavy for the roof to support. The physical structure of the building was not strong enough.

Not at today's power prices. A typical kitchen will easily cost as much or more than solar and solar ROI is about 20 to 25% right now, no kitchen will come even close to adding that kind of value to a house. If you can afford to do both, do both, but if you have to choose solar is #1 from an investment perspective (assuming you already have a kitchen...).

Being in a rain forest doesn't help. Don't get me wrong, the summers are as bright as anywhere else, but the cloudy winters are brutal if you want sunshine.

If it's financed with a mortgage that's another thing to consider.

I just don't ever hear solar come up in conversations about resale. I've heard a couple Realtors mention that energy efficient design is something coming up most often. The big questions are still about the area and how many bed/bath rooms there are.

>(assuming you already have a kitchen...).

You can always get a second kitchen....a summer kitchen.

And it's just the first step.

As for the support structure: the ones on the flat roofs are part homebrew and part standard components, the ones on the slanted roof are on a standard off-the-shelf support.

I'm not agile enough any more to work on a roof so I had the slanted roof done, the other part I did myself.

That leaves armchair-level pondering to theoreticals: is the perfect "any angle" surface even physically possible or are there physical limits that only leave tradeoffs?

And another aspect I don't know: do the cells mind? Does that "punch an electron" principle still work out when photons come in almost parallel to the electrodes? (in practical terms: if we compensated the lower effective cross section and reflectivity with higher light intensity, would we still get the same voltage?) When I was a kid I had a miniature cell in an experiment kit that had a deep plastic top layer with angled prism structures under the surface almost like those of a retro-reflector and I always wondered why it would have that. Was it because the cell could only collect from photons coming in almost perpendicular, and the job of the plastic structure was to make sure that there would always be some photons making the angle threshold (certainly by sacrificing a huge amount of power in the well-aimed case)

This all almost sounds like an argument for heliostats (which get the best yield per module surface, but the worst yield per acre), and which would be a perfect match for agrivoltaics. But that's an approach that hinges entirely on the cost and (far more importantly, at scale) resource use of the mechanical structures required. Which is a mechanical engineering problem that you'd have no problem explaining to a victorian era engineer. Genius "inventors" to the rescue?

I've used two heliostats in the past (see other comment in this thread) and on a $/Watt basis you're better off putting them flat, regardless of the perceived advantages, after all is said and done you will have more power, be out less money and have a more reliable system.

Now if only the sun would shine...