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Satellite powered estimation of global solar potential

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Re: Satellite powered estimation of global solar potential

#121

Post by PaulDavisThe1st »

jcgrillo wrote: post #20
elric wrote: post #14

Earlier quoted context omitted.

That's terrible advice unless it's tied to local energy storage. When every roof and every solar panel is angled the same way, a sudden cloud (or a sudden lack of clouds) can cause huge fluctuations in power output. Diversity is protective.

Are you signing up to point your panels north and take a 30% efficiency hit? Or east/west for a 15% penalty? People point them south because it's the most efficient fixed orientation north of the equator. A more efficient solution is to use a tracker which keeps them pointing directly at the sun as it traverses the sky.

The potential for mechanical failures in trackers makes them quite unpopular now (unlike in the 70s when they first started to appear, and seemed like an obvious win).

You're better off just adding however many extra fixed panels you need to make up for the lack of tracking (and its normally not very many).

Re: Satellite powered estimation of global solar potential

#122

Post by bruce511 »

XorNot wrote: post #44
ijustlovemath wrote: post #37

Earlier quoted context omitted.

As someone who recently lost power and water for weeks post Helene, do not discount the power of distributed grids. Distributed core infrastructure will make for much better climate resilience. Don't miss this in your efficiency calculations.

Grid connected solar goes down when the grid is out though. You need specific inverters to retain power. You also just have issues like the low chance of having clear skies after a hurricane or a bushfire. For disaster situation power, a diesel generator is still the cheapest and most reliable option.

>> Grid connected solar goes down when the grid is out though. You need specific inverters to retain power.

Yes, and sort of.

Inverters will prevent power flowing to the grid if the grid is off. However most inverters will continue to supply power into the house while the grid is off.

There are various factors in play here, and you need to do proper homework, but certainly a fraction of the house can be powered, if not all of it.

I'm not sure if this is "special" inverter or not. Every one I researched had the same functionality.

Re: Satellite powered estimation of global solar potential

#123

Post by rgmerk »

xnx wrote: post #12

This is a very impressive refinement of their existing tool, but is this type of advanced calculation of roof-pitch (etc.) still relevant? Haven't we more or less concluded that a million piecemeal rooftop installations of solar are about the worst way to do it? More complicated and expensive to permit and install, less efficient operation, difficult to repair, difficult to insure, difficult to upgrade, inefficient t…

Australia manages to install rooftop solar at well under half the cost the USA does (most of that is soft costs) and integrate large amounts of it into the grid.

As of lunchtime today, nearly 50% of all electrical generation on the national grid was rooftop solar (and another ~10% was utility-scale solar).

Rooftop solar works just fine if utilities don’t actively try and obstruct its use.

Re: Satellite powered estimation of global solar potential

#124

Post by bruce511 »

xnx wrote: post #12

This is a very impressive refinement of their existing tool, but is this type of advanced calculation of roof-pitch (etc.) still relevant? Haven't we more or less concluded that a million piecemeal rooftop installations of solar are about the worst way to do it? More complicated and expensive to permit and install, less efficient operation, difficult to repair, difficult to insure, difficult to upgrade, inefficient t…

>> Haven't we more or less concluded that a million piecemeal rooftop installations of solar are about the worst way to do it?

It really depends on what you mean by 'worst'. In terms of land-usage it's the best. In terms of speed-of-deployment it's the best. In terms of distributing capital spend its the best.

In terms of capital return, that will vary from one house to the next because it depends on location, energy consumed (and when), elec prices in your region, grid stability, and so on.

Re: Satellite powered estimation of global solar potential

#125

Post by XorNot »

wongarsu wrote: post #76
NavinF wrote: post #74

Earlier quoted context omitted.

> Interlinking local capacity Is this a thing IRL? Every system I've looked at stops feeding the grid as soon as the grid goes down

They have to. Feeding your own home needs some setup but is fine. But electricity companies require you to disconnect generating capacity from the grid when the grid is down to make it easier to effect repairs. But that's more a policy decision than a technical restriction. We could change it so power can flow on both sides of a fault instead of only the "upstream" grid side.

I mean it isn't though: it's defense in depth - policy is you must disconnect. Line workers will drive a ground stake in on both sides anyway, but if you don't disconnect then they'll just short your inverter to ground.

Re: Satellite powered estimation of global solar potential

#126

Post by rsanek »

bruce511 wrote: post #124
xnx wrote: post #12

This is a very impressive refinement of their existing tool, but is this type of advanced calculation of roof-pitch (etc.) still relevant? Haven't we more or less concluded that a million piecemeal rooftop installations of solar are about the worst way to do it? More complicated and expensive to permit and install, less efficient operation, difficult to repair, difficult to insure, difficult to upgrade, inefficient t…

>> Haven't we more or less concluded that a million piecemeal rooftop installations of solar are about the worst way to do it? It really depends on what you mean by 'worst'. In terms of land-usage it's the best. In terms of speed-of-deployment it's the best. In terms of distributing capital spend its the best. In terms of capital return, that will vary from one house to the next because it depends on location, energy…

what do you mean by "distributing capital spend"? as in the money to pay for the installations is not concentrated to large utilities? why is that desirable?

Re: Satellite powered estimation of global solar potential

#127

Post by adrianN »

rsanek wrote: post #126
bruce511 wrote: post #124

Earlier quoted context omitted.

>> Haven't we more or less concluded that a million piecemeal rooftop installations of solar are about the worst way to do it? It really depends on what you mean by 'worst'. In terms of land-usage it's the best. In terms of speed-of-deployment it's the best. In terms of distributing capital spend its the best. In terms of capital return, that will vary from one house to the next because it depends on location, energy…

what do you mean by "distributing capital spend"? as in the money to pay for the installations is not concentrated to large utilities? why is that desirable?

Sometimes it’s easier to find a thousand people with a thousand dollars than one guy with a million dollars.

Re: Satellite powered estimation of global solar potential

#128

Post by BonoboIO »

ccozan wrote: post #60
stainablesteel wrote: post #52

Earlier quoted context omitted.

i've heard of some business models that install these and have you pay what would be the difference to your electric bill to the company until they pay themselves off, not sure if the panels last long enough to make that work though

Yes. In Germany they are selling a lot of models, but none, I mean, really, none asked about the rentability. So I went to a neighbour who just installed his 25kW and was very proud and happy, and asked him, in how many years is the return of investment. Siderated, he could not answer and then a few days later, with a very stern face: 25 years or more because if more people install these, the price that the city is p…

Damn, your neighbor got robbed by the installer …

Re: Satellite powered estimation of global solar potential

#129

Post by mlsu »

tsycho wrote: post #93
mlsu wrote: post #92

This is fine and all, but each individual having a solar panel introduces a lot of issues. Your energy bill is about 1/4 or 1/3rd distribution. As you take less power from the grid because of the solar on your roof, that proportion grows larger and larger. At the same time, the power company makes less money off of you, because you are using less power. Therefore, they have less money to invest in distribution, which…

Valid points. Is there a known solution to this, even if it's too expensive today? Would it make sense for local electricity companies to go full solar with large battery backups? Or are batteries too expensive, or don't last long enough, for this to be feasible? What about a wind+solar combination? Both of them are unlikely to go offline at the same time. I see articles that the cost of wind and solar keep going dow…

The most sensible solution in the short term is to keep the distribution that we have in place and aggressively invest in large solar plants coupled with very large battery systems to ease the duck curve.

Individual homeowners can do their part with solar + heat pumps to shift that duck curve. Power rates should see way more wild swings: 0c at the trough around 11am-2pm, $.50 at the 5pm peak. That aligns consumers to make sensible investments, either the energy they use or the energy they produce/store.

Smart charging of cars, so that those car batteries can help shift the load? But that requires global coordination that is nonexistent today.

Solar is no doubt the energy solution, there's really nothing better. It's low maintenance and lasts a long time, capital scalable, and can be deployed basically anywhere. Solar is far and away the cheapest thing for about 70% of our energy needs. For the last 30% that is very tough to squeeze out -- that baseline power for 24/7 stuff like aluminum smelters, datacenters -- you basically have: high voltage transmission (only available if you have land to your west), big battery banks (tenable, but only if batteries follow solar's dramatic reduction in cost), or nuclear (but requires a big culture change that I cannot really imagine). Or fossil fuels but those are not good obviously.

Basically any of the other green stuff (hydro, wind, geothermal) can't be built at any price most places.

Re: Satellite powered estimation of global solar potential

#130

Post by malfist »

PaulDavisThe1st wrote: post #107
malfist wrote: post #89

Earlier quoted context omitted.

There's a program involving F150 lighting trucks out in CA that pay you to grid tie them, that way a couple of them in your neighborhood can power the neighborhood for a day or so if wildfires take out the local grid

Anything grid tied is generally required to have phenomenally reliable shutdown if the grid goes down OR proven (and very expensive) automated switching that disconnects it from the grid if the grid goes down. This is so those F150s are not backfeeding the wires while a repair crew is trying to fix it. Ergo, if the local grid is "taken out", those F150s cannot be "on the local grid".

I'm sure you know what you're talking about, but Duke energy is running the program, and they wouldn't be paying people to grid tie their EV for disruptions unless they could use it: https://news.duke-energy.com/releases/illuminating-possibili...

The lightning extended range has a 135 kwh battery and can backfeed 90A@240V. That's a heck of a lot of power.

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