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Satellite powered estimation of global solar potential

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Re: Satellite powered estimation of global solar potential

#111

Post by Scoundreller »

WillAdams wrote: post #47
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…

Yes, but one back-of-the-envelope calculation (it was a Python program someone wrote up as part of a comment on Slashdot as I recall) demonstrated that if all of New York's roofs were covered in solar panels there would be enough energy to run the city....

Enough energy or enough electricity?

Re: Satellite powered estimation of global solar potential

#112

Post by PaulDavisThe1st »

wongarsu wrote: post #65
Glyptodon wrote: post #59

Earlier quoted context omitted.

At a certain point shouldn't things get good enough you don't really need a traditional power grid?

Residential power demands are highest in the morning and in the evening. That's when people shower, cook, and are generally around using power. Solar peaks at noon. Maybe when battery prices come down even more. But the cost of grid-level storage are also falling, and wind pretty much only works at grid scale. Grids have to change but won't become obsolete anytime soon.

That usage pattern will be quite different in places with cold winters when most people there are using electric-powered heat pumps (which is "the plan").

Re: Satellite powered estimation of global solar potential

#114

Post by PaulDavisThe1st »

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…

> Would it make sense for local electricity companies to go full solar with large battery backups?

Sure. But opposition to those battery energy storage systems (BESS) is intense and growing.

Re: Satellite powered estimation of global solar potential

#115

Post by bruce511 »

nine_k wrote: post #100
dzhiurgis wrote: post #78

Earlier quoted context omitted.

One of these wouldn't sign me up as they couldn't offer any savings (92% of my use is off peak, around 16ct NZD (9 USD) / kWh). A lot of the time such companies pray on people on stupid plans (or those paying thru the nose for "exclusively renewable") power.

This exactly the case when a battery would make an immense difference. (9 USD / kWh sounds terrifying. Not only an electric kettle begins to cost you; probably playing computer games at high quality / resolution comes with a noticeable price tag in electricity that the GPU would eat.)

I think he meant 9 USD cents per kw. (He included ct with NZD but forgot it with USD.)

Re: Satellite powered estimation of global solar potential

#116

Post by rgmerk »

rrr_oh_man wrote: post #96
pyaamb wrote: post #70

This is really incredible. If they could plug in local utility prices and come up with estimate for dollars saved per year, that would be an incredible conversation starter for homeowners who might not have considered taking on a home solar project otherwise.

> incredible conversation starter for homeowners who might not have considered taking on a home solar project otherwise Once you do the math in a Northern country (sans subsidies) it's not as compelling as you might think.

Because (at least in the USA) the soft costs are excessive:

https://pv-magazine-usa.com/2022/11/16/tackling-soft-costs-a...

Re: Satellite powered estimation of global solar potential

#117

Post by notatoad »

pyaamb wrote: post #70

This is really incredible. If they could plug in local utility prices and come up with estimate for dollars saved per year, that would be an incredible conversation starter for homeowners who might not have considered taking on a home solar project otherwise.

like this? https://sunroof.withgoogle.com/

Re: Satellite powered estimation of global solar potential

#118

Post by PaulDavisThe1st »

jjcm wrote: post #7
ben_w wrote: post #5

Nice to see, I hope it helps people get more cheap energy. All I have are nits to pick: > 10.7k TWh globally This brings back memories of the time I almost shortened "thousand kilometres" to "kkm". Also, and this is not a criticism of Google, the IEA link on that text looks suspiciously like the IEA is still forecasting linear deployment of PV between 2025 and 2035, despite at least a decade of people pointing at it…

> 10.7k TWh globally Agree I hate this, but at the same time I don't know if I would have groked it correctly on first read if it had listed "10.7Pwh globally". We simply aren't exposed to numbers at that scale on a regular basis. Not sure what the correct solution is here.

We should be. Why? Because reasonable estimates of the amount of extra energy contained within the atmosphere due to anthropogenic effects are in the single digit petawatt range. It's a number everyone should be carrying in their heads.

Put a different way: the total annual harvestable solar yield is within an order of magnitude of the energy we've caused to accumulate inside the atmospheric boundary. Think about that, for a second or two.

Re: Satellite powered estimation of global solar potential

#119

Post by PaulDavisThe1st »

szvsw wrote: post #30
janitorHenry wrote: post #4

Builders: optimize energy capture, put roof planes directed south (in northern hemisphere).

There’s not always a lot of freedom to control roof angles like that - it might eg be directly determined by the orientation of the street - and even if there is, it might come into conflict with other thermal considerations. For instance, perhaps orienting the building such that the roof midline is E/W and the surface is due south results in more windows pointed due south, which in turn drives much more solar gain o…

> more windows pointed due south, which in turn drives much more solar gain on the interior and greater cooling loads as a result

C'mon ... people figured this out in 70s ... and centuries before that in various parts of the world.

You put a shade above the window the excludes direct summer sun, but allows direct winter sun to enter the window. The angle and extent of the shade depends on where you are in the world.

On my old adobe in New Mexico, a roof at about 30 degrees with about an 18" overhang prevents all direct summer sun from entering our south facing windows, but provides 6-10F of additional ambient temperature during the winter from direct sunlight.

Re: Satellite powered estimation of global solar potential

#120

Post by bruce511 »

macintux wrote: post #43
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…

I’m amazed at the amount of opposition to centralized solar generation. I assume there’s a fair bit of fossil fuel industry astroturfing involved.

There's the perception that it's an "either" question. When in reality its both.

Home solar is a big win, and if nothing else allows capital to be sourced from a million home owners.

Centralized solar is a big win, generating grid power Erich is obviously important.

It's not a question of either, it's a question of both.

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