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Satellite powered estimation of global solar potential

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Re: Satellite powered estimation of global solar potential

#82
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…

There are enough panels available to do both and there is no overlap in financing for both. So just do every installation that is economically viable, they don't compete for money or panels.

Re: Satellite powered estimation of global solar potential

#83
post #7

Earlier quoted context omitted.

> 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.

Joules is the solution to both the problems (the second is that Wh for energy is as silly as speed hours for distance)

>(the second is that Wh for energy is as silly as speed hours for distance)

This would be a devastating own if a single Joule wasn't exactly equal to a Watt-second.

Re: Satellite powered estimation of global solar potential

#84
post #66

Estimate for a house in SF with a typical roof and typical electric bill. $20k upfront cost. $4k in savings over 20 years. That's an implied rate of return of 0.9% annually. No thanks.

How are you calculating that? Solar installations are around $2.50-$3.50 per watt, so $20k would get you 6-8kW. Assuming actual output is 10% of capacity, that's 14-19kWh/day or 5,000-7,000kWh per year. Current residential electricity prices in SF are 38.9 cents per kWh[1], so that's $2,000-2,700 per year in savings, or $40-54k over 20 years. The actual amount saved depends on how much electricity you're consuming du…

I didn't calculate anything I just put in an address and a monthly electricity bill.

https://sunroof.withgoogle.com/

Re: Satellite powered estimation of global solar potential

#85
post #6

The image processing described is very cool, but I have questions about the application. Google started doing these solar potential estimates about 10 years ago, so let's imagine that they have been developing the capability since about 2010 or so. In that time the cost of PV has fallen by an order of magnitude. Hasn't that settled the question of where PV should be installed? I thought the answer is now "yes" everyw…

A lot of new homes are still constructed without solar. Either market participants are sleeping on easy money or the answer isn't a simple "yes, everywhere". The cost of panels has fallen a lot, but the cost of mounting hardware and installation is still pretty high in the US.

That's exactly my point. This isn't telling you anything about the controlling variables: labor, G&A, taxes.

Re: Satellite powered estimation of global solar potential

#87
This is a very neat exercise but I don’t think it’s going to create change. These models already exist and I’ve never met anyone who said their reason for not investing in solar is because they felt the accuracy of existing models is not good enough. I say this as someone who lives on a part of the world where a large % of the inhabitants could have solar but do not - and I find it sad, frustrating and puzzling.

Biggest blockers for solar are (total conjecture) : 1- Inertia - flat out. 2- Long-term ROI is not totally clear - How long till I need to replace, roof damage, ability to hold up in storm. 3- Cost - You need to invest sig $ to see your electric bill decrease meaningfully. Gov subsidies are nowhere near where they should be.

I am praying for a major breakthrough in cell efficiency to make it a no brainer. Does anyone have any insight on that?

Re: Satellite powered estimation of global solar potential

#88

This is a very neat exercise but I don’t think it’s going to create change. These models already exist and I’ve never met anyone who said their reason for not investing in solar is because they felt the accuracy of existing models is not good enough. I say this as someone who lives on a part of the world where a large % of the inhabitants could have solar but do not - and I find it sad, frustrating and puzzling. Bigg…

I think it has to do with the assurance of the warranty. The ROI is loooong; solar contractors can go out of business leaving the parts on the roof lacking in the promised energy savings. Who wants to litigate against a bankrupt company?

Re: Satellite powered estimation of global solar potential

#89
post #74

Earlier quoted context omitted.

Sure, but that's why my emphasis was on distributed grids . Interlinking local capacity / having one or two neighbors with fully fledged systems is way better than going weeks charging stuff in your car. When you're without power for weeks, you'll probably have enough sun for more than enough days to get yourself sorted. Hurricanes also tend to sweep up any other systems in the region, so once they disperse, it's pre…

> 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

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
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