[ExI] The Futurism of Elon Musk

Tue Sep 8 15:47:34 UTC 2020

> On Behalf Of William Flynn Wallace via extropy-chat
Subject: Re: [ExI] The Futurism of Elon Musk

>…So, Spike, rather than use your generator, why not put solar cells on your roof?  You are a cheapo like me and in the long run you will save $$$.  Probably could not run a compressor?

bill w

BillW if I had enough money to buy rooftop solar panels, I wouldn’t spend it on that.

I would spend that on additional efficiency upgrades on my house, such as full attic ventilation (which I may do anyway) and window upgrades.  Reason: I am good with a spreadsheet.

Plenty of people around here went for rooftop solar when the power company and state government were offering incentives that added up to nearly half the cost for some consumers, but those incentives expire (no surprises, they told us the expiration dates.)  People who know how to do a spreadsheet did spreadsheets and recognized that rooftop solar is only a payback under certain not all that common conditions: you have a lot of south-facing roof area for instance where there is little risk from trees growing into your sun path and low risk of the trees dropping stuff on your panels, all the real-world limitations, and after all that… if someone does the spreadsheets, it becomes clear that to make it pencil out, one must choose the less reliable, shorter-lived, lower efficiency but much lower cost panels.  Hmmm, damn.  (There’s a reason for all this, available on request.)

Well… the power company knows this too, as well as these local companies who work deals to do the installation free, the panels are free, your maintenance and equipment (such as inverters) are actually rented, so all of it costs the homeowner nothing up front, and the company pays a monthly fee (a pittance of course) but there it is: no upfront cost to the homeowner and she gets a check for allll thaaaat power she generates on the roof, oh how green it is.

Well, so it would seem, but… those “free” panels are relatively low efficiency and (in accordance with the contract) the homeowner may not remove those panels if they go to sell the house and part of the buying public doesn’t want a house with those up there.  Then the homeowner has to pay the solar power company to come out and take their panels down and buy her way out of what amounts to a 20 year lease on their own roof.

Meanwhile… some people did buy their own panels, pay to have them installed, only to find out… they don’t generate as much power as the glossy pamphlets claimed they would, which spawned a new industry: these fellers come out, take those panels off your house, free!  They keep the panels of course, but now you have your roof back, ready for repairs from where the panels were mounted.  These fellers will even buy your inverter and take those copper cables off your hands, and evem give you a few hundred bucks.  So you get five cents on the dollar back from your rooftop solar misadventure.

But before I go on, sounding as if I am disparaging all rooftop solar, I am not.  I am disparaging it when the engineering is done incorrectly.  But there are a few cases where it does pay and does make sense.  It will make sense if the cost of power triples.  For now, not really in most cases.  Suburban roofs aren’t usually enough area, it is too tree-ey down in there and most roofs are not oriented optimally.  A few are.  A few homeowners know how to do the calcs, and of course some of those will recognize an even greener solution: rooftop water heating, which is extremely green but is even uglier than rooftop solar.  

Conclusion: if you hire people to install rooftop anything, they will sell you a system which maximizes profit to them, not to you.  If so, there is a very good chance you will be paying again to hire guys to take it back down within a decade.  We are not there yet on suburban green energy. 

spike

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