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Solar Roof

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311–320 of 455 posts

Re: Solar Roof

#311

Earlier quoted context omitted.

I don't really see the selling point, or value here. Tesla's calculator estimates $40,500 for a roof that generates half our power needs, and should provide $20,400 worth of energy over 30-years. Add in a PowerWall and federal tax credit, and I'm still losing $15,400 over 30-years. If I put that same $40,000 in an index fund that got the stock market's historical 7% average, and waited 30 years, I'd have $308,000. To…

> Add in a PowerWall and federal tax credit, and I'm still losing $15,400 over 30-years. Which you probably sink into a second layer of asphalt shingles 15-20 years in (at least up here in upstate NY where there's plenty of rain/snow). Hopefully it's not a tear-off, as that'll cost more.

It's always tearoff. A lay over is saving 2k and shortening the life of brand new roof. Always a bad idea. Unless maybe selling the house soon to a naive buyer.

Re: Solar Roof

#312
I see a lot of these personal level-vs-global level discussions here but ultimately not enough posts celebrating the fact that we're looking at both, here, and looking at a potentially much better future because of it.

Go, Tesla.

Re: Solar Roof

#314
post #43

Earlier quoted context omitted.

It's not really a lifetime warranty though. If you click through to the Tesla purchasing page, there is (only) a 30 years Power Warranty and Weatherization Warranty... which in my mind renders calling it a lifetime warranty sort of silly, as the purpose of the shingles (power generation) is not covered by the lifetime portion of the warranty. 30 years still seems like a significant warranty for a product like this th…

You can readily buy a 30 year shingle roof. Calling it a lifetime warranty when it is no better than a common, good quality shingle roof is absurd. Metal roofs have even longer warranties.

50 year asphalt roofs are all over.

Re: Solar Roof

#315
For a counterweight let me present this interview[0] with the CEO of "the largest privately held solar contracting company in America", near the end of which he says several disparaging things about Tesla's roof, including,

> When I saw the demo he did at Universal Studios... What I saw was a piece of glass that looked like it had a cell in it. The challenges he’s going to have is, how are you going to wire it? Every one of those shingles has to be wired.

> Roofs have valleys and they have hips and they have pipes. … How are you going to work around that? How are you going to cut that glass? Are you going to cut right through the cell?

The latter question is perhaps answered by the posted article, "Solar Roof uses two types of tiles—solar and non-solar." So Petersen's question is moot, the glass/solar tiles don't have to be cut to fit in a hip or around a flue, that will be done to the non-solar tiles that look the same.

The question of wiring is open: imagine the grid of wires that have to underly that roof, and getting them all put down without a break or a short, by big guys with nail guns (if you've ever watched roofers at work -- it isn't a precision operation).

Then Petersen goes on to say,

> So I would say for the record ... it’ll be cost-prohibitive. ... For $55,000 I can give you a brand-new roof that will last forever — 50 years — and I can give you all the solar you can handle. ... (Musk’s) product is going to be north of $100,000.

The graph in the posted article does not directly address total up-front installed cost, but rather tries to combine cost with some anticipated lifetime energy return -- a procedure with a LOT of variables and assumptions. I would like to see real numbers for a Tesla roof, $/sq.yd installed.

[0] http://www.mercurynews.com/2017/05/04/from-summer-job-to-sol...

Re: Solar Roof

#316
post #206

I'm super excited about all of the great stuff happening in solar recently, but whenever I read about the economics of home solar, I'm also always reminded of how stacked the deck is for wealthy people vs. poor folks. There's a very large federal tax credit for solar investment. That's great...but, people who can't afford their own home get no such credit, and there's no way for them to get such a credit. That's a su…

This is tautological; the reason poor people don't get a lot of tax breaks is because they don't pay a lot of taxes. The government does spend a lot of money helping poor people, but not via tax credits.

I'm speaking of incentivizing reducing power usage in the general case, not merely tax credits. The current solution is "let's give wealthy people more money to play with" (to questionable benefit to the general welfare). I should be clear I'm not saying I oppose tax credits for reducing usage; I'm just saying that poor people aren't getting the same kinds of benefits for using less power, even though they are using less power than the wealthy folks getting kickbacks.

And, again, I don't have ideal answers. But, I think there's a problem with the government consistently serving wealthy folks, even when those folks are living in much larger houses and consuming far more resources. Should a person with a 4000 sq ft house, consuming 5x the power of a lower income family in an 800 sq ft apartment, really be getting paid off to reduce their consumption?

If we're serious about the problem of climate change, energy independence, etc., we have to start looking at the actual numbers. If five low-income families are consuming the same resources as one wealthy family...what needs to change to bring the 5x family's consumption down? Solar incentives are one of the options; but, again, they serve only the wealthy (and, as far as I know, most solar installations do not replace the entire household usage, and only reduce it by 30-50%). That outsized power consumer is costing everyone more in terms of what it will cost to respond to climate change.

The question is why are the wealthy being rewarded when they're still consuming more than their poorer neighbors (well, probably not actually neighbors...the poor folks are on the other side of town due to zoning laws).

And, on another "class war" theme, the poorest people are the ones being hit hardest and soonest by the effects of climate change. The multiple "100 year record-setting flood" events in Austin destroyed poor southeastern neighborhoods twice in the past five years. Those were the lowest cost neighborhoods, and decisions were made by the Army Corps of Engineers to protect more expensive homes, and ignore the risks to the poorer neighborhoods. Lousiana, Florida, the Carolinas, have all had major weather events in the past several years (not all can be proven to be the result of climate change, but the severity and frequency seems clearly on an upward trend) and the impact has been predominantly borne by the poor.

OK...I went off on a bit of tear there. My point is that I feel a certain discomfort at how readily environmental causes are used to strengthen the position of those who are already wealthy and already relatively safe from environmental destruction, while the folks most likely to be impacted are invisible.

Re: Solar Roof

#317

Earlier quoted context omitted.

Lots of houses over 100 years old out there. No reason to think a lot of houses today won't still be standing in 100 years.

roofs != houses

Houses need roofs that last. Why put a new roof on every 15-20 years if you can put one on that lasts the lifetime of the house?

Re: Solar Roof

#318
Hrmmm... I just signed a contract a few weeks ago with SunPower solar panels. Over 40K for almost 8kWh of electricity. It's a hefty cost but it's ready now.

It's a nearly flush mount so I'm ok with it and it's still a traditional look in the front where it's concrete tile that would last longer than I will live.

Lastly though, I wonder how they deal with valleys and different roof pitches. It would look a little odd unless it is non functional.

Re: Solar Roof

#319

Earlier quoted context omitted.

I agree with the sentiment, but I have to correct your idea that global warming is a species-ending problem. The worst-case scenario of global warming (which might be inevitable given the current CO2 levels) is a 216 foot rise in sea level [1]. This will cause mass migration and be extremely expensive and unpleasant for society as a whole, but poses little threat of ending humanity. NASA's JPL did a great lecture a f…

Should I start buying 215 foot above sea level for future beachfront development?

Maybe if you want the place to be in 1 foot of water?

Re: Solar Roof

#320
post #315

For a counterweight let me present this interview[0] with the CEO of "the largest privately held solar contracting company in America", near the end of which he says several disparaging things about Tesla's roof, including, > When I saw the demo he did at Universal Studios... What I saw was a piece of glass that looked like it had a cell in it. The challenges he’s going to have is, how are you going to wire it? Every…

You can use their calculator to edit any of the assumptions, and the math is fairly transparent.

The question of installation is a straightforward challenge that's easily testable, presumably they have a solution that works or they wouldn't announce yet. It's pretty obvious to see if it's going to work or not: just send a team out to put on a test roof and see how much work it is.

[0] https://www.tesla.com/solarroof

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