Tesla's "solar roof" Event - Hosted at Universal Studios

[Peter_M]

A lot more questions than answers at this event. How are the tiles attached, how will they cope with high winds and freeze-thaw cycles, how is the wiring installed, how can it be cost-effective with such a low cell density and with the heat of the roof/attic degrading performance, how would you isolate a faulty tile/cell (i.e. will they have per-tile or "tile-group" monitoring), can you walk on the tiles and lift some in the middle of the roof if needed?

Also, will they have matching non-solar tiles, in case you want to put solar on just part of the roof due to orientation, shading, etc.

One thing I'll be very interested to see is if they will include per-cell MPPT electronics on each tile to optimize at the cell level. The trend is going that way, with the MPPT function migrating from a central inverter, to multiple MPPTs per inverter, to per-module MPPT (SolarEdge) to per-cell-string MPPT (Maxim Integrated). One more step to per-cell MPPT would make sense if they can get the costs down.

It will be interesting once all the details come out.

 

[mtndrew1]

Apologies in advance for the uninteresting question, but does anyone know what that song was at the end of the presentation video? I've done all the usual methods of searching (Shazam, Soundhound, Google, etc.) to no avail.

I would be very grateful if someone could identify it.

 

[Krugerrand]

A lot of all of this can be addressed better with house design.

Bingo. So now Tesla is going to disrupt the housing market.

 

[slcasner]

In 1999 there was a product called SunSlates which were a similar idea to what Tesla and Solar City presented today. These were larger imitation slate tiles with 6 solar cells on the exposed part of the tile. They were interconnected in strings with connectors on each tile. They were installed on 2x2s running up the slope of the roof applied on top of the roof sheathing plus tar paper. There would be an opening at the bottom roof edge and a shielded vent at the top forming a chimney under the tiles to allow convection of heat from the tiles. There were also cheaper inactive imitation slate tiles for use on the portions of the roof not used for sun collection (these were an already existing roofing product).

We tried for a year to go solar with these tiles, but had to give up and go with regular panels. The problem was that they were much heavier than the home's original wood shake roof. Our rafters were strong enough to hold the additional weight, but the outside sheathing on our home was not applied in a manner required to act as "shear walls" to avoid collapse with the extra weight in case of an earthquake (we are in California).

So. this experience leaves me with many questions for Tesla / Solar City to answer.

One question unrelated to the above, which I did not notice in earlier posts here: Who actually made the tiles shown on the demo houses today, and where were they made?

 

[Garlan Garner]

Regarding hail:

Those glass shingles looked to me of the same order of thickness as a conventional PV panel. Now, I am sure one can find examples of hail damage to them but:

1. Our Alaskan PV panels have withstood 7 winters of horrific snow+ice events, and been exposed to temps of -58ºF. "Snow+ice" means as snow melts, the ice build-up along the panels' bottom edges is absolutely terrible - for the first several winters I really worried about their being torn apart.

2. Our Arizona PV panels have withstood three summers of +118ºF ambient shade temperatures - I have seen molten steel underneath their glass surfaces (I kid, of course). AND....this summer my mother-in-law reported they passed through thirty minutes of continual hail - including some monsters. Now, as a NWS APAID Weather Observer, I have been treated to many tales of exceptional weather, and I never have heard of a hailstorm lasting that long. At any rate, those panels also came through unscathed.

So, on the face of it, I am absolutely willing to believe that the (obviously tempered) glass these shingles (is that what they're being called?) are at least as up to hail and some amount of tree windfall damage as any other roofing. I hope they don't have to come up against a wayward returning 2nd stage booster; otherwise, we should be good.

Whats most devastating to Solar Cells are microfracturs that are invisible to the naked eye. They surface upon extreme cold conditions. That's far more detrimental devastating than a full visible split/crack. The only way you would know to swap out a microfractured cell is to watch them individually. There is no monitoring system that monitors on a per cell level.

Another question arises. How difficult would it be to swap one of these new tiles out?

 

[Zapped]

A lot more questions than answers at this event. ..........can you walk on the tiles and lift some in the middle of the roof if needed?

Walking on glass will be an interesting challenge. Suction cup shoes perhaps ? I was also thinking about the reflective characteristics that might be problematic for near airports for airline pilots during landing and take off. The Bob Hope home is Palm Springs had a huge copper roof that eventually was painted a flat black color for that reason.

 

[Ulmo]

These seem like things I would address in a reveal. I wonder why he thought it strategic to leave out details? Perhaps they are too early in design and engineering stage.

 

[Ulmo]

It'd be covered by your insurance. hail damages normal roofs too [...] If the Solar Roof is around the same price as a normal roof then to insure it should be around the same... (one would think)

Elon said solar roof costs less than current roof + electricity. That's significantly more than a non-solar roof.

There is no monitoring system that monitors on a per cell level.

That would be relatively inexpensive in an integrated chip, but I don't know the end cost. For sake of dealing with this, I hope something solves that.

Another question arises. How difficult would it be to swap one of these new tiles out?

I hope they solve this. Either make repair easy, and/or make it redundant against failure. Details that weren't explained. Maybe they didn't finish multipath engineering on that network yet, so details not forthcoming.

Anyone else expecting a new charger today?

Tweet from Elon end of Sept

Aiming for Oct 28 unveil in SF Bay Area of new Tesla/SolarCity solar roof with integrated Powerwall 2.0 battery and Tesla charger.

Yes.

The event seemed hurried and cut short.

Maybe the charger seemed too technical to an aesthetics crowd. A lot of specifications and specifics were left out. Is this like an initial reveal, before engineering is done?

Something seems odd with the quiet crowd, too.

 

[Owner]

We tried for a year to go solar with these tiles, but had to give up and go with regular panels. The problem was that they were much heavier than the home's original wood shake roof. Our rafters were strong enough to hold the additional weight, but the outside sheathing on our home was not applied in a manner required to act as "shear walls" to avoid collapse with the extra weight in case of an earthquake (we are in California).

This is an excellent comment. How much more weight do the tiles add to the house? Will the house structure be strong enough to support the weight?

A neighbor on my street with existing solar and a shake roof just went through this process also to replace his deteriorating and fire attracting roof. They decided to go with a steel roof. But low and behold in the middle of the process, they had to reinforce their roof. i think the project is like 4 or 5 months old now after some house reinforcement went in. If I had to guess the house is around 40 years old.

side note: they lost all their seasonal solar energy. No Tesla but they do have an electric car.

Lesson in all of this: for most existing housing stock in California the extra weight of these tiles could be an issue.

I'm not sure about the rest of the country or the parts without earthquakes if this is a big issue.

 

[deonb]

Where do you live? You get terminal velocity hail?

I'm going to have to stay away from there. Poor birds.

Umm...

All hail falls at terminal velocity.

 

[Ulmo]

If I had to guess the house is around 40 years old.

Lesson in all of this: for most existing housing stock in California the extra weight of these tiles could be an issue.

I'm not sure about the rest of the country or the parts without earthquakes if this is a big issue.

From what I was told, California homes have been required to be built for solar panel loads for a while now.

I am getting conflicting results from my Google search. One result says 2015 IBC standard is first IBC to require solar panel loads. Another result says that California has had this requirement already.

I liked the reminder that so much of this is regional: in one California document, I found one of the safest assumptions funny as compared to many queries to this reveal event: they assumed 0 snow load, ever (safe assumption). I presume hurricanes and extended extreme freezing events in California are similarly assumed to never happen, and no provisions for such events. (To be accurate, the doc referred to a particular snow region of California, that which gets none, and refers to the vast majority of the building areas, and no attempt seemed necessary to spend extra time on specialty climates in the state; I assume anyone building in unusual climates in California has alternate engineering requirements.)

 

[mikevbf]

[QUOTE="Ulmo, post: 1806132, member: 42562"
The event seemed hurried and cut short.

Maybe the charger seemed too technical to an aesthetics crowd. [/QUOTE]

Yes, I would agree that he dumbed down the presentation to keep the message straight forward and clear. This was probably an overall good decision. Nothing douses the flames excitement more than confusion; detail can be added as interest increases.

I was waiting for this event before ordering my home charger. Would someone tweet Elon in case he is still on and ask if they plan to introduce a new home car charger to integrate with these products. Should I continue to wait a couple more weeks and use my local super charger for keeping my Model X charged?

 

[CitizenKane]

Apologies in advance for the uninteresting question, but does anyone know what that song was at the end of the presentation video? I've done all the usual methods of searching (Shazam, Soundhound, Google, etc.) to no avail.

I would be very grateful if someone could identify it.

Had the same question. Great song, who / what was it? Repeating question to be noted of answer.☺

 

[TexasEV]

Also, will they have matching non-solar tiles, in case you want to put solar on just part of the roof due to orientation, shading, etc.

Press kit says yes.

 

[nativewolf]

Yes hail storms here in North Texas can demolish an asphalt shingle roof easily. If this is more fragile than a normal roof it will cost more to insure. Also, I think the website says the cost was comparable to a normal roof after energy savings. (Which not to get too off topic reminds me of quoting the price of a model S after gas savings). The problem is my ins company doesn't benefit from the energy savings so they are insuring a roof that costs more to replace.

Oh they'll insure anything. You'll just pay more for it and it might take a while for the market to figure out what that correct price should be.

 

[JeffK]

Oh they'll insure anything. You'll just pay more for it and it might take a while for the market to figure out what that correct price should be.

Doesn't matter Elon resolved the question last night when he posted it would withstand heavy hail.

 

[nativewolf]

Doesn't matter Elon resolved the question last night when he posted it would withstand heavy hail.

Well I've seen hail destroy car sheet metal, blow out tempered glass...I'm not sure I'm going to believe that until I see them fire up the testing guns.

 

[nativewolf]

Well I've seen hail destroy car sheet metal, blow out tempered glass...I'm not sure I'm going to believe that until I see them fire up the testing guns.

or steel ball drops depending on what impact test they are going to do. The good news is that hail impact testing is fairly well known and studied, not a thing that has to be guessed. In fact, much like UL certification.

 

[Waiting4M3]

One thought on how the roof tiles could be connected, what if it uses same method as wireless charging? put a sheet full of induction antennas on the roof, lay the tiles on top, done! You can replace a tile just like a regular roof, no need for any new electrical work.

 

[AudubonB]

A bit of far-fetchedness going on here, I think ( aka "Live from The Internet---it's Saturday Morning!"

* Q: Weight?
A: Swap out your existing (or planned-for) Spanish tiles, or your French slate tiles, etc. for your hydrographically-printed quartz glass solar tiles....and your weight difference is 2/3s of 3/5s of squiddly-all. Swap out your Wasilla-special blue tarp roof for the same, and yep, there's a difference.

* Q: Durability? What if a meteorite hits it?
A: You've got bigger problems to worry about, bub. Otherwise, it's a tile roof: if what it's substituting for can take it, so can the ones we saw last night.