Tesla Glass Tile Solar Roof Update

[Sir Guacamolaf]

I wonder how accurate their cost estimate is. With anything construction, I always assume 10-20% over in terms of permits, contractors etc. Also it would be good to know more technical details, the tiles/cost all sound great (okay slightly pricey but),

how are the wires laid out?
How different do the blank tiles look for the solar tiles?
What kind of service does it need?
How does the inverter look?
How does the efficiency compare with normal solar panels?

Sorry if I missed these details.

So far, given the cost difference alone, I am leaning more towards the low profile solar panels over solar tiles - UNLESS - I was putting on a new roof. But as it is, you can't get these solar tiles until 2018 anyway, and until then its an interest free loan to Tesla.

 

[3Victoria]

The solar/non-solar tiles look the same, from the street. I think the inverter is in the Powerwall. Likely needs next to zero maintenance. You should price out both options and then choose the one that's best for you.

 

[MP3Mike]

I think the inverter is in the Powerwall.

Nope, you don't have to have a powerwall, so that isn't how they are doing it. I'm sure the invertor will look just like what Tesla Solar City uses now for standard solar panel installs. (Unless they use micro-invertors; which might make sense to deal with un-even shading on the roof.)

 

[cpa]

Here comes the buzz kill.

I wonder if Tesla has obtained a private letter ruling from the IRS regarding the amount eligible for the solar energy credit. Tesla's promotional example assumes the 30% income tax credit applies to the entire cost of the roof. I am not convinced that this was Congress' intent when they passed the legislation last decade. Clearly, Congress did not contemplate the fact that perhaps one day some clever entrepreneur would design roof tiles with photo-voltaic cells therein.

Code Section 25D defines "qualified solar electric property" thus:

(2) Qualified solar electric property expenditure


The term “qualified solar electric property expenditure” means an expenditure for property which uses solar energy to generate electricity for use in a dwelling unit located in the United States and used as a residence by the taxpayer.

The section goes on to state

(2) Solar panels


No expenditure relating to a solar panel or other property installed as a roof (or portion thereof) shall fail to be treated as property described in paragraph (1) or (2) of subsection (d) solely because it constitutes a structural component of the structure on which it is installed.

It is this part of Section 25D that is really ambiguous. It is unclear whether solar tiles are considered a "solar panel" or "other property installed as a roof." It is more unclear whether the plywood base, felt, flashings, non-solar tiles and other ordinary roof materials would be considered "other property." Personally, I would read the "other property installed as a roof" narrowly; just those costs associated with securing the tiles to the roof safely. But then, I am not a contractor or electrical engineer.

It would seem prudent business sense to me for Tesla to pony up the $5,000-$10,000 to request a private letter ruling as to how much of the cost of a solar roof would be eligible for the credit. While private letter rulings only apply to the taxpayer who requests them, they do provide guidance for the rest of us peasants as to how the IRS thinks about the situation.

Methinks the marketing department at Tesla did not consult with their income tax advisors.

 

[D-egg-O]

You mean the active area of the active tiles? Judging by this photo of the smooth tiles, I would've guessed closer to 80% of the area of the active tiles

Since when are there 2 cells per glass tile?!

 

[MP3Mike]

Tesla's promotional example assumes the 30% income tax credit applies to the entire cost of the roof.

Nope, they make it very clear that the 30% only applies to the portion of the roof that is solar, not the non-solar tiles.

 

[cizUK]

Ok, is it just me , but watching to video showing various tiles shattering is deceptive ! They hold the Tesla glass tile horizontally, with clamps much closer together. Show all samples held the same way !!
Come on Tesla, your better than this

Jeff

Hate to disagree... but...

I believe the positioning is harder on the Solar Roof Tile as the others have cracked over much longer lengths than the Solar Roof Tile can.
Therefore the Solar Roof Tile is under more pressure from the hailstone, however is doesn't crack.
The distance between the rails is constant, so we can discount the extra length the SR Tile has off each side as this won't be taking any pressure.
This shows that the SR tile has less area and length (top to bottom) in which to absorb the energy.
However, I don't know why they didn't keep the orientation continuous.
Hope this helps!

Edit: And the 'clamps' aren't actually clamping the tiles, they're just holding them loosely in position - you can see the SR Tile moving on impact.
Also the tiles are shown in their final installed orientation, which would explain the differing orientations.

 

[electracity]

Nope, you don't have to have a powerwall, so that isn't how they are doing it. I'm sure the invertor will look just like what Tesla Solar City uses now for standard solar panel installs. (Unless they use micro-invertors; which might make sense to deal with un-even shading on the roof.)

In the U.S. I thought the solar inverter could was in the "DC" powerwall? The rest of the world would have a regular grid connected solar inverter, with the "AC" powerwall connected to the house's main panel.

The question with this solar roof is how they are doing power optimizers, and if they are charging powerwall from DC. Power optimizers are used to handle shading and produce consistent voltage for battery charging. A premium product like this should have power optimizers. Where this circuitry would be placed I don't know.

At one volt per tiles large groups of the shingles would need to be put into series. Perhaps multiple tiles are pre assembled into panels.

Edit: And the 'clamps' aren't actually clamping the tiles, they're just holding them loosely in position - you can see the SR Tile moving on impact

Perhaps Tesla used the actual support points for the various roofing products tested.

 

[hockeythug]

LOL. That is all.

 

[ecarfan]

In the U.S. I thought the solar inverter could was in the "DC" powerwall?

THere is no inverter in my Powerwall V1, which is DC. The Powerwall V2 DC has no internal inverter. It requires DC in and can only output DC. The Powerwall V2 AC does have an internal inverter. It can take DC in and it outputs AC.

 

[FlyF4]

They should just release a kW/sqft number so that we could figure things out the easy way.

RIGHT. I wonder if it isn't being published because the efficiency is so poor (compared to traditional panels).

 

[ElectricTundra]

RIGHT. I wonder if it isn't being published because the efficiency is so poor (compared to traditional panels).

Possibly. Or perhaps they're still tweaking and hoping for a better number 'soon'. In my case the comparison is to no solar rather than to panels. My wife won't allow the panels on our roof in her lifetime, or infinity, whichever ends first.

 

[electracity]

THere is no inverter in my Powerwall V1, which is DC. The Powerwall V2 DC has no internal inverter. It requires DC in and can only output DC. The Powerwall V2 AC does have an internal inverter. It can take DC in and it outputs AC.

Is Tesla using Solaredge with Powerwall II DC, or did they make an inverter?

RIGHT. I wonder if it isn't being published because the efficiency is so poor (compared to traditional panels).

Probably. Efficiency doesn't matter if there is sufficient roof space to meet the production goal. All that matters is cost.

Although a low calculated efficiency will keep the Seeking Alpha writers busy.

 

[BrokerDon]

I estimate that you get 2.8 W per sqft. of solar portion of the roof.

I didn't see you say what portion of the roof was active. Using my estimate you would need 2,214 sq. ft of solar roofing to get a 6.2kW output. (To put it in the middle of your two estimates.)

Google Project Solar calculates 1,180 sq feet "available for solar panels"... which is the South facing portion of my almost perfectly south facing portion of my east / west Spanish tile roof. Since only 1/2 of my roof faces south... and the Tesla Solar calculator allowed a 50% maximum "solar coverage", so I changed the crazy Tesla default "Roof square footage" estimate from 5,620 sq. ft. to 2,214 sq. ft. (2 x Google Project Solar "available for solar panels").

 

[jeff mccabe]

Hate to disagree... but...

I believe the positioning is harder on the Solar Roof Tile as the others have cracked over much longer lengths than the Solar Roof Tile can.
Therefore the Solar Roof Tile is under more pressure from the hailstone, however is doesn't crack.
The distance between the rails is constant, so we can discount the extra length the SR Tile has off each side as this won't be taking any pressure.
This shows that the SR tile has less area and length (top to bottom) in which to absorb the energy.
However, I don't know why they didn't keep the orientation continuous.
Hope this helps!

Edit: And the 'clamps' aren't actually clamping the tiles, they're just holding them loosely in position - you can see the SR Tile moving on impact.
Also the tiles are shown in their final installed orientation, which would explain the differing orientations.

View attachment 226422

" as the others have cracked over much longer lengths than the Solar Roof Tile can"

This is the precise reason the others failed the way they did. They where unsupported along the entire length. The Tesla cell set sideways is supported at least 40 percent better, which didn't allow it to flex and fail. I know why they didn't show the cell arranged the same as the others....it would of failed.
Come you structural analysis engineers out there, lets here what you think.

Jeff

 

[MP3Mike]

The Powerwall V2 AC does have an internal inverter. It can take DC in and it outputs AC.

Are you sure about that? I thought the Powerwall V2 AC only had AC as input and output.

 

[KidDoc]

Here is mine in Texas. >$200,000 for a roof? hmmm

$150,300

Value of energy

-$189,000

Cost of roof

-$23,500

Cost of 4 Powerwall batteries

+$55,300

Tax credit


Roof square footage 6385


Monthly electric bill $400



Powerwall batteries 4




$6,900

Net cost over 30 years

 

[cdub]

???? HOW the HECK is it that expensive? I thought it was supposed to be "cheaper" than a "regular" roof? Sigh.

 

[u00mem9]

Usual Tesla games...anyone manage to reverse calc the output per sq ft?!? I'm driving.

Why does everything have to come with free horsesh*t?

 

[EV-lutioin]

I put my house in the calculator and it said the cost of the roof would be $77,000 (before rebates and power savings). And it recommended 50% solar tiles for a roof with about 25% total solar exposure (which can easily be determined on Project Sun Roof Project Sunroof). I am totally confused by the price... Really, $77K???