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Tesla Unveils Residential 'Solar Roof' With Updated Battery Storage System (theverge.com)
Tesla founder and CEO Elon Musk today unveiled the "residential roof" -- pegged as a roofing replacement -- with solar energy gathering powers. Unlike other solar systems which must be mounted on top of a traditional roof, these new panels are actually integrated within glass roof tiles, replacing a home's roof, Musk said. And because they're made of glass, Musk says they will last "quasi indefinitely," even in harsh conditions where snow and ice make short work of traditional asphalt shingles. Musk said that 50 years of lifespan should be no problem, and they offer efficiency that is 98 percent as good as a traditional, ugly photovoltaic panel. From a report on The Verge: There are a number of different versions of solar panels: Textured Glass Tile, Slate Glass Tile, Tuscan Glass Tile, and Smooth Glass Tile. Tesla says its glass tiles are much more durable than conventional roof tile -- something that's important in areas with risk of hail.The products are a "joint collaboration" between SolarCity and Tesla, according to SolarCity CEO Lyndon Rive. Tesla is attempting to acquire SolarCity for $2.6 billion and shareholders of both companies will vote on the proposed acquisition in the middle of November. The Powerwall 2 can store 14 kWh of energy, with a 5 kW continuous power draw, and 7 kW peak. The battery is warranted for unlimited power cycles for up to 10 years. It can be floor or wall mounted, inside or outside. It can be used for load shifting or back-up power. Musk says there are three parts to the solar energy solution: generation (solar panels), storage (batteries), and transportation (electric cars). Musk's plan is to sell all three of those products through Tesla.
Had a friend buy a hail-damaged car. He'd heard about hail sales and was looking to buy at the time. We walked the lot after a hail storm. The damaged cars had lots of dents in the metal, but not a single broken glass. The Texas dealership said that was common. Glass designed to take it is quite strong. Even bulletproof.
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"quasi indefinitely," even in harsh conditions where snow and ice make short work of traditional asphalt shingles. Musk said that 50 years of lifespan should be no problem
Europe has buildings with 1000 year old roofs, and it is somehow a little bit amusing to hear 50 years referred to as "quasi infinite".
In other words, they've improved it from storing $1 worth of electricity to $1.40. But you still need to cycle it many thousands of times with FREE electricity before it breaks even.
A quick search shows that the average household electricity usage is about 10K kWh per year (900-ish per month), ranging from 14K in Louisiana to 6K in Hawaii.
Using your numbers, that would be roughly $1000/yr. The powerwall costs roughly $7000 installed with inverter and other extras, or you can lease it for 9 years for $5,000 which includes installation, a maintenance agreement, the electrical inverter and control systems.
Tesla is offering a ten year warranty on the batteries, and there's some discussion about how a battery can last for 3650 cycles (mostly because the 14K powerwall is a 20K battery pack that's discharged much more shallowly than if it was an actual 14K battery, and other tricks).
The total cost comes out to about 0.15/kWh.
"Tentative Conclusion: The battery is right on the verge of being cost effective to buy across most of the US for day/night arbitrage. And it’s even more valuable if outages come at a high economic cost."
Glass is tougher than most people think.
Irony: Agile development has too much intertia to be abandoned now.
I purchased a hail damaged Accord in north Florida for $7K off the price and got a paintless dent repair guy to pull up the dents with a suction cup attached to a compressor for $500. Total win. You can't tell the car was damaged, at all.
That is actually quite irrelevant. Glass is weak and depends on it's structure to make it strong.
Is hail that big a problem for most people? I'm sure for some people it is, just like some people have to deal with tornadoes, and others have to deal with heat waves, and others flooding. But most people don't have to worry about them, and for them, this is great.
BTW we get the odd hail storm here, in the lat 30 years we've had two big ones that were enough to break stuff, and even the it was only in some suburbs, not the entire city. So these rare cases would be covered by insurance. A small additional cost is still probably going to be cheaper than 30 years of paying electricity bills
I think the PowerWall would be most useful with a smart panel that allowed individual circuits to be prioritized in various ways when running off battery power to maximize run time.
Like maybe the lights should be always on, the fridge given a high priority, the dishwasher not on, some circuits which could be cycled off to meet some other intermittent circuit's demand for power, and what order circuits could be killed off to maintain run time for the highest priority circuits.
Of course, most houses aren't wired that sane. Even in parts of my house where new circuits were run from a new panel during remodeling, electricians are prone to tapping whatever's close for power. I demanded a 20A dedicated circuit for the entertainment center, but the junior guy didn't get the dedicated message and tapped it for two ceiling lights and a hallway outlet.
I don't know how totally new construction is done, but I'm guessing its not done in a completely structured way except where code dictates dedicated circuits. But it would be great if there were individual circuits for lights by room, outlets by room, and then various specialty circuits for fridge or other items that should be addressed individually.
It's also a matter of scale - the metal panels of cars are quite thin compared to their glass. And then there's the classic flexible vs brittle contrast - metal will flex and permanently deform, while glass will flex and rebound - until it flexes so far that it shatters.
Hit a glass panel with a big (fast) enough hailstone and it will break - it's just a matter of making the glass strong enough to survive the typical hailstones encountered within a 50 or 100 or 500 year period (depending on how much you are willing to pay now to not have to replace your roof later.)
The fun part of this is changing weather patterns, how accurately can we predict the size and speed of hailstones 50 years from now? Since Elon's shingles are a brand new concept with essentially no competition, if he's got any class at all he'll over-design them so that they are more robust than they need to be. 15-20 years after they gain significant adoption in the marketplace, competition will shave their structural integrity down and down, saving a few cents on production costs in order to be the low price leader in the marketplace and simultaneously creating a shingle replacement labor market which actually costs far more than stronger (thicker) glass shingles that last twice as long would.
Could be even less. Our typical roof tiles last 40 years (mine are now at 75 years, and it's definitely time to replace), but solar panel output drops to a level where you need to replace them after 20 or so years. Longevity of the tiles isn't the issue, it's the dropping power output and the high cost of replacing the roof ever 20 years versus the cost of replacing the roof every 40 and separate panels every 20.
If construction was anything like programming, an incorrectly fitted lock would bring down the entire building...
Disclaimer: I work for a solar panel manufacturer.
Our best prediction is that at least 99% of our panels will output at least 70% of their power after 40 years. Trying to get that out to 50 years now.
Panel longevity and reduced output has come a long way.