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Tesla announces plans for solar roof, second-gen residential battery system

By Shawn Knight · 28 replies
Oct 30, 2016
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  1. Shareholders on November 17 will vote on whether or not to approve Tesla’s $2.6 billion all-stock offer to purchase SolarCity. In the lead-up to the vote, Tesla CEO Elon Musk – who also happens to be the chairman of SolarCity – is doing everything in his power to persuade voters to approve the acquisition.

    At a recent event held on the Universal Studios lot in Los Angeles, Musk unveiled a line of textured glass tiles with built-in solar cells designed to replace traditional shingles on a home’s roof.

    The hydrographically-printed panels would be offered in your choice of slate glass tile, textured glass tile, smooth glass tile or Tuscan glass tile – all of which are said to be more durable than roofing materials in use today. The solar cells integrated into the tiles are invisible when viewed from the street but are fully exposed to the sun from above.

    Accompanying the solar roof was an updated version of Tesla’s residential battery system, appropriately named the Powerwall 2. The new $5,500 battery system will offer 14kWh of storage which, according to Musk, is enough to power a typical four-bedroom home for a day.

    Musk didn’t mention how much the solar roof would cost consumers, even when asked by journalists after the event. He did, however, concede that it would not make sense for someone to replace a brand new roof with a solar roof. In the event that your existing roof needs replacing, however, it could make sense for many families.

    Announcing the new products ahead of the shareholder vote on the merger is absolutely a strategic move. As Ars Technica notes, Musk said that if the merger isn’t approved, collaborating with SolarCity on the roof panels would make far less sense.

    Permalink to story.

  2. captaincranky

    captaincranky TechSpot Addict Posts: 14,830   +3,922

    That conspicuously sounds like blackmail!
    JaredTheDragon and EEatGDL like this.
  3. risc32

    risc32 TS Addict Posts: 209   +96

    They already have solar shingles. not that I'm saying it's not good to have more, as it is. when I ran my numbers it didn't make sense at my location(I also needed a new roof) anyway, elon isn't onto a new idea or anything, but I hope it's a good product. I'll need another roof in 25 or so yrs....
  4. yRaz

    yRaz Nigerian Prince Posts: 2,865   +2,169

    The musky scent aside, selling the solar shingles to solar city would only raise the price on the consumers end since two companies have to make money instead of one.

    The cost of solar panels is now ~90cents a watt. I think it needs to get down to ~20 cents a watt before it is affordable and makes sense to the masses. I've been watching solar prices like a hawk over the last 5 years and in just the last 3 years I've seen it go from~$2/watt to under ~$1/watt. I give it 8-10 years before people in largely overcast areas are going to have solar. It'll probably be 3-5 years before solar has a strong foothold in sunny areas.

    for a 24/7 off grid solar system ( panels, batteries, inverter) to make sense the cost with installation included needs to be about that of a used car.
    TheDistraction likes this.
  5. Uncle Al

    Uncle Al TS Evangelist Posts: 5,308   +3,715

    Solar panels are said to have a lifespan of 20-25 years and the current output doesn't break even until around 15-18 years. This was based upon installation in the South where there is a much higher rate of sunshine. Since the shingles are "fixed" in place, they don't follow the sun which decreases the amount of power gather. it would be interesting to hear what the maximum storage is (in days) and the buyer must consider if they live in an area where they can attach to the grid for those times when there is bad weather, cloudy days, snow, etc. They do seem to be getting closer for the average consumer, but I don't think he's quite there yet.
    JaredTheDragon likes this.
  6. yRaz

    yRaz Nigerian Prince Posts: 2,865   +2,169

    The average household uses ~10KWh a day. Assuming you have a maximum of 8 hours of sunlight during the winter a 2kw solar set up would exceed your needs. You can get 2kw of solar for ~$1800, build a 15KWh battery bank for ~$2500 and get a 5000W puresine inverter for ~$1000. I pay about $1200 a year in power meaning that it will have paid for itself in about 5 years.

    stewi0001 likes this.
  7. captaincranky

    captaincranky TechSpot Addict Posts: 14,830   +3,922

    Where in God's name did you come up with this estimate? I live in a tiny 2 bedroom row house. With the 1st floor and 1 bedroom air conditioned, I hit 625 kWh, two months running. My floor runs about 359 kWh during off peak months. And yes most of the house is either equipped with LED or CFL lights, if not that, dimmers on any incandescent lights. I do stop short of obsessively turning out lights, and walking around the house carrying a candle.

    I am however, completely unwilling to sit around a house in the asphalt jungle, on a hundred degree day, with no air.
    JaredTheDragon and GRich like this.
  8. yRaz

    yRaz Nigerian Prince Posts: 2,865   +2,169


    I live with 3 other people and we have an electric dryer, we use about 12-13 a day in the summer, drops to around 9 in the winter
  9. captaincranky

    captaincranky TechSpot Addict Posts: 14,830   +3,922

    Your usage claim doesn't even come close to the link you posted to support it.

    "In 2015, the average annual electricity consumption for a U.S. residential utility customer was 10,812 kilowatthours (kWh), an average of 901 kWh per month. Louisiana had the highest annual electricity consumption at 15,435 kWh per residential customer (about 1300 kWh/month), and Hawaii had the lowest at 6,166 kWh per residential customer" (about 550 kWh month).

    OK that table is based on yearly usage. Your claim of "9 to 13 kWh a day", would average out to at most, 3600 to 4000 kWh a year., or about 1/3 to less than half, of the table's claim of "average". Even in Hawaii, which has an ideal climate, (very little need for air or heat), the article claims the average residential usage is approaching double yours..

    Depending on whose numbers you'd like to believe, that usage article would render your cost estimate, (or even need), for solar investment, (in the broader general populace sense), moot, pointless, and wrong. Still at your service Prince yRaz, but also, still quite ..... :confused: :confused: :D

    Electric resistive heating produces 3412. BTUs of heat per kWh. 10,000 BTU / hour, is not unreasonable to keep even a small house warm on a very cold day. So that's 3 kWh used by the hour, or 72 kWh per day! There are older households in many places, which are stuck with electric baseboard heating. Consider those numbers annually.

    OK, I realize new construction, involves much more energy efficient equipment and building techniques. Still, the conditions I've just described, do exist.
    Last edited: Oct 31, 2016
    JaredTheDragon likes this.
  10. yRaz

    yRaz Nigerian Prince Posts: 2,865   +2,169

    I was talking about a day, not per month. Although 9KWh a month is about what the dorms for my slaves use.
  11. captaincranky

    captaincranky TechSpot Addict Posts: 14,830   +3,922

    Well, I appreciate and understand that. However, I am also capable of doing basic mathematics. 10 Kwh per day equals 300 kwh per month, (a month is 30 days on average), times 12 (a year has 12 months), which equals 3600 kWh per year.
    GRich likes this.
  12. Ian Allso

    Ian Allso TS Rookie

    How did you calculatethe cost per unit?
  13. yRaz

    yRaz Nigerian Prince Posts: 2,865   +2,169

    ahhh, I see what I did now. I'm quite hungover from a Halloween and I was doing lots of guesstimating which makes the numbers in my post BS. Looking at my bill now and I used 1302KWh last month.

    I wonder what it would take to actually live on 9Kwh a day.
  14. yRaz

    yRaz Nigerian Prince Posts: 2,865   +2,169

    Solar panel cost here:

    Energy storage and inverter were not included in that, I was only talking about the cost of power generation.
  15. Ian Allso

    Ian Allso TS Rookie

    My biggest usage month, July, I averaged 53kw/day but average production was 9kw/day, come January I expect usage down below 10kw per day and I'm still waiting to see what production can reach, but during a somewhat mixed (weather wise) October production exceeded 540kw. Even during the winter we were exporting excess production during the day so we hope to get a battery soon to maximize production and reduce future the draw from the grid.
  16. mbrowne5061

    mbrowne5061 TS Evangelist Posts: 1,183   +651

    Probably being some kind of disconnected hermit.
  17. p51d007

    p51d007 TS Evangelist Posts: 1,945   +1,211

    How well do these handle hail stones. Here in tornado alley (southwest Missouri) we get hit with these normally between late March through mid July.
    If they can make a go of this, MOST people would not have a problem with these on the roof. Those "ugly" panels are probably not allowed by some HOA's.
  18. Mike89

    Mike89 TS Booster Posts: 71   +30

    Surprised someone has not come up this idea before now. Solar panels on a roof are butt ugly. This seems like a good alternative.
    GRich likes this.
  19. GRich

    GRich TS Rookie

    A 10KW system (more than enough) typically takes up about 25 to 40 panels that measure roughly 3 by 5 feet, and would be close to full coverage on most roofs (most sellers offer a 3KW system). Such a capacity may work best when less than ideal light conditions exist and still be capable of selling excess power back to the grid and charge your electric vehicles. When you look at the cost per week to fill your tank at the pump, the payback period quickly diminishes to a shorter time span, the more you drive.

    Most regulators only offer subsidies on systems up to 3KW so I'd make sure to write to your representative to increase that number to 10KW to allow for complete roof/carport/awning coverage. Also, if you look at the cost of replacing 25 to 30 year roofing, then your payback on the added cost and system is much less than buying them separately to take advantage of tilting solar panels that can yield more per square foot yet look unattractive.
  20. GRich

    GRich TS Rookie

  21. GRich

    GRich TS Rookie

    Your consumption of power would go up with electric vehicle charging but go negative due to elimination of petroleum consumption. It makes more sense to buy the integrated package due to accelerated buy back periods, especially if you drive to work as opposed to other transportation methods. The cost is further negated if your roof is due for a replacement (considering you have to pay for it anyway). The incentives and available loans also make even more sense if they can be integrated into the valuation of the house.
  22. Dusty Trails

    Dusty Trails TS Rookie

    Let me add my usage no to your calculations
    Source Arizona Public Service, aka APS electricity
    October 2016 1770 KWh 3° COOLER than average
    July 2016 2777 kWh ~4° WARMER than average
    Yearly average ~65kWh/day 27500+ per year
    Do these panels make sense in the desert? You do the math, show me your formulations and lets us {me} know.
  23. GRich

    GRich TS Rookie

    I'm not sure if you have a typo or are giving me incorrect numbers.
    1770KWh is 1.77 Megawatt hours. did you mean 1770 Watt Hours instead?

  24. captaincranky

    captaincranky TechSpot Addict Posts: 14,830   +3,922

    No, 1770 kWh (kilowatt hours) is 1.77 megawatt HOUR < singular. 1770 watt hours would be 1.77 kilowatt hour. Which BTW, wouldn't run a Walmart electric space heater for an hour and a half.

    I sincerely hope I've deconstructed dat decimal point dilemma for you.

    All my silliness notwithstanding, the decimal point has been misplaced and misused throughout the entirety of this thread. Not to mention wayward "ballpark estimates".

    Everybody has misplaced the decimal point, the period of usage, basically whatever they could.

    "Average" usage is alleged to be about 10 kWh per day, which would, (as we both know at this point), be 10,000 "watt hours". Obviously, this could only attach to a portion of spring and fall. since electric heat or air conditioning nullify that estimate.
    Last edited: Nov 5, 2016
    JaredTheDragon likes this.
  25. GRich

    GRich TS Rookie

    Arizona has good solar potential due to location but does lose some performance due to high heat most of the year. Since I don't live in your region, I can't give you realistic calculations that would benefit your conditions. At least not without more information. Your numbers offer a starting point. But, you must realize that different solar panels have their sweet spots when it comes to what wavelengths of light they best perform in and may have lower peaks but better match your daily wavelength spread.
    Also, I don't know your energy consumption profile to know if conservation measures are overlooked.
    I'd say a 15kW system with 2 days worth of storage could make you energy independent.

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