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Power Transportation

Tesla Plans To Disconnect 'Almost All' Superchargers From the Grid In Favor of Solar and Battery Power (electrek.co) 230

Only half a dozen Supercharger stations or so out of the over 800 stations have solar arrays and batteries, but that may be about to change. Elon Musk said Tesla plans to deploy more battery and solar systems with the upcoming "Version 3" of the Supercharger, adding that "almost all Superchargers will disconnect from the electricity grid." Electrek reports: Previously, Musk said that Tesla's new Powerpack and solar arrays will power some Supercharger stations in sunny regions to go off-grid -- adding that "the grid won't be needed for moderate use Superchargers in non-snowy regions." While it makes sense to add solar arrays and battery packs, it's not clear why there would be a need to completely disconnect from the grid, which is often still useful -- especially if net metering is available. Even in regions where coal dominates electricity generation, electric cars are still more efficient than some of the most efficient gas-powered cars. Therefore, the argument could have ended here, but Musk apparently wants to take Tesla's Supercharger network off-grid as part of the company's mission to accelerate the advent of sustainable energy. Depending on the size and popularity of a Supercharger station, which generally varies from 6 partly used stalls to 20 stalls in almost constant use, Tesla would need some significantly large solar arrays at some stations -- almost football field in size. Unless there are some impressive advancements in efficiency, it's not clear how they would make it happen.
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Tesla Plans To Disconnect 'Almost All' Superchargers From the Grid In Favor of Solar and Battery Power

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  • by TheNarrator ( 200498 ) on Friday June 09, 2017 @10:39PM (#54589645)

    There are so many, for lack of a better word, "Haters" who think that we can't have nice things and all technology must be destroyed if we are going to save the earth. By disconnecting from the grid Musk wants to make a point: This technology is sustainable. There are no outside inputs that need to go into it to make it work once it's setup. Somebody will say that the batteries or the cells will wear out eventually, but if it lasts for more than 20 years, what are they really going to say then? That's the point he wants to make, that there is hope for the future, we're not all going to die, there is another way to save the world besides deindustrialization and the massive drop in standards of living and population that would have to follow.

    • I have a camper that is normally parked behind my house. For two years now it has not been plugged into the grid once. I have modest solar capability on it, and have switched all the lighting over to LED, and have low-power DC electronics as much as possible (a 12V TV, a Nintendo Wii - which runs off 12V DC FYI, switched out the furnace for non-electric gas heater, etc). I know it is silly, but there's something about "knowing" that everything is functional and is totally stand-alone and self sufficient in

    • by thegarbz ( 1787294 ) on Saturday June 10, 2017 @05:29AM (#54590601)

      The problem is that this is not feasible with current technology going forward, not unless you fill up just a handful of cars per day.

      I did a study recently for an company looking at the capability of converting a few petrol stations to fast chargers. We took some simple assumptions: Take the average city edge fuel station (not country station, and not a heavily loaded inner city one). Assume 5% of the amount of cars end up wanting to charge up. Assume out of those that 40% will be charging during peak travel time and 10% at night time (that last bit works in our favour here). And a nastier one: Assume that anyone charging will be doing a 75% charge (incapable of charging at home, or doing a long distance route). What we came up with:

      a) 10MVA grid connection (24x larger than the largest petrol station) without storage.
      b) 1.5MVA grid connection + local battery storage. The local battery storage in this case ended up being grid scale sized storage and looking at suppliers of vanadium redox batteries we were looking at a 5 shipping container batteryfarm at every servo.
      c) Local microturbine system + battery storage (rejected because the idea of people visibly seeing that their green cars are being filled by burning hydrocarbons was a mental hurdle that would affect people using the service).

      Personally I like Elon Musk's idea of swapping batteries better. But this to me looks like little more than marketing. It is something that is feasible now but ONLY now. It won't work going forward without a massive leap in battery performance. If you're filling up a handful of cars a day, no problem providing it's sunny. If Tesla is successful in making the world switch to electric cars, it will fail in keeping it's service stations off the grid.

      Rule of thumb: If you need a MV or HV grid connection, chances are you're not going off the grid with solar. Tesla should focus on houses, commercial properties, schools, etc. Don't distract from where they can make a real difference in the world.

      • by AmiMoJo ( 196126 )

        The plan likely involves solar roof tiles on nearby buildings, and maybe some small solar farms.

        Brilliant business move. Sell the cars and the "fuel" they need.

      • I'm guessing that "most" Superchargers aren't heavily used. Those are going to be the ones that get a field of solar panels next to them, not the 20-stall beauties that average 60% utilization over 24 hours.
        From a PR standpoint, being able to say that "80% of our Superchargers are off-the-grid" is a beautiful thing; one can quietly ignore that the other 20% are consuming 80% of the kwh being dispensed.

  • Someone in California has forgotten that it can rain in non-snowy regions. It can even be heavily clouded when it doesn't rain.

    • It rained 70 inches this year here in California. We're well aware of rain. Clouds and rain do not block all light or even most of it. Solar panels do in fact generate energy while it's raining. Not quite as much as on a sunny day, but that just means you need a few more of them.

      • by Nutria ( 679911 )

        Clouds and rain do not block all light or even most of it. Solar panels do in fact generate energy while it's raining.

        You'll have to prove to me that they generate electricity when the clouds are so dark that street lights come on in the middle of the day.

        • thats why you don't put all your eggs in one way of generating power, a few turbines can add to the mix. but if you have enough storage, you can get through a few days of low generation
    • Rain doesn't affect solar output at all. Actually it's good for panels, it washes the dust and bird-crap off.

      The clouds, however, so result in power output dropping. You still get some power in cloudy weather, but a fraction of what you'd get from clear skies.

  • by Gravis Zero ( 934156 ) on Friday June 09, 2017 @10:45PM (#54589667)

    Don't you people see what happening here?! Elon is going to suck up all the sunlight with his solar panels and we'll have to pay him for electricity to turn on LED light bulbs! With no sunlight, all the plants will die and we'll have to pay him for electricity for our oxygen scrubbers! Someone has to stop this mad man! ;)

    • In fact, the whole reason Musk started SpaceX is so he can launch a mission to capture and retrieve the sun for his own solar energy purposes.

      • by Jeremi ( 14640 )

        In fact, the whole reason Musk started SpaceX is so he can launch a mission to capture and retrieve the sun for his own solar energy purposes.

        Oh dear. If Musk brings the sun back to Earth, won't that increase global warming?

        • I know you are kidding but in case anyone is wondering, solar panels actually lower albedo because their backs are white, and most of the energy that strikes them which is not converted into electricity is reradiated as IR, and mostly in the skyward direction. Of course, then it tends to run into GHGs, but that would happen no matter what it was being reradiated from.

          • solar panels actually lower albedo because their backs are white, and most of the energy that strikes them which is not converted into electricity is reradiated as IR, and mostly in the skyward direction. Of course, then it tends to run into GHGs, but that would happen no matter what it was being reradiated from.

            That's actually a problem if the panels absorb and re-radiate more energy in IR form than the surface they are covering, which is fairly likely given their color.

  • by h33t l4x0r ( 4107715 ) on Friday June 09, 2017 @10:46PM (#54589669)
    As in, over time, batteries will become so awesome that we won't need to be connected to the grid anymore. He doesn't say it's happening today.
    • As in, over time, batteries will become so awesome that we won't need to be connected to the grid anymore. He doesn't say it's happening today.

      Is he saying that overtime Tesla will be a failure and people won't charge their cars?

      Prediction: Batteries will get better over the next 10 years. Maybe 2 fold or 4 fold.
      Other prediction: The number of electric cars filling up at charging stations will increase an order of magnitude, and due to the aforementioned battery improvements will draw an even higher load.

      If Tesla succeeds at putting their superchargers off the grid, they likely failed at selling cars.

  • and that is going away. My utility no longer does net metering. They pay me about 10c/kwh generated and in summer I pay them about 15c/kwh for every kwh I consume. Yeah, you guessed it, I pay a nickel per kwh my panels produce and I consume. Winter I am in a lower price tier so my consumption price drops to about 10c/kwh so it is basically net metering. But they keep dropping the price they pay me per kwh and raising the price I pay them.

    • by msauve ( 701917 )
      "But they keep dropping the price they pay me per kwh and raising the price I pay them."

      It's perfectly reasonable for them to charge more than they pay. They have transmission lines, maintenance personnel, and other basic costs to cover. There's no reason they should transport energy you generate to another customer, and pay/charge the same on both sides. And, as there's more private energy sources connecting to the grid, that price difference will increase, since they'll be making less from power generati
      • if a power company can't beat a small scale operation then it doesn't deserve to be in business. if we can all produce electricity for 10c/kwh then why have power companies at all. setup a solar panel at every house and business if individually we're really as efficient as the price tiers of the power company implies. Which is kind of what Elon Musk is realizing.

        • by Jeremi ( 14640 )

          if we can all produce electricity for 10c/kwh then why have power companies at all.

          I imagine you're still going to want access to power at night, and on cloudy/rainy days... so until a week's worth of battery-backup is affordable, you're still going to want a grid-tie in most cases.

          • I imagine you're still going to want access to power at night, and on cloudy/rainy days... so until a week's worth of battery-backup is affordable, you're still going to want a grid-tie in most cases.

            I don't think I would, since I'd have a Tesla battery. Which is already affordable.

        • by msauve ( 701917 )
          "if we can all produce electricity for 10c/kwh then why have power companies at all."

          Whoosh. It's not production cost, it's distribution. If you want to try to compete with a power company at distribution, go for it.
          • Whoosh. It's not production cost, it's distribution. If you want to try to compete with a power company at distribution, go for it.

            Woosh. We can already distribute power by truck, as solar panels and battery packs. The distribution technique used for the last 100 years has served us well, but it's not necessarily the only possible solution to the problem of getting power to every home and business.

        • by AHuxley ( 892839 )
          Power companies have one new federal trick to try. A government backed solar export tax. To keep a nation grid fully funded.
          Export power back to the grid, pay some extra tax.
    • Sounds like a great case for home storage
      • Home storage is great, but it still makes sense to export your excess. I would rather import my neighbors' electricity when my dryer and water heater and A/C are all running, and then export some when the dryer and water heater shit off, for them to use. Then, we could also all have home storage, but it wouldn't need to be anywhere near as large as needed if going fully off the grid.

  • As it is, tesla/solar city continues to push all to stay connected to the grid. Now, he wants to separate? Big mistake.
    • by Socguy ( 933973 )
      The utilities are probably charging them an arm and a leg for a ultra high voltage industrial type connection since superchargers are capable of pulling so much energy in a short period of time. Cutting the link could be a substantial cost saver.

      Compare that to a house which is much more of a low steady draw. In order to guarantee 365 days of off grid capability for a house, Solar city would have to massively overbuild to account for that one crazy energy usage day.
      • there is a real reason why Super chargers are done by malls and restaurants. They have PLENTY of high-voltage/high-amperage electricity. And oddly, utilities charge these malls and restaurants the lowest rates going.
        You would think that utilities would charge more for it, but they don't. The reason is that malls and restaurants are predictable in their electricity needs.
        And to be fair, Tesla NEEDS to remain connected to the grid. If something like Yellowstone blows, then the midwest and eastern seaboard
  • Pretty simple. Animal-powered electrical generators. [offthegridnews.com] He might even have some type of "Wheel of Pain" [wikia.com] for those people who want to buy a Tesla but just can't afford one with money.
  • Depending on the size and popularity of a Supercharger station, which generally varies from 6 partly used stalls to 20 stalls in almost constant use, Tesla would need some significantly large solar arrays at some stations -- almost football field in size. Unless there are some impressive advancements in efficiency, it's not clear how they would make it happen.

    Simple, change the business so the 20 stall location isn't so busy. You can close the stalls, or you can charge a surge price based on demand for stalls.

  • by Solandri ( 704621 ) on Saturday June 10, 2017 @02:14AM (#54590263)
    Assume on average a 85 kWh battery pack getting a 50% supercharge. 85 kWh * 0.5 = 42.5 kWh. Real-world charging efficiency is about 80% [tesla.com], so 53.125 kWh is needed to put 42.5 kWh into the car's battery.

    Assume 160 W/m^2 commercial panels. PV solar capacity factor in the desert Southwest is about 0.185. That is, over a year, a 100 Watt panel will produce the equivalent of a constant 18.5 Watts. So the 160 W/m^2 panels will produce 160 Watts * 0.185 = 29.6 Watts average over 24 hours, or 0.7104 kWh / m^2 in 24 hours.

    This means to supercharge a single Telsa S requires 53.125 kWh / 0.7104 kWh/m^2 = 74.78 m^2 of solar panels.

    Oh wait, you're gonna store that solar energy in a battery first? That's going to introduce more charging and discharge losses. If you figure 90% for both, that's 74.78 m^2 / (0.9*0.9) = 92.32 m^2 of solar panels needed for every car you want to supercharge that day.

    How busy is a Supercharger station? Summary says 6-20 stalls per station, so say 13 average. Figure they're half occupied during day hours, empty at night. At 30 minutes to charge, that's 2 per hour per bay, or (6.5 bays occupied)*(2 vehicles per bay per hour)*(12 hours) = 156 vehicles charged per day.

    So to generate enough electricity to supercharge those 156 vehicles requires (156 vehicles)*(92.32 m^2/vehicle) = 14,401 m^2 of solar panels per Supercharger station. Or approx 120m x 120m of solar panels. Or put another way, the average home solar installation is about 30 m^2. So each Supercharger station would need as many panels as 480 homes.
    • by vtcodger ( 957785 ) on Saturday June 10, 2017 @04:30AM (#54590501)

      That's roughly what I came up with. But I don't have a lot of faith in my math. And we're being rather generous I think. Remember that this needs to work on a cloudy week near the Winter Solstice with short days and low sun angles.

      Not that the concept is necessarily unworkable. But maybe we need 2067 technology and costs not 2017 technology.and costs, for it to work.well.

    • Figure they're half occupied during day hours, empty at night.

      Bad assumption. We did a similar study using real petrol station numbers. Consider your distribution to be lumped in a set of a few hours before and after work. During most of the day it will be reasonably quiet, and there WILL be a few cars at night.

      That makes your scenario even worse. The storage size we came up with was incredible and we were looking at it to reduce the grid connection without even attempting to go fully green and found it infeasible.

      • by The_Noid ( 28819 )

        In your study, did you take into account that for petrol cars ALL filling up happens at petrol stations, but for EVs most filling up happens at home? In other words, you have to remove all petrol filling used for daily commutes from the numbers, and only count he petrol filling used for long-distance driving.

        This will also drastically change that pattern where the distribution is lumped in a set of a few hours before and after work, since those people will just charge their EV at home or at work, not at a s

        • You're probably right that much/most vehicle charging will be done at home or maybe even at work. But I think that just means that we don't need drive up charging stations on every second street corner. Doesn't affect the sizing of individual charging stations?

        • but for EVs most filling up happens at home

          Yes we did, but it didn't change much. The result was a total of less cars but the distribution is still highly dependent on convenience and timing. I.e. Less people already fill up on the way to work unless they absolutely have to than on the way home, unless they a travelling long distances. This means that the afternoon peak is larger than the morning peak and this isn't going to change with EVs.

          The study we did also took into account that emerging models from Porche and BMW won't be able to be charged a

      • "That makes your scenario even worse. The storage size we came up with was incredible and we were looking at it to reduce the grid connection without even attempting to go fully green and found it infeasible."

        That brings up an interesting question. How much storage is needed to back up a given amount of non-dispatchable storage like wind and solar? The short answer seems to be everywhere and always an infinite amount. That would seem to make planning a bit difficult.

    • by The_Noid ( 28819 )

      Yay, someone actually does the numbers! Thanks! :)

      How large (in area) is such a supercharger station in general? Would it be feasible to put the panels above the station? That would also give some nice shade for the charging cars below the panels.

      • "Would it be feasible to put the panels above the station? "

        That's what the artistic conception in the article shows.

        My best guess. A typical sedan (e.g. a Toyota Camry) is a bit less than 5m long and 2m wide = 10 square meters.. If we assume that there's about twice that much space for each stall, that's 20 square meters of panel per charging station. Theoretically, there's about 1kwh per square meter available at high noon in the tropics, but there are a zillion inefficiencies, so lets assume 6 hours o

    • by AmiMoJo ( 196126 )

      Exactly, 120x120m isn't much for a small solar farm or a number of nearby buildings and the cover over the chargers themselves. It would allow superchargers away from grid ties too.

    • Your last assumption is out, you don't need enough panels to charge all 156 vehicles, you need enough to power the 6-20 stalls at the same time while there are vehicles present. When there are stalls open, the same panels can recharge the local battery banks for when there is no sun.

      I can't find a decent voltage/current breakdown of the Tesla Supercharger, only 130kW at maybe 248VDC, you can't vary the voltage, so it looks like each charger pulls 525A at 248VDC. Taking a 325W Renewsys panel, it can supply

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