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Solar power complemented Superchargers

Discussion in 'Charging Standards and Infrastructure' started by setherme, Jan 4, 2014.

  1. setherme

    setherme Member

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    The resources that TMC brings together has made it an outstanding resource for TESLA information. I think one thing that we haven't yet captured is data on the roll-out of solar power to the ever expanding Supercharger network.

    We know from the quotes below and many interviews with TESLA executives that the goal is to have all Supercharger stations complemented with solar power. Elon has also mentioned the ultimate goal of a solar powered Supercharger network is a net contribution of power back to the grid. A station with a solar canopy is reportedly $300,000 to complete.

    The questions I hope this thread could contain answers to are the following:
    Which Superchargers are currently complemented by solar power?
    How many panels comprise the canopy?
    What is the rated power output of the canopy?
    This thread could use a table listing number of panels and power output for each site.

    I know the Los Angeles (Hawthorne) and Tejon Ranch sites have solar canopies and the solar panels on the fuel pump canopies on both Milford sites may be TESLA's, but that is not confirmed. Each Milford site has 96 panels.


    From the Supercharger website:
    "Select stations utilize canopies covered with solar panels to offset energy use and provide shade. Over the next few years, we plan to cover more stations in sunny locales with solar canopies as part of our commitment to the environment."
    "Over time, Tesla plans to add solar canopies to all Supercharger stations."
     
  2. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Here are some round numbers for you for your estimates. Every site will be different, but this will get you +/-20% for most places.
    • Panels sell for $1 per DC Watt or less these days.
    • Install cost can be more than that, and the fancy canopies will probably be some multiple of panel cost.
    • In a sunny place like Colorado, figure on 1.5 kW-hr production per year per DC Watt.
    • Typical panels are 250 DC Watts each and are 2.5 x 5 feet in size.

    The 96 panels at Milford therefore are probably something like a 24 kW DC system that produces 36,000 kW-Hr per year and cost $60-120k to install.

    Here is a some historical data on a 9.8 DC kW solar PV system that I installed in Boulder several years ago. Cottonwood Grove Annual Comparison
     
  3. BlueShift

    BlueShift Member

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    For the weather and latitudes of the United States and Europe, typical insolation ranges from 4 kWh/m²/day in northern climes to 6.5 kWh/m²/day in the sunniest regions. Typical solar panels have an average efficiency of 15%. Thus, a photovoltaic installation in the southern latitudes of Europe or the United States, with all panels titled toward the sun (latitude tilt), may expect to produce 1 kWh/m²/day.

    Assume 20 ft x 20 ft = 37 m² of solar panels above each bay. These panels will produce around 37 kWh per day, less than enough for a single charge of a 60kWh battery.
     
  4. markb1

    markb1 Active Member

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    The Milford panels are not Tesla's. They predate the superchargers.

    Hawthorne and Tejon are it, AFAIK.
     
  5. KJD

    KJD Member

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    Interesting discussion. I doubt that everyone is going to show up with the pack nearly empty. Another thought is do most people wait for the battery to get completely full or do they leave when they get enough to safely make their destination ?

     
  6. liuping

    liuping Active Member

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    Many people optimize supercharger travel by arriving close to empty to maximize the charge rate and minimize the time.

    I usually shoot for arriving with 30 miles to spare in case of headwinds,etc, assuming a I'm traveling at a reasonable speed (not 65mph :)). But I almost never get anything near a full charge, unless the final destination requires that range.
     
  7. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    #7 Cottonwood, Jan 5, 2014
    Last edited: Jan 5, 2014
    Take a look at Tesla Supercharger network - Supercharger Dashboard; in the upper left, is a histogram of kW-hr per charge. It looks like the mean is something like 30-35 kW-hr per charge; let's call it 33.3 kW-hr or 3 charges per 100 kW-hr produced to do some rough calcs.

    As a place to start thinking, a 96 panel, 24 DC kW array that would be about 20x60 feet in size (about 5 Charging Stalls), would produce about 36,000 kW-hr per year in the SW USA. That is 1,080 charges per year or, on average about 3 per day. Please note that the grid, local batteries, or most likely, a combination of the two is needed to average this out and offer high speed charging when needed.

    For example, here are the results of a 24 DC kW system that I have in Southern Colorado. December is one of the worst case months. You can see the results of a couple of storms in the first part of the month and a minor one on the 21st and 22nd. A typical sunny day is displayed at the top. The "tails" of the production curve are truncated because this array is in a mountain valley, but it does get full sun from 9am to after 3pm; not much production lost.

    Your mileage may vary, but I hope this is one practical example to help get your arms around the scale of these solar systems.

    HitW Solar.png


    For comparison, June was the best production month for this system in 2013. Here is what that looked like:

    HitW Solar Jun 2013.png
     
    • Helpful x 1
  8. setherme

    setherme Member

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    #8 setherme, Jan 5, 2014
    Last edited: May 3, 2014
    Assuming 250W per panel, 2.5x5ft panels, and 15% efficiency (too high, too large?) and using NREL’s PVWatts Calculator.

    Los Angeles (Hawthorne)
    Online NLT: September 24, 2012
    Solar radiation: 5.54 kWh/m2/day
    5x20=100 panels
    25x50ft=116.1m2
    25 kW
    Yearly output: 35.2 MW
    Hawthorne.jpg

    Tejon Ranch
    Online NLT: October 1, 2012
    Solar radiation: 5.82 kWh/m2/day
    7x13=91 panels
    17.5x65ft=105.7m2
    22.75 kW
    Yearly output: 33.7 MW
    TejonRanch.jpg

    Beijing – Mobile carport
    Online NLT: April 23, 2014, claim up to 20.5% efficiency
    Solar radiation: 4.87 kWh/m2/day
    ?x?=? panels with energy storage
    ?m2
    ?kW
    Yearly output: ? MW
    BeijingSCsolar1.jpg

    Jiading, Shanghai
    Online NLT: April 23, 2014, claim up to 20.5% efficiency
    Solar radiation: 4.09 kWh/m2/day
    ?x?=? panels
    ?m2
    ?kW
    Yearly output: ? MW
    JiadingSCsolar.jpg

    Jinqiao, Shanghai
    Online NLT: April 23, 2014
    Solar radiation: 4.09 kWh/m2/day
    ?x?=? Solar panels according to post #124
    ?m2
    ?kW
    Yearly output: ? MW
    JinqiaoSCsolar.jpg
     
  9. AMPd

    AMPd Active Member

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    Tejon im counting 7x13? am I missing some panels?
     
  10. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Hawthorne may be a little close to the coast and get more May/June Gloom fog, but 1.5 kW-hr annual production per DC Watt won't be far off. If you want to be more exact use the calculator at NREL: PVWatts - PVWatts Grid Data Calculator (Version 2)

    Hawthorne : 25.00 DC kW => 37,500 kW-hr/yr or 1,120 charges per year
    Tejon Ranch: 36.75 DC kW => 54,750 kW-hr/yr or 1,642 charges per year

    Given what I have heard about usage at these two sites, Tesla may need more Solar there or at least get PV arrays at more of the lesser used Superchargers to compensate.
     
  11. setherme

    setherme Member

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    Updated the original post with better calcs.
     
  12. setherme

    setherme Member

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    Updated post #8 with Chinese solar powered Supercharger information. Requested further details from Hanergy Solar.
     
  13. ThosEM

    ThosEM Space Weatherman

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    Tesla needs to be more proactive about their promise to generate as much power from sunlight as they are dispensing at the superchargers. Calculations above suggest that a single site generates about 40 to 50 MWh in a year, so it would require about 240 such sites to have generated the 1 GW in a month that Tesla recently touted as a milestone, without mentioning the solar generation against that. Tesla has only about 140 sites worldwide, and if our experience in the northeast is any guide, only a fraction of the superchargers actually have generating capability. I have yet to see a solar array or even a canopy on a supercharger along the East coast.

    Even if the promise of generating more power than is consumed at superchargers is empty, we need canopies in the East, because we have that thing called weather, which is the reason most if not all of our gas stations are covered these days.
     
  14. purplewalt

    purplewalt Active Member

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    Although they were not on a canopy, there are solar panels adjacent to the Supercharger station @ City of Blanding, UT.
    I do not know if they are charging the Superchargers or not.

    As far as the rest of the existing Superchargers getting the Solar Panels with canopies, I would prefer that Tesla build out and fill in major routes of connectivity first, then come back with Solar Panels.
    I think we would be overtaxing TM financial and people resources to build out the Supercharger network with Solar Panels at this time.
    Maybe in 2016 or so....
     
  15. Peter_M

    Peter_M Member

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    #15 Peter_M, Aug 26, 2014
    Last edited: Aug 26, 2014
    Solar canopies on SC stations are great for the visibility and marketing value, but it would make more sense financially for Tesla to build or fund a small number of large solar PV farms, located where there is good weather, good access to the grid, and good economics (i.e. feed-in tariff rates and local construction costs). There are a lot of companies doing this kind of work (Solar City being an obvious choice), so if Tesla has the money but doesn't want to spend the time or lose focus on building cars, they could write a cheque and make this happen pretty fast. It would be the quickest way to be able to say they are offsetting all the SC energy use with solar generation.
     
  16. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Here is a little better way to look at it:

    • If I assume that the size of a Charging Stall is 12.5 by 25 feet, then that will hold a 5x5 panel array of the 250 Watt panels I mentioned below.
    • 25 panels times 250 Watts per panel is 6,250 DC PV Watts.
    • At 1.5 kWh per year per DC Watt, that is 9,375 kWh per year per stall. This is for the sunny Southwest. Most other areas will be less.
    • 9,375/365 is 25.7 kWh per day per stall, average.
    • The average charge per Tesla using a Supercharger is a about 35 kWh.
    The bottom line is that you get a little less than one Supercharge per day per Stall with solar canopies. Solar canopies are good for shade and show, but don't provide much practical energy for Superchargers.



     
  17. liuping

    liuping Active Member

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    So far I've been quite close to empty each time I pull in to a supercharger. I've only pulled in once with more than 40 miles range left. At two sites I had to range charge to 100%

    I suspects that is more common for sites like Yuma and will get less common as the SC map fills in.
     
  18. liuping

    liuping Active Member

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    The shade alone is almost worth it I my opinion. During the day some of the site in CA and AZ are brutal in the uncovered sun.

    While they do not cover the supercharging usage, the amount of electricity generated is still significant. A 10 stall site could generate almost 100 Megawatt Hours of electricity per year. 100 such sites could generate 1GWh per year.
     
  19. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    With the shade also helping to keep the car cooler, it might help slightly to lower the cooling requirements while charging.

    But anyway, the point is that on-site PV will be helpful, but not that helpful by itself.

    I'm sure that Tesla's long-term approach will be to have batteries and canopies, with priority on the batteries. Really long term, why have canopies when BEV allows you to park in a building? Cover the whole damn lot with a continuous structure that blocks and redirects precipitation, generates power and is vented as appropriate. You don't have to plow or de-ice a parking lot that doesn't get precipitation.
     
  20. paulkva

    paulkva Member

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    +1 on solar canopies (or, frankly, any canopies) for shade/shelter, especially in warmer areas. (I just took a very hot summer trip down I-95 to FL.) They would have the added benefit of incremental increase in charging speed on hot days (less work for the HVAC to do), in addition to any solar power and increased passenger comfort getting in/out. But I'll admit I'd rather see Tesla spend their money and time on expanding the supercharger network.
     

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