TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

Living with Solar and Model S

Discussion in 'Model S: Battery & Charging' started by andydoty, Feb 2, 2014.

  1. andydoty

    andydoty Member

    Joined:
    Jan 12, 2014
    Messages:
    226
    Location:
    Massachusetts
    #1 andydoty, Feb 2, 2014
    Last edited: Feb 2, 2014
    So, in a previous thread I alluded to my having solar and looking forward to parking a Model S in my driveway.
    Brief excerpt:

    "...Here is Mass, we have a "grant" process for installing solar which I took advantage of. My rebate was $10500. Since then, the rebate has dropped to around $4k. This is largely due to the decrease in panel costs. My panels were $600 each. You can by an equivalent panel today for around $200. Oh well... Such is life!

    I installed a "Grid Interactive" system that requires batteries. So, you become a quick study on how to keep them properly topped off. Lithium ION batteries are pretty cost prohibitive in a home situation so we generally use AGM (absorbed glass mat) batteries if kept inside the home. The grid interactive system acts like a really big UPS in that I had to split the house circuits into "critical load" and "main panel". Grid tied systems are required to "island" themselves when power from the street stops flowing. Mine only islands the grid side..."

    My question is how many people have solar? What kind of system? Grid-tied or grid-interactive? Located? Has the Model S experienced issues with the inverters? Also, how big of a system? Have you been able to calculate your savings based upon solar. If you feel comfortable sharing the costs and rebates that would be great as well.

    IMG_0682.JPG

    Andy
     
  2. Lloyd

    Lloyd Active Member

    Joined:
    Jan 12, 2011
    Messages:
    4,885
    Location:
    San Luis Obispo, CA
    I installed a 17kw Grid tied system. No inverter issues. I got some California rebates and some Fed tax credits, but can't recall how much exactly. Invested about $40K, my labor, and it saves me about $1,200 per month. I produce more than I use slightly and get ~$150 refund each year from PGE.

    photo PVcars.jpg
     
  3. dtich

    dtich #P708

    Joined:
    May 31, 2012
    Messages:
    428
    Location:
    Los Angeles
    nice system andyd.

    i have an 8kW system here in los angeles, grid-tie, sma inverter and aleo panels (both excellent imo. very happy.) zero issues with power, tesla-related or otherwise, it is seamless. i also have outback and evergreen in the cabin in maine, a stand-alone battery system, and that has been running strong for over 12 years now.. just this year i think the lead acid batteries will have to be swapped (trojan). pretty good if you ask me. the system here (la) maxes out about 52kWh/d in the summer, which is more than enough for the car and house on a daily basis. annually i think i break even or just fall short of usage, so sometimes a tiny utility bill, other times little credit. works for me. i spec'd a $32k system and at the time (3 years ago?) the rebates got me about half that back. i bought the system, but i know there are many people leasing now. reasonable way to go, no outlay of cash. not sure what the drawbacks would be, but.. the more solar the better afaic.

    thanks for posting.
     
  4. EdA

    EdA Model S P-2540

    Joined:
    Mar 24, 2011
    Messages:
    1,885
    Location:
    Massachusetts
    I have an 8.2kW system in MA. I had it installed in the middle of 2011, I had it all of 2012 before I got my Model S. Mine is grid attached, meaning when we lose power my panels shut off. There is no storage. No problems with the car charging (can't wait until the sun is out when I get home from work)
    but its not like I *know* the energy is coming directly from the panels - what's not used goes back into the grid.

    My average cost of electricity per year from 2006-2010 was $2,177.10. 2011 is a split year so I'm skipping it. In 2012, before my Model S I paid $510.41 for electricity. In 2013 (I got the car on 1/8) I paid $1,498.40 for electricity. I also drove nearly 21k miles in that time including 3 supercharged road trips. Around July of last year we also got a charger at my office so half of my commute was paid for from July forward.

    /Ed
     
  5. dhrivnak

    dhrivnak Active Member

    Joined:
    Jan 8, 2011
    Messages:
    2,150
    Location:
    NE Tennessee
    I have a 7 KW system that is grid tied. If you have not yet taken the poll add your vote. It looks like over half of Tesla owners are on Solar power.

    Driving on Sunshine - Page 3
     
  6. andydoty

    andydoty Member

    Joined:
    Jan 12, 2014
    Messages:
    226
    Location:
    Massachusetts
    @Lloyd
    Fantastic picture!


    @dtich
    Thank you! It's 8.4kw of DC. Those are (8) 8A8D batteries. Runs a 3 ton heat pump without issue.
    I estimated that in June, based upon my normal driving habits, it should cost me about $3 to keep the Model S topped off.


    @huntjo
    I stand corrected.
     
  7. SeminoleFSU

    SeminoleFSU Member

    Joined:
    Apr 5, 2013
    Messages:
    718
    Location:
    Atlanta, GA
    I'm in the process of pricing systems this year- hoping to find a nice system that will be removable if I wanted to take it with me... The reason is I'm moving into a family owned property that could be sold later on down the road if the right offer came along... and the house would likely get bulldozed to develop the land it sits on
     
  8. AnOutsider

    AnOutsider S532 # XS27

    Joined:
    Apr 3, 2009
    Messages:
    11,923
    Seems if I want to do this, I'll also have to go ground mount. Any notable issues with your system? Cleaning? Animals/other things getting on it? I'll admit, I'm more interested in this to save money and be "free" than anything else.
     
  9. Owner

    Owner Active Member

    Joined:
    Dec 20, 2012
    Messages:
    1,228
    Location:
    San Francisco Bay Area
    I have a 3.8 watt system for 7 years, and Teslas for almost 5. I have been documenting this on my blog if you want to know more details. I am basically running even with the house and Model S now. Various different posts about this here:

    solar | Tesla Owner
     
  10. Merrill

    Merrill Active Member

    Joined:
    Jan 23, 2013
    Messages:
    2,096
    Location:
    Sonoma, California
    mine is a 4.5 Sun Power system grid tied, unfortunately could not install more panels anywhere on my property and only could face southwest. I have an e-7 TOU net metering system from PG&E. I also installed a second meter for the Tesla. Because I generate most of my solar during the peak pricing 12 to 6 it works out that I generate 40 % of my electricity from the solar but pay for about 70% of my bill. With the Tesla on the second meter since July of 2013 my total cost to drive for 6 months (5000 miles) was net $50. Got a $6500 federal tax credit and paid for the system which was installed in 2010.
     
  11. roblab

    roblab Active Member

    Joined:
    Jul 15, 2008
    Messages:
    2,024
    Location:
    Angwin (Napa Valley) CA
    Way to go Andy!

    I got started about 10 years ago with a few panels on the roof, then got a RAV4EV. Got irritated with power outages happening several times a year, sometimes for days. Decided to spend the money on Grid Tie and batteries. Then the Model S, sold the gas car, and started using a few more kWh for driving.

    Recently decided to add a few more panels, so we are at 11 kW. Should get some back from PG&E (hahahah, joke. They only pay if they HAVE to).

    Nearly everyone who has done investment recovery studies says that solar recoups your investment in 6 years or so. Good enough for me. I tell everyone that it's paid for and I don't worry about keeping records any more than I worry about where to charge during a day of driving 200 miles or so. We have 36,000 miles on the S in 16 months.

    But if you don't buy it, it will never pay off. If you let someone else buy it and lease it back to you, you will never have free power. Mine is free, now, for the rest of my life. Sort of like driving cross country on Superchargers.

    What I planned on was a system that takes absolutely NO watching or messing. If my wife was left to run the place, she never has to worry about battery maintenance, charging, anything. She prefers to use the power on off peak, but not necessary even for that. It just runs itself. With Absorbed Glass Mat, if the batteries are kept full, they last sometimes Eighteen Years, with no watering or any maintenance at all. The Outback Charge Controllers keep them full so they don't sulphur. No problems in ten years, don't figure on any for years yet. Any marginal cost is well worth it to never have to think about it. And the battery prices have come down.
     
  12. Lloyd

    Lloyd Active Member

    Joined:
    Jan 12, 2011
    Messages:
    4,885
    Location:
    San Luis Obispo, CA
    #12 Lloyd, Feb 2, 2014
    Last edited: Feb 2, 2014
    No issues at all!

    I'll post my drawings for permitting if anyone wants them.
     
  13. tezco

    tezco Sig P85

    Joined:
    Nov 9, 2012
    Messages:
    818
    Location:
    Colorado
    We've got a 10.4 kW grid-tied system with panels on the garage roof. Expect payback in about 5 years and a 6.6% rate of return over 20 years even if electricity rates don't go up. Our local utility (Xcel) is trying to quash owner operated solar, and instead wants to build large solar farms that they can own and operate (and thus expand their monopoly to solar and wind as well.) They are currently pushing our PUC to discontinue net metering.
     
  14. Cottonwood

    Cottonwood Roadster#433, Model S#S37

    Joined:
    Feb 27, 2009
    Messages:
    5,062
    Location:
    Colorado
    #14 Cottonwood, Feb 3, 2014
    Last edited: Feb 3, 2014
    I live in two places, Pagosa Springs and Boulder, CO.

    Pagosa is my primary residence, and I have 24 kW of grid-interactive/off-grid solar PV there with 150kW-hr, 4 tons, of lead-acid batteries for energy storage. The back-up power system has a 14-50 connected to a protected panel, so that I can charge the Teslas when the gird goes down, adding the Tesla batteries to the energy storage puzzle. There is an HPWC on a 100A circuit there, but I chose to keep that on an unprotected grid-only panel. Here are the panels above the driveway. Because I am in a deep box-canyon, I put the panels in a good sun location above the driveway. Note this is a shot from today after a big snow storm over the past few days. The panels at 40˚ tilt, shed the snow well. The south side of the panels are at 4-5 feet above ground to allow for snow storage in big snow years.
    HitW-Solar.jpg

    Boulder has 9.9kW of grid tied solar PV. Here are the panels on a south facing roof with my two Teslas. Roof mount is cheaper than ground mount if you have a roof with good sun.
    Solar PVs.jpg

    In addition, I added a few kW of Solar farm capacity to Boulder when they were running a deal on a Boulder solar farm last year, to go above the 10 kW, limit. Excel limits a typical household to 10kW of gird-tied, net-metered solar. With an easy application, the La Plata Electric Association in Pagosa allowed me to put in the 24 kW system there. Electric consumers should have the choice of net-metering or solar farms, and they should be allowed to go up to 25kW on a Split Phase connection.

    If it were not for the electric heat in Pagosa, I would be a net generator of electricity to the grid in Pagosa. Even with the electric heat, I am close to net-zero in Pagosa. With off-peak rates, electric heat is cheaper than propane, and a whole lot less work than wood. Boulder is net-zero on electricity, but does use natural gas for heat.
     
  15. lloyds

    lloyds Member

    Joined:
    Apr 3, 2013
    Messages:
    890
    Location:
    Bay Area
    You're bold to have done it yourself, but you saved quite a bit of money from the self labor. Hats off to you. I went with Solar City PPA instead as it really didn't cost me anything out of pocket.
     
  16. andydoty

    andydoty Member

    Joined:
    Jan 12, 2014
    Messages:
    226
    Location:
    Massachusetts
    @Lloyds
    I didn't do it myself. Actually a friend was working for a local electrician. In Mass, to qualify for the grant and $1000 off of your state tax return, you need to hire an electrician as it's their license that's attached to the grant request. My friend had actually taken courses specifically in renewables so it was a perfect match. However, he had never done a grid-tied system. So I worked with him to engineer it. I like to clearly understand how things work prior to committing to it.

    Aside from the battery maintenance, there is little to do. Massachusetts is a SREC state, so I actually get paid to produce the power whether I use it all or sell it back. Going rate in Mass is around $270 or so per SREC (1 SREC = 1 Megawatt hour).

    It's awfully nice to have a standby generator that doesn't make any noise! I chose Outback as they are the premier in grid-tied systems. The system is capable of starting a 3 ton heat pump without issue. Very clean power as well.
     
  17. tezco

    tezco Sig P85

    Joined:
    Nov 9, 2012
    Messages:
    818
    Location:
    Colorado
    #17 tezco, Feb 3, 2014
    Last edited: Feb 3, 2014
    No go.jpg

    No go on the solar today.
    Must be a Bronco's curse.
    A freezing rain and then snow.
    Snow's not going to slide off easily.
    Maybe a ground mount next time...
     
  18. justaddsun

    justaddsun Member

    Joined:
    Dec 22, 2012
    Messages:
    403
    Location:
    DC
    @Cottonwood, all I can say is WOW!
     
  19. andydoty

    andydoty Member

    Joined:
    Jan 12, 2014
    Messages:
    226
    Location:
    Massachusetts
    @Cottonwood
    I know this is a Tesla forum, however, I think the Tesla and solar/savings go hand-in-hand. Have you considered a heat pump? Far more efficient that electric heat.
     
  20. Cottonwood

    Cottonwood Roadster#433, Model S#S37

    Joined:
    Feb 27, 2009
    Messages:
    5,062
    Location:
    Colorado
    I have considered the heat pump idea, but there are a few issues that make it less than optimum in this location and pushed me away.

    1. With good insulation and opening the windows at night, the house never goes over 75˚ F. in the late afternoon. A good part of the justification for a heat pump is summer air conditioning. I don't need any.
    2. With my electric co-op, the off-peak rates are less than half the normal rates. It is difficult to store heat from off-peak to on-peak with a heat pump system meaning that I get to compare electric heat at half price to heat pump usage at full price.
    3. The deep ground temp at my location is pretty low, between 45˚ and 47˚. With no summer heating, the ground just gets colder. It's a cold valley. If I don't use a ground source heat pump, the monthly average air temperature in January is 16˚ F. (the average low is 8˚F.). Heat pumps are not very efficient at that large a difference in temps.
    4. The Electro Thermal Storage (ETS) system was already installed and paid for when I bought the place. An ETS system is way more than a few electric base board heaters...
     

Share This Page