GT @ $.50 per watt still valid???

Knd870
Knd870 Solar Expert Posts: 32 ✭
in General Solar Power Topics #1
All,
I've read in a couple of places that as a rule of thumb you should consider about $.50 per watt installed for a GT system and about $1.00 per watt for off grid.

Are these numbers still valid for the way the panel prices (and other equipment) have dropped?

I would think with some serious shopping one could get a GT system installed for around $6.00 per watt. Over a 25 year life, without the government incentive this works out to about $.18 and with the incentive to about $.13. Granted this simple math doesn't include inverter replacement. This is based upon 5 hours of sunlight and about 70% harvest (this is what PVWatts shows for my proposed location).

At $.50 per watt, the installed cost would be $16.25 per watt, which seems high to me, base upon the reading I have done.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #2
    Re: GT @ $.50 per watt still valid???

    I got a quote yesterday for a 2.3Kw system installed and commissioned using Enphase M190 for just $4.90 a watt before any rebates or tax credits. My net after all the rebates and tax credits would be $2.31 a watt.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #3
    Re: GT @ $.50 per watt still valid???

    I think you are off by a factor of ten. ~$5/watt for grid tie, $10 for off grid. Raw panel prices start ~$2 per watt.

    Tony
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: GT @ $.50 per watt still valid???

    A GT inverter itself is probably around $0.50 per watt or a bit more (discounted retail price for larger inverters).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #5
    Re: GT @ $.50 per watt still valid???

    No the other hand, if you are talking about the cost of the power, ~$.50 kwh/$1 kwh is not too far off according to my memory of what Bill has posted before.

    Tony
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #6
    Re: GT @ $.50 per watt still valid???

    Cost for GT kWH power... Probably around $0.15 to $0.30 before rebates, depending on where the system is installed (amount of sun) and cost of install...

    I would guess a Hybrid system (Grid Tied+Batteries for emergency backup power) would be around $0.45 per kWH (just for hardware and battery costs).

    Not difficult to do your own calculations:
    • (total cost of system + 1 inverter replacement)/(20 years * kWH per year generated)
    You can add other costs (loan costs, taxes, credits from rebates and green tags).

    Panels may last longer than 20 years--but that is probably far enough for most people who will possibly moved out of their home/kids inherit the home by that time.

    Also, check with your local realestate sales person... I would not plan on the GT system adding much value to a home. Just working backwards (cost of money to pay for system vs amount of money saved on power bill, etc.)--and it seems difficult to justify more than 10-20% of the system adding value to the home.

    And, there is a good chance that for some buyers, they would actually pay less because of the system (which they don't understand or want) is part of the home.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #7
    Re: GT @ $.50 per watt still valid???
    solar_dave wrote: »
    I got a quote yesterday for a 2.3Kw system installed and commissioned using Enphase M190 for just $4.90 a watt before any rebates or tax credits. My net after all the rebates and tax credits would be $2.31 a watt.
    Wait - are you planning on adding to your system again? Details please. :)
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #8
    Re: GT @ $.50 per watt still valid???
    drees wrote: »
    Wait - are you planning on adding to your system again? Details please. :)

    Figure I have to charge the Volt,;)
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #9
    Re: GT @ $.50 per watt still valid???
    solar_dave wrote: »
    Figure I have to charge the Volt,;)
    Nice - I'm thinking of an expansion to charge the Leaf when it gets here - what panels are you looking at? $4.90 is a great price installed w/micro inverters...
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #10
    Re: GT @ $.50 per watt still valid???
    drees wrote: »
    Nice - I'm thinking of an expansion to charge the Leaf when it gets here - what panels are you looking at? $4.90 is a great price installed w/micro inverters...

    Actually I am still taking bids, that was the first one in and used Sunpower panels I think. I may go back and play them off against each other to use higher efficiency panels as it is the absolute last south facing roof real estate available. I do have some minimal east and west facing roof that could take a few panels. That is one factor for determining the use of micro inverters along with a tree in my neighbors yard that will have some minimal shading effect near the winter solstice.

    Now the local code has changed and limits panels to three ft below the ridge and that may be impacting as well.

    BTW that quote included the addition of a 220 outlet in the garage to run the Volt charger.
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  • Knd870
    Knd870 Solar Expert Posts: 32 ✭
    #11
    Re: GT @ $.50 per kWh still valid???

    I had an error in the title that you folks pointed out. I changed it to $.50 per kWh.

    Thanks BB for your detailed (as usual) calculation. This was the same approach as I was using and thought that $.50 per kWh seemed high for today's prices.
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  • Knd870
    Knd870 Solar Expert Posts: 32 ✭
    #12
    Re: GT @ $.50 per watt still valid???
    solar_dave wrote: »
    I got a quote yesterday for a 2.3Kw system installed and commissioned using Enphase M190 for just $4.90 a watt before any rebates or tax credits. My net after all the rebates and tax credits would be $2.31 a watt.

    There is an enphase D380 that is two controllers in one case and it is less expensive that 2 separate controllers. It's not a lot of difference in price, but may be able to lower your cost some more. I think they claim a little less wiring is required also.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #13
    Re: GT @ $.50 per watt still valid???
    Knd870 wrote: »
    There is an enphase D380 that is two controllers in one case and it is less expensive that 2 separate controllers. It's not a lot of difference in price, but may be able to lower your cost some more. I think they claim a little less wiring is required also.

    Yeah the guy doing second quote is talking the D380, still waiting on his numbers.
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  • Juram
    Juram Solar Expert Posts: 36 ✭
    #14
    Re: GT @ $.50 per watt still valid???
    solar_dave wrote: »
    Actually I am still taking bids, that was the first one in and used Sunpower panels I think. I may go back and play them off against each other to use higher efficiency panels as it is the absolute last south facing roof real estate available. I do have some minimal east and west facing roof that could take a few panels. That is one factor for determining the use of micro inverters along with a tree in my neighbors yard that will have some minimal shading effect near the winter solstice.

    Now the local code has changed and limits panels to three ft below the ridge and that may be impacting as well.

    BTW that quote included the addition of a 220 outlet in the garage to run the Volt charger.



    Sunpower mono or Sunpower Serengeti panels? If its the mono's then that's an insane price although typical of this suicidal race to the bottom that solar companies in AZ are engaging in. I think they're all going to under-price themselves out of the market and when the smoke clears, there will be like 5 or 6 PV installers left standing.


    There's more than a couple of the larger installers who are literally staving off bankruptcy on a month to month basis. :)
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