trying to get a big picture

Tamasciernos
Tamasciernos Registered Users Posts: 1
in Solar Beginners Corner #1
Hey yall,

I'm trying to figure out what is the best way to go with a solar rig. complete power independence, or supplemental?

if i go for independence I'll need to be able to generate about 47 kw/day i don't think my house is big enough for me to do that on the roof. that plus i only have a quarter acre. I'm not sure my yard is big enough for that either. I'm just trying to figure out how much power would make a dent in my power bill. I have asthma and even with medication I'm really hard pressed to do much of anything in relative humidity over 50% so AC is not an option. If i could find a way to run 3 window units on solar that would go a long way to fixing my problems. I have 3-900 watt window units that run almost all the time. when I'm not home, I still have to leave one on to keep the humidity down to a reasonable level......40% or so.

I'm open to any ideas yall have.

thanks so much

Tamasciernos
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: trying to get a big picture

    Welcome to the forum.

    Your best bet is to spend the money on conservation. It will return you more energy savings per $ spent than any form of solar, and makes any subsequent solar installation more worthwhile.

    Solar is expensive. Off-grid most of all. It rarely is the economic option if grid is available. Grid-tie can be viable under the right circumstances. But getting that usage down will be the first step no matter what. Honestly we're talking $0.50 per kW hour for grid-tie solar, and chances are your utility doesn't charge that.

    47 kW hours per day is a substantial amount of power. You probably would be better off replacing those window units with more efficient mini-splits or even a central unit with a good SEER rating.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #3
    Re: trying to get a big picture

    Not sure of your location, but 47 kWh a day is pretty huge and to go off grid is a real expense and definitely not cheaper than the grid. If your power is reliable then you might consider grid tie to supplement your consumption, but the right think to do is look at conservation first. Those window rattlers are a huge consumer and perhaps the first step would to be looking at mini-split inverter type AC units and added insulation in your home. I run one 3 ton on my new shop/office/harley house with 3 indoor wall units and the power consumption is pretty minimal. Look at all your lighting and convert to CFL or LED for a nice reduction. Consider energy star appliance replacements.

    Do you have electric hot water, there is one place a big reduction can be made using the heat pump DWH units.

    My Grid Tie system generates about 65-75 kWh a day in pretty ideal sun conditions (but not ideal temp conditions) . Give us some more detail and how much you are planning to spend to get this supplemental energy.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #4
    Re: trying to get a big picture
    Cariboocoot wrote: »
    Your best bet is to spend the money on conservation. It will return you more energy savings per $ spent than any form of solar, and makes any subsequent solar installation more worthwhile.

    I couldn't agree more about spending the money on conservation. But, ironically, conservation may make a solar installation less worthwhile.

    In most grid-tie situations, conservation may actually reduce the ROI on a solar installation. As your power consumption goes down (because of conservation) there is less electric bill to offset with a solar investment. Of course, this depends very much on the net metering arrangement with the power company.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #5
    Re: trying to get a big picture
    vtmaps wrote: »
    I couldn't agree more about spending the money on conservation. But, ironically, conservation may make a solar installation less worthwhile.

    In most grid-tie situations, conservation may actually reduce the ROI on a solar installation. As your power consumption goes down (because of conservation) there is less electric bill to offset with a solar investment. Of course, this depends very much on the net metering arrangement with the power company.

    --vtMaps

    You are assuming a particular GT install size. Don't. If your energy use is smaller you do not have to have as large a solar install regardless of whether it is off grid or on. That equals less capital expenditure up front.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #6
    Re: trying to get a big picture
    vtmaps wrote: »
    I couldn't agree more about spending the money on conservation. But, ironically, conservation may make a solar installation less worthwhile.

    In most grid-tie situations, conservation may actually reduce the ROI on a solar installation. As your power consumption goes down (because of conservation) there is less electric bill to offset with a solar investment. Of course, this depends very much on the net metering arrangement with the power company.

    --vtMaps


    Really the most advantageous ROI comes from a good net-metering plan and a TOU rate tariff. So you just replace your peak consumption with solar. I could never have covered my peak load with solar, it is about double my generation capacity but with net-metering and TOU I still get a great return. I have yet to buy an on-peak kWh this year. Some of the off grid crowd seem to miss this point.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #7
    Re: trying to get a big picture
    solar_dave wrote: »
    Really the most advantageous ROI comes from a good net-metering plan and a TOU rate tariff. So you just replace your peak consumption with solar. I could never have covered my peak load with solar, it is about double my generation capacity but with net-metering and TOU I still get a great return. I have yet to buy an on-peak kWh this year. Some of the off grid crowd seem to miss this point.

    And some of the grid-tie crowd seem to miss the point that not every utility has TOU or even buys electric back from you at any rate.

    A lot of people miss the point that GT systems only reduce the kW hour charges (and related fees/taxes) and not base charges, connection fees, and all the other little "et ceteras" utility companies cook up to keep the money flowing in from people practicing the conservation they've been told to do even by said utilities.

    Every installation is different. Sorry if I don't cover every possible scenario when giving preliminary generalized answers.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #8
    Re: trying to get a big picture
    Cariboocoot wrote: »
    And some of the grid-tie crowd seem to miss the point that not every utility has TOU or even buys electric back from you at any rate.

    A lot of people miss the point that GT systems only reduce the kW hour charges (and related fees/taxes) and not base charges, connection fees, and all the other little "et ceteras" utility companies cook up to keep the money flowing in from people practicing the conservation they've been told to do even by said utilities.

    Every installation is different. Sorry if I don't cover every possible scenario when giving preliminary generalized answers.

    Your absolutely correct, it is just that some of the off-grid crowd assume that is the route to go when people show up here testing the waters, and mostly that is a huge expense that many need not incur. The fees I pay for grid attachment are a small price to pay for the storage I consume compared to a battery based system, and yes it all hinges on the TOU and net-metering plans. Because of the net-metering mandated in California one can put in a fairly small array and get to net zero $$$$ fairly easy, not the case here. I would not recommend trying to replace off-peak power unless I had a sweat deal like the California crowd. It all hinges on the situation and each installs requirements.
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  • TucsonAZ
    TucsonAZ Solar Expert Posts: 139 ✭✭
    #9
    Re: trying to get a big picture

    Buy a Kill-O-Watt meter and figure out why you're using so much. I use a lot, average is about 30wkh a day but in the summer I would bet it's double that with the 105 degree days every day. That would be a heck of a system to maintain.
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