plan/estimated cost

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I live in Florida. I've been thinking about getting a generator (because of the hurricanes, bird flu, whatever comes along) but was wondering if solar energy might be a more cost effective and environmentally better way to go. So, I was wondering if anyone has recently put together a system and this could give me their plan with a cost estimate.

I have a typical 1600 sq ft house. Common appliances - stove, refrigerator or, water heater, AC unit.

I was wondering what other people have done - anyone out there with this info that would be willing to share?

Thanks in advance,
LWood

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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: plan/estimated cost

    lwood,
    the cheapest way out of backing up your power is by generator, but it's not the most reliable. unfortunately gasoline won't be available during major events as they need the electricity to run the pumps and it doesn't store very long. as to the environment, renewable sources like solar, wind, and hydro power are great, but costly for the amount of power you reap from it. most panels that we call pvs(photovoltaics) are rating in watts of power and most never see more than 90% of the stc rating which is what you will usually see on pv ratings. ptc is more reliable of a rating, but isn't always known. this would be for each full sun hour you receive(rated 1000w/meter^2). even if you would manage to afford many pvs it has to be regulated and stored in batteries. when the time comes this is put through an inverter(most go with grid tieable sinewave inverters) that recreate your ac power at power levels limited by the inverter's capability.
    there are many from florida on the forum and they can add their 2 cents as to what they have and the costs involved. do know there are incentives to do this and you can check it out as to how much you may think you can get for certain applications that are used.
    www.dsireusa.org
  • BB.
    BB. Super Moderators, Administrators Posts: 33,476 admin
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    Re: plan/estimated cost

    Solar backed up power should be a neat way to do... However, (you know that there would be a however...) there are issues.

    1. Solar power only pays for itself if the power it generates 365 days per year is used. If it is only used for 2 weeks per year, the costs "per kWhr" generated are 25x or more.

    2. Solar usually needs to be backed up by battery, so you now have the maintenance and losses associated with a battery pack (not cheap).

    3. Generators are cheap, and only use fuel when running. If you have a place to store the fuel for the runtime needed, they can be pretty cost effective.

    4. Solar, usually needs a backup (three days of stormy weather and you are out of power). You might have a generator anyway.

    5. Solar is expensive, so installations tend to be on the smaller side. For example, a 3kW peak GRID TIED system that can generate ~10-20+ kWhr per day (on a sunny day) is going to be somewhere between $20-$30,000 installed (not including batteries). And, you are not going to run much in the way of heavy loads (Airconditioning, electric heat, etc.).

    6. A typical grid tied Solar PV panel system usually is connected for higher voltages (180-550 Vdc) than the typical battery backed Solar PV Chargers/Inverter systems (12-60 Vdc). So, it is, currently, difficult to even switch the panels from your main Grid Tied inverter to a small solar/battery backed system (as the main solar buss voltages are so different).

    7. A quiet 2kW rated Honda Generator will cost you less than $1,000 and will use ~2-5 gallons (depending on load) of gas per day to power the same loads as a 3kW solar system or more (10-30 kWhr/day) rain or shine. Larger systems and Diesel generators can even be more efficient--less fuel or more kWhrs per gallon.

    The least expensive method to install Solar PV panels is to install a Grid Tied inverter system. However, there are no batteries and it cannot run if the utility power is out.

    You can install a different inverter system + batteries and get the advantages of a Grid Tied system (saving money by offsetting your utility power) and backup power via batteries/Solar-charging. But it will cost (very roughly) ~20%+ more to install, plus you will need to replace the battery pack every 7-15 years. And, unless you size it really large, it will not support A/C and other heavy electrical loads.

    To figure out whether to go Solar and/or generator, you need to identify the minimum amount of power you need to have during the two weeks (or whatever) the power is out. If you need A/C (medical condition, climate), then generator is probably the way to go.

    In any case, Solar or generator, conservation is going to be your friend. Changing lights to compact fluorescent fixture, insulation + double pane windows to keep the home comfortable, efficient refrigerator/washer/drier, electric ceiling fans instead of A/C, etc. is going to be a much better place to start spending your money. Usually, it will cost you less to save a kWhr of electricity than to purchase an extra kWhr worth of Solar PV Panels (and batteries, generator capacity/fuel, etc.) to power the "excess load".

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: plan/estimated cost

    bb,
    that is called grid tie with battery backup and it still affords the selling of power after topping off the batteries used for backup and is less efficient than the high voltage no battery backup systems.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,476 admin
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    Re: plan/estimated cost

    Hi Neil,

    Yes, I agree with what you are saying... I have always assumed (maybe incorrectly) that a full grid-tied system with battery backup that could also sell power on the grid would be way-overkill, both in costs and complexity for somebody living in the city with pretty reliable power.

    I was hoping to find a smallish high voltage compatible solar charger that I could use as a simple manual backup.

    Use the Grid Tied inverter for the day in and day out usage... And a small charger controller (like an Outback MPPT 60 amp charger tied to a 320 Vdc nominal 10 amp set of panels) with a few storage batteries + inverter that can handle lights and maybe a refrigerator on a sunny day--less need for the generator. The backup system would have not be too expensive (or large or even particularly efficient) and I would have the efficiency of the larger Grid Tied inverter for the rest of the time.

    I would just float the batteries with utility power for 99.9% of the time, and throw a DPST switch on the DC Panels when the power goes out.

    For my area, the power is probably more likely to go out in nice sunny weather (like we did in 2000) or an earthquake (which is not weather related). So far--knock on wood--I know of only one time when we lost power for more than a a few hours due to weather--and that was ~50+ years ago (4-5 days--before I was born).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: plan/estimated cost

    bb,
    as far as i know they don't make controllers for the high voltages you describe to be downconverted from high voltage pv systems for low voltage battery configurations. maybe just buy a quality 110vac charger for a battery bank/inverter arrangement. if power goes off your pvs disconnect from the grid and no power generation from the pvs from then on until the grid goes back on. this is the best arrangement so far unless somebody else is aware of a product that fits this bill.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
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    Re: plan/estimated cost

    Over the last 23 years I have continuously upgraded my backup system here in Florida.

    I started with a 4 kW generator after hurricane Andrew. Problem with the average 4 or 5 kW generator is although I needed the 4 kW to start my well water pump I end up only averaging 500 to 1000 watts draw which is very inefficient from a gasoline consumption point of view.

    My next step was to a single SW4048 starting with 210 A-H's of batteries. During a several day hurricane power outage it halved the gasoline overall consumption because I could run the generator for about hour in morning and hour in evening at near full load to recharge the batteries. Also reduces the generator noise time.

    I now have two SW5548plus's and two SW4048's. The SW5548+'s are solely for 240 v supply to central AC, range, hot water heater, clothes drier. The SW4048's run rest of house. I have a noisy 15 kW generator and a quiet Yamaha EF3000sei that makes less noise then the central A/C outside unit. I use the Yamaha as sort of a "trickle charger" and during daylight morning and evening run the 15 kW to heat up water and top off charge the batteries if needed. The battery system will run the central air during night time so I don't have to make any noise. I almost never have to run the 15 kW generator, instead, with the Yamaha as a trickle charger, the battery/inverter system takes the startup's and intermittent heavy loads and makes up the deficit during light load times of just lights and T.V. periods.

    I have some solar hot water panels which is likely next project. I have thought about getting 5kW worth of PV panels but it is tough to economically justify. After hurricane, gasoline is gold so the PV supplement is interesting. Probably the main hold back for me on PV, besides cost, is the thought of having to disassemble them and store them before a storm. I don't think it would be wise to leave $25K worth of PV panels outside to face a hurricane rath. Last year I had about a dozen of my cement roof tiles broken by flying debre so I can easily imagine what would happen if there were PV panels there.

    As a minimum backup system, I would recommend something like a DR inverter/charger, and a quiet 2 or 3 kW generator. The batteries need to be sized to at least supply refrig + lights for 15 hours. This translates to about eight 50 lbs batteries. About $850 for inverter, $500 for batteries, $1600 for generator, and add about $200 for misc hardware, total a little over $3K. If you need to have electrician do install, add another $500
  • System2
    System2 Posts: 6,290 admin
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    Re: plan/estimated cost


    I thought homeowners insurance would cover the panels?

    brad

  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
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    Re: plan/estimated cost

    If you can get homeowners insurance. It's becoming very difficult in FL.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: plan/estimated cost

    even if you have insurance if a hurricane takes out the electric long term in the area and does your pvs in you're sunk for power excepting whatever is left from what you can produce with a generator.