Help!! Newbie needing advice on choosing a solar system and manufacturer

palmspringspalmsprings Registered Users Posts: 3
Hello. I am wanting to install a solar system at my residence and have spoke to 3 different installers about quotes. I am needing some help from someone who actually has a clue about solar to help me decide if the systems are comparable, or if the installer who is trying to get me to buy the more expensive system is truly selling more a superior product or just selling me a line. Installer # 1 has recommended a Canadian Solar CS6P-230P panel (99 panels) with 3 sunny Boy SMA inverter covering 96% of my usage and giving me a 22.8 KW sytem. Installer # 2 has recommended a Mage or Schuco (depending on color of panel) panel (96 panels) and 3 Solectria Renewables inverter giving me 72% of usage and producing a 18.24 KW system. Installer # 3 has recommended a Sunpower SPR-240E-WHT-D panel (75 panels) with 2 Sunpower SPR-10001f-240v inverter covering about 75% of my usage and giving me a 18.0 KW system. Installers 1 & 2 are about the same price while installer # 3 was about $10,000 more. Can anyone give me any feedback on the panel and inverter manufacturers or all they all relatively about the same and should I go with the cheapest price and highest KW system. Thanks for your advice and expertise. Just needing an independant expert opinion on products.

Comments

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer

    welcome,
    i read 99 pvs and i went into shock and it took me a moment to pick up my jaw from hitting the floor. all of them should've recommended a smaller system while giving you advice to conserve power. i guess they saw bigger $ signs.

    in any case the sunpower system is more costly because of the higher efficiencies of the pvs. you obviously have the room for allot of pvs so why pay more for a few more percent on efficiency as you aren't getting more power produced per $?

    so it becomes a choice of the other 2 and i think i'd pick number one for both the inverter and pv choices.

    how much power do you use in a month? and why? yikes.:confused:
  • palmspringspalmsprings Registered Users Posts: 3
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer

    We average 3237 KW per month with a peak of about 5500 KW in the month of August. Installer # 3 really seemed to be critical of the Canadian Solar panels because they were made in China and said the the Sonyboy inverter was a bottom of the barrrel inverter which would perform poorly in the heat of the summer due to a lower temperature rating. Have you had any experience with either of these companies and do you have any concerns or is the installer just trying to sell me on the more expensive unit? Thanks in advance for your advice and expertise.
  • solar_davesolar_dave Solar Expert Posts: 2,346 ✭✭✭✭
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer

    Ok so these,are grid tie systems, how many kWh do you use annually? How does the utility account your grid tie net metering? Are there metering plans that help your cost model? You may need to consider how your back feed is going to effect your service entrance. The first systems seems to be the best deal but I would question why the total sizes needs to be this high.

    I have a 25000 cu ft house in Phoenix with a pair of 3 ton Trane heat pumps, a 700 sqft office/workshop with a 3 ton mini .split with a wall unit in each room, a swimming pool and a pair of Chevy Volts to charge. I am almost break even at a 12.5 kw system. We did a lot of conservation items to get there. To add this much solar to our setup we had to upgrade the service entrance too.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer

    i'm only going on general feedback i've heard as i don't have any of those here. i've not heard bad about those in #2 for the record, but i have heard good on those in #1. sunpower has things to note too as it requires a positive ground and they use relabled xantrex inverters. if you have the room then don't pay another $10000 for sunpower pvs no matter what others you go with as you're just throwing away money. if you want to throw it away then throw it my way, please.;):p
  • palmspringspalmsprings Registered Users Posts: 3
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer

    Our annual usage is 38,317Kwh/yr. I know the utility company does net metering, but I am not sure about how they account for the grid tie net metering or about any effects on our service entrance. You have definitely given me some good questions to ask all 3 installers. Thanks and please feel free to forward any more questions I might need to find out before moving forward. Thanks again, your knoweledge and wisdom is appreciated.
  • BB.BB. Super Moderators, Administrators Posts: 29,698 admin
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer

    Also, in California, the rules for solar PV systems >10 kW rating are different than those for less than 10 kW. It may change the rebate schedule and you may have to receive your rebates based on actual power vs estimated power produced (I am not sure--I looked at the rules a year or two ago and it was not clear too me).

    Anyway--back to conservation. A large home/office in a hot climate is going to use a lot of power. But if you can look at conservation (the usual; insulation, double pane windows, energy star appliances, using less energy in the home means less spending to move the heat outside, etc.) and new heat pump A/C and Heating/Hot water--You may significantly reduce your power needs.

    Note that (at least in Northern California), we have to use Time of Use power metering. If you have loads between ~10am and 9pm or so that you cannot shift--You can end up paying a bunch more money for power.

    For us, we have an older plan that is noon to 6pm for summer week days--And it is easy for us to time-shift our loads outside of Peak Power charges. Basically, our solar GT system generates at $0.30 per kWH and we buy back nights/mornings/weekends at $0.09 per kWH... For Example, the current rates for solar in Northern California (E-6):
    Total Energy Rates $ per kWh) [B]PEAK[/B] PART-PEAK [I][B]OFF-PEAK[/B][/I]
    Summer
    Baseline Usage [B]$0.27883[/B] (I) $0.17017 (I) [I][B]$0.09781[/B][/I] (I)
    101% - 130% of Baseline $0.29640 (I) $0.18775 (I) $0.11538 (I)
    131% - 200% of Baseline $0.44610 (I) $0.33745 (I) $0.26508 (I)
    201% - 300% of Baseline $0.48610 (I) $0.37745 (I) $0.30508 (I)
    Over 300% of Baseline $0.48610 (I) $0.37745 (I) $0.30508 (I)
    Winter
    Baseline Usage – $0.11776 (I) $0.10189 (I)
    101% - 130% of Baseline – $0.13533 (I) $0.11947 (I)
    131% - 200% of Baseline – $0.28503 (I) $0.26917 (I)
    201% - 300% of Baseline – $0.32503 (I) $0.30917 (I)
    Over 300% of Baseline – $0.32503 (I) $0.30917 (I)
    

    Hmm... They have dropped the peak power pricing a fair amount.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 29,698 admin
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer

    Forgot to add--If this is a business, the regulations around how businesses are charged for electricity (again in Northern California) can make it very difficult to figure out if Solar GT will save you very much money, or possibly even cost you additional money instead.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • solar_davesolar_dave Solar Expert Posts: 2,346 ✭✭✭✭
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer
    Our annual usage is 38,317Kwh/yr. I know the utility company does net metering, but I am not sure about how they account for the grid tie net metering or about any effects on our service entrance. You have definitely given me some good questions to ask all 3 installers. Thanks and please feel free to forward any more questions I might need to find out before moving forward. Thanks again, your knoweledge and wisdom is appreciated.

    WOW my worst month is Aug of course @ about 3500 kWh. but my best is MAR with about 1100kWh, neither taking into account the Auto Charging which is a new load here in the last 10 months.

    I would first start to classify what the loads are that could drive your consumption so high. Think about then using monies to reduce some of the loads if possible. Certainly ask your utility about the net metering plans, how the power is accounted for makes a big difference in what is an effective ROI. Perhaps with a TOU plan the best deal is just shaving the tops off the peak usage and continue to buy off peak from the utility. I know the tier systems in California are pretty tough to figure out but a couple other people here can better address that.

    The reason I as about the service entrance is you can only backfeed a certain amount into an existing panel, the Rules are 120% of the buss bar rating in the panel. so if you have a 200 amp panel the max you can backfeed that panel is 40 amps without derating the main circuit breaker. (200 * 120%) = 240 amps of total source power on the buss bar. With your 22.8 kW system the back feed is going to be pretty large like about an 70-80 amp backfeed requirement. Ours was only a 46 amp backfeed into a 60 amp breaker in the panel, but the local code would not allow us to derate the main breaker because of the amount of house loads and our only solution was a service entrance upgrade to dual 200 amp panels (one derated to 175 amp main) with a 400 amp transformer feed in line. Read a $4300+ upgrade to just allow the grid tie @ 60 amp rated breaker.
  • icarusicarus Solar Expert Posts: 5,345 ✭✭✭✭
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer

    104 kwh/day! Wow, that is 103 times what I use! (not that I am typical!)

    That said, conservation is way cheaper than PV on a KWH basis. Increasing you A/C efficiency for example might save ~25-50%? of A/C running cost, far cheaper than providing PV to power inefficient A/C units. Adding insulation, especially in the attic/roof will further reduce the A/C load. Solar water heat or hot water capture heat pumps are way cheaper than similar PV capacity. And on, and on,,,

    Tony
  • TnAndyTnAndy Solar Expert Posts: 249 ✭✭✭✭✭
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer
    niel wrote: »
    welcome,
    i read 99 pvs and i went into shock and it took me a moment to pick up my jaw from hitting the floor....

    That makes two of us....ahahahaha.......the utility company send a fruit basket to ya'll at Christmas ?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help!! Newbie needing advice on choosing a solar system and manufacturer

    don't take any of us wrong here as we mean well for you and we are all being somewhat candid and blunt about it. you can very well place whatever amount of pv in that you wish to and it is quite rare to find somebody drawing that much power that would need to generate that much power. all areas touched upon are good points and i'd be curious of what your present service entry capacity is and what any of those installers intend for a new service entry capacity as it will need to be upgraded i'm sure? do any of those installs differ on the service entrance upgrade?
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