Remote Island Solar System

larrybc1larrybc1 Solar Expert Posts: 44
Hi.. I am NEW to solar and wind..but here is what I have..
I have a small beach resort in the Philippines that is off the grid..I currently use a 15 KW diesel gen to power the place and I use 3-4 gals of Diesel per day at $4 a gallon..so i want to go to Solar and wind--get a strong seabreeze everday..So here are my power requirements. I use about 7,000 to 8,000 watts per day..Everything there is 220V..My question is how many solar panels do i need and what kind of batteries and how many batteries..also charge controller, inverter etc would I need..Any HELP would be greatly appreciated as I need to evaluate if this is economically feasible..Thanks Larry

Comments

  • BB.BB. Super Moderators, Administrators Posts: 28,163 admin
    Re: Remote Island Solar System

    Welcome to the Forum Larry,

    First question, is the 7,000-8,000 Watts per day actually 7,000-8,000 Watt*Hours per day?

    The options, as I see them are:
    1. Use a smaller genset to power minimum loads 18 hours per day, use your 15kW genest 6 hours per day to power heavy loads (typically evening time).
    2. Install a battery bank + AC Inverter to run low power 18 hours per day and use existing genset to recharge ~6 hours per day (aim to run genset at a minimum of 50-60% rated output load for good fuel efficiency and long life--Genset operated at less than 50-40% rated output tend to waste fuel, and have shorter life between service/overhauls).
    3. As #2, but install solar panels and DC Solar Charge Controllers to assist charging batteries during the day. Add panels as personal financing permits.
    4. As #3, but install larger battery bank and full complement of solar panels to support ~9 months without having to use the genset (use genset during bad weather/low sun conditions).
    Anyway, do you have a good source for equivalent hours of sun per day (or kWH per square meter per day by month/season) for your area?

    And, as always, we recommend "extreme conservation" before spending the first dollar on Solar/Wind/etc... Reduce power use, buy most energy efficiency appliances you can, etc.

    Wind tends to be a real issue... Finding good quality turbines that will not need major service/replacing (pull off tower with rented crane/etc.) every year or so is difficult. And to get "good wind" you need to mount the turbines, at least 20-30 Meters high (and 100-200 meters from any major wind obstructions).

    If you have trees or other vegatation that "flags" from the prevailing wind, then you may have enough to make a wind turbine useful.

    Hold off on spending any money on wind just yet (I am not a wind turbine fan)... Do your research on conservation and defining your loads (peak watts, average WH per day by season, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • larrybc1larrybc1 Solar Expert Posts: 44
    Re: Remote Island Solar System

    Hi Bill..I face directly south and I am located at 14 * North latitude..I bought a 100 watt panel as an experiment 2 years ago and it has done well. I figure that I get 4-5 hrs good sun per day..I dont use much power during the day except for 2 -19 cu ft freezers that I need for the restaurant..most of the power--lights TV etc is used at night for 4 hours or so.I am probably overestiamting my power usage..it is basically, the 2 freezers, lights and some kictchen applicances (coffee pot)...I am taking a 40 foot container over in May and I could take the panels and batteries as buying them over there is at least double the price of here..Thks for the help and any advice....larry
  • limelime Registered Users Posts: 5
    Re: Remote Island Solar System

    Maybe slightly off topic but there are some all in one systems that do wind solar and water - these are kind of for emergency zones or for off grid farms etc... I can dig up a link to them and can post later if you're interested.

    K
  • icarusicarus Solar Expert Posts: 5,108 ✭✭✭✭
    Re: Remote Island Solar System
    I am probably overestiamting my power usage..

    I actually would argue quite the contrary.

    One of the basic rules of PV is that most people over estimate the amount of solar harvest they can reasonably expect, while at the same time they underestimate their loads, leading to a double whammy of poor system performance.

    Here is a pretty simple rule of thumb for off grid that makes calculating pretty easy, even if the numbers are not always 100% accurate. Take the name plate rating of the Pv, divide by 2 to account for all cumulative system loses (from PV through inverter and line losses), then multiply that number by the number of hours of good sun one might logically (and locally! ) expect per day, on average over the course of the year. I tend to use four, you might get less, you might get more, but 4 seems to be a pretty good average.

    So, for example, a 2000 watt system might deliver something like this:

    2000/2=1000*4=4 kwh/day

    So you can see, that for your 8 kwh need you are going to need a Pv system in the order of ~ 4 kw, at a North American cost of perhaps ~$8/watt, or $32,000

    My best piece of advice is to consider everything, ask questions, especially here before you buy a single piece of hardware. Do good load calcs, conserve anywhere and everywhere you can, then design a system that truly suits your needs.

    The second mistake that many folks make is "Ready, Fire, Aim". That is they make quick assumptions, buy some stuff, and then are stuck with having made square pegs for round holes. If you do your homework, you will end up with a better system for your money.

    Folks here are very sharp, and are more than willing to help in any way possible.

    Tony

    PS On the conservation front, any load you can off load to other energy (Oil/nat gas/propane etc will result in a smaller, cheaper system etc) For example, If you have gas (LP/Nat etc) available in the kitchen, consider getting rid of the electric coffee maker in favour of a Stove top Coleman "Mr Coffee" or some thing. There are a ton of little things you can do to reduce consumption around the edges that can make a real difference.
  • BB.BB. Super Moderators, Administrators Posts: 28,163 admin
    Re: Remote Island Solar System

    Larry,

    Pushing the conservation angle--Avoid loads like a coffee pot unless you are already running the genset. And use a thermos for keeping the coffee warm during the day. There are stove top automatic coffee makers such as the Mr. Coffee from Coleman and Thermos Cooking Pots (soups and stews) that are vary popular in Asia. Laptop Computer instead of Desk Top, and any other way to reduce electrical power is almost always a good investment.

    Yes, a system as large as yours can run a coffee pot, but, figure that you are spending $1-$2+ per kWH (USD pricing) for electric power. If it is worth using solar electricity for heating/cooking--then go for it (and design for it). Electrical use is a highly personal series of choices. We here just wish to help you make those choices up front and implement as you understand your needs.

    Another thing to do is monitor your current electrical use. For example, you are spending ~$16 per day to generate ~8kWH of useful power. Or:
    • $16fuel/8kW=$2 per kWH for power (excluding generator maintenace/capital costs)
    Assuming $15,000 for a 15kW genset that will last ~10,000 hours:
    • $15,000 capital / 10,000 Hours life = $1.50 per hour runtime costs
    Assuming you run the genset 16 hours per day and 8kWH per day of useful power:
    • $1.50 per hour cost * 16 hours per day + 8kWH*$2/kWH per day = $40 per day genset cost
    • $40 per day / 8 kWH per day = $5 per kWH for you
    Yes, I probably made a whole bunch of assumptions that are not anywhere close to how you operate your genset, how much it cost you, etc... The above was just an example of how you can take Apple to Orange comparisons and get a valid Mango to Mango difference.

    Hopefully, we can do better with solar.

    Let us assume 4 hours of full noon-time equivalent sun per day (not a bad estimate if you have reasonable amounts of sun). And plan for 8kWatt*Hours per day of power usage (all season long). Assume your loads would be satisfied with as small as 2kWatt Inverter (setup your two refrigerators so that both do not start at the same time, as typically a modern energy efficient fridge needs about 1,500-1,800 watt inverter minimum to start the compressor and run the ~500 watt defrost heaters).

    Knowing a 2kW inverter, we are in the 24 Volt and, perhaps, 48 Volt battery bank to handle the currents. Size for 24 Volt battery bank for now.

    Just running some rules of thumb to get you in the area of a reasonably functional/reliable system.

    First, the battery bank. Assume Flooded Cell (80% efficient), an 85% efficient inverter, 24 volts, 50% maximum planned discharge (for longer battery life). Normally, we size a bank for 1-3 days of "no sun"--For the math here, lets choose 2 days. (note, will will use 3-4 place accuracy for math so you can reproduce my errors. :roll: If we get within 10-20% of your needs and available sun/usage--color us happy :D).
    • 8,000 Watt*Hours per day * 1/0.85 eff inverter * 2 days * 1/0.50 max discharge * 1/24 volt battery bank = 1,569 AH @ 24 volt battery bank
    Double check that we have a large enough battery bank to handle 2x 2,000 watt inverter surge power. Note that the recommended surge current for a flooded cell battery bank is around C/2.5 or 40% of battery bank AH rated capacity at 20 Hour rate:
    • 2x 2,000 watts * 1/24 volts * 2.5 Battery Surge Capacity = 375 AH @ 24 volt minimum (check, we are fine)
    Next, we want to calculate the size of the solar array using two different methods. The first method is the classic, I have XXXX amount of load and Y amount of sun per day:
    • 8,000 WH load per day * 1/4 hours of sun per day * 1/0.52 end to end system efficiency = 3,846 Watts of Solar Panels (STC/marketing rating)
    The other way to look at the amount of solar panels is do you have enough charging current to properly recharge the battery bank. That rule of thumb is around 5% to 13% of bank capacity rate of charge. With 10% being a largish sized solar array:
    • 1,569 AH bank * 29 volts charging * 1/0.77 solar+charger derating * 0.05 rate of charge = 2,955 Watts of panels minimum
    • 1,569 AH bank * 29 volts charging * 1/0.77 solar+charger derating * 0.10 rate of charge =5,909 Watts of panels (high nominal)
    • 1,569 AH bank * 29 volts charging * 1/0.77 solar+charger derating * 0.13 rate of charge =7,682 Watts of panels (maximum useful)
    So, a good range of solar array for this setup (assuming 8kWH per day and 4 hours of full noon time equivalent sun per day, with 2 days of no-sun battery bank) would be around 3,846 to 5,909 Watts of solar panels (again, remember that within 10-20% is pretty much the same as these numbers).

    Cost for solar system, assuming around $15 per Watt for hardware and batteries, $7.50 per Watt for replacement parts/batteries 10 years from now, generating 8,000 WH per day for 20 years (very rough numbers--mostly to estimate a rough range of cost--do your own costing). 5,000 watts of panels:
    • 5,000 watts * ($15 capital + $7.50 maintenance) per watt / (8kWH per day * 365 days per year * 20 year life) = $0.64 per kWH over life of system
    • 5,000 watts * $15 per Watt capital cost = $75,000
    Of course, you should not plan on pulling 8kWH exactly per day from your system--some days may be more, and many days will be less. Plus you may wish to plan for growth--Or figure out how to reduce your power needs so you can reduce your costs for solar power too...

    I am not in the solar business, so I cannot give you an accurate quote (I would be doing the same as you--Going to our host, and others, website to pick hardware and get costs). And I have made a whole bunch of assumptions which may not be true for your situation.

    The above is more of a template for you to fill in your actual needs and costs and see where you come out at the end. Obviously you can add other costs, taxes, cost of money, present value/future worth, etc...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • larrybc1larrybc1 Solar Expert Posts: 44
    Re: Remote Island Solar System

    Hi Bill..thanks for all the great info..I guess it might be too costly to go the solar route at least for 8000 watt system..I was figuring on 20x 225 Watt Canadian solar panels for $4500, 16 --305 AH Lifeline 6 Volt batteries at $5200, a 48 V magnum inverter/charger for $2100, and charge controller for $600 and cables and breakers..I know that wouldnt be 8000 watts per dayI but maybe 6000? I can t see spending $75,000 on a system..maybe just run the generator for now I guess although I dont want to.. ..thks Larry
  • mike95490mike95490 Solar Expert Posts: 8,023 ✭✭✭✭
    Re: Remote Island Solar System

    You already have the generator, but I'd consider going to a 48V system, easier to handle surges, less batteries in parallel.

    And since you already have a genset, you *dont* need to plan on 2 days no sun, you can fire up the genset.

    Creating a hybrid system, use big genset to bulk charge the batteries in the AM for an hour before the solar gets going, and let the solar take over. Now you only burn 1 hour worth of fuel, and the rest is silent, unless it's a cloudy day.

    You can use a small genset at evening/night, to power the club, and not drain batteries so much.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Remote Island Solar System

    I agree with Mike; it's not impossible, if you're willing to go 50% DOD.

    Something like this:

    8000 Watt hours / 48 Volts = 167 Amp hours *2 = 334 Amp hours. Round up to 390 Amp hour L16's or parallel banks of "standard" T105's @ 225 Amp hours = 450 Amp hours.

    To recharge: 45 Amps @ 57 Volts = 2565 Watts less "typical" derating = 3332 Watt array. One 60 Amp MPPT controller should handle it.

    Depending on how big your maximum draw is, you might want a Xantrex XW 6048 for the inverter.

    Check the PV Watts program to get a more accurate idea of "harvest" for your area: http://www.nrel.gov/rredc/pvwatts/

    Or I may have got the wrong end of the stick or done the calculations wrong or both. :blush:
  • larrybc1larrybc1 Solar Expert Posts: 44
    Re: Remote Island Solar System

    hi Mike..Thks..thats a good idea and that is what I was thinking of..So 48 volts with a 2500 watt panel array would give me 11,250 watts per day..at 48 volts how big a battery bank would I need just to have a 1 or 2 day supply if I used 6000 watts per day ? Also to charge the batteries would I use a combination inverter/charger? was looking at the magnum 48 volt/3500 waTT inverter/charger..thks larry
  • mike95490mike95490 Solar Expert Posts: 8,023 ✭✭✭✭
    Re: Remote Island Solar System

    magnum is good http://www.solar-electric.com/maenms4444wa.html 2 year warranty

    I favor the Xantrex xw6048, http://www.solar-electric.com/maenms4444wa.html
    has a bigger charger, much more overload power for starting well pumps or garbage grinders, floor buffers... has 5 year warranty

    both have internal chargers, both need extra external boxes for advanced control features, Generator auto start (and your genset needs auto start too, if you want that)

    Both will generally benefit from a "Wiring Box" to hold battery circuit breakers, AC breakers, and stuff like that. Epanels: http://www.solar-electric.com/misoe.html
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Remote Island Solar System

    You may have 5 hours of "equivalent good sun" instead of the usual 4 hours expected.

    Thus the fast calc:
    2500 Watt array * 5 Hours = 12500 Watt hours / 2 = 6250 Watt hours.

    That's why I'd up the array size a bit.
    As far as the batteries are concerned, 6 kW hours @ 48 Volts is roughly 125 Amp hours, so that's an absolute minimum 250 Amp hour bank. Something closer to 500 would be better - reduces the Depth Of Discharge.

    If you're going with Magnum inverter (good chargers): http://www.solar-electric.com/maenms4444wa.html
  • BB.BB. Super Moderators, Administrators Posts: 28,163 admin
    Re: Remote Island Solar System

    And Larry,

    You only need 3,846 Watts of Solar Panels to make ~8,000 Watt*Hours per day on 4 hours of sun per day.

    Your 20x225 watt panels = 4,500 Watts of Solar panels--So, you are golden there:
    • 4,5000 Watts * 4 hours of sun * 0.52 over derating = 9,350 Watt*Hours per day
    Battery sizing -- You can choose between 1 to 3 days with a maximum of 50% discharge (longer life)... I showed 2 days, but you can do less.

    Basically, because you have a very capable genset, as others have said, you can run it a few hours in the morning when you have a day of bad weather.

    The big things, try to never discharge the battery below 20% state of charge (risk of permanent damage to one or more cells).

    And the second is to never let the battery set below 75% state of charge for days/weeks/etc... Below 75% state of charge, the lead sulfates begin to crystallize--which permanently removes that material from the battery capacity.

    I try to start conservatively, to get people to look very closely at their entire setup/power usage.

    You are at the point where you can trade off battery bank size for generator run-time.

    After a year or so, you can always look to add more panels, etc. and decide how to better optimize your system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • larrybc1larrybc1 Solar Expert Posts: 44
    Re: Remote Island Solar System

    ..Sure glad I found this forum..lots of good info..I have recalculated my loads and with conservation I can get down to 6000 watts per day..So if I get 12 225 Candian Solar Panels I would have 225x12x4.5 hrs sun =12,150 watts per day..divided by 2 is 6075 Watts per day..
    Ok for batteries...I am figuring a 48 Volt system..so what is a good choice on batteries (AGM?) and how many batteries ? Figure 1-2 days reserve as I can use gen to charge batteries if too low..
    Charge controller--Outback FM 80 ?
    Inverter /charger Magnum 4448--4000 Watt inverter and also 120/240 as we use 220 in Phils
    What is a good resource that show how the wiring should be done..I have an electrician there but has never done solar..thanks in advance and everyone has been a GREAT help Larry
  • mike95490mike95490 Solar Expert Posts: 8,023 ✭✭✭✭
    Re: Remote Island Solar System

    Xantrex xw6048 has "generator support", meaning if you are running a small genset, and it needs more power for a bit, the inverter will switch from battery charging to inverter, and assist the generator.

    I would sugest you get regular lead acid batteries to start with, everyone seems to agree that the first set gets toasted breaking in the new user. Save the $ for the 2nd set next year.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Remote Island Solar System

    "I can get down to 6000 watts per day.."

    try not to downsize the pvs too far even if you can conserve enough to warrant only 6kwh per day. loads usually increase as time goes on and rarely decreases so allow yourself a bit of extra power as a kind of buffer. the little bit of extra pv power could be handy if you need to recharge faster for whatever reason such as visitors, bad weather, etc. or just increased your future loads.
  • icarusicarus Solar Expert Posts: 5,108 ✭✭✭✭
    Re: Remote Island Solar System

    From 8kwh/day to 6kwh day,, a 25% reduction. Do I hear 4 kwh/day?

    Tony
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Remote Island Solar System

    I'd plan for 10 kW hours per day. That'd be a 4kW array and 500-600 Amp hours of battery.
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