10 X Condo's sharing wind/solar grid.


I need to convince the corporate body of a pro rata Condominium Site to accept wind and power over a conventional diesel generator system. I have found Kerosene Fridges and Stoves which are more reliable and cost efficient over Propane or electricity so this will offset their power needs to basically large screen TV's, fans, computers and lights (the elevator will start when needed and run off a generator that will in turn charge the batteries)

8 x CFL 11w Bulbs = 88w
42" LCD = 125w
Ceiling Fan = 75w
Laptop = 100w


I have found Indian made wind turbines (4.75kw) that cost around $15000USD each. I'm not a hundred percent sure of what battery type to select considering there a 8 - 10 apartments that will need to operate at full capacity during peak holiday season, also I need to know what kind of inverter to be looking at and a device that would preferably split the electricity available and being generated on average and divide this load between the 10 apartments which would encourage conservation of energy or meter the load out on a user pay's system. Otherwise they'll opt for a prehistoric genertor when there is wind 60% of the time and clear sunny skies every day at the site, what a waste, considering the technology is getting better by the day, I will put any information gathered here into the proposal as I am starting to become outspoken on the issue I need some pro advice

thanks for reading.


  • BB.
    BB. Super Moderators, Administrators Posts: 33,500 admin
    Re: 10 X Condo's sharing wind/solar grid.

    You are probably fighting an up-hill battle on your proposal... And where you are located also makes a big difference--Are you in the Fiji/South Pacific area?

    My two cents... Look at designing a battery system that can handle ~6 days of average load. This will be the core of your system. You then need to decide how you are going to power the condo's... One (or several) large UPS's, or 1 per condo small UPS's...

    Next... Getting power into the battery system. Solar RE systems only make sense if they power occupied units (or average power) over ~9+ months of the year. If the condos are only occupied for 3 month of the year--the fixed costs of solar, wind, etc. are very high vs the amount of power consumed (you can only store about 3 days worth of power in your battery bank assuming 50% maximum discharge).

    With the battery bank in the "Middle" of your system design--you now have a "Hybrid" system. You can connect solar, wind, and diesel generator. And build out the system as makes sense (add your wind turbine--see how it performs;put an Amp*Hour meter on it--add some solar, see how that performs, etc.).

    Also, even if a genset is the decision--the batteries will let your complex have power during the day (when it may not be worth running the genset because the power needs are low)--and in the evening when everyone is home, cooking, lights, tv, stereo, etc. is running... You can run the Genset at 50%+ rated power to supply the AC loads and bring the batteries back up to full charge.

    The Hybrid Generator system has been used in Africa with good results... Supports light loads (computer, radio, music) during the day from battery bank, and heavy loads in the evening with genset (plus battery charging)... Can save a lot of fuel (50% or more fuel reduction--depending on power usage pattern and diesel loading). Even without solar RE/Wind.

    Once you have the core system running--then adding solar RE (wind, solar PV) can be done in stages to reduce overall genset runtime and demonstrate cost effectiveness...

    Regarding metering... You are talking about $1-$2 per kWhr (USD) at least for off-grid power (probably more depending on your local cost structure). Metering each unit might make sense--but just adding a $5 per night energy charge might make sense too.

    A lot depends on the "owner/members" of your association. And such a system will need maintenance (battery care and replacement, generator servicing and fuel, monitoring to ensure everything is running OK, warning residences on excessive usage (electric hair driers, TV/Lights/Fans left on and nobody home, etc.).

    Generally, extreme conservation is important to make economic sense for off-grid systems. And having a mix of user/owners makes things difficult to sort out and fund.

    Regarding Wind Turbines--they are expensive to properly install and maintenance heavy (pull down once or twice a year just to inpect, lubricate, and tighten bolts). If it is mounted on a 20-60 meter tall tower (60' / 18 meter minimum recommendation, at least 10 meters above any trees/buildings/etc.)--the costs of just servicing the unit can be high. Let alone trying to keep a mechanical device running smoothly in a marine environment.


    PS: I am not a believer in small wind turbines at all--they tend to be unreliable and generate little output (especially if mounted on short towers)... Solar Panels, while expensive, have almost no maintenance requirements and produce power reliably day after day (assuming in a reasonably sunny location, clear of shade).
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • blackswan555
    blackswan555 Solar Expert Posts: 246 ✭✭
    Re: 10 X Condo's sharing wind/solar grid.

    My 50p`s worth
    I look after several sites with the approximate same setup in different stages of "build", from 1 outback inverter to 9, 3kw> 27kw, (Max 10 outback inverters per system) You could either use 1 inverter per condo(3kw), or as I do,have them stacked, then feed that out to a main distribution board, this allows them to turn on and off sequentially depending on load, this also should have no problem running your lift, (probably going to need a min of 3 inv)

    They all started with 24hr gen, then added batteries + inverter, + panels, (I would not go near small wind for the same reasons as mentioned below) the initial benefit`s of just adding inverter + batt`s are a considerable reduction in gen time and service intervals (24hr run, 400hr service interval = every 16 days) along with reduction in noise & pollution, It then comes down to how many panel`s they want to invest in, but as a basic rule I look at the panels paying for themselves in gen savings in about 5yrs at todays fuel prices,

    Metering/Display, I use these, http://www.diykyoto.com/uk people do seem to use less if the know how much they are using.

    Have a good one