Can Solar Power to Drive an Alternator?

I am looking for a way to use solar power to drive a 100KVA generator-Alternator (vs using a diesel engine) order to provide electricity to a small village in Africa. The idea is as follows:

1. Use solar to generate about 4 Kw of electric energy via batteries
2. Use the generated 4KW energy to power an electric motor
3. Boost the RPM via a gear system
4. USe the boosted power to drive an alternator
5. Recharge the batteries via solar

I guess this will probably be more expensive than buying even a 250 KVA generator but the benefit will be that the villagers will not have to spend money on diesel (Since they can't afford the diesel cost in the long run anyway)..

Does this idea seem technically feasible?

HG

Comments

  • halfcrazyhalfcrazy Posts: 716Solar Expert ✭✭✭
    Re: Can Solar Power to Drive an Alternator?

    NO there is no free lunch if the solar makes 4kw then you only have 4kw period what you describe is perpetual motion.
  • BB.BB. Posts: 25,623Super Moderators admin
    Re: Can Solar Power to Drive an Alternator?

    Each conversion step resultes in losses:

    Solar to charge controller to battery ~77%
    Battery to load ~80% (~80-90% efficient--depending on battery tech).
    DC load to AC inverter output ~85%
    AC motor ~50% eff
    Alternator+gear train ~50% eff

    0.61*0.77*0.85*0.50*0.50=10% solar panel to DC output efficiency

    VS

    0.77*0.95*0.80=0.59 Solar panel to charge controller to battery to DC load.

    What has worked, as I understand, in Africa was to use batteries for off-peak loads (radios, small computer, etc.), and fire up the genset for evening use for "heavy loads" (lots of lights, fans, cooking, coolers, etc.) + recharging the bank... Much better than running the genset by itself 18 hours per day (for example).

    Running the generator at 25-50%+ loads (good fuel efficiency), and run the batteries (with AC inverters?) for the minor loads during the day (less than 25% generator loads where fuel flows are high, and power used is low).

    Very much like running a "hybrid" car...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Can Solar Power to Drive an Alternator?

    you might have better luck trying to use solar thermal energies to turn the alternator. for that much power this would be large and i think you would need to be very inventive to carry it out.
  • BB.BB. Posts: 25,623Super Moderators admin
    Re: Can Solar Power to Drive an Alternator?

    There is the STG project.

    Not that I believe that is it anywhere near practical yet (or even working)... But I am not part of the project--so what do I know. :confused:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Can Solar Power to Drive an Alternator?

    Thanks Guys for the quick response. I very much appreciate this
  • mike95490mike95490 Posts: 6,665Solar Expert ✭✭✭✭
    Re: Can Solar Power to Drive an Alternator?

    Skip the motor and alternator. Use a good quality Inverter. Invest in a source for distilled water which the batteries need, using well water or river water will destroy the batteries.
    Build a 48V system, which will have less losses than a 12V system.
    Parallel batteries in a 12V system often have imbalance problems which can ruin batteries early.
    obtain a 48v - 12v converter to power 12v items separately, do NOT tap into a 12v battery from a 48V bank, you will ruin that battery in a few months.
    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 ,

  • peterakopeterako Posts: 144Solar Expert ✭✭✭✭✭
    Re: Can Solar Power to Drive an Alternator?

    Bravo Mike that is also my answer

    Plus a wind generator local made.

    The only correct setup is solar panel charger to Battery to inverter. combine this whit a diesel generator ( old lister or indian listeriod ) or wind generator.

    p.s. in affrica put the battery's under ground away from the heat.

    Greetings from Greece
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