Estimated Costs of Generator Power

Discussion in 'Survival & Emergency Preparedness' started by Ernie, May 24, 2011.

  1. Ernie

    Ernie Well-Known Member

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    Yesterday while listening to the hum of the generator, I came up with some numbers I thought I'd share with you.

    My 6500kW generator can power just about the entire house (so long as I don't kick on the air conditioner). It runs on gasoline. I paid about $700 for it.

    Gasoline runs at roughly $4.00 per gallon here right now. The generator tank holds 7.2 gallons.

    According to the manual, it will run for 10 straight hours on a full tank of gas.

    That's $28.80 to fill her up, and the operating cost is $2.88 per hour, give or take variations in the fuel quality, height above sealevel, etc.

    As an interesting aside, according to the electric company's website, the average cost for 1 kilowatt hour is $0.50. So if my generator is producing 6 of those, am I in fact generating my own power cheaper than it's being delivered to me?

    Electricity is not my area of specialty. I know just enough about it not to touch the red wire.
     
  2. mightybooboo

    mightybooboo Well-Known Member

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    50 cents a Kw/hr?????

    Mine is 13 and Ive heard thats on the high side.

    You use exactly 6.5 kw/hrs when your machine is running? Bet ya dont.

    So,30 dollars a day,30 days a month,900 month for 10 hours of energy a day?

    I see no bargains here......
     
    Last edited: May 24, 2011

  3. Wags

    Wags Well-Known Member Supporter

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    Hubby and I have been mulling over getting a generator - thanks for the numbers. Wonder how big of a generator we would need.
     
  4. tkrabec

    tkrabec Well-Known Member

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    6.5 kw (for ease of use) Your Generator
    A few questions
    How often & how much oil does it take + Filter
    What is the life expectancy of the generator in hrs? 1,000 10,000 hrs?

    I'll assume that 10 hr run is at 50%
    so you get 10*6.5*.5 = 32.5Kw for 2.88+Oil + Filter costs + Generator costs
    I get about $0.0886/kwh
    we pay 10-12 cents/kwh here possibly a bit more.
     
  5. whodunit

    whodunit Well-Known Member Supporter

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    Like Ernie, I'm not an electric guy, but I thought 50 cents KWH didn't sound right either. I think we are at 8 cents.
     
  6. barnyardfun

    barnyardfun Happy Homemaker Supporter

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    :happy0035:LOL, Ernie! That is about the same way here although I lost count of how many times DH has zapped himself!! I think he is starting to learn to JUST LEAVE IT ALONE!!!

    We woke up this morning to our power line about five foot off the ground! Guess the wind played jump rope with it last night and broke the support cable loose.

    Sorry back to the OP. I highly doubt running the ginnie is anywhere near cheaper then on the grid BUT it sure sounds like cheap insurance the have it as a backup! Hope y'all get hooked back up soon.
     
  7. Ernie

    Ernie Well-Known Member

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    Don't have the answer to those questions, but the 10 hr run IS at 50% load, the manual says.

    I don't know how the generator works, so maybe y'all can enlighten me.

    When I power it up, am I generating the full 6.5kw or am I only generating what is needed? In other words, is excess going to waste since I'm burning gasoline anyway?

    Looking back at the site where I got the $0.50 figure, I can see I read it wrong. It's citing an average $0.0050 per hour. That didn't absorb right with a quick glance. :)

    I can't find much more specific information. Looking at my electric bill, it shows me a base price of $0.12 per hour but that's before they add about 7 or 8 cents in surcharges. I'm not real clear on what that is.

    Regardless, I like having a generator anyway. Our power here this year has been extremely unreliable, often going off for an hour or less but several times going off for more than 4 (and for no visible reason). Just part of living out in the sticks, I reckon.
     
  8. mightybooboo

    mightybooboo Well-Known Member

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    Yikes!!

    Nothing personal but I dont want to go to math classes with you guys!

    Lets say you are producing 3 kilowatts/hour at 50% load, Times 10 hrs is 30 kilowatt/hours(30,000 watts for one hour) .At 20 cents a kilowatt/hr (HIGH figuring) thats 6 bucks from the power company. For the ten hours electric your genny is making for about 30 dollars.

    Or this,you are making 30 kilowatts in 10 hours for 30 dollars,Im coming in at about 1 dollar per kilowatt for genny power.
     
    Last edited: May 24, 2011
  9. texican

    texican Well-Known Member

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    If memory serves me right, if your load starts getting above a certain point (50%?) the engine starts pulling harder... get up to 100% and your fuel consumption gets higher.

    Hope ya'lls grid comes back soon.... might want to look at your manual and see how often oil/filter needs a'changing. Most regular gennies aren't designed for full time usage, and using em full time (esp. if the oil and filter aren't changed) will wear them out quickly.

    Nothing beats grid power for costs... if one only looked at the price of fuel consumed in genny power, one would be mistaken... the lifetime of the genny itself should be taken into consideration. A genny that costs a thousand, and wears out quickly, will need to have that 'cost/hour' figured in.

    I'm saving up for a whole house genny, one designed for long term usage. Alas, they're around 4K. When I do get one, I'll get a stockpile of oil filters...
     
  10. Harry Chickpea

    Harry Chickpea Well-Known Member Supporter

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    When you run a generator, it has a governor that attempt to keep the speed constant, so that your power will be 60 Hz, like your equipment wants. There will be variation, unlike the power a power company supplies. In a few cases, that can shorten equipment life. Anyway, under a no-load condition, only a minimal amount of gasoline is used to keep it up to speed. When the draw on the power increases, more gas is fed in to keep the speed up. You can often hear this, sometimes it may even "bark".

    If you heat water with propane, and have a gas stove, yeah, your generator could supply your whole house. It can also power a 5000 BTU room air conditioner safely.

    Remember that the generator exhaust is dangerous. One thing above the carbon monoxide danger, is that you may get a scratchy throat just from running the generator, refueling, and otherwise tending to it. If you can make a stack for the exhaust to get it up in the air and away from you, your lungs will thank you.
     
  11. InvalidID

    InvalidID Too Complicated For Cable

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    What is the difference between a 2 phase and a 3 phase gennie? I have an old Kohler 3phase that everyone seems to want, but I love it and it stays with me.
    As far as I can tell, the engine RPMs are more constant but that is all I know so far.
     
  12. Harry Chickpea

    Harry Chickpea Well-Known Member Supporter

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    Tesla was the absolute genius that devised polyphase or multiphase generators. Describing the full differences would take a book. In short:

    Two phase: Power is generated or transformed through a single coil of wire. Instead of just tapping the two ends of the wire, there is a center tap. If you tap the two ends, you get 240 volts. If you tap one end and the center you get 120 volts. If you tap the other end and the center, you get 120 volts. For home use, this is fairly simple, and the way almost all homes are wired.

    Three phase: I am going to give this short shrift intentionally. There are two main configurations. In one three coils radiate from a common center. In the other, three coils are daisy chained end to end in a loop. Depending on the windings, you can get a variety of voltages. 110, 220, 440 etc. The sine waves lead each other in an overlapping fashion. A primary reason for the use of three phase is that motors using three phase have tremendous torque (especially starting torque) and CANNOT run backwards. That is the main "need to know" info.
     
  13. Darren

    Darren Still an :censored:

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    $2.88 cost per hour divided by 3.75KW (50% load) = about 77 cents per kilowatt hour. Cost around here (WV) is under 10 cents per kwhr.

    If you could run at full load (6.5 kw) for ten hours on a tank, your cost would be 33.5 cents per kilowatt hour. You might want to consider a natural gas conversion to lower the cost of operation. If you do that, you'll get something less than 6.5 kw out of the generator. Your fuel cost should be around 20 cents per kilowatt hour or less. If you live in a cheap area for natural gas, maybe around 10 cents per kilowatt hour.
     
    Last edited: May 24, 2011
  14. InvalidID

    InvalidID Too Complicated For Cable

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    Ok, that was way over my head. Really interesting to know though. I suppose I should have asked it this way. Why is a 3 phase genset advantageous.
    From what you've said above I'm thinking it works out like this:
    A 3 phase gennie runs at lower RPMs as the extra coils would produce more power at lower speed. This is why the engine needs more torque? This would also explain why my genset seems to run at a much lower and constant speed. Right?
     
  15. AngieM2

    AngieM2 Big Front Porch advocate

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  16. Wags

    Wags Well-Known Member Supporter

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    So can anyone point me to a good site that would help us figure out just how big of a gennie we would need to run our house?

    My biggest concern is keeping the well pump going and the frig. After that would be hot water heater and the stove both of which are electric.
     
  17. shawnlee

    shawnlee Well-Known Member

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    A quick thing to mention......

    Natural gas is tops when it comes to genny use......it burns cleaner{longer gen life} and stores practically forever, unlike gas which has a very limited shelf life. Natural gas is subject to tank leaks...other than that it can be stored practically forever.

    When running a genny it provides more power potential than is used in most cases and also burns more fuel than is needed for said power.....a bank of batteries like a solar set up is ideal when using the genny....all extra potential power is stored for later use, reducing genny run time,wear and tear and fuel, and making more bang for the buck in terms of fuel used and hours on the genny.

    A hybrid system of just a few solar panels to keep the batteries topped off and a genny that runs when more power/ charge is needed will give the best bang for the buck invested and can be had far cheaper than a stand alone solar/ wind system, with room for future growth.

    For the short term , the smallest genny that will charge the batteries in reasonable time will use less fuel and cost less to buy and replace.....this is not soo good for a long term survival situation where a new genny might be hard to get, but for now it is one of the cheapest ways to get a hybrid system started.

    One could have a more industrial genny on reserve in the shed for a survival type scenario that is kept fresh and new to replace the cheaper smaller genny if and when it fails.......

    A few solar panels and associated stuff about 500, batteries..about 500 and a cheap small genny about 1000...about 500 for a inverter and about another 500 in associated parts to get it installed is a good start to cheap system to run that will last quite a while.....give or take 1000 bucks depending on size and quality on that price.
    A system like this will last longer and be easier on all the parts in the system....

    Definatly not the only way or the best way.......but is a cheap entry into a hybrid system that will give some power at a decent price and not break the bank......this is for emergency, primary needs and is not a system to run a 3,000 square foot house at full tilt with everything on at once.

    In a emergency power levels will and need to be reduced......in a survival off grid situation power beeds must be reduced.

    Like everything it depends on your usage needs......I live in southern cali where power is fairly exspensive and my power bill is only about 30 dollars average a month strictly using power company power....so you can see my needs might be different than others and my system could be fairly small....considering power consumption would be further reduced from this in a emergency/ survival situation.

    Just something to think about and look into since the topic has come up to be discussed......thats my 2 wooden nickles worth anyway.
     
  18. Ernie

    Ernie Well-Known Member

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    I considered natural gas, but it seemed to be difficult to come by as compared to gasoline where I can just fill up anytime, anywhere.
     
  19. ||Downhome||

    ||Downhome|| Born in the wrong Century

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    ever look into wood gas Ernie? you could still run gas and if you installed a propane carb you could also run that or natural gas possibly methane.

    but for the most part you will not make electricity cheaper then you buy it for. but nice to have a back up.

    don't know how you set up but I really like the idea of water battery. not super efficient but pretty low tech. can serve as a cistern and to rise fish also.

    the battery bank gen combo is what a lot of folks I know use, they only run the gen when necessary (run the pump or washer) and to top off the batteries sometimes. then run off the batterys for the duration.
     
    Last edited: May 24, 2011
  20. Callieslamb

    Callieslamb Well-Known Member

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    You go around your house and add up the wattage usage of all the appliances/instruments you want to keep running and that will tell you what size you need. Then you take your check book to the store and start deciding what energy guzzlers you can do without. You don't have to run everything at once - in fact, it's probably best not to. Pick and choose and add up what you can run at the same time without overloading the genny. We just went through that exercise to see what appliances to put on what circuits so we can flip switches at the elec box as needed.

    I don't think generators are best used to run continuously. We plan to run ours to chage up battery packs and use elec from them for the smaller things - like lights an computers. We will add more batteries as we can. We will run the well until the tank is full and then the well gets turned off. Once the well is off -we can run the freezers (or something else) for a while. But the generator is not on all the time - only for short periods. You can do the same with a water heater. Ask yourself what you really need hot water for in an emergency? Can you not produce those smaller amounts more cleaply with a BBQ grill or camp stove? You would be better off with the propane camp stove to cook on than the elec oven anyway. Refrigerators and freezers will keep cold/cool for long periods of time if you keep the doors shut. We have already determined that the fridge is not essential to us. What's in there can be eaten quickly. We will keep the freezers frozen though. Think about what's in your fridge - what absolutely HAS to be cooled?

    Just think it through one step at a time. What to you absolutely have to have and what can you do without?