Break-even point for home electric generator powered by natural gas? What about NG-powered AC compressor?

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Home depot is selling natural-gas powered home electric generators (7 kw and larger). The price for a 7 kw system is $3000 (I think it's a turn-key system). This works out to a constant 120v/50 amp (240 v, 25 amp) supply.
If I'm comparing the cost of electricity (in cents per kwh) vs the cost of natural gas (in terms of cents per cubic meter or cubic foot) does anyone know the break-even ratio that would make it economical to generate most (or all) the electricity for your house from your natural gas supply using one of these units?
What about natural-gas-driven AC compressors? Wouldn't that be a smart choice to run your AC compressor on natural gas in the summer (when NG demand is low) ?
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Ask Home Depot how many hours is the generator expected to last. I am not sure if you would get a meaningful answer. Usually, it would not be an impressively high number of hours. Let's say that it is made like a very good automotive engine and could last 5,000 hours. (equivalent of 250,000 miles at 50 mph).
5,000 hours is 208 days. That's how long it would last if it was run 24/7. You may be able to get away with running it less if you had a battery/inverter system, but that is also big bucks, with batteries needing replacement etc.
That means that cost of the generator, amortised over its useful life, is going to be substantial.
I doubt that you would be able to get any better than 2-3 times the cost of utility supplied electricity.
i
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You could just leave it at:

and
There's nobody at the box stores that even comes close to having a clue anymore.
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Oil change every 6000 miles? Twice a week?
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If they were knowledgeable about it they wouldn't be working there earning $7.50/hr.
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After checking out the consumption of my Hatz 4 cylinder Diesel generator a couple of weeks ago, it would cost me in fuel alone around $AUS 800.00 per 31 day month (about $US 625.00 per month) the current power bill here for 3 months is 600-700 Australian $$ It will be higher this quarter as it has been hot and the air conditioning units have been on more I will expect it will be up around $AUS 800.00 for the quarter.
Oil changes, repairs, depreciation and basic cost of the diesel generator are NOT included in this cost or running the generator, only fuel.
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"Geoman^^" <Geo2> wrote in message

Actually, it's been an interesting discussion, with an exception of a few AH's. The usual alt.hvac suspects?
Bob
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wkearney99 wrote:

Ever hear of "you get what you pay for"? People are attracted to big box stores becuase of cheap prices (which almost always means the level of service has to be downgraded) and seem to be surprised when the service they get doesn't match the marketing hype that all of the "associates" are experts.
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Maybe 2.00$ a kilowatt as an example only, but possibly true for some . The Generac air cooled HD is not designed for prime continous power, Any 3600rpm units life is 3000-5000 hrs or 4 months or so, how it is loaded is important. Im sure Generac has other prime power units, but the cost. Figure only 1/3rd of the ng burned is converted to electricity, heat and friction make up th other 2/3 . An 1800 rpm unit lasts 4 times as long 10-20000 hrs. A 900 rpm Lister over 100000 hrs, that is prime power. A cheap Honda or Yamaha inverter type with load dependant rpm could theoreticly last 100,000 hrs. if you kept rpm under 900. The 3000w unit can do that developing only 1-200 watts. For longest life get a Yamaha or Honda inverter converted to Ng and keep rpms low. 10,000-12,000 hrs off them is common at medium 50% load , but at 900 rpm 100000 is possible. Yamaha is heard to have superior electronics, but I wonder if it isnt really that most people buy the 1600-2000 watts units and just overload them and never consider surge load, effectively people just abuse them.
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Maybe 2.00$ a kilowatt as an example only, but possibly true for some . The Generac air cooled HD is not designed for prime continous power, Any 3600rpm units life is 3000-5000 hrs or 4 months or so, how it is loaded is important. Im sure Generac has other prime power units, but the cost. Figure only 1/3rd of the ng burned is converted to electricity, heat and friction make up th other 2/3 . An 1800 rpm unit lasts 4 times as long 10-20000 hrs. A 900 rpm Lister over 100000 hrs, that is prime power. A cheap Honda or Yamaha inverter type with load dependant rpm could theoreticly last 100,000 hrs. if you kept rpm under 900. The 3000w unit can do that developing only 1-200 watts. For longest life get a Yamaha or Honda inverter converted to Ng and keep rpms low. 10,000-12,000 hrs off them is common at medium 50% load , but at 900 rpm 100000 is possible. Yamaha is heard to have superior electronics, but I wonder if it isnt really that most people buy the 1600-2000 watts units and just overload them and never consider surge load, effectively people just abuse them.
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Did the math on this a while back when these things just came to market...
I found that i'd need to sell the power back to the utility and run the generator all the time to break even. Then what I'd get is free heat from the generator exhaust.
Some electric utilities (because of regulations) do have to buy back power--your meter just runs backwards and you get a check.
You also need a source of cheap fuel! (Good luck with that, now...)
Check out microturbines; I believe a company called "capstone turbine" makes them.
A fun project might be to build one yourself (Tesla turbine). Don't know about efficiency as a gas turbine, but people still build (and even use) these. It's kind of a hobby thing; google TEBA (Tesla engine builders ass'n, or something.)
m Ransley wrote:

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You can`t break , the utility here buys back at 1/10 of what they charge, then with initial cost, maintenance,operating cost and depreciation you can never win. Unless you can dam a river.
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Some utilities have to pay MORE than they charge you, at least for solar generated power. Would they also have to for something like this?
Bob
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Try alt.energy .homepower So what is you rate at 50x normal prices in summer peak. Probably less than what we south of you consider cheap.
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m Ransley wrote:

?
Not sure if I understand what you're saying.
What I'm saying is that for probably a couple dozen days this past summer, Ontario Hydro has had to import electricity from the US side of the grid because Ontario_demand exceeded Ontario_supply. The handfull of mega-watts that need to be imported for a few hours each time come at a high price - they come at the market-price and it's the same price that your local utility would pay if it had to buy that same electricity at the same time of day on the spot-market.
Here's a link to the current electricity demand and price situation in Ontario:
http://www.ieso.ca/imoweb/marketdata/marketToday.asp
Today we went from a low of just under 17,000 MW (3 am) to a high of 22,000 MW around 6pm. It looks like anything over 20,000 mw came from outside Ontario (hence the huge price increase just after 4 pm).
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Canada is the 51st state they just dont know it
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Generac Ng or propane generators are set up to self cycle every week , schedule can be changed though. Talk to an owner of one to see what he pays in summer to maintain the gen for gas on self cycle . Ive been told it adds apx4- 6$ a month for it to self test itself.
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I usually don't answer posts with more than one x-post. but...
Simply look up how much NG that generator takes at 50% load. Multiply times 720 to get your monthly gas usage, figure out how much that will cost, and compare to your present power bill. I guarantee you, you will have no further questions. Believe it or not, it would cost me the best part of $1000/month to run my little 4KW generator 24/30.
Please can the excessive crossposting.
Vaughn
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Vaughn wrote:

Please tell me which ->one<- of the following 5 news groups you would have posted this question to then: alt.hvac alt.home.repair alt.energy.homepower sci.engr.heat-vent-ac misc.consumer
Perhaps I could have dropped misc.consumer or alt.hvac, but even those groups touch on the house-hold energy plants and energy-consuming devices. And my subject was very descriptive, allowing anyone to simply not read the post if they didn't want to.
I think it would be wise to focus on the subject of the post, and not get an ulcer over the relatively small and focused distribution of the post itself.

We will soon be moving (1 to 2 years at most) to "smart-meters" in Ontario (which means our electricity use will be billed based on hourly use and time-of-day electricity costs). Because of collusion of the electricity-generating-cabal on the east-coast of North America, some of our nuke plants in Ontario have been shut down to reduce supply so that various plants on the grid can provide very expensive peak power to the grid. At times, we must import power from the US and pay 25 to 50 times what it normally costs us to generate an equivalent amount of power. This normally happens only on the hottest days of the summer, usually starting at 10 am and lasting until 4 pm until the load drops to the point where Ontario_supply Ontario_demand.
Hence my question about the merits of home generation of electricity from a natural gas generator, which I agree are likely not built for 24/7 operation and (even given NG's superiority when it comes to btu/$ vs electricity) would not likely pay unless we're talking about operation only during summer peak hours.
Which leads to my related question about NG-powered air conditioning compressors, because during peak summer electric loading the culprit is usually AC units. Perhaps the simple answer to avoiding large bills in the summer is to move to a NG-powered AC compressor?
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"Please tell me which ->one<- of the following 5 news groups you would have posted this question to then:
alt.hvac alt.home.repair alt.energy.homepower sci.engr.heat-vent-ac misc.consumer
Perhaps I could have dropped misc.consumer or alt.hvac, but even those groups touch on the house-hold energy plants and energy-consuming devices. And my subject was very descriptive, allowing anyone to simply not read the post if they didn't want to.
I think it would be wise to focus on the subject of the post, and not get an ulcer over the relatively small and focused distribution of the post itself. "
Don't worry about the complaining about the cross posting or your questions....there are *ssholes everywhere and they all come to Usenet sooner or later.
Hang in there and be patient....you'll get your answer in time.
And oh...the USA is lucky to have a great neighbor to the North.
TMT
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