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Permalink Reply by ledlights on September 12, 2010 at 9:10

Our local residential electricity costs 8.4 cents/kWh and is tiered to 9.2 cents/kWh for anything over 600 kWh in a month. If I was able to take NG at our local cost ($1.09/therm) and convert it at 80% efficiency to electricity that electricity would cost approx. 4.65 cents/kWh. Our local utility now buys back excess electricity, but I think they only pay their cost - not what they charge us. Still seems kind of interesting, although peak residential for individual houses is far less than 25 kW so this system should be serving multiple houses, a business, and/or selling excess back to the utility. The cost of electricity in the east is typically much higher, so the economy of this generation would probably be much higher in such regions (I don't think the difference in NG cost per region is nearly as great).

However, I followed the link to the CA info and it has a discrepancy - it says the efficiency for systems that are recuperating waste heat is only 20 - 30% which is more typical of our large scale electrical generation and delivery. So I am wondering which is it? 30% or 80%. And what are the ball park costs for these systems? What is their expected lifespan? What is a reasonable maintenance cost estimate? And taking these all into account, what is the overall SIR (savings to investment ratio)?

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Permalink Reply by dbob on September 12, 2010 at 9:44

Capstone is one of the leaders in this field. you might find thier site interesting.
http://www.capstoneturbine.com/

and

http://www.capstoneturbine.com/apps/EconCalc/EconCalc2.asp

and

http://www.capstoneturbine.com/prodsol/products/

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Permalink Reply by ledlights on September 12, 2010 at 10:01

Thanks dbob,

Using your second link which only requires my gas and electricity (I used a tiered average) costs, the Capstone calculator projects that their turbines can generate electricity from my natural gas at a cost of 6.3 cents/kWh. This calculates as 59% efficient in its conversion of NG to kW.

The calculator does not state all of the assumptions that it is making but it estimates that a Capstone turbine would pay for itself in my region in approximately 4.45 years. Not bad at all if it is anywhere close to accurate.

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Permalink Reply by sesport on September 12, 2010 at 10:22

Thanks, guys. I'm sure as of now that the costs of this may be a little higher because it's newer technology, but as the demand & competition increases (as with all things neuveau) the costs will come down. And I wouldn't consider as little as a 30% decrease in my energy bill anything to hiccup at.

The other thing that has me going "hmmmm" is the increase in the information available that indicates changes in the architectural design of the power supplies. Seems to be some kind of shift from mega grids to smaller, more manageable (and secure) grids & supplies. Imagine if there were a security threat, only those served by the bigger grid would be affected. Those on a more independent supply, like residences & small businesses, may remain unaffected. I think it's also one of the ways that businesses such as banks & hospitals can now be powered. I know many several years ago that banks had their own alternate power source to keep necessary operations functioning.

Oh, and of course, this kind of power generation uses a cleaner fuel source. That should make somebody's mamma happy. lol

80)

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Permalink Reply by dbob on September 12, 2010 at 10:36

The Capstone turbines are flexible in that they can use the "dirty" natural gas fuels, including that from methane digesters and landfill gas. I've seen a couple of them at a natural gas compression site in east texas. I didn't get any details on their costs, but they were viewed favorably by the folks operating the compression site, particulary when compared to some diesel generators on site.

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Permalink Reply by sesport on September 12, 2010 at 10:47

dbob - Yes, I'm aware that this is one of the ways, along with recycling frac water, that industry is trying to "clean up" it's image, leave even less of a carbon footprint.

thanks again, 80)

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Permalink Reply by Two Dogs, Pirate on September 12, 2010 at 11:40

My mom always left the Christmas tree up till after Easter. It was late in March and a late cold spell. I decided to light the fireplace but the firewood was a bit wet from the cold rain that had been falling. The newspapers weren't doing the job of getting the fire going and I didn't have anything for kindling, so I decided to use the Christmas tree. It was still green because it was a green color. I stuffed a bunch of it under my logs and struck the match, I didn't know no better cause I was about 20 and crazy as a bat. Needless to say the fireplace exploded, flames were coming out big time going up the chminey. Then this sound like a blue northern blowing into room, kind of like an atomic vaccum cleaner. Firery crap started falling from the chminey and the nuke vac got louder. There was a piece of plywood behind the bench on the front porch that we used during the summer to cover the fireplace opening so that all the air conditioning wouldn't go up the chminey. I ran out and got it and stuffed it in front of the opening and the vaccum cleaner stopped. I did the same to a 16 cylinder Alco diesel engine about a year later out in the Gulf but I used a big box to rags to throw down the intake. About 10 years ago I did the same thing with a ladies F-250 diesel at a gas station after she filled up about half the tank with gasoline. In any of the situations a turbine in the exaust would have spun like a siren. I would think that one could build a DIY turbine with stuff laying around the house. The propellers from the old windmills around Dorothy's house in Kansas may work for the turbine, or maybe an old attic fan, the bigger the fire the more it would push the windmill blades. I would think that using old asphalt shingles and all the crap that is left over from a logging operation would be the right stuff for fuel. This could be a low cost alternative for some retired people. They could set a co-op in their community and share the power generated.

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Permalink Reply by sesport on September 12, 2010 at 12:35

ROTFLMDO!!! Two Dogs, someone needs to give you your own PBS show!

BTW, who's writing your biography and when do you expect it to be published? Promise your first book-signing stop will be here.

Now, until then I'll caution you to keep some of those ideas under wraps. Don't want to see at some time in the future that some company took one of your ideas, R&D'd it, then took the credit & moo-lah.

80)

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Permalink Reply by Two Dogs, Pirate on September 12, 2010 at 12:47

They can't keep up with my stories and organize them all together. If some would go back to the old www.landmen.net posts when Conner Smith owned the site, they could hear more stories but that site, the old site is spooked. Ghosts are hiding there.

Permalink Reply by Two Dogs, Pirate on September 12, 2010 at 13:05

Thanks sesport.

Permalink Reply by P.G. on September 13, 2010 at 1:56

Could you get a government permit for that?

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Permalink Reply by JHH on September 12, 2010 at 13:38

Looked around for prices...as a whole-house back up generator and for a stand-alone system. send a link for prices if available. good articles and web sites.. but still very unsure about products. thanks, jhh

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