power ratings

[Maveth]

I am new to the wind turbines and have been pricing things out.  I am attempting to generate 31,000 kWh/yr.  I saw some 12kW  models that claim to generate the proper amount but what I don't understand is what factors they are using to state the end output.  I am aware that wind is variable so I averaged 50% operation.  Say 180 days or 4320hrs times 12kW should be 51840kWh, but their site says 32297kwh  and the price 20k plus 4k plus 8k = 32Grand!  that's a buck per kWh!  It would be 16 years before the thing paid for itself!  By that time all sorts of things would undoubtedly be failing! So that's why I ended up here, there's gotta be a cheaper/better way!  I am going to try to learn how to do this from scratch,   --  Ha,  and maybe find a way to get them into many peoples hands for half these prices (God willing . . . I'm dumber than I look!)  But to start off, I really don't understand how this company rated this machine at 12kW and ends up with those annual figures . . . knowing me I am missing something.  Any body have a moment?  Thanks in advance!

[amiklic1]

It's hard to get 12kW homemade "cheap" turbine, as it would probably be very big, expensive and hard to control. Maybe the best way to start is to change all lights, appliances and other electrical stuff with energy eficient ones, ant to get the consumption down before starting to build anything. Then, (as 31000 kwh/yr is a BIG amount of power)... 31.000 !!!?? Are you heating the sky above your home? (my Dad says that when the furnace is burning and someone leaves the door opened) That's 85 kwh/day. It seems that you're using some 7kW devices all the time, night and day, 24/7. Maybe it's best that you list devices you run, and we'll sure help to start with it. But 7k permanet a lot of power to use, and i'm sure lot to waste. Sure there is the place for improvement.

[maker of toys]

you need 85kWh a DAY?  yow.  what are you powering with that sort of juice?  

In the dead of winter, I'd be suprised if I used 10 kWh a day, and I have all electric appliances and heat here in my apartment.  (granted, I live in california and like sweatshirts, but still . . .)

in any event: manufacturers claims are usually, um, optimisitic, shall we say?  so unless you're living on the Altamont pass or the Tehachapi pass, you're not likely to see rated output very often at all.  I see much conservation in your future. <G>

(according to your figures, the manufacturer expects to average about 1/3 rated power over the year.  I think most of the truely off-grid folk here would be glad to make 20% of rated power on a yearly basis. . .  maybe DanB can give you the benefit of his experience.)

[TomW]

Just a simple huh?

Whatever you do, do not provide the web site address so we can look at their claims and perhaps help by deciphering the actual technobabble! It is much more fun for us to guess. And, in general most, if not all, manufacturers rate their devices rather generously and without us being able to read the claims in context we cannot really respond with any better information.

Tap Tap is this thing on?

T

[wooferhound]

If you already have Grid Power, then you have the cheapest power. If you are interested in making your own power, it will cost more so you would consider it a FUN hobby. You just need to learn conservation and teach the Family too.

It is cheaper to buy mass produced power from the grid, than it is to make your own power. So start with conservation. It's a lifestyle change, turn off electrical items when not being used, install energy efficent appliences and lights, SuperInsulate your house, etc. once you can get control of your electrical usage, then start thinking about making your own power that is more expensive than you could buy.

[Maveth]

To the best of my knowledge from limited research :  The average methane (natural gas) consumption for a single individual  {obviously effected by environment, this is Midwest US climate}) is approximately 72,000 to 90,000 cubic feet/yr @1031 BTU/cuft (methane heat rate) = 92,790,000 BTU/yr (high end). The average electricity consumption (Not used for heat) for a single individual   is approximately 3500 kWh/yr.

One kWh converts to 3413 BTUs = 27183kWh of heat plus 3500kWh elec =  30687.  That is how I arrived at the power needed.  I could be wrong.  

My 2000sqft duplex here in pittsburgh is 100yr old and poorly insulated and uses approximately 70,000 BTU of Methane/year @ 60 degrees.  So I fit in these averages.  Granted average people (especially in America) are not conservative conscious.  I actually only use about 3000 kWh/year at this property because of gas heat.

However all this exploration on my part is for the future when I attempt to build a self sufficient geodesic dome!  For at the present moment I am in the heart of the city.  The new home will most likely be smaller, more modern, with better insulation etc.  I was also thinking about geothermal heat and solar thermal heat, with solar roof panels also!   So granted I will not require so much power - or will I . . .  At that time I may need power to run other operations such as a small (domestic) grain mill and press, hydrogen electrolysis, small multi-purpose distiller (for water, plant extracts) to achieve utter self sufficiency!  Yes it will be very expensive for me . . . but my children will live for free!   Any way . . . He who dies with the most debt wins!!  (as long as nothing is in your name of course  : )   )

Hopefully the sun and wind compliment each other to generate enough hydrogen for the odd days when neither are producing.  I have three years before I sell this property, a lot of time to research learn and plan out a design.

So on with the learning!

Since every one so far is jumping at my electric heat figures, With your experience, How many BTUs on average are required to heat  a 1000 sqft (modern) home one year?

Thanks for your time!

[Maveth]

 

http://www.windturbine.net/prices.htm

[Bruce S]

Maveth;

  I took several times to look at your math to finally come up with what I believe is the leap.

In your math you are doing calculation for the entire year, but you're looking at trying the generate that much at one time.

That is not necessary, and the math is done on an average. Some days you may need more other much less.

After looking into the Penn State averages. You'll be happy to know that your needs are 1/10th of your final numbers on average.

remember the usage you're seeing 3000kwH is an average.

The EPA has a website I think that lists what each device uses, from there you can get a ball park idea of what you could be looking for in terms of daily needs.

With that knownledge you can then plan for say 50% more available , this way you can plan on those extra cold days when that 10" of snow shows up over night, or that BBQ party goes into extra innings.

Also, while in the planning stage, you could instead of converting the methane into electrical energy, store it at low pressures and use it straight into the heating system you have. It's already ready, and natural gas is compossed of 95% methane anyway.

So in reality the 12Kw genset look like it could work out as it's max output could work as it's max output per hours is more than your needs may be.

Or I missed something and my figures are totaly wrong.-)

Thoughts?

Bruce S

[nothing to lose]

"Yes it will be very expensive for me . . . but my children will live for free!"

No, they will say let's sell out, grab the money, move to a city, think they are rich for 2 years, then wonder why they ever did such a dumb thing when the Feul bills roll in and they have no money left.

Don't worry so much about life, you won't survive it anyway

 Now that the jokes are out of the way, you are smart to be planning ahead.

 First I would suggest looking at the type of home you plan to build and where it will be. That will be the largest factor of the amount of heat you will need. An under ground house in Nevada will use far less heat I think than a 2 story in Main or Rhode Island.

 Personally I would like to live in a cave

Seriously! I have been in many caves. Silver Dollar City, Branson MO. A reely nice clean one in Springfield MO. and cleaned nicly a good cave is great. The one in Springfield, MO I was in was at one time an old speak easy I think they said, then it was a theater at one time. Now it is a tourist trap

Think about it, a cave stays nice and cool in summer no Air conditionare needed. A cave stays nice and warm in winter, a bit cool, moderate heat needed. Some caves are a bit damp perhaps. Well heres a great thought, move a nicely insulated trailer house into a cave. You have the best of everything right. Low heating, no cooling needs. No storm worries, caves are toronado proof prety much. You got a house insulated in a warm weather proof place. You need to run in power lines from the wind genny and your all set

I am pretty serious there. Find a nice hillside and dig your own cave, real caves are hard to find availble to buy reasonable.

So like I said, you need to study the house and location your planning, and figure real power needs based on that. Your Kwhr is probably way off base if your going to build a new modern home and have any intention of being energy efficeint at all. Like you mention Hydrogen? Ok what are you thinking of using that for, and why electrolisis anyway. Solar hot water heating could do wonders for warming the house, even if not toally heating it, thus cutting down on electric needs for heating.

 If your planning for the future, why figure only one massive large wind gennie? Plan 3 gennies of 4Kwr each instead of 1 for 12Khr. Sooner or later you will need to take it down to clean it, check for loose parts, general maintinance stuff. With 3 gennies flying your never without power even if you have one down for a few days. With one genny only you got a problem if a crazed flock of geese attack it suddenly and break a blade. Would take a mighty large and determined flock of geese to take down 3 mills at once though.

Got to eat, foods done. Another energy waste. Got a hot wood burner heating the house, wifes uses propane stove. Oh well, good food anyway.

[Clifford]

Don't forget to look at the wind speed ratings of the windmills that you are pricing.

For example, on the site you were looking at...  see the 20 KW generator:

http://www.windturbine.net/20%20Pwr%20Curve.htm

It hits 1 KW output at a 10 MPH wind (which is quite brisk).

Then, up to 10 KW at up to 20 MPH wind.

It only hits 20 KW at 30 MPH....

The ratings are "reasonably attainable" as you will often see other windmills only producing their peak power in a hurricane (just before being blown off of the towers).

Let's see...  the 10-17 power curve on that site:

http://www.windturbine.net/10-17%20Pwr%20Curve.htm

for the 12.5 gen:

1. KW at 10 MPH
   
2. KW at 15 MPH
   
4. KW at 20 MPH
   
12. 5 KW at 30 MPH
    
    

However, I would certainly look at the average wind speed in your neighborhood (at altitude) before making any decision.

Ummm...

That site is also listing HUGE towers.  

Hopefully you have space for an 80 - 200 ft tower.

[ruddycrazy]

Any household that needs the kind a power quoted above must want to live like a snob. Sorry for that it just had to be said!!! For a comparasion we run a passive solar array on our farm house. For a $25,000 investment less $8,000 we got in a govt rebate we have a 3Kw RE system. We can run just about everything a normal household uses barr a microwave only as we don't need one and we do have gas hot water, stove. Now in the 2 years we've had this system running only once did the batteries drop below 2 volts nom per cell. In winter in the past I've had to run the 5kva genset to top up the batteries after a few overcast days. So in my opnion solar has to be a viable option on any RE array and wind gennies are good aswell but what happens when the wind doesn't blow for a week.... Just ask Murphy!!!!!!

Cheers Bryan

[Maveth]

I am using stated annual averages of power usage across US from many different sites.  They are averages of averages leaned towards worse case scenario.  Being that the average human being in the US is working class blue collar types,  is this what a snob is???  Or maybe they are sadly uneducated  purposely by the industry leaders to irresponsibly  consume thus funneling more money down industry throats???   I imagine it is more the latter.

How many kWh do you consume per year?  How many cu/ft of gas does your hot water and stove use annually?  How is your home heated?  

Thanks

[paradigmdesign]

Simple answer, mills are rated at there highest, not average output.  If you live in PA you most likely fall into a Class 2 - 4 wind site.  Anything less than a 4, or high 3 is very hard to make wind energy practical.  Also, did you include the towers, and inverters in thoes prices, they are usually as or more expensive than the mill itself (expecially the tower).

[Maveth]

Ha!!  Nice, kids would do that now that you bring it to my attention!!  LOL!

Funny you mention caves!  I am planning on burying a modified geodesic dome structure.  The roof will be a much smoother and gentle arc than traditional.  It will have a few sky light windows and the rest will be a solar array in betwwen which is laced solar thermal tubing.

There will also be two closed  geothermal pipe loops.

I hear what you are saying about location and agree, however at this point I am working everything off worse case averages and exploring the potential of each option doing the job itself (in ideal conditions).  Then when I understand all these potential abilities I will then consider as to what extent to utilize each in tandem  to  maximizing the energy of the choosen environment.  

As for a wood burning stove here are some figures:

The avarage piece of wood contains about 7500 BTU /lbs.  Burning at approximately 80% efficiency one would need  approximately 7.75 tons of seasoned wood per year to meet the US average 92,790,000 BTU/yr in household heat.  This is approximately 24 avarage trees per year.    You can fit 303 12 high (approx 12ft wide) trees on one acre.  By harvesting 24 trees and ensuring the healthy growth of 24 new ones each year.  It would require one arce of trees per home to utilize wood heat as renewable.  At the end of 12 years your fist bornes should be about 12 feet again.   (This is not including the acreage of the homestead)

 By useing all solar and wind ( which I don't even use one bit!)  This one arce would be free for other use or left as wild.  And almost no wastes are produced.

Another reason why wind and solar electric should be used by everyone is:

On Average, a modern `combined cycle' gas turbine (CCGT) generator operates at 7000 BTU to produce one kWh (49% efficiency) in cool, dry weather.  (These are the best and most efficient plants today beside nuclear.  Most plants would use about 8500BTU to make a kWh)  So using  say 8000 for average.

     To Generate one kWh of electricity at a plant (which would light a 100 watt bulb for 10 hrs)  on average it takes 8000 BTU (about one pound of coal).  To Convert that electricity back into heat when it reaches it's destination you will can only get 3413 BTU of heat out. That's a loss of 58% of the Coal.  Every plant uses MILLIONS of tons of coal, for every million in, over a million is wasted.  This is absurdly primitive yet goes unquestioned.  By the way this does not take into consideration all the BTUs generated by the colossal mining and transporting of the coal nor the BTUs spent in making the railroad, the train or the titanic draglines and articulating end dumps All of which are solid steel (some created in electric furnaces?!?!?  remember the already heat loss above!?!?!?) and diesel guzzling monsters.  By the time this is factored in, there is scarcely any return from coal.  Kinda disgusting isn't it?  

 This "Infrastructure"  that many people try to warrant as reason not to go utterly green is a groundless argument, as the infrastructure itself Takes half the energy it is trying to make!  An approximation is that about 10% of the potential energy in the coal is actually  used by a customer.

Just my silly opinions of course, Thanks for the reply!

[Maveth]

 There may be a small misunderstanding,

1. you are right this is an annual snap shot.
   
2.  you forgot to factor in the 27211 kWh of heating.
   
3.  I don't convert methane into electric.  I have natural gas heat which is methane as we both stated, directly from the gas company.  The figures in the previous post were just a representation equating the two methods of heating.   One cu/ft of natural gas generates 1031 BTU,  1 kWh generates 3413 BTU  so it is just saying that it takes 3.31 cu ft of natural gas to equal the same heat given off by one kWh or vise versa.
   
4.  I too agree that the 12 may work in ideal conditions.
   
   

Thanks for your response and

Best Regards!