Author Topic: Oklahoma Wind Question (Read 1639 times)

Hoskald · « **on:** July 18, 2006, 06:35:48 PM »

Greetings all!

We are preparing to build a new home in South Central rural Oklahoma. We have done some calculating and think we will need to generate 500 KWh/month. Now the average wind speed here, according to AWES is 10 - 15mph. Could we expect to come close to this with wind in any practical sense? If so, how would one configure a system for optimum perforance (i.e., two 20'. one 10' one 20', etc)?

Thanks in advance,

Hos

DanB · « **Reply #1 on:** July 18, 2006, 01:32:17 PM »

Probably the most popular choice in your situation - especially if your grid tied, would be a 10KW Bergey machine. My guess is if your building a place, and you need lots of power... you may not have the time to screw around trying to build something yourself (though maybe you do and it's lots of fun!) Lots of good reading on this page anyhow and they sell wind turbines with a good reputation. http://bergey.com/

Hoskald · « **Reply #2 on:** July 18, 2006, 02:05:46 PM »

DanB,

a Bergy 10KW (or two) would be nice, but at 24k per, not including tower, it's somewhat out of my comfort level. Not to mention it would completely be missing the tinker factor. I have talked a few times with Mike Bergy, they are a great company that seems to want to take the time to anwser questions. When talking with Mike, he thought the 1KW machine might be a better fit, since, he said, I could expect 300 KW / month in the location that we are looking at. Now at $4,500 including tower, this is a good deal. But after looking at your guys mills, it seems reasonable that I could do it for at least the same cost (possibly less depending on how many I break ;P ). Plus, I actually Like doing things myself where possible.

Now all that being said, could we do it ourselves without going insane?

Thanks!

Hos

billymc · « **Reply #3 on:** July 18, 2006, 03:43:09 PM »

If you are planning to go with a grid tie system the generator output voltage looks like it needs to be a lot higher and better controlled than with most of the homebuilts here which are mostly used to charge a battery bank. I've been looking at the Windy Boy Grid Tie inverter. It needs the generator power curve so they can program the controller. It could get pretty complicated trying to design a homebuilt system for grid interconnection.

Just my $0.02 worth.

billymc

paradigmdesign · « **Reply #4 on:** July 18, 2006, 03:55:53 PM »

Also, atleast in Ohio, if you are going to grid tie a.k.a. NetMetering, you will need to have a UL (Underwriters Laboratories)certifided inverter and turbine.

Hoskald · « **Reply #5 on:** July 18, 2006, 04:21:45 PM »

Some very good points to consider. I do plan on being grid tied, but for only two applications for the time being, to run the geo-thermal heat pump for A/C and as a backup battery charger. I really have never intended to sell back to the grid, not enough return on investment there. The long term goal is going to be completely off grid, but that is long term as time and money allow. Now the question becomes, in the charging application, will I need a UL Listed turbine? The local power company doesn't have a clue, and is researching the issue.

The original plan was for solar with wind backup, but the even at 500KW/month it's cost prohibitive for us. So we will start with wind (I hope) with grid backup and add solar as time moves on.

As for time, we will build a small "house" this fall to act as the HQ while we build the Big House starting next spring. The current plans and time line are looking at 18 - 24 months to complete, so I think I have plenty of time to play with wind.

Ungrounded Lightning Rod · « **Reply #6 on:** July 18, 2006, 05:09:17 PM »

Now the question becomes, in the charging application, will I need a UL Listed turbine? The local power company doesn't have a clue, and is researching the issue.

I think that, for battery charging, it's an issue between you and your local building code people and your homowner's insurance company.

Power company only gets involved when you're driving the grid, or when they're hooking up or changing a drop and need a certification from the local code people that you're OK by them. On the "driving the grid" side I think their issues are just that the equipment connecting battery to grid is up to code, safe for their linemen (i.e. won't drive a downed wire), doesn't exceed your drop's capacity, and sometimes that the capacity of the renewable energy system meets the requirements for any special billing rate deals you're getting.

The code enforcement people and your insurance companies (homowners, maybe umbrella) may have issues with details of the charging side of the system.

Remember that UL started as a certification organization run by and for fire insurance companies. They certify equipment as being unlikely to start or spread fires, toxic/damaging smoke, damaging water leakage, etc. Then the fire insurance companies made it a condition of insurance, or gave a lower rate, if all installed equipment of interest to them. (UL = (insurance) Underwriters' Laboratories.) Electrical codes as law came later, IIRC, and nowadays incorporate the UL approval by reference for many items.

billymc · « **Reply #7 on:** July 18, 2006, 05:12:46 PM »

I don't think the turbine would need to be UL listed. As long as the distribution panel for the battery/inverter system is not tied into the public utility. The big problem may be with local building codes and inspectors.

I guess you would need two breaker panels, one for public utility and one for the off grid system. As long as the two are kept separate I think the issues are back to the inspectors and insurance company.

I live in OK too and PSO (Now AEP) used to let you run your meter backwards if your generator was less than 10kw and UL approved. Therefore you get full retail value for the electricity you produce. That was a long time ago though. Not sure now.

billymc

jmk · « **Reply #8 on:** July 18, 2006, 05:18:26 PM »

I went to a seminar here in Michigan. The R/E installer told me that the electric co here doesn't even ask what's powering the inverter. He says all they care is that it is being feed to the grid from a piece of equipment certified by an electrical engineer, and has the data to go along with it. He told me we could hook my Hugh 12' turbine up with a SW/2440 Xantrex inverter. I think you would need something bigger than 12' though. That is to get the power you want.

Hoskald · « **Reply #9 on:** July 18, 2006, 06:31:06 PM »

Well, where we are building is a "no code" area meaning there are no local codes to contend with. The house plans will still go through engineering however, to make sure that the roof doesn't cave in or something unintented.

As far as insurance, we are still looking since our current carrier doesn't insure strawbale or cob construction. They only recently started insuring log homes! We may be force to build "at risk".

After thinking about the posts that I've read today, I see the layout as this:

Grid power to a panel that supplies the A/C unit and the battery charger

The wind turbine/solar panels will feed an inverter/charge controller. Do I have this right? (Always learning!)

Given a 10 - 15 mph average here, what would it take to produce 500KWh/month, roughly? I understand that this would be an average, because our hottest months (July and August) are also almost totally windless. Winter is much better with fairly high winds (20 or so).

Thoughts?

Thanks,

Hos

RP · « **Reply #10 on:** July 18, 2006, 07:48:46 PM »

Well there are an average of 728 hours in a month and you want 500KWhrs so you need a power source that can provide about 688 watts and it has to do it 24/7 all month. Assuming your windmill only produces power 20% of the time (a guess, others here will have better assumptions) then you'll need to it to produce 5 times that much power when it's working or about 3440 watts. This is still doable and could be augmented by solar...

You can download weather history data from Noaa for your area and get an idea of the wind conditions throughout the year. My diary has an example of doing this.

wdyasq · « **Reply #11 on:** July 18, 2006, 07:53:50 PM »

Hos,

I will suggest you do what any of us would have to do to get a proper number. We would need to find the average wind speed per month of the year for the site (Even a region of Okiehomie is a wide variance), pick a number and start calculating. There is 3-3/8 times the power in a 15mph wind than is in a 10mph wind.

Anyone who tell you a set number without surveying the site will have more manure on the inside of the boots than the outside and likely to have brown eye color.

Ron

thefinis · « **Reply #12 on:** July 18, 2006, 09:53:07 PM »

Hos

I think that you may be biting off more than you can chew all at once. I watched a straw bale house being built in Utopia, Texas and it was quite a feat. Dangest foundation pour for a house, footings as wide as a straw bale in load bearing areas. Nontraditional methods require a lot more sweat equity and time investment than normal? traditional methods plus it is harder to find help/builders and suppliers for such a project. Better expect to hear the phrase "you want what?" a bunch. To add to this mix trying to set it up to be off grid will just increase the difficulty level.

When and how will you find the time to experiment and build the wind turbine while building this house in the next couple of years? I think your goals are great but feel that you might be better off to build the house and then the turbine. You could set up the house electric system to run the way you want it but supply base power from off the grid instead of a battery bank. Not efficent but it insures that you will work on getting off grid and that the house and you are ready to do so. This would give you a chance to work out the kinks and quirks. It would also allow you to accruately determine electric usage before sizing and installing the turbine and battery bank.

I really admire what you are trying to do but unless you have a crew that has built straw bale houses before and hopefully wired one for off grid before then I really think that your time is better spent on the house first. From your posts it seems that you are new to the wind turbine/tower/dc power so expect it to take some time(like in years) to design/build a total system that is sized right/workable/reliable from scratch.

Best of luck and don't let me throw cold water on your plans.

Finis

DanG · « **Reply #13 on:** July 18, 2006, 10:41:19 PM »

The UL Labs were originally organized by a Doctor who earlier on had gotten released from his duties as Surgeon General when he disproved of a food additive. "Anybody who says saccharin is injurious to health is an idiot," said President Theodore Roosevelt. Of course there were buckets of money and years of time involved but saccharin, the most studied food in history, is why the good Doctor extracted his revenge on the world with the UL Labs. Factoid courtesy of Public Broadcasting and a little google.

~

drober23 · « **Reply #14 on:** July 19, 2006, 08:54:33 AM »

I agree that the best idea may be to concentrate on the house first, then the windmill. I am taking that course myself. My geodesic dome is almost complete. I have been working on it steadily for 3 years now. Once the dome is done, I will begin working on a couple wind projects.

I did not have trouble finding insurance for my 'odd' house. I suggest that you keep looking for insurers. Perhaps a board on alternative housing might have some suggestions. You may try the Yahoo Group Dome Owner Builder Group. Some folks there might have ideas for you.

I made an Excel spreadsheet to help estimate how much power was available in the wind. It can be downloaded from www.otherpower.com/images/scimages/4269/Wind_Power_Calcs.xls

There is a worksheet for commercial units, where you have a power curve available. You could enter the power curve data from the Bergey windmills to get an idea of how much power you would make with them at your site.

The Excel sheet uses the Rayleigh distribution to estimate how many hours per year you will get at each wind speed given your average wind speed (which you already know!). It then factors in things like height and terrain, to take the power curve values and turn them into KW/h per year.

Let me know if it is helpful to you.

DJ Roberts

drober23 · « **Reply #15 on:** July 19, 2006, 08:59:28 AM »

Hmm, maybe this link will work for that spreadsheet.

Wind Power Calcs

DJ Roberts

Hoskald · « **Reply #16 on:** July 19, 2006, 03:25:14 PM »

We agree, and when time comes next spring, the house will come first. But for right now, we are in a period of "slack" while we wait to close on our land, and the next iteration from the designer. So I am laying the groundwork for what will be the Phase II project. Consider this the fesibility study! This fall, aside from some strawbale workshops and some "team building" with our construction crew (it pays to have a large cadre of brothers and cousins with a wide range of trade skills!) we want to get hands on with wind turbines (possibly a small one to power the construction shed. But we need to know what is possible to do ourselves. Thanks for all the links to the spread sheets, I see how they were constructed and understand the rational behind them...I'll let you know when I get a working one under AppleWorks.

Thanks for the info so far, you guys are best!

Hos

Hoskald · « **Reply #17 on:** July 20, 2006, 09:27:44 AM »

DJ,

I have spent some time with it at work (MS Office) and if I am reading it right, it looks doable.

With an anualized wind average of 11.2 mph, assuming a 75' tower, 20% efficiency a ten foot rotor would just cover our estimated 6000 KW/year (7997.9 KWH from the spreadsheet).

On my 4 year average wind speeds for this area I see that Aug is the only bad month with a speed of 8.6 mph. Not too much there to play with!

Do these numbers look close to the mark for a homemade turbine? I had to make a few assumptions...

Cheers,

Hos

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