My Turbine and it's Output Grid-Tied

[Rock]

Well the turbine Dan and company built for me is up and running.  Its a 16 footer mounted 20 feet high.  It has survived 50 mph winds and has produced about 150 KWHRs in 2 weeks.  50 KWHrs have been pushed back to the grid and about 100 KWhrs have been used by my home.  

Maximum output just before furling is about 1800 watts AFTER INVERTERS.  I say after inverters because there are losses in the battery bank and in conversion thru inverters.  I assume a 20% loss thru inverters and batteries so 1800 X 1.2 = 2.16 KW.

My system is 48 VDC and my Outback GVFX 3648 inverters are set to Sell to the grid at 52 VDC.  A 5 MPH wind will start blades on turbine turning.  With just that low of wind my batteries will float at 52 VDC.  Nothing sells or supports but the turbine will power inverters.

Only issue is the Outback inverters.  My master inverter will activate the slave at about 800 watts and both will Sell at about 400 watts.  Not too efficient for a couple of 3600 watt inverters.  I would like to shut off second inverters Sell function but Outback cannot seem to come up with a good way of doing this.

Power company installed a dual meter and has made sure I cannot feed power to grid if it is down.  I also needed a lockable disconnect so power company can physically disconnect me from grid if need be.  

I also have a Lakota turbine.  Just for comparisons the Lakota averaged about 2 to 300 watts in 30 to 50 mph winds.  Dan's machine averages about 900 watts with peaks of 1900 and lows of 300 watts.  I took the lakota down to install Dan's machine.  I will be putting it up in another location soon to suppliment the home built unit.  Between 360 watts of solar panels, a lakota, and the home built my power bill should consist of just a facility charge of $9.00:)

I am in a net metering state WYOMING and any extra I push back I can retrieve later for free, as the power company only pays me for my extra produced once a year.  And they only pay Defered cost so about 4 cents per KWhr vs the 10 cents I pay for it.  So I guess an electric boiler will be in the works!!

[Flux]

Sounds as though you are doing well. The battery driven inverter is simple and you can use most of the power from the batteries and just export the rest.

Nowhere near as efficient as using a windy boy inverter that could mppt track the alternator and extract far more power to the grid but you have a simple scheme with no worry about voltage clamps and you have battery backup if you loose the grid.

Flux

[Rock]

Flux, you are correct and you hit the nail on the head with the back up power.  If grid goes down (usually 5 or 6 times per year) my system acts like a Whole House UPS system.  When I loose grid I do not even know it because not even my TV will pop off during the transfer from grid to batteries.  

I also have a 5 KW DC generator that is hooked to battery bank and to a 1000 gallon propane tank for those week long outages due to blizzards.  It automatically kicks on at 48 VDC and shuts off when battery bank has maintained 52 VDC for 30 minutes.  Its a alphagen 5KW filtered DC ouput genset.  

I am WAITING paticantly for the Classic Controller from Midnite to take care of the MPPT issues.  However I do realize a certain amount of loss will still happen thru batteries and inverters, its a cost of needing the back up power.  

Granted Sunnyboy AND Powerone make a system that has battery backup capability but I do not like the windyboy's algerithum and Powerone's came out after I had purchased the outbacks.  Powerone's MPPT is programmable, and I belive at least one of thier units can "learn" via freq inputs from turbine.    

[Ungrounded Lightning Rod]

I am in a net metering state WYOMING and any extra I push back I can retrieve later for free, as the power company only pays me for my extra produced once a year.  And they only pay Defered cost so about 4 cents per KWhr vs the 10 cents I pay for it.

Wish I could get that deal in NV or CA.  Both of them seem to have a "annual surplus is a gift to the power company" deal as the best I can find.

Annualized net metering with surplus sold at wholesale and deficit bought at retail is a good deal for both sides.

 - When you sell (if you only sell or for the surplus if you do both) you get paid what they pay themselves/other power companies.

 - When you buy (if you only buy or for the deficit if you do both) you pay what other retail customers pay.

 - When you do both (to the extent you do both equally) you get to use them as a big enough battery to run your house for a year at a cost of only $9/month  This lets you size your own batteries much smaller - only to regulate voltage and cover outages (which tend to happen during weather where there's lots of wind) - or eliminate them entirely (if you don't mind going dark when the grid fails).  And though they are paying you flat-rate retail rather than wholesale for the generated power that you later buy back, you tend to sell it during peak hours (when power costs them more) and buy it during off-peak (when it costs them less), with the difference enough to pay for their transmission losses with some left over.

All three are fair to, and good for, both parties (though in varying degrees).

So I guess an electric boiler will be in the works!!

Entirely appropriate.  Just size it so it doesn't QUITE kill your annual surplus rebate.  Then you maximize the "sell and buy back" mode of the above three, which is the one that's the best deal for you.

[Ungrounded Lightning Rod]

My master inverter will activate the slave at about 800 watts and both will Sell at about 400 watts.  Not too efficient for a couple of 3600 watt inverters.  I would like to shut off second inverters Sell function but Outback cannot seem to come up with a good way of doing this.

They've got their outputs in parallel, right?  If so there's no point in trying to get one to run in "sell" and the other not to:  Once the relay closes they're both selling.

"Sell" doesn't hurt you when the grid is up if you really have net metering - either by using the same meter or by using two but with the equivalent billing algorithm.  If you're drawing more than they're putting out, everything they put on your wiring comes right back to you, reducing your drain (and bill) by that much power.  And if you're drawing less than they're producing only the difference goes up the wires to the power company.

They should go into "sell" mode as soon as they have enough surplus from running the battery charging algorithm that being in "sell" is stable.  As long as it doesn't appreciably degrade battery charging it's fine.

[warpsta]

This may sound like a stupid question, but what is MPPT?

[DamonHD]

Maximum Power Point Tracking

The electronics works out what current to draw (and thus at what voltage) to extract the maximum power from the device.

Rgds

Damon

[DanB]

Hi Rock - nice to hear you have it up/running.  Do you notice the machine furling very much?  Sounds like you are doing OK - but I think you could do better.  I knew how tough your wind site was so we built your machine as a 16' version of the 17' machine we normally build.  I also raised the cutin speed and build the stator with lower resistance.  I have a feeling that you may be stalling a bit in higher winds if the best peaks you've seen are 1900 Watts.  TimS has an identical machine with slightly larger blades and slightly higher resistance in his stator and we've seen peaks over 4KW so far...

I know your tower is quite short, that's not helping...  but,  you might experiment with adding a bit of resistance to the line - or - just keep it slow and safe as it is.

[Rock]

Dan, I have the ability to increase and decrease SELLRE voltage.  I believe that is a way of "artifically" increasing resistance???  I have played with it a little and when I set the SELLRE voltage to 56VDC turbine seems to spin alot faster and I get a slight wobble.  Guess I need to re-balance everything.  

Yes, it spent almost 10 min fully furled last weekend while I was watching it.  Was putting out about 800 watts then.  

I did use #6 wire from turbine to batteries.  70 foot of it for one run.  So a total of 210 feet of #6 wire.  Rectifieres barely even get warm.  

This is one of the reasons I only put it on a 20 foot tower.  I can take it down by my self and adjust things and retorque things the 1st year easily. It will go on a 35 foot tower next summer, but I still worry that my 80 mph gust and 60 mph sustained wind events will cause issues.  Guess I am babying it!!!

Guess I should ask at what head voltage do you think unit would put out the largest and safest amount of power?  I assume 56 VDC at batteries is close to 58 VDC or so at head.  So, if I put a resistor that increased head voltage to XXX I should be ok?  What type and size of resistor do you think I should purchase?  

Next wind event I will try to count rpms and see if in fact I do have a stall issue.  What rpm should I expect just prior to furl?

Please note that my inverters "clamp" voltage to the SELLRE figure so my batteries never see any voltage spikes above 52vdc.  

[DanB]

It may not be worth messing too much with at this point.  I really expect the 20' tower is messing with things quite a bit.  I'll think about all this though and try to give good guesses about some of your questions...

I am curious - do you have data about average kWH per day that you're getting from the machine?  You say it's averaging 900 Watts - is that a 24/7 sort of thing?  I'd love to see pics of the setup and I'll definitely have to get up there one of these days soon.

[Rock]

Please note that my data is after the inverters.  With substantial losses because of the in-efficancy of my HUGE inverters.  I bet my 3600 watt inverters are barely 75% efficant at less than 1000 watts.  So, even though I "see" 1900 watts the turbine is probably putting out 25% to 30% more.  

I have a program called Winverter that is on my computer that I leave on 24/7.  The computer is hooked to the Outback Mate via a serial cable and that is how I track the KWHrs sold/supported/and to load.  

As of yesterday NO WIND 60 KWHRS have been supported to load.  63 KWHrs sold back to the utility, and 110 KWhrs have been imported from grid.  Total grid usage to date would be 110 KWhrs minus 63 Kwhrs = 47 KWhrs.  

Total usable KWhrs produced by turbine and panels are 60kwhrs + 63 Kwhrs = 123 KWhrs in 2.5 weeks.  By usable I mean the amount not creating heat in inverters due to efficancy issues.  

I sent you a photo via email.  I am too dumb about proceedure to post here.  

 

[jmk]

 Nice looking machine. I went to your files to look at the picture there. Your getting some great power!

[ohiowinds]

From what I have read on Lakotas, yours is need of repair or rewiring.  A Lakota should produce about 1300W or more in 30mph winds.  I have done in-depth research on this turbine as it is the lightest, and therefore easier to mount, and one of the lowest in price for the power output.

The turbine can be re-wired to match the wind condition it is installed in.  Look at post here titled "A little help with my Lakota.......Jerry!!!"

Before you put it back up, check the wiring or get it fixed.