Billy's Wind-Talk Blog

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Average wind speed for 59 years    

Note: Most wind generators start generating at 9mph, and are at full load at 16 mph

September 02, 2009

We are now in our 10th day of low wind or no wind.  With the (2) 2kw wind generators the battery voltage was 110 volts DC this morning.  The energy management system modified the load on the 8th day, but has since returned to normal operation.  The new 60 tower is due to arrive next week as is the new 5kw inverter.  Even in low wind by adding the last 2kw generator, the battery voltage should stay around 120 volts. 

September 02,2009  Grid-tie or off grid

I have seen several wind systems on the television in the past few weeks, both of them were grid-tie system.  The electric company is buying the power back at .08 cents a kwh.  Both said that they were only producing 1/2 of the power they needed.  With this system you are not using the power generated by the wind, it first is metered into the grid at 8 cents a kwh, then it is metered back into your site at .13 to.20 cents.  That looks like a good deal for someone, you buy you own power back at a cost of .05 to .12 a kwh or what ever.  If you power cost more than .08 per kwh then you are buying your own power back.  This is why the utility companies have gone to 2 meters, you are not going to win.

In an off-grid system none of the power is metered back into the grid, you use what you need and store the rest.  If you want to use the grid as backup power then leave the meter and install an automatic switch that will disengage you system and engage the grid. 

In the month of August the house at Santa Maria used 600 kwh, I want the system to pay for itself in 60 months, that is $266.00 per month for 60 months.

Grid tie 600 kwh @ .08= $48.00 savings and a continuous bill of $ 120-48= $112.00.

Lets look at 10 years 120 months, grid-tie savings= $5,760.00. Total power cost= $13,440.00.  There is no way you can recuperate your investment.

Off grid I pay $16,000.00 the first year to pay for my investment. my savings over the 10 year period are $16,000.00. Power cost = -$16,000.00

This does not take into consideration repair costs on either system.

Sept 16,2009

We have now been over 30 days with average winds of less than 9mph, batteries are low 109 volts dc.  The system has maintained enough power to power the house.  With wind of 10-15 mph on an average of 5-6 hours per day.  Calm winds or 0 mph the rest of the time.  It will now take 3 days of 15-20 mph winds to float the battery pack.  Sense the battery pack never got below 100 volts it is still considered the same charge.  The 5-6 hours of wind bring the voltage back to 120 volts but there is no reserve.  I never expected for the wind to remain this calm for this long.  I estimated that the batteries would last 30 days at a low charge rate.  The system in now in its 31 day.

Sept 22, 2009

It is the first day of fall and we have made it all the way through the dog days of low wind summer.  The new tower has arrived and the 5kw inverter is scheduled to arrive tomorrow.  The wind is starting to pick back up,  I have converted one of our 12 volt dc 800 watt generators to 120vac 3 phase and placed it into operation as a test.  I have hooked it to a 120vac to 120vdc analog controller.  It seems to be working fine it should give about 7 amps of charging power at 20 mph wind.  Our system should be at 100% power by the end of the week.  That will give us 6kw of power at a 16mph wind.  I am thinking that the small units in a high wind situation will give enough power to charge the battery pack.  If this is so then I will be able to break the larger units during high wind periods and charge with the small blade systems.  I have 3 of these 800 watt units that we were using on a mobile home at 12vdc and I have converted each of them to 120vac 3 phase. I am going to install these with the analog controllers because they are cheap.  This will be 2400 watts of power at high wind.

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