WHAT IS THE MOST COST EFFECTIVE, POWER GENERATING WIND TURBINE FOR A GRID TIE SYSTEM?

There are many variables here. First is your location. Defining factors are sustained wind velocity and average daily unobstructed sun. If you have average winds of 12-15 MPH or 6 sun hours the next consideration is initial cost. Large wind turbines need sustained winds in the 20 + Mph range for peak efficiency and become less cost effective if your wind energy is less. Wind generators are now much more expensive than photovoltaic panels but if you have the correct wind – much more efficient. Solar panels however are totally passive, twice as efficient as one year ago and virtually maintenance free with 25 year warranties. Wind turbine maintenance on the other hand can be 25% of initial cost as often as every 2 years. With the new grid tied systems batteries, inverters and converters are eliminated.
The amount of power generated may also qualify you for State Grants at different levels of Energy generated and may also make you eligible for additional grant money or a higher percentage of State funding. Check these things with your States “Alternative Energy” page.
Another consideration is payment for your Carbon Credits. Our local utility pays almost 2 to 1 for Kwh’s generated from Photovoltaics – since there are few if any Wind generators locally I don’t know if this would be true for them as well.
Depending on your state there are different grants for each type of generating device and the individual utility companies reimburse for “carbon credits” at individual rates. Either system gets a 30% Federal Tax Credit in “actual dollars” against the amount of tax liability (but not refundable over this amount – until 2016)
In my area (Southwest Ohio) we have good sun but nowhere near enough wind so our system is Solar. Hope this helps.