However, the most important thing about wind is- feed-in-tariff?
Net metering doubles or triples the payback period when net metering means wind output has to be <= usage.
If you can sell the extra generation, (which the OP's customer I believe can) it is a whole different ball game.
SMA will withdraw from the small wind turbine industry at the end of 2013 at which time production of the Windy Boy inverter will cease.
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[h=5]what are the reasons for withdrawing from the small wind turbine industry?[/h] Volker: Unfortunately, changes to the political landscape in important sales markets have caused the market for small wind turbines to collapse. The UK government, for example, has cut funding for wind power plants below 1.5 kW – the size typically used in domestic applications – so unfortunately, in some cases, it is simply no longer worthwhile for the customer. http://en.sma-sunny.com/en/sma-to-part-ways-with-windy-boy-inverters/#comments