How about using mini wind turbines?

I briefly look at the economies of PV panels.

But how about wind turbines?

Look at the links below:
http://store.sundancesolar.com/airxwitu.html
This one is US$625 for 400W (at 12.5m/s)
(P.S. I've seen the real product in front of me. My boss ordered one from USA to look at feasibility.)

http://cgi.ebay.com.au/EnviroWin ... 64865QQcmdZViewItem
This one "may be" A$400 for 200W (RRP$589).

If I use the same methodology:
For the first one, US$625 = HK$4875

Assume electricity rate = $1.1/kWh for simplicity.

kWh required to payback the wind turbine = 4875 / 1.1 = 4432 kWh

Time required to generate = 4432 kWh / 0.4 kW = 11080 hours

Now I need to check the "wind flower" of HK. But just assume we can have 16 hours a day of wind for the wind turbine.

Then no. of days = 11080 / 16 = 692 days = 1.9 years

This seems quite attractive!

For case 2,
For the first one, A$400 = HK$2600 (for A$1=HK$6.5)

Assume electricity rate = $1.1/kWh for simplicity.

kWh required to payback the wind turbine = 2600 / 1.1 = 2364 kWh

Time required to generate = 2364 kWh / 0.2 kW = 11818 hours

Assume we can have 16 hours a day of wind for the wind turbine as before.

Then no. of days = 11818 / 16 = 739 days = 2.0 years

This also seems quite attractive!

But practically, do you have the space to install the wind turbine?

And also, some costs were not taken into account, like battery, regulator, installation, freight charge, etc.

But it worths a look.

But I better declare that I have no interest in the wind turbine manufacturing industry.

Maybe I should have some interest or investment in this!