WIND TURBINE COST EFFECTIVENESS?

[voiceofreason]

I am trying to understand what the payback could be for a wind turbine to power our lights.  I estimate we use about 100kWh on lighting.  Is there a wind turbine with a generating capacity between 20kW and 600kW?  The lights are on 24/7.  average wind speed of 5.5 m/s

Any suggestions?

[martin]

using simplistic "rule of thumb" calculations, if you're talking about 100kw per DAY, that's about 10 times the average daily household needs - that usually equates to a 2kw turbine to balance the load when grid-tied - so you'd need somewhere in the 20kw upwards range of turbines - 20-30kw should "balance" your consumption - the larger turbines allow a net export to the grid - at 8p per unit, plus 4p for ROCs, payback can be in as little as 5-6 years!

[voiceofreason]

Thats all well and good however at 5.5m/s average i really cannot see this project as being viable unless I am missing something obvious. A 20kw wind turbine is simply not effective at such low average wind speeds is it?