This is a UK query.
If I want to use a small solar cell or wind turbine to charge my mobile phone battery, then I can just hang such an item out of the window.
If I want to erect a huge solar cell or wind turbine to supplement my domestic power supply, then clearly I need planning permission.
My question is, what is the maximum size of a wind turbine I can erect in a residential garden in the UK that does not require planning permission?
I been considering building and installing a wind turbine to provide the power for a koi pond pump (about 100 watts at 12v). Something like this
http://www.reuk.co.uk/Chispito-DIY-Wind-Turbine-Plans.htm

[Corey USA]

To make those wind turbines effective you need to get your energy consumption to absolute minimum. Which means getting your heating, cooling, electronics consumption down.

here are the there big ones that have the greatest impact

Sunfrost Type in to google they will custom build for your location for electrical connection for both ac/dc system or 120v 230v or what ever is in your location. There is no better unit on the market for it was originally designed for a solar system to help reduce the cost of the solar hardware cost(You don't need as many solar panels and batteries.

families who use minimal hot water use a tankless water heating system

Lots of insulation to control heat gain and loss of your home also insulate the hot water pipe.

here is one you don't want to hear stop using electronics unless its absolutely necessary to use.