The Wind is Free!

Re yr wind generator - from a practical perspective, how do you incorporate the electricty generated by it ino yr domestic set-up?

Hi ariel. There are two approaches, sometimes called Grid tied, and off grid.

Grid tied: this needs a large synchronised inverter which are locally unfortunately still very expensive (I last saw a quote for about R30000). This feeds the power into your existing wires, so that you draw what power you need from the grid, and supply what you can from the wind generator. It is very simple in that you just connect the inverter centrally in your house, and no batteries are needed. Of course it generally means that during power failures you don't have power.

Off grid: This involves a bank of batteries, and you can use the battery power in two ways. The most efficient is to use DC (direct current) appliances, such as DC CFL light bulbs or better LED lights, and other appliances meant for battery power (often available from camping/4x4 accessory shops). Almost all electronic equipment runs of DC internally. The second way is to use a small inverter for those appliances which need AC power, such as desktop computers. It is also possible to buy power supplies for desktop computers which are designed for use in cars (typically for mp3 music systems) which use battery power without inverting. (a normal desktop power supply just converts the AC back into DC anyway). In this scenario, even during mains power failures you still have power.

Bear in mind that reducing energy use is an important part of switching to renewable energy. The greatest use of power in a home is for heating, eg. heaters, electric stoves and hot water cylinders. So where possible these should be replaced with gas or direct solar heaters.

Hope that helps, and please ask if anything needs more explanation.

Hi Windgat,

I live in Plett where the wind seems to be pumping more and more these days. What percentage of my electricity do you think I might be able to obtain from the latest wind generator technology? Our last months elec bill was for 751kWh.

Anthony

Say you have a 6m/s average wind and a 1m radius blade. Being a bit conservative, that would give you 200W average (in high winds you would get a lot more than that, which would actually push the average higher).

That makes about 144 kWh per month, about 1/5th of your needs.

It seems from your figures you have an electric geyser - that is the first thing to change! Perhaps you are also cooking with electricity, which is also a big consumer. If you changes those two it may change to 1/2 your electricity needs.