If you are considering wind power ...

Most solar system owners dream about some additional electricity from a renewable source when the sun fails to shine. Adding a wind generator to your solar system is a very logical choice.

Now I hate being the bearer of bad news but unfortunately in the majority of cases wind generation does very little in most installations and has caused a great deal of disappointment. Sad but true!

If you are considering a wind generator, look at your area. Is it flat and clear or wooded and hilly. Fact: All commercial wind farms are on flat open country that is mostly devoid of trees. Is this your location? For a wind generator to work efficiently it needs to be located in a steady stream of air. Trees, hills, buildings and obstacles up to 400 metres away or further will cause turbulence and disturbed wind flow. If any such obstacle is upwind of your turbine performance will suffer. Hilly areas rarely have steady wind, hill tops while seemingly perfect can be anything but!

OK let's say you have a great wind area, my first suggestion would be to look at meteorological data for your area and see just what winds can be expected at what time of year. Use a compass and look carefully in the direction the wind will predominantly come from when standing at your proposed wind site.

Still looking good? Your next recommended step would be to either purchase a weather monitoring station, nothing that flash, just something that will measure wind speed and direction from your local electronics store will do. Mount this on a small tower and monitor the results.

An alternative to this would be to buy a small low cost wind turbine like the Air Breeze we sell and give it a go. I strongly advise against spending up big on a wind generator without some sort of site monitoring.

It is virtually impossible to determine how much power you will get from a wind generator without either fitting one or monitoring the wind speed and direction for several months or more!

Finally, there are a few other facts to consider, firstly the higher up you go the better the wind will be. The higher your tower the more difficult the engineering required for building, erecting and lowering will be. Wind generators make noise. While most owners happily live with a bit of wind generator noise and even enjoy it somewhat, your neighbor may well think differently! Wind generators require maintenance. Blades can easily be broken (often killing a bird at the same time), bearings wear out and moving parts develop wear. Your wind generator tower will by necessity have to be easy to raise and lower for maintenance and repairs.

All the above aside, in a good location a wind generator is very hard to beat for power per buck!

Micro Hydro

If you are lucky enough to have a permanent stream, creek or river nearby micro hydro may solve some or all of your power needs. The power of falling water was the first means of generating commercial electricity and is still a very viable method of generation. Before you consider micro hydro here are some facts.

The power you will get from a hydro electric plant is directly proportional to two things, these are head and flow.

Head: The height of the water source that is providing the water above the location of the generator. You must get this totally clear. This is the height where the water comes from before it begins its journey to the turbine. This height cannot be changed by re-routing pipe, changing pipe length, doing dances in circles or getting your mother in law to help. Head is related to gravity and cannot be changed!

Flow: This is the amount of water available to do the work of generating the power. You will either need vast amounts falling a short distance or a lesser amount falling from a big height.

Measuring Head

This cannot be guessed. You can survey the distance and slope using a level and measuring tape, you can possibly use a GPS unit for larger falls or you can install a pipe, get water flowing down it, seal if off and measure the static water pressure in the pipe.

Measuring Flow

Use a bucket or other measuring device and a stop watch.

Calculate the amount of energy you can get

Power = Head (in metres) x Flow (litres per second) x Gravity (the acceleration due to gravity is 9.81 meters per second per second so use 9.81 for gravity)

Example: You have surveyed 22 metres of head and measured 15 litres per second of water at the supply

22 x 15 x 9.81 = 3237 watts

Unfortunately it will not actually be this good ... There will be losses caused by pipe friction and in the conversion process to electricity. Hydro power is considered to be around 60% efficient.

3237 x 60% = 1942 watts x 24 hours = 46608 watts or 46.6 kW

Compare this to the solar system on the previous page. We worked out we would need 10 x 130 watt panels for around 3.56 kW of power. Obviously the hydro will produce substantially more power and cost a lot less. Clearly a stream of this caliber is a substantial asset.

Before we move on to other things lets look at another hydro set up. This is at a local house. Measured is 60 metres of head and 1.5 litres per second.

60 x 1.5 x 9.81 = 882 watts x 60% = 529 watts x 24 hours = 12.6 kW - No need for solar panels here!

Let's move on and fill ut our own load chart!

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