Home Wind Turbine: Where, how big; how much energy to expect

This wind turbine charges a 12 V battery to ru...
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In principle, home wind turbines of an appropriate size can, or at least should be allowed to be installed anywhere; at the home, on the farm, in your rural garden, by your caravan, on your boat. In reality, of course the story is different! Restrictions do apply in some sense to all of these and other applications.  You may be allowed to install a 5 – 10 Kw turbine on a farm, but certainly not in you back garden. In fact if your back garden is in a housing estate, you will probably be allowed no more than a mini turbine – at a push. So DIY wind power is not always as simple as it sounds as sometimes the application mechanism and associated ‘red tape’ can be more exhausting than the installation.

Further, as is the case in some countries, you may not be allowed to install a larger wind turbine on a DIY basis. You will be required to have an officially accredited supplier and installer. Also most governments want to have some control over our energy supply; and to take any credit for going renewable. Thus, we have the incredible escalation in the development of wind farms. The truth is that whilst on the surface, officialdom won’t be publically seen to discredit your quest for clean energy it still does not want you to be independent of the ‘system’. The national grid wants you tied to it! Yes, the apparent story behind the restrictions is often more than the real story behind the restrictions.

So what size turbine are we likely to be allowed to put, where, and how much is it likely to cost? One or more Bergey XL.1, 1 kilowatt turbines is a good choice for a DIY wind power project on a farm, to supply outhouses, barns etc with power. The turbine will cost about $3,000 inc. controller. Then of course you have the additional costs for your tower, batteries and ancillary equipment, which could almost double your outlay, especially if a quality inverter is involved.

Wind turbines are most at home in rural areas and that is where they are needed most. Residential areas are not really suitable.  A ‘residential’ wind turbine of any useful size will be seen as invasive and in the unlikely event of your being allowed to have one your neighbours are unlikely to accept it.  In any case this is the niche that the ‘rooftop solar’ companies are addressing and this make more sense – if it wasn’t for the fact that they are trying to tie you to the grid in doing so!

If you want to power a country home, again a minimum requirement would probably be a pair of Bergey XL.1 turbines working in tandem. But remember that certain technical / economic restrictions still apply. For example, for cost-effectiveness home heating should be provided by another source. Equally standard air-conditioning units should be counted out; and to further enhance you cost effectiveness, cooking ideally should be done by gas. So, carefully evaluating your needs, and working towards optimum energy efficiency is directly related to keeping you system cost down, and you sense of satisfaction up.

But then what about the days when the wind doesn’t blow?

My own favourite system is at a medium sized farm house, one that I had some involvement in, in Ireland. Cooking is done with gas, heating by two wood and peat fired stoves, (in turn feeding four radiators) and ‘air conditioning’ provided by open windows and the occasional use of fans.

So, all lighting, refrigeration, small workshop appliances (occasional use) radio/music system, TV/DVD (2-3 times a week), some kitchen appliances, ironing (1 hour per week) etc. is covered by a DIY wind power system, incorporating three ‘Air Breeze’ wind turbines rated at 500 watts total, backed by a solar array of 500 watts. So, the owners have a potential rated output of just 1 kilowatt, which generally gives them 2-3 kilowatt hours per day – more than enough to cover their requirements, and incidental needs that may crop up.

The system was easy to install and works perfectly!

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Mini wind turbine for your home

Rutland 504 mini turbine

Rutland 504 mini turbine

A mini wind turbine is a very attractive option where power requirements are low, space is tight, noise needs to be minimal and portability is important. They are simple to set up and install, and represent an ideal way for the newcomer to wind energy to get familiar with it, and its uses.

Examples of their useful applications include:

  • trickle chargers for battery top-up and maintenance
  • home stand-by lighting
  • small water pump operation
  • low energy garden lights
  • boat battery charging
  • Caravans lighting              etc.

They are highly effective in such applications and if ever the term ‘small is beautiful’ applied, it applies well to a mini wind turbine!

The little Rutland 504 mini turbine is a fine example. With its low start-up wind speed of 5 mph, it will generate 25 watt of power in a 22 mph wind. What at does this mean in terms of average power output and, more importantly, amps going into a battery? Well, if we allow for an average daily wind speed of around 10 mph over a 10 hour period, we would have a 6 watt output, trickling half an amp per hour into a 12 volt battery. Thus over the 10 hour period (10 x 0.5 amps) we would harvest 5 ampere hours on such a day;  a very useful amount of current for all the above applications – and more!

I would be prepared to install such a mini wind turbine on the roof or at the gable end of the house, for as regards noise, they emit a mere faint purring sound. At around a mere 8-10 pounds in weight, installation is simple. These turbines are very suitable for built-up areas, and on apartment terraces, particularly in locations exposed to adequate winds. Mini solar, of course will have the edge in locations where solar exposure is more favorable.

Planning problems are not an issue. It would be a hard and cold-hearted official (or neighbour) that would put in an objection. Indeed for official – and neighbour, such a mini turbine should be seen as an item to please, to educate, to make a small environmental statement – and be encouraged!

The modern commercially produced mini wind turbine is a big improvement on the old farm and hobbyist models, in terms of efficiency, size, weight, and output. My only reservation about them is that they tend to be over-priced. This (they say) is because their main target market is boat owners, to facilitate on-board battery charging – and so they are “marinised”!

The reader will have noted that in this series of articles on home wind power that I favour the viewpoint that for 90 per cent of those thinking wind power, self-building a highly efficient larger turbine power head is not for the untrained and unskilled in such work; remembering that the main purpose of the exercise is to provide long-term reliable power to the home.

However, for the mini wind turbine I would lean otherwise! With their small size and weight, their relatively inexpensive parts, minimal need for high tech casing etc. weighed against the high price of commercial models, I would say, yes, in this case ‘give it a go!

And so, in closing this article, I would like to pay homage to William Kamkwamba. From a small unknown poverty-stricken village in Malawi, William, who at 14 had been forced to drop out of school for lack of school fees, wondered in despair what he could do for his village. With nothing else to do, he spent his days browsing in a local bush library, where he discovered a tattered book on wind energy. The account of his subsequent achievements using junk is a joy to read; the story of a young teenager determined to succeed ‘against all odds’ has charmed millions and powerfully illustrates the value of the mini wind turbine!