The windmill has been at the forefront of the Australian pastoral industries for over 150 years – without it the sheep and cattle industries could not have grown. Today the windmill is still the lowest cost method for pumping water. With a design life between 30-60 years there is no pumping system that can compete. “With a capital cost less than solar, a non existing running cost, no fancy electronics, and a design life probably 10 times any other pump – what else can compete?”

So, Windmills v’s Solar – Which is the best?

This is no easy question, and the correct answer depends on the size of the system and local circumstances. The most important issue has nothing to do with how the systems work but is the cost of maintenance.

In general, solar is becoming dominant in the debate, especially in the small systems. Two factors seem to have influenced this – firstly, 6ft and 8ft windmills can now be replaced with cheaper solar systems, and second, the buying decision is often made based on what the customer wants rather than what the customer needs (or what is best in the long term).

With bigger solar systems the cost is still prohibitive. A windmill will do much more work for dollars invested than a solar pump. The cross over point is a 10ft windmill. It is in this area that the critical issue of cost of maintenance comes into play.

A good example of this lies in a story out of the Cyclone belt in Western Australia. In the year 2000, Cyclone Vance crossed the coast north of Carnarvon. It was a dry Cyclone that followed a period of unusually wet weather – the Nor-westers know that this is a ferocious wind and a dangerous set of circumstances. When the wind died down there were 400 windmills blown over.

The State government recognised the disaster and offered 1.6 million dollars to the pastoralists to assist them to rebuild their water supplies. There was a special emphasis placed on modernising and promoting the take-up of solar power. After all most of the windmills had been there for more than 50 years, and in some cases they were over 80 years old.

Amid the euphoria of being given $ 4,000 per damaged windmill and the possibility of the insurance money matching the government grant, there was a need for some serious debate. This came in the form of a casual field day held in the car park of the Minilya Roadhouse, 250 kilometres north of Carnarvon. All the windmill and solar pump manufacturers were invited to attend and present their products.

Geoff Moore of W.D.Moore & Co. was the first to present his company’s products. What he had to say went like this. “W.D.Moore & Co. has been selling windmills to pastoralists, your fathers, and your grandfathers in this district for the past 100 years. This country has a passionate connection to us. Although the organisers want us to talk about solar pumping systems, I have a concern that needs to be aired. You will be given $ 4,000.00 from the Government, and will probably get another $ 4,000.00 from your insurance. For $ 8,000.00 we, and any of our competitors, can sell you a very serious solar pump – the latest in you-beaut technology, with all the bells and whistles. The problem I have is that the pump is a submersible pump, not your off-the-shelf AC submersible, but a high tech Brushless DC submersible. Of the $ 8,000 nearly $ 5,000 is the down hole pump and motor.

My question is “how long do submersible pumps last?” “Is it 10 years? Is it 5 years? ….” One pastoralist shouted out “about 5 months in my bore” “Lets assume its 5 years. $ 5,000.00 in 5 years adds up to $ 1,000.00 a year in maintenance cost. That’s too much. Many of you pastoralists are growing wool, and the margins are not there to support such a cost to pump water.” “In most cases you haven’t spent $ 100.00 a year maintaining your windmills.”

The outcome of this talk has been that the debate on windmills verses solar, at least in WA, is now firmly on the question of maintenance cost. Although $ 1,000.00 a year probably overstates the average cost of maintenance, there are many who are beginning to understand that the high cost of maintenance is a fact of solar water pumps.

The popular perception of most farmers and pastoralists is that solar pumps are maintenance free and that it costs a fortune to maintain a windmill. It is not clear where this perception has come from. It does not appear to have come from current solar pump manufacturers, although they do nothing to dispel the myth. It may have come from early providers of solar pumping systems who were generally solar experts rather than water pumping people. In the main these people have not survived in the business. Most likely the perception has grown out of the wants of customers – most customers want solar pumps to be maintenance free and end up convincing themselves that they are. The unfortunate fact is that when it comes to pumping water there will always be maintenance.

The perception that windmills have a high cost of maintenance is equally dangerous. Here however it is clear to see where this perception has come from. The cost of windmill parts has grown over the years at a rate that has exceeded inflation. This is because of the declining nature of windmills, and their age. Parts are still available for windmills made in the 1920’s, and today they are made in very small batches – this cost money. There are also a reducing number of contractors who will work on windmills. Most farmers hate windmills, they don’t like climbing towers, and they are dirty, and old. The same farmers usually acknowledge that they don’t spend much on the windmill – a couple of pump cups every couple of years. Other arguments against windmills centre on safety issues, and these more than any other are valid. Although windmills as such are not unsafe, there are inexperienced people working on them. Experienced contractors should do the work on windmills and the cost of doing this work needs to be recognised. On the safety issue it should be noted that most big solar pumps use lethal voltages, and are more dangerous than most windmills.

When it comes to making the decision to buy either a windmill or a solar pump the decision will probably be made in favour of what the customer wants, not what he needs. All that is necessary is enough arguments to justify the decision they want to make. But if a customer wants to make the “right” decision they should ask the question “What will be the annual cost of maintenance?”

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