WINDMILLS:YESTERDAY'S ANSWER TO REMOTE WATER DELIVERY

There are still thousands of windmill water pumping units standing in the western U.S. Regrettably, many are inoperable. These pumpers were very valuable for remote (off grid) sites, with the proper minimum wind conditions, when man-power was plentiful and cheap. Windmills, though potentially long lasting, need dedicated maintenance. The downhole leathers require inspection and high winds can cause mechanical damage to the blades. Parts for these mills are expensive and sometimes hard to find.

Solar water pumping systems have many advantages over windmill water pumpers. Though the initial cost of solar powered systems can be similar to that of windmills (however, in many cases far less!), the lifetime costs are much lower. Windmills must be used where there is a steady, constant wind for maximum results while solar powered pumps operate anywhere the sun shines. Solar pumping systems can be installed in less than a day by an individual or small crew and can be portable, while windmills (because of the need to erect a tower) can take a larger crew a much longer time to install. Windmills are secured to the ground and are stationary. Solar powered water pumping systems are the modern day, upgraded version of the windmill - using natural resources to deliver water in off grid locations.

GAS-FIRED GENERATORS VS. SOLAR ENERGY

Generators are commonly used to provide power beyond the powerline.

We have several economic studies concerning the economics of solar versus generators as a power choice. These studies consider all costs involved: modules, mounting structure, pumps, miscellaneous components, installation, operation, maintenance, yearly inspection, component replacement and salvage value. With this we can deter-mine a life cycle cost and a present value. One such comparison was done by the Bureau of Land Management at Battle Mountain, Nevada, specifically comparing solar water pumping systems to generator systems. For one 3.8 gpm system with a 275 foot design head, the PV system cost only 64% as much over 20 years as the generator system did over only 10 years. This remote solar site also used only 14% as many labor hours.

In 1989 Sandia National Laboratories noted that photovoltaic pumping systems in remote locations would often be cost effective compared to generators, even with 5 times the initial capital cost. Low end generators, which are initially inexpensive, require consistent maintenance and have a design life of approximately 1,500 hours. Small to medium sized solar pumping systems often cost less initially than a durable slow speed engine driven generator.

Most larger pump systems cost more initially than generator systems, but tend to be far more economical in the long run.

SOLAR PUMPS VS. GAS-FIRED GENERATORS & WINDMILLS

PUMP TYPE ADVANTAGES DISADVANTAGES
Solar electric power systems
  • low maintenance
  • Clean
  • No fuel needed
  • Easy to install
  • Reliable long life
  • Unattended operation
  • Low recurrent costs
  • System is modular and can be matched closely to need
  • Relatively high initial cost
  • Lower output in cloudy weather
Diesel (or gas) power systems
  • Moderate capital costs
  • Can be portable
  • Extensive experience available
  • Easy to install
  • Needs maintenance and replacement
  • Maintenance often inadequate, reducing life
  • Fuel often expensive and supply intermittent
  • Noise, dirt and fume problem
  • Site visits necessary
Windmill
  • Potentially long-lasting
  • Works well in windy site
  • High maintenance
  • Costly repair
  • Difficult to find parts
  • Seasonal disadvantages
  • Need special tools for installation
  • Labor intensive
  • No wind, No power

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Malibu, CA 90265 		Phone # (310) 589-9544
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