July 2003 • NREL/SR-500-30361 Renewable Energy for Water Pumping Applications in Rural Villages Period of Performance: April 1, 2001–September 1, 2001 N. Argaw R. Foster and A. Ellis New Mexico State University Las Cruces, New Mexico National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401-3393 NREL is a U.S. Department of Energy Laboratory Operated by Midwest Research Institute • Battelle • Bechtel Contract No. DE-AC36-99-GO10337 July 2003 • NREL/SR-500-30361 Renewable Energy for Water Pumping Applications in Rural Villages Period of Performance: April 1, 2001–September 1, 2001 N. Argaw R. Foster and A. Ellis New Mexico State University Las Cruces, New Mexico NREL Technical Monitor: L. Flowers Prepared under Subcontract No. RAM-1-31224-01 National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401-3393 NREL is a U.S. Department of Energy Laboratory Operated by Midwest Research Institute • Battelle • Bechtel Contract No. DE-AC36-99-GO10337 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Available electronically at http://www.osti.gov/bridge Available for a processing fee to U.S. Department of Energy and its contractors, in paper, from: U.S. Department of Energy Office of Scientific and Technical Information P.O. Box 62 Oak Ridge, TN 37831-0062 phone: 865.576.8401 fax: 865.576.5728 email: [email protected] Available for sale to the public, in paper, from: U.S. Department of Commerce National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 phone: 800.553.6847 fax: 703.605.6900 email: [email protected] online ordering: http://www.ntis.gov/ordering.htm Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste Forward The availability of water and the ability to access it are key issues facing the world community. Faced by needs in developing regions as well as rural portions of the developed world, these issues are truly a global problem. The global nature of these issues opens the door for the application of communal solutions, as was demonstrated by the discussions surrounding the Johannesburg global climate meeting where water issues were a key concern that all nations could come together to support. Like energy, the need for water is increasing rapidly as supplies of traditional resources continue to diminish due to overuse, waste, and pollution. Unlike energy, the ability to harness local resources to produce water is not possible. However, we do have the capability to use local energy resources to gain access to water supplies that would otherwise be unavailable. This water is either located underground in deep aquifers or in surface lakes, rivers, and streams. In many cases, the absence of available, inexpensive energy makes gaining access to this water expensive, time consuming, and potentially dangerous. The proper application of any of a number of energy options available today can make gaining access to this water a reality in many areas not previously considered. This report, one of three written by the author, provides insight into accessing water through the use of modern pumping technology and a variety of energy sources available to rural and remote areas. The report is unique as it provides a very evenhanded approach to the selection of different pump and power choices to supply the needs of the user. It also provides comparative measures to help determine the most efficient and cost-effective method to provide energy, whether it is from renewable or non-renewable resources. Although publications on water pumping are common, few equally address all of the different technical approaches to water pumping, ranging from diesel technology to the use of photovoltaic systems. This document is not a guidebook on the implementation of water pumping systems. Its purpose is to provide insight into the different options that are available and it provides methods to understand which technology may be the best for specific needs, conditions, and locations. We hope to dispel some of the misconceptions about appropriate or inappropriate technologies through the publication of this document Because water issues are so encompassing, all solutions have their place. The difficulty is determining which technologies are most appropriate for each user’s specific need. This book is one in a series of guidebooks that NREL has produced, with the support of the U.S. Department of Energy, to couple commercial renewable energy systems with rural applications, including other water issues, rural schools, health posts, and micro-enterprise. Other water related publications in this series describe the technical aspects of water pumping technology and provide insight to issues of water treatment, specifically purification, desalination, and wastewater treatment. E. Ian Baring-Gould International Programs National Renewable Energy Laboratory iii iv Contents Foreword.................................................................................................................................. iii Figures...................................................................................................................................... ix Tables....................................................................................................................................... xi Chapter 1: Introduction.............................................................................................................1 Chapter 2: Water Resource Considerations ..............................................................................3 Water Resources ............................................................................................................3 Water Demand ...............................................................................................................4 Water Storage and Distribution .....................................................................................6 Storage....................................................................................................................6 Distribution.............................................................................................................7 Chapter 3: Energy Resources: Background Information........................................................10 Wind.............................................................................................................................10 Wind Speed Measurements ..................................................................................12 Solar .............................................................................................................................12 Estimating Solar Energy Resources .....................................................................14 Grid Power...................................................................................................................14 Diesel/Gasoline/Kerosene............................................................................................15 Diesel Engines......................................................................................................17 Gasoline/Kerosene Engines..................................................................................17 Chapter 4: Pumps and Motors Technology ............................................................................19 Motor–Pump Subsystems ............................................................................................19 Pumps...........................................................................................................................20 Positive Displacement Pumps ..............................................................................20 Rotodynamic Pumps.............................................................................................22 Motors..........................................................................................................................24 v DC Motors............................................................................................................25 AC Motors............................................................................................................26 Chapter 5: Selecting Power and Sizing Renewable Energy Water Pumping Technologies...27 Wind Pumps.................................................................................................................27 Mechanical Windpumps.......................................................................................29 Electrical Windpumps ..........................................................................................30 Solar Pumps .................................................................................................................32