Solar-powered Water Pumping Systems for Livestock
Overview and Costs
• Steve Miler
Issued in furtherance of extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Glen Whipple, director, University of Wyoming Extension, University of Wyoming, Laramie, Wyoming 82071.
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solar-powered water-pumping systems for livestock
Part 1: Overview and costs
Editor: Steve Miller, College of Agriculture and Natural Resources, Office of Communications and Technology.
Graphic Designer: Tana Stith, College of Agriculture and Natural Resources, Office of Communications and Technology.
©2016 B-1289.1 by Milton Geiger made available under a
Solar-Powered Water-Pumping Systems for Livestock, Part 1: Overview and Costs is a peer-reviewed publication.
Original available at:
Suggested acknowledgment: Geiger, Milton. Solar-Powered Water-Pumping Systems for Livestock, Part 1: Overview and Costs. B-1289.1. 2016.
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Western agricultural producers have many options for supplying water to livestock in remote settings. The iconic mechanical windmill provided the first, and still common, option for pumping groundwater in distant pastures. The extension of utility-provided electricity, often from local rural electric associations, offered a more reliable option. Gasoline, diesel, and propane generators provided further alternatives for using electricity to pump water. Most recently, the emergence of solar-powered water pumping systems (SPWPS), using photovoltaics (PV), has provided an additional opportunity for ranchers and small-acreage owners.
Part 1 of this bulletin series is the foundation for a two-part discussion of where and when SPWPS are most advantageous for Wyoming agricultural producers. Livestock water needs are diverse, with seasonality, well depth, flow requirements, proximity to utility-sourced electricity, and distance from the homestead impacting options. Ranchers and small-acreage owners need to know how SPWPS work and what factors influence their cost. Part 2 of the series, SPWPS for Livestock: Where and when do they pay? addresses scenarios where utility-connected sys
tems, fossil-fueled generators, and SPWPS are the most cost-effective options.
Through these two UW Extension (UWE) bulletins, livestock producers and small-acreage can identify the general characteristics that define a profitable SPWPS opportunity and when other alternatives are preferable.
SPWPS are not a new technology for Wyoming livestock producers. Wyoming ranchers and small-acreage owners began using SPWPS over 30 years ago. Declining costs and greater confidence in reliability and performance has led to SPWPS becoming increasingly common on Wyoming rangelands, often displacing mechanical wind pumps. With statewide access to low-cost PV panels, direct current pumps, and qualified installers, SPWPS is poised for further adoption by Wyoming’s livestock producers.
SPWPS are used to pump groundwater or surface water for livestock and wildlife in remote, off-grid settings. SPWPS explored in this UWE bulletin series are not connected to the electrical grid (i.e., grid-tied).
overview and costs | 1
• Steve Miler
SPWPS use sunlight to produce electricity, which is then used to pump water (Figure 1). PV panels produce direct current (DC) electricity, but unlike in grid-tied settings, no inverter is required to change DC to alternating current (AC). Grid-tied (e.g., residential) applications require inverters because our appliances and electric-grid use 60 hertz AC electricity. In SPWPS, PV directly supplies electricity to a DC pump, increasing efficiency and reducing costs. SPWPS do not require batteries, as pumped water held in a tank efficiently stores energy. With no inverter or batteries, SPWPS are among the simplest application of PV.
Pumping groundwater is the most prevalent use of SPWPS, often providing the sole source of water in remote rangelands. Surface water installations are also becoming increasingly common, as land managers seek to encourage livestock to disperse from riparian areas.
Flow and pumping depth determine pump type (diaphragm, helical rotor, etc.). SPWPS can be used to pump water from depths exceeding 1,000 feet, allowing commercially available DC pumps and PV panels to serve most water pumping situations.
Numerous publications explain SPWPS technology, site selection, operation, and system design. Colorado State University Extension’s Solar-powered Groundwater Pumping Systems and New Mexico State University Cooperative Extension Service’s Designing Solar Water Pumping Systems for Livestock offer excellent introductions to SPWPS. In addition, New Mexico State’s Solar Water Pumping Design Spreadsheet Version II: Instruction and User Manual and the USDA Natural Resources Conservation Service’s Technical Note No. 28 Design of Small Photovoltaic (PV) Solar Powered Water Pump Systems allow for highly detailed sizing and site analysis.
Importance of solar resource
As we estimate costs for SPWPS, the location of our example matters. Wyoming’s overall excellent solar resource varies throughout the state (Figure 2).
The quality of resource dictates how many solar panels are required to produce the energy needed by the water pumping systems. For example, a standard 200 watt PV panel, tilted at latitude (41° in Laramie and 45° in Sheridan) and facing due south, will produce an average
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Figure 1: Schematic diagram of a SPWPS (Source: University of Wyoming Meah et. al 2008)
Figure 2: Wyoming global solar radiation at latitude tile – Annual (Source: National Renewable Energy Lab)
Figure 3: Estimated production of a 200 watt solar panel fixed at latitude (Source NREL PVWatts)
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of 332 kWh per year in Laramie and 302 kWh per year in Sheridan (Figure 3). Both are considered relatively robust solar resources, as a similar installation in Michigan (same latitude as Sheridan) would produce only 245 kWh.
How much do SPWPS cost to install?
The cost of SPWPS varies widely, as site-specific issues strongly influence final installed cost. Three principal factors affect system costs:
1.Total dynamic head,
2.Required water production (flow-rate),
3.Season of operation.
Simply, a system requiring a larger pump and more PV panels will be more expensive. Also, the need for production during the short days of winter increases the required number of PV panels as opposed to a seasonal, summer system. Figure 4 displays the principal parameters for determining the cost of SPWPS.
Knowing these system characteristics allows for a calculation of the amount of energy needed by the system to pump water. The system requirements permit sizing of the solar panels and a comparison with a
Figure 4: The required system parameters for costing SPWPS
Figure 5: Equipment and installation costs for a SPWPS, utility-sourced and generator water pumping system
generator (fuel) and utility-sourced electricity (purchased electricity).
The system characteristics from Figure 4 inform the equipment and installation costs for different water options. Figure 5 shows the main components of SPWPS, utility-sourced, and generator water pumping systems.
The cost of the installation, especially for SPWPS, is influenced by the federal, state, and local incentives. The primary incentives are federal programs (Table 1).
Not all incentives can be combined. For example, an agricultural producer could not use both USDA REAP and EQIP grants. Combining grants with the tax credits and accelerated depreciation is typically permissible, although receiving a grant can proportionally reduce the value of tax credits and deductions. The easily used BITC and MACRS lessen the cost of solar equipment (not pumps) by around 45-50 percent, as MACRS has a present value of roughly 15-20 percent of the installed PV equipment. The use of other federal grants and the existence of some local funds (e.g., Conservation Districts or electric utilities) can further lower the cost for SPWPS. Remember, an agricultural producer must have a tax liability to use the tax credits.
If a small-acreage owner does not operate a commercial enterprise with her/his livestock, then the Residential Renewable Energy Tax Credit could also be used. The tax
credit is similar to the BITC at 30 percent, with declining values in 2019, 2020, and 2021. The tax credit fully expires at the end of 2021.
The number of factors that dictate the cost of a system can seem daunting. Before gathering detailed information, most agricultural producers appreciate a rule of thumb. For SPWPS, the following rough estimates are valid in 2016:
Per watt capacity is a standard term in the solar industry but is a strange term to many agricultural producers. For example, a common two-panel system (typically 400 watts of capacity) would cost $600-1,200 for the panels and racking. Although required for any type of livestock watering system, the highly variable cost of fencing, plumbing, overflow shut-off devices, storage tanks, and labor can also affect the cost of SPWPS. For example, a larger storage tank, to account for daily production variability, can be an additional cost for SPWPS compared with other water pumping options. Most extension livestock specialists recommend three days of water storage for PV water pumping systems. Similarly, more fencing may be required to protect the PV panels compared to alternatives (e.g., a utility pole or generator).
Applying the parameters shown in Figures 4 and 5 to a theoretical Kaycee, WY, installation results in the approximate costs shown in Table 2.
Table 1: Business and agriculture incentives for SPWPS
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Notes: MACRS also includes special renewable energy system bonus depreciation. Equipment put in service before January 1, 2018, can qualify for 50 percent bonus depreciation. Equipment placed in service during 2018 can qualify for 40 percent bonus depreciation, and equipment put in service during 2019 can qualify for 30 percent bonus depreciation.
All systems are assumed to operate during the summer grazing season (May-October).
The design assumes the use of a SunPump brand DC pump. Other manufacturers, such as Dankoff, Grundfos, Lorentz, Robison, or ShurFlo, could also be substituted for the example. The estimated costs originate from New Mexico State University Cooperative Extension Service’s Solar Water Pumping Design Spreadsheet Version II. No incentives, such as the Business Investment Tax Credit and Modified Accelerated Cost Recovery System depreciation, are included.
How much do SPWPS cost to operate?
The upfront costs are an important consideration for the initial evaluation of SPWPS, but the long-term operations and performance truly determine viability. Figures 6 and 7 shows the system characteristics and operating costs needed to compare SPWPS to utility-sourced electricity or generators.
Finally, four additional factors significantly influence
the long-term operating costs of the
respective systems: the discount,
inflation, real energy escalation,
and tax rates. The discount
rate reflects the time value of
money. If you spend $5,000 on a
PV array, you cannot invest
that money in something
else. Alternately, if you
borrow $5,000 to buy
a PV array, your
credit union or
bank will charge
interest on the
Table 2: Example equipment costs (excluding tanks and wells) for a fixed SPWPS installation in Kaycee, WY1
1 From Jenkins, Thomas. Solar Water Pumping Design Spreadsheet Version II: User Manual. New Mexico State University Cooperative Extension Service Circular 671. 2012. Available from: http://aces.nmsu.edu/pubs/_circulars/CR671.pdf; Cost of PV without racking reduced to $1.50/watt from $2.50/watt based upon 2014 solar industry price reports.
Figure 6: System characteristics that inform operating costs
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* Includes selected UW Extension suggestions
loan. The inflation rate reflects changing prices over time. The real (above inflation) energy escalation rate is vital. In the last 10 years, electricity, gasoline, and diesel prices have increased at rates greater than inflation. The tax rate influences the value of some incentives, particularly MACRS-driven deductions.
Unfortunately, general estimates for SPWPS costs are difficult to provide due to unique site-specific characteristics. Total dynamic head, required flow-rate, and season of operation all significantly affect the installed cost of SPWPS. The cost of components can be estimated but only within relatively wide ranges. Thus, correctly evaluating SPWPS compared to utility-sourced electricity and generators requires agricultural producers and small-acreage owners to understand both how and where the respective system will function. Choosing the most cost-effective option requires spending the time to collect the necessary information shown in Figures 4-6. Part 2: When and where do they pay? provides tangible examples to help determine if SPWPS is right for anoperation.
To evaluate your water-pumping situation, please visitor contact your local University of Wyoming Extension educator.
Buschermohle, Michael J. and Robert T. Burns. Solar-Powered Livestock Watering Systems. University of Tennessee Agricultural Extension Service. PB 1640. Available from:
Jenkins, Thomas. Solar Water Pumping Design Spreadsheet Version II: User Manual. New Mexico State University Cooperative Extension Service Circular 671. 2012. Available from:
Jenkins, Thomas. Solar Water Pumping Systems for Livestock. New Mexico State University Cooperative Extension Service Circular 670. 2014. Available from:
Meah, Kala, Steven Fletcher, and Sadrul Ula. “Solar Photovoltaic Water Pumping for Remote Locations.” Renewable and Sustainable Energy Reviews: 472-87. 2008.
United States Department of Agriculture Natural Resources Conservation Service. Design of Small Photovoltaic (PV) Solar Powered Water Pump Systems. Technical Note No. 28. 2010. Available from:
United States Department of Agriculture Natural Resources Conservation Service. Solar-Wind Water Pumping
Figure 7: Variable costs for SPWPS, utility-sources, and generator systems
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* Includes selected UW Extension suggestions
Energy Self-Assessment. Online tool. Accessed June 4, 2015. Available from:
Van Pelt, R., C. Weiner, and R. Waskom. Solar-powered Groundwater Pumping Systems. Colorado State University Extension. No. 6.705. 2012. Available from: