Topic Area: Solar Energy
Geographic Area: Wyoming, United States
Focal Question: Is solar energy a cost-effective alternative energy
source for pumping water in rural areas?
(1) Chowdhury, Badrul H., Sadrul Ula, and Kirk Stokes. "Photovoltaic-Powered
Water Pumping - Design, and Implementation: Case Studies in Wyoming." IEEE
Transactions on Energy Conversion volume 8, number 4, December 1993:
(2) Hoagland, William. "Solar Energy." Scientific American. volume 273,
number 3, September 1995: 170-173.
Reviewer: Jill M. Maccaferri, Colby College '96
This study, conducted by five rural electric cooperatives in the state of
Wyoming with the help of Sandia National Labs and the University of Wyoming,
examined photovoltaic-powered water pumping systems installed in seven rural
areas in Wyoming. A major objective of the project was to introduce and test
alternative energy sources in rural areas located far from the established
electricity grid. The study found that indeed photovoltaic-powered systems were
cost-effective for these sites and were denoted as satisfactory sources of
energy by the system owners.
Photovoltaic pumps use solar panels to collect and convert solar energy into
electricity which is then used to power the electric water pumps. Systems may
include batteries or sun trackers although these are not necessary. The systems
have few moving parts and are relatively easy to maintain. Owner feedback from
the study asserted that an example of the maintenance required was simply to
clean the modules periodically due to the accumulation of dust and bird
droppings. On days with insufficient sunlight to run the system, a battery or
generator may be used as a back-up power supply.
Before the systems were set up in the rural areas, extensive site testing was
needed in order to determine the type of system necessary for the specific area
as changes in pump requirements change the cost of the systems. Technical
factors that needed to be examined were the site terrain, storage system
details, the amount of water that was to be pumped, the season during which the
water would be pumped, and the uses for the water. It was important to optimize
the technical factors in order to provide the user with the correct type of
pump. For each of the seven locations chosen the end use for the water was for
livestock, although the seasonal use of the water varied from location to
location. Six of the seven sites used a panel-direct system without a battery.
The panel-direct system is used for low volume pumping, requires a large number
of photovoltaic modules to generate enough energy to run the motor, and
generally will not operate on days with inadequate sunlight. As such the storage
systems are very important so that water will be available even on those cloudy
days when the system does not operate to capacity. The remaining system used a
battery to run the motor and was studied to determine the ability of batteries
to withstand freezing temperatures.
The study found that the photovoltaic-powered pumping systems were
cost-effective alternatives to extending the existing power lines to the rural
areas. Although the photovoltaic systems do have high initial capital costs, the
same is true for extending power lines to remote areas (See table). Once the
costs of excavation, wiring costs, and the costs of transformers are considered,
it is evident that extending the power lines can be quite costly. The cost of
the photovoltaic system is related to the amount of water pumped and the
distance from which the water needs to be pumped. As either of these
requirements increases, the amount of energy required also increases. In order
to generate a sufficient amount of power, more solar panels would need to be
added. This can significantly increase the cost of the photovoltaic system. For
instance, the cost of a photovoltaic system to pump 570 gallons of water per day
up 50 feet would amount to $1400 and would use 40 watts of electricity. To pump
6480 gallons of water per day up the same 50 feet would require a system that
cost $6500 and used 250 watts.
The sites were monitored and owner feedback was recorded. Of the seven systems
in operation, five reported system problems. However it must be noted that the
majority of problems were not directly due to the failures of the systems
themselves but instead to non-system-related problems. One problem was damage
caused by wind. The high winds that can often occur in Wyoming damaged the shock
absorber at one site but on both occasions the shock absorber was repaired. At
two locations the pump clogged due to sand from the well. Another site reported
a well collapse and the final site reported the electric float switch froze due
to freezing temperatures. The switch was replaced by a ball float and continued
to operate as planned. Despite these setbacks, on the whole owners reported they
were satisfied with their systems. The results of the study sparked interest for
other rural sites in Wyoming. Currently over 20,000 photovoltaic-powered water
pumps are in operation around the world.
Utilizing photovoltaic-powered water pumps promotes sustainability by decreasing
the demand for non-renewable energy sources such as fossil fuels. This can
result in many environmental benefits such as decreasing the levels of
atmospheric carbon dioxide, air pollution, and acid rain. The photovoltaic pumps
in Wyoming benefited both parties involved as neither the owners of the sites
nor the local utility had to pay for extending the power grid to remote areas,
while at the same time improving the environment by reducing the demand for
fossil fuels. In conclusion, this study has demonstrated that
photovoltaic-powered water pumps are a cost-effective solution to conventional
energy sources for rural sites and photovoltaics are certain to become more
prevalent in other aspects of daily life.
Thanks to PROFESSOR TOM TIETENBERG
Want awesome ideas when designing your own passive solar home plan?
How about a simple system for creating a solar home or structure?
Back to Solar Articles
Other Helpful Solar
Panel and Solar Power links
Our top solar power/solar concept product
This solar power design is great! It uses solar panels and solar power in its plan.
In 1980, Mike and Lisa Kraft set out to build a really cool solar home. They used many solar concepts, including solar panels, solar power, and solar water heating, in their plan. They still live in the same home today, and offer you a great way to learn everything that they have learned--Only you won't have to study for hundreds of hours, and live in the house for 20+ years, like they did. Learn from their solar experiences by checking out their ebook!
Welcome to the State of Wyoming
Consumer Protection Section, Wyoming Attorney General's Office. Official state site. General overview, visitor information, business climate,
Wyoming.com - Wyoming's Leading Internet Service Provider
Wyoming.com, Wyoming's Leading Internet Service Provider. Specializing in local dial up access, High-Speed Internet, network security, and Web design...
Wyoming Game and Fish - Home - 1
Official information about hunting, and fishing in the state of Wyoming. The home page for information about hunting, and fishing in the state of...
University of Wyoming - New Thinking
Official web site of the University of Wyoming, located in Laramie, Wyoming--colleges, libraries, directories, faculty, student information,
Jackson Hole Wyoming Travel Guide - Lodging, Skiing, Hotels, Real
Complete travel guide to Jackson Hole Wyoming and Yellowstone Park.