Project Description
Introduction
The Ute Mountain Ute tribe in southwestern Colorado brings in considerable income from its cattle-ranching operation, with a herd of nearly 2,000 head. Since annual rainfall is only 10-15 inches and the only stream is dry part of the year, the tribe must rely on groundwater for cattle watering. Traditional wind pumpers have been used in the past, but they are not satisfactory due to seasonally inadequate winds and high maintenance costs (estimated at $1,200 per well, per year). Power line extensions by the local electric cooperative would cost $4,400 per well, per year/well-year. The tribe is therefore replacing about 35 wind pumpers with photovoltaic (PV) pumps, which have an estimated annual maintenance cost of $500. In this project, the performance of several selected pumping installations will be monitored for a year.
The Ute Mountain Ute Indian Reservation, is located in extreme southwest Colorado with portions extending as far as White Mesa, Utah, and northwest New Mexico. It is homeland for the Weeminuche Band of the Ute Nation with a population of approximately 1,850 tribal members, and the reservation covers 597,288 acres (933 square miles of trust land) and 27,354 acres of fee land, which accommodates eight ranches throughout the state of Colorado.
The tribal seat is the town of Towaoc, Colo., which is located at the base of the Sleeping Ute Mountain in Montezuma County, Colo. This area is commonly referred to as "the Four Corners region" bringing together the states of Colorado, Utah, Arizona, and New Mexico at an intersection of right angles. The reservation is within the vast region of the Four Corners and isolated from services other communities take for granted. There are no large cities nearby, the closest being Albuquerque, N.M., approximately 260 miles to the south. The tribe, located on what is now their homelands, must compensate for this lack of services by looking for other means of implementing progress and creating successful enterprises.
Topographically, the area is located on the Colorado Plateau, which is characterized by high desert plateaus with canyons cut deep into the land. The land is covered by sagebrush scrubland, cedar, pinion pines, and ponderosa pine forests scattered across the upper elevations of the Sleeping Ute Mountain, the dominant geologic feature of the Ute Mountain Ute Indian Reservation. To the east, the reservation borders Mesa Verde National Park, which contains cliff dwellings of the ancient Anasazi, who lived, farmed, and irrigated the mesa tops more than 900 years ago. During this time, it is estimated that 40,000 Anasazi lived in Montezuma Valley and cliffs of this high desert terrain. The Ute Tribal Park, which occupies 125,000 acres, adjoins the southern boundary of Mesa Verde National Park. The Tribal Park has more ruins than Mesa Verde and can be explored only with a Ute guide. The largest canyon within the Tribal Park is the Mancos Canyon which was carved by the once powerful Mancos River.
The climate of the reservation is semi-arid; the average annual precipitation generally ranges from 10 - 15 inches. The Mancos River is the primary source of surface water that flows southwesterly through the reservation, consisting of 70 stream-miles. In most years, the stream does not flow at times - particularly during September, October, and November.
Goals and Objectives
It is the tribe's intent to improve the overall range condition on the reservation as a result of the conversion to solar wells. According to the most recent soil and range inventory completed on the reservation, 436,850 acres can be classified as range suitable for livestock. Of that total, 3% can be described as excellent condition rangeland, 26% as good condition, 42% as fair condition, 26% as poor condition, and 3% has been reseeded.
This goal of improving range conditions will be achieved by the expected improved efficiency and reliability of the wells. This expectation should allow for more rotational grazing schemes which will lead to more uniform use of the forage. Proper rotational grazing will result in a rest from grazing at key points during the growing season. Improved range condition and trend should follow.
Project Actions and Resultant Data
Due to the lack of surface water and the dry climate of the reservation, the tribe relies solely on groundwater as the source of water for stock. Cattle ranching is an important enterprise to the tribal members. Before the Utes were forced to move onto their federally designated reservations, they were nomadic hunter/gatherers. This stationary lifestyle forced the Ute people to turn to farming and raising cattle. Today, the tribe and individual members own more than 1,900 head of cattle.
The tribe's precious groundwater resource is presently being tapped by a majority of wind turbine units on wells spread throughout the reservation. This type of natural energy source may be a proven success and the best alternative in some areas of the country, but for the Ute Mountain Ute Indian Tribe, a more consistent and efficient source of renewable energy needs to be investigated. The wind turbine units provide several wells with adequate water supply, but are cost prohibitive and are labor intensive as to the operation and maintenance.
The Ute Mountain Ute Indian Tribe would like to further explore the PV energy source as the alternative to replace the current wind turbine units. This solar energy source currently is pumping well water and also powers the de-icers for the passive solar designed stock tanks. During the 1994-1997 timeframe the Ute Mountain Ute Tribe, in cooperation with the Bureau of Indian Affairs (BIA) and the Department of Energy (DOE), scheduled the replacement of 19 of the current wind turbine units with the PV energy source. This has created a great interest across Indian country wanting to look at the feasibility of solar power as a more consistent source of power for water resource development in the rural reservations.
The tribe feels that PV energy is the best option available in order to improve and utilize the natural resources and improve the efficiency of the wells. This is based on the following facts.
A lower maintenance demand would be more feasible and also practical because of the isolation and vastness of the reservation, with many areas inaccessible at certain times of the year.
The current wind turbine units have proved to be inconsistent in vital areas due to unfavorable wind conditions, especially during the winter months.
The annual solar radiation for the reservation of 570 langleys per day (as calculated by the U.S.G.S.) is more than an adequate supply of renewable energy to pump the wells.
The wells that would be converted to PV have sufficient yield and have accurate historical aquifer data from the U.S.G.S. to substantiate this claim.
This project allows for the education and training of tribal employees, as other solar projects on a larger scale are implemented in the future on the reservation.
To implement this project, the tribe provided a department(s) or agency(s) to assume responsibility of administering the grant. The selected department(s) or agency(s) provided qualified technical personnel to participate in training and assist during the conversion and installation of the solar technology on 20 more well locations on the reservation. This qualified personnel will then maintain and operate the solar equipment indefinitely. This is important because of the lack of technical support available after the initial purchase and installation with this project in this sparsely populated region. The tribe is convinced there is a future for the PV technology, and shall continue to seek the assistance of the local technical college in order to be updated frequently on the latest advances in this innovative technology.
The project will contribute significantly to improved environmental quality and environmental protection activities. It is anticipated that the environmental consequences of the conversion to solar well will be positive. This is in keeping with the Ute Mountain Ute Indian Tribe's belief and desire to create minimal disturbance to Mother Earth by human activities. The tribe has some 50 years experience with windmills as a clean alternative form of energy. The conversion to solar energy is expected to continue that experience.
A number of important wildlife species significant to the tribe and the ecosystem are known to use the areas where the solar wells will be installed. These species include mule deer, antelope, elk, golden eagles, red fox, pheasant, ducks, geese, coyote, sage grouse, quail, and cottontail rabbits. It is expected that they will benefit from a more reliable water source.
The windmill towers will remain erect because of the nesting habitat they provide for many species of birds, including birds of prey such as eagles and hawks.
Consistent ground water wells will contribute significantly to the current water quality program, which is funded by the Environmental Protection Agency. There are many oil and gas producing wells on the reservation and the quality of the ground water can be easily monitored by sampling the water wells. The tribe's Farm and Ranch enterprise has just started the irrigation of a 7,500-acre project on the western part of the reservation. Drainage information is critical as well as the impact of the possible runoff from chemicals such as fertilizers and pesticides. These environmental concerns can be investigated through consistent ground water monitoring, which is essential for a sound water quality protection program.
The project will contribute significantly to overall economic, employment, and educational opportunities on the reservation. The tribe has a past performance of utilizing natural resources to develop strong Tribal enterprises while, at the same time, promote and extend education and employment to Tribal members.
The proposed project continues to employ three full-time employees, who are trained in the technical aspects of PV. The training included the conversion, operation, and maintenance of the solar wells.
The overall distribution of the solar wells across the grazing lands of the reservation will allow for the further development of Tribal member-owned cattle enterprises. The expected improved reliability of the solar wells will lead to improved average daily gains for the cattle which, in turn will lead to greater sale weights at the livestock auctions. This directly benefiting the tribe and the individual cattle owner.
The technical education from solar photovoltaic which was provided to individual tribal members is invaluable. Training was offered to employees of the tribe who are concerned and involved with the continued operational activities of the project and Tribal cattle ranchers who are interested in improving the rangeland.
The tribe is convinced that solar energy is their future because of the high cost of utilities on the reservation. The opportunity to expand our capabilities to ensure the future of the tribe is greatly needed. The tribe feels that this grant would be a stepping stone to expand into the development of both PV and solar thermal technologies on the reservation.
Photovoltaic technology has been advanced and developed over the past decade. The conversion of solar energy into electricity is vastly becoming a common source of power. Corporations in America have developed PV cells using silicon semiconductor diodes, which produce direct current electricity. This technology is readily and commercially available nationwide. The risk of using and developing photovoltaic technology is decreasing with time.
Currently the cost of operation of a line extension power source from Empire Electric Association Inc. is estimated at approximately $4,400 per well site per year. It also has been estimated that the continued maintenance of wind turbine technology is $1,200 per well site per year. The maintenance and operation of PV is very minimal compared to these other sources. The estimated cost of maintenance for the solar wells is approximately $500 per well per year. The tribe believes that this is a high estimate since the technology we are proposing is self contained without many moving components. The ease of operation and maintenance of solar photovoltaic technology is a major consideration in the development of this project to service the vast, isolated areas on the reservation.
Project Activities
The solar well demonstration project was broken down into eight tasks, consisting of work plan development, solar well design, procurement, training, well rework & equipment installation, operation and maintenance, performance evaluation and Tribal awareness campaign.
A work plan to insure project completion was established early is the project. The plan insured milestone and goals, and responsibilities of the partners involved. The majority of the objectives were accomplished by coordination between the Bureau of Indian Affairs, National Resource Division, the solar mill technician, and the technical distributors.
The identification of problem areas and planned conversion wells was accomplished by cooperation between the independent cattleman, Ute Cattle Association, Bureau of Indian Affairs (BIA), and the Tribal Resource Department. When this was accomplished, each identified well was tested to determine pertinent technical data and information required to complete the photovoltaic design. Information such as static water level, casing size, recharge rate, well depth, and amount of water needed.
Solar well design considerations are usually determined by equipment needs based on the well information. Photovoltaic power is produced directly by sunlight shining on an array of PV modules, requires no moving parts, and is extremely simply and reliable. Many materials respond to visible light; the most common is silicon, a constituent of ordinary sand. A thin, silicon cell, 10 cm across, can produce more than 1 W of d.c. electrical power under clear sky conditions.
Generally, many individual cells are combined into modules sealed between layers of glass or transparent polymer to protect the electric circuit from the environment. These modules are capable of producing tens of watts of power. Several modules are then connected in an array to provide enough power to run a motor-pump set in a pumping system. This array is usually mounted on a simple, inexpensive structure oriented toward the sun at an inclination angle close to the latitude of the site. This ensures that ample energy from the sun will shine on the array during all seasons of the year.
A PV-powered water system is basically similar to any other water system. All PV-powered pumping systems have, as a minimum, a PV array, a motor, and a pump. The array can be coupled directly to a d.c. motor or, through an inverter, to an a.c. motor. For both a.c. and d.c. systems a battery bank can be used to store energy or the water can be stored. The motor is connected to any one of a variety of variable-speed pumps.
Pumps of many different varieties are suitable for inclusion in a PV-powered pumping system. They do, however, fall broadly into two categories, centrifugal (rotodynamic) and volumetric (positive displacement), which have inherently different characteristics.
Centrifugal pumps are ideally suited for conditions of moderate-to-high flow in tube wells, cisterns, or other reservoirs. These pumps are designed for a fixed head and their water output increases with rotational speed. Their efficiency decreases at heads and flows away from their design point. Centrifugal pumps have been installed with capacities as high as 1,200 cubic meters/day and can be used for flow rates as low as 10-15 cubic meters/day. However, these pumps are not recommended for suction lifts higher than 5-6 meters or 16-20 feet.
Volumetric pumps have a water output that is almost independent of head but directly proportional to volume. There are many different types of volumetric pumps. The most interesting for inclusion in PV-powered pumping systems are the counter balanced piston pumps, usually called jack arm or donkey pumps, and the progressive cavity pumps commonly called screw pumps. The efficiency of these pumps increases as the head increases. Volumetric pumps are ideally suited for conditions of low flow rates and/or high lifts. Pumps of this type have been installed with flow rates as low as 0.3 cubic meters/day and as high as 40 cubic meter/day, and with lifts from as little as 10 meters to as great as 500 meters.
As with pumps, there are different types of motors, the choice of the motor for a PV-powered system is dependent on the size requirement, need for the motor to be submersible or not, and availability of driving electronics. Three basic types are permanent magnet d.c. motors (brushed or brushless type), wound-field d.c. motors, and a.c. motors. The choice of a d.c. motor is attractive because PV arrays supply d.c. power. However, a.c. motors in conjunction with d.c.-a.c. inverters can be used for high-power applications.
The criteria for choosing a motor are: efficiency, price, reliability, and availability. Generally, the wattage determines the choice of the motor; permanent magnet d.c. motors under 2,250 watts (3 horsepower), wound-field d.c. motors for 2,2507500 watts, (3-10 horsepower), and a.c. motors above 7,500 watts (10+ horsepower).
Generally, a.c. motors are limited to high-power applications in PV-powered pumping systems because they require inverters, thereby introducing additional costs and some energy loss. Although a.c. systems are usually less efficient than d.c. motors, special improved efficiency models are becoming available for PV systems.
Motors and pumps are essential components of the PV system, but for efficient operation, it is necessary that the voltage or current characteristics of the pumpset match those of the array. There are three basic ways in which a pumpset can be connected to a PV array. The simplest is to directly couple the pumpset and array. Another method is to interpose a batter. The third is to use an electronic controller.
The operation characteristic of centrifugal pumps are reasonably well matched to the output of PV arrays. Therefore, the two are most often directly coupled. This direct coupling required that gear ratios, motor speed, and voltage and pump stage characteristics be carefully chosen for proper operation. Array matching to pump characteristics is complicated by the limited number of pump sizes.
Electronic controls can enhance performance of a well-matched array pump system by 10% - 15%. These controls are frequently used in locations with fluctuating water levels or weather characteristics.
The operating characteristics of volumetric pumps are badly matched to the output of PV arrays. Batteries can improve this match and allow the motor to be started at low sun level. However, batteries have drawbacks.
Maximum power controllers are usually used with volumetric pumps. They employ "intelligent" electronic devices to transform the array output to match pumpset poser requirements. These controls allow operation over a wide range of irradiance levels, water levels, and flow rates. In addition, they solve the volumetric pump starting problem. Electronic controls typically consume 4% - 7% of the array's power output.
Water tanks and Batteries are an important consideration, regardless of the intended use for the water. A pump powered by a PV array supplies water during sunlight hours only, unless storage batteries are included. Should batteries be included was a question which was asked early in the project. It was determined to be financially unfeasible. The introduction of batteries into the PV systems might decrease its reliability and increase it maintenance requirements. The inclusion of batteries is justified when the maximum yield of the well during sunlight hours is insufficient to meet the daily water requirement.
Pumps without batteries will not produce any amount of water when the sun does not shine. This is least troublesome in those places where the water is for irrigation. The evapotranspiration of plants is proportional to the solar intensity; or the plants need less water when the pumps are producing less water. But in our situation the wells are not being used for irrigation but for livestock use. Water needs of livestock also vary with the solar intensity. On all tanks, water storage sufficient to hold several days of water is designed into each well site.
The volume of water needed is probably one of the most important factors in the design other than the amount of water the site can produce. The volume of water required per day and the amount of energy available from the sun can determine different alternate systems.
Three different needs should be considered to determined the quantity of water to be pumped by a water system: water for drinking and cooking (domestic), water for livestock, or water for crop irrigation. Human and animal water needs is determined by estimating the daily usage by the population of the animals.
| Animal | Water Usage (liter/animal) |
|---|---|
| Horse | 50 |
| Dairy cattle | 40 |
| Steer | 20 |
| Pig | 20 |
| Sheep | 5 |
| Goat | 5 |
| Chicken | 0.1 |
Water usage is the first requirement to be determined. If water usage varies over the year, the mean daily water requirements for each month must be calculated. For drinking and livestock water, water needs will be about the same every month. The critical month from a design viewpoint is the one with the minimum ratio of sunlight available to the amount of water required and available. The month with the least sunlight is the month in which the least power is produced by the PV system (e.g. 50 steers in a pasture for 3 months would require 1,000 liters (264 gallons) of water per day). Or a pump that would need to produce 0.88 gallons per minute in a 5-sun-hour period.
The power produced by a PV system depends on the insolation available or amount of sunlight. This insolation varies for each site and month to month, due to seasonal and climatic variations. Insolation is usually measured in sun hours (1 sun hour = 1 kWh/m2, about equal in intensity to sunshine on a clear summer day at solar noon).
If water needs stay the same year-round, solar design calculations should be based on the month with the lowest insolation levels to ensure adequate water throughout the year. If water is to be used for crop irrigation, the months with the lowest insolation often correspond to those which crop demand for water is also the lowest. But if water consumption varies throughout the year, the system design should be based on the ration of water required to insolation available. The month in which this ratio is largest will determine the PV array size. When determining irradiation for a specific location, data should be obtained from the nearest available meteorological station and allowance made for any known climate differences.
The orientation of the PV arrays would refer to the position of a surface relative to true south. Although PV arrays that face within 15 degrees of true south receive almost full sunshine, any unobstructed, generally south-facing surface is a potential array location. In many areas, a slightly westerly orientation is preferable to due south to avoid morning haze or fog. An array should not be shaded by obstructions like buildings or trees. Obstructions that cause no interference in summer may cause long shadows when the winter sun is low in the sky. Insure the best location during the times when the water is need the most.
Module surfaces titled at a right angle to the sun's rays catch the most sunshine per unit area. An angle equal to the local latitude is the closest approximation to that tilt or slope on a year round basis. This means that the ideal pitch of an array for year round operation is about the same as the number of degrees of local latitude. If the water needs are not the same throughout the year, a higher or lower array tilt angle may be advantageous and lead to better system performance. For our example when the winter months have the highest water needs, increasing the tilt by 15 degrees is to be installed.
Insolation is measured in sun-hours. If, for example, 5 sun hours per day are available at a site, this does not mean that the sun produces 1 full sun hour for 5 hours. In actuality, the sun produces less than 1 "full sun" for a period longer than 5 hours. The maximum required water flow in liters per hour will be approximately the system's requirement divided by the number of sun hours. Dividing this figure by 3,600 second/hour gives the maximum expected water flow in liters per second.
The amount of water produced by the well, like the amount of water needed by the number of animals, is one of the most important factors in the design of a pumping system. A correctly operating pumping system should not exceed the well's production. For example, if a well can produce only 0.5 liter/second, a pumping system capable of pumping twice that amount will only pump the well dry. For that reason, and for future planning, it is important to know how much water a well can produce.
There are techniques commonly used to determine the amount of water a well can produce. These methods can be used to work with both shallow, hand dug wells, and deep tube wells. To perform this test, a portable pump or a bailing system is needed. First, measure the depth to water in the well - this is known as the static water level. We will be using a sounder and steel tape lowered in the hole to determine the static water level. Due to the rural nature of our locations we will be using a bailing system to determining the water production levels. Once the static water level is determined, now insert the bailer to the bottom of the hole and measure the distance. This will determine the depth of the well. At this time the well is bailed a minimum of 10 times as quickly as possible. Reinsert the sounder and steel tape to determine the bailed well depth. At this point the time is recorded. The sounder is reinserted into the well to determine the recharge rate of the next 30 to 60 minutes. This method will allow the determination of the aquifer in which the well has been drilled recharge rate. This flow rate should be at least as high as the peak flow required by the application. If the water level drops to the bottom of the well the well would be determined pumped dry and may not produce enough water for the tribe's needs and would be determined not to be viable and not converted.
The proposed water pumping site has now been evaluated, and both water needs and the power required to produce that water have been determined. The next step is to begin the procurement process.
Buying the components from individual vendors and assembling them on site to your own design specification can be a problem. The difficulties of proper design, installation, and checkout, coupled with the difficulty of securing a system warranty, might make purchasing a system on a component level inadvisable except for the most knowledgeable and experienced users. The two usual choices in procurement are:
- To purchase the total system designed by a qualified vendor an have it installed and checked out for you.
- Perform the installation and test of a vendor designed and supplied system yourself.
Due to the numbers of systems which the tribe is proposing to install the second option as being the best for the tribe with a training sessions provided by the qualified vendor. In either case a performance specification must be prepared that requires design calculations and performance guarantees. The technical specification is a critical component in procuring the system or the right vendor.
After including the acceptance test in the technical specification, the next greatest protection is to buy the equipment from a bidder who is active in the field. These manufacturers supply systems that work. It is also unwise to buy a system from a manufacturer of limited experience. Manufacturers must have a level of experience that is needs to make the proper choices in designing a PV-powered pumping system. Prospective companies will be required to demonstrate their experience and resources to meet the requirements of the project.
Warranty and service after the sale is a problem that the tribe has experienced in other areas requiring technical parts or service. The ability of a company to provide the full-coverage warranty for a period of time sufficient to assess the pumping system's acceptable performance. Typically, this period is one year, but the rural nature and amount of units we are looking for an extended period past one year. The vendor will be required to provide training and technical support after the installation. It is especially important to warranty service is the availability of service within the region, or at least in a timely fashion.
Proposals will be assessed in detail for compliance with the specification, system design capability, capital and life cycle costs, and the overall credibility of the supplier.
Training will be established by experts in the industry on the following but not limited to the following areas; general operations of the systems, general system inspection, troubleshooting, repair, tools, wire specification, module specifications, solar jack pump and controller information, wattsun tracker information, and installed systems (system information & wiring diagrams). A program which will have certification of completion of such training.
The well rework and installation of the solar well equipment will include the assistance from the BIA's Natural Resources Division and the equipment supplier chosen for this project. The majority of the rework will be performed by the tribal solar smiths under the supervision of the BIA and vendor. This rework will include the testing process and the installation of the actual solar equipment such as panels, inverters controllers, pumps, motors, and final inspection or checkout to insure the proper operation and performance standards of the well design.
Operation and maintenance of the systems will include, at a minimum, to operate the solar wells and data systems for a minimum of one calendar year following the installation and operational checkouts. To insure operation the solar smiths will prepare and maintain logbooks to record the work preformed at each site and include the pertinent information from the logbooks in the performance evaluation of the project.
The performance evaluation will include monitoring the performance of the test pump and well for one calendar year. This will allow for measuring certain parameters on some of the wells. The parameters to be monitored could include time of day, global solar irradiance (kWh/day/meter), battery voltage, battery state of charge, inverter power, inverter current, battery charger current, and pump flow rate. This analysis could include the preparation of a time series representation of each measured parameter on a daily and monthly basis: the calculation of the solar energy supplied (kWh), energy (kWh) supplied by the inverter to the pump, the total gallons of water supplied, and the solar conversion efficiency (ratio of solar energy supplied to the inverter energy supplied to the pump).
Finally, the last task is the Tribal awareness campaign, which is to consist of quarterly meeting to inform the Tribal members of the project objectives, work plan, and activities. These quarterly reports will be prompted by the use of the Tribal newspaper and cable television to insure a greater amount of coverage to the general population. It also includes soliciting and discussing comments from the Tribal members as part of the project evaluation report.
Results, Conclusions, Findings, and Recommendations
During the 1995-1997 time period the Ute Mountain Ute Tribe successfully converted 30 windmills to solar powered water wells. The conversion of these wells was funded by the tribe and, in part, by a grant from the DOE Indian Energy Resource Development Grant.
After the grant application was approved, the tribe requested the full time assistance of Bill Mellick and Paul Schalfly of the BIA, Ute Mountain Ute Agency, for the express purpose of working on the solar well project. The tribe requested a survey to be conducted of the current conditions of the windmills across the reservation. This survey was conducted with the assistance of the BIA. Of the 35 locations surveyed, 12 were operational. Twenty-three windmill locations were found to be defective in some way. In some cases the towers had been pulled. In other, there was broken pipe in the hole, or other parts of the windmills were missing. This information was gathered and became the backbone of the project.
At the beginning of the project the tribe retrofitted a BIA one-ton truck into a boom truck, a 20-foot-long flatbed trailer, and a flatbed truck to perform the work. BIA personnel were sent to Albuquerque to research what companies would be able to provide the parts necessary to convert the wells to solar power and provide assistance and training to Tribal staff on maintenance of the solar equipment.
In order to procure this high-tech equipment, proposals were requested to insure price and service after the sale. Due to the rural nature of the reservation and the project a distribution location and available services we major factors in determining the right company. In doing so, Direct Water and Power, located in Albuquerque, N.M., was the closest company available to fulfill the contract equipment needs and the service needs also required. They also were contracted to provide a maintenance & training program.
Engineers and specialists were used to train the solar smiths in solar mill techniques. The initial training was provided by Direct Water and Power on maintenance and installation of the systems. Each system was deigned independently so maintenance and trouble shooting is different. Initially the San Juan Vocational School was to provide a certified program for the solarsmiths, but this proved to not be feasible. Other professional outside training was accomplished in cooperation with Los Alamos Labs in New Mexico.
The solar personnel consisted of three tribal member staff and the two BIA Natural Resources personnel identified previously. The work process on each well location proceeds something like the following;
The support poles for the windmill tower are cutoff. The boom on the boom truck is extended and cable line from the boom truck on one side of the tower and a rope and chain attached to the flatbed truck on the other side of the tower are secured. The sucker rod is disconnected from the windmill and secured so that it does not fall to the bottom of the well. The flatbed truck is backed up until the rope attached to the tower is taut. As the cable form the boom truck is slowly released, the flatbed truck is backed up to pull the tower over. Once the tower has been pulled over and moved out of the way, the crew pulls the sucker rod and pipe out of the hole with the boom truck. After the hole is open, a sounder and steel tape are lowered into the hole to determine the static water level of the well. The bailer is then rigged up to the sandline from the boom truck and lowered to the bottom of the hole. The sandline is marked when the bailer reached the bottom of the hole so that the depth of the bottom of the well can be determined.
The well was then bailed at least 10 times as quickly as possible. The sounder and steel tape are then lowered back into the hole in order to determine the bailed well depth. The time was recorded. The well was sounded repeatedly over the next 30 to 60 minutes in order to determine the recharge rate of the aquifer in which the well has been drilled. The above information is gathered and recorded and a determination of whether or not to convert the well was made depending on its static water level, bottom depth, and recharge rate. If the well has been determined to be viable, the information gathered was sent to Direct power and Water Corporation where they assemble and design a solar array suited for the sites potential.
The parts necessary for a solar powered well consist of; 60, 90, or 12 volt d.c. submersible pump, 1-inch diameter PVC pipe, a spool of electric wire which spans from the pump to a control box, a 6- or 8-inch diameter steel pole to support the solar panel array, and a 1,000 gallon stock tank.
The panels are wired and mounted on to the solar array in Towaoc by the Tribal member crew. All the parts are then transported to the well site. The pump, wire and PVC pipe are lowered into the hole with the boom truck. The positive, negative, and ground are then wired into the control box. The leads from the solar array are wired into the control box above ground. The switches are then thrown and the process is complete. If everything works, water was pumped out of the well within a minute or two.
At this point he stock tank is installed in order to create a surplus of water needed for the amount of animals that are drinking the water. Each site is determined to have a minimum of 1,000 gallon storage tank or drinkers. Other systems were designed to produce more water because of a larger need they had 1,000 barrel tanks installed or dirt tanks installed and filled.
Each well was designed and installed independently for all of the rest. Attached is a copy of a report which was designed for a particular well site with the estimated performance of the PV system based on the tilt of the panels on a fixed angle versus a sun tracking system. The results show the amount of gallons which would be pumped per day.
Most of the training for any technical application is best learned in a hands on environment. The solar smiths encountered all kinds of different ways to handle both the installation and maintenance of the solar mills. Between June 10-14, 1996, the tribe and Direct Water and Power sponsored a Solar Water Pumping School in Towaoc. This school was opened to both Tribal solar smiths and other individuals who have interest in the project. Attendance included cattleman, solar smiths, BIA employees, and other Tribal Natural Resources employees.
This school began with the general operations of a PV system and their operation. The different types of PV systems, how they work, what components make up the systems, and how those components work. Attached is a copy the first section of the training Manuel titled "General Photovoltaic System Operation."
General PV system inspection was the second category addressed in the training school. The technical and general information on the inspection of PV systems. Also, enough material to be sufficient for an annual control inspection (ACI) when no repairs or maintenance operations are to be performed. An inspection checklist is prepared to insure proper installation.
Photovoltaic system troubleshooting was the third issue in which the training focused. Troubleshooting, repair, tools and materials, and wire ampacity were all covered in the trouble shooting section. After the initial installation, we must be able to determine what is wrong with a photovoltaic system. Fundamental troubleshooting techniques for PV systems were explained along with the tools and materials needed to perform this function.
During the module specifications section of the training class, the water system design considerations for the system were taught. In most cases engineers design the PV systems which are to be installed. But the actual installers are not trained enough to know the intricacies of the system design. The students were taught the methodology of design which was the basis for our approach to accomplish this project.
Specific equipment types were used as hands on models during the next part of the training class. SolarJack pumping systems, Wattsun Tracker, and the different types of controllers. These were the actual products being specified for the project systems.
Finally, the class ended with some of the systems which had already been installed and designs of those systems. Both hydraulic information and wiring diagrams were discussed at length. The work performed involved a combination of training and actual installation of the systems. Thirty systems were installed in all corners of the reservation, especially those rurally located.
Changes to the Project
The changes to the original project scope of work was the certification of the Tribal member solar smiths. Instead of having them entering into the San Juan Vocational Technical School, this training and completion training was accomplished by Direct Water and Power and the experts at Sandia Labs in Albuquerque, N.M. Also, there were no batteries installed on any of the wells on the project.
Description of Results Achieved
In completing the project, we found multiple results based on the deference in the locations of the wells. The recharge rates of the water in the wells created situations were the amount of water is only minimal. Well sites were designed to only produce 1 gallon per minute. It was determined at the being of the project that do to security and weather batteries charged by photovoltaic systems were not financially feasible.
Therefore, optimal pumping systems were needed to be maintained during the day light hours. In doing so we implemented sun tracking systems, which allowed the maximum amount of energy conversation. But as was stated prior, water recharge rates created shut down periods at the height of the solar day. These wells were eventually decreased in design of gallons per minute.
Also, track arms were moved into stationary positions where teaching systems were not required. Individuals were trained even further then in the solar energy process. Each well was measured with the array with the peak watts available with the design also the amount of water produced by each of these wells during operation was measured.
The test well was established from the first phase of the project due to its proximity to the community so that monitoring could be accomplished. This well is known as Stevie South. This well had an initial static water level determined at 175 feet with a bottom depth of 399 feet. This well was determined to have a recharge rate of 3 gallons per minute with a 6-inch casing. The pump was set at 240 feet with a 2 gallon per minute pump designed in the hole. Also the original design had a 4-325 pump with 480W peak array measurement. The system voltage was also 90 VDC with six panels. This well was not producing the amount of water for which it was designed. Therefore during the second phase of the project, the well was reworked for a second time. The results were quite different during the draught conditions. It was determined that the static water level had changed to 169 feet and the bottom was at 407 feet after the pipe was fished out of the hole. The drought conditions measured the recharge rate at 0.9 gallons per minute a chant of 2.1 gallons. The new design moved the pump level to 380 feet to receive the 2 gallons per minute production that was required. A different pump was placed in the hole with an array peak watts measured at 742 W. The system voltage also increased to 105 VDC and the panel modules was increased to 14.
An hourly analysis report was developed for our test well. The results showed well production from 1,644.32 gallons per day in the highest production month to 974.19 gallons per day during the lowest. Daily kWh/M2 measurements also changed for the different months of the testing period. December measurements proved lowest with a daily measurement of 5.1 kWh/M2 and the summer months proved the highest with a measurements more than 10 kWh/M2 in May, June, and July. Those months also proving to be the major producing months.
These measurements from the test results show the actual amounts of power and water which the system provided, based on an hourly test analysis for every month in the calendar year. The results are measured for every hour increment for kWh/M2, cell temperature, array VOC, array ISC, array IMAX, pump volts, pump amps, dynamic head flow, and flow in gallons per minute.
The overall acceptance of the project was considered excellent. In many cases Tribal members and cattleman did not know what the solar power was or how it would increase the production of the water resources on the reservation. Interviews with individuals was accomplished during all phases of the project. Also, articles were put into the Tribal newspaper to gather support and explain the differences of solar power versus other types of energy sources.
Currently, the Ute Mountain Tribe is exploring the possibility of developing a facility in Utah powered primarily from solar energy. This facility is also in a remote area with power connections more than 13 miles away. The knowledge gained from this project has opened other doors and opportunities for the Ute Mountain Ute Tribe.
Project Status
For current project status or additional information, contact the project contacts.
Project Contact
Ute Mountain Ute Tribe
PO Box 52
Towaoc, CO
Telephone: (970) 565-6485
<p><strong>Tribe/Awardee</strong><br />Ute Mountain Tribe</p><p><strong>Location</strong><br />Towaoc, CO (Includes land in New Mexico and Utah)</p><p><strong>Project Title</strong><br />Solar Water Pumping Demonstration Project</p><p><strong>Type of Application</strong><br />Deployment</p><p><strong>DOE Grant Number</strong><br />DE-FG48-94R810521</p><p><strong>Project Amounts</strong><br />DOE: $194,965<br />Awardee: $85,696<br />Total: $280,661</p><p><strong>Project Status</strong><br />Complete</p><p><strong>Project Period of Performance</strong><br />Start: September 1994<br />End: June 1997</p>