Wheatland Reservoir Number 1
Site Location, Ownership, and Access
The Wheatland Reservoir Number 1 is a re-regulation reservoir owned and operated by the Wheatland Irrigation District (WID). The reservoir is on Reservoir Road approximately 4 miles southwest of Wheatland. The reservoir supplies water to agricultural producers within the boundaries of the Wheatland Irrigation District. The WID has an easement to access and maintain the reservoir and the existing access roads are adequate.
Water Rights
WID owns the water rights that would be used for hydropower production; however, the beneficial use is permitted as irrigation. WID would have to file for an enlargement to add power generation as a beneficial use to the water rights. The water right for power generation would be non-consumptive and secondary to irrigation. The need for any additional water rights is not anticipated and the hydropower facility would utilize existing rights.
Estimated Head and Flow
Since Wheatland Number 1 serves as a re-regulation reservoir, the water level can vary significantly. The elevation difference between the spillway and outlet is approximately 40 feet. When the reservoir is full, the elevation difference is approximately 39 feet. On average the reservoir operates half full, and the elevation difference is approximately 27 feet. This elevation difference was used to estimate the net head available for hydropower generation. A more detailed analysis is required to properly determine the net head and is beyond the scope of this assessment. The turbine would utilize the existing outlet works of the reservoir and would be installed on the existing outlet pipe. The condition of the existing pipe is unknown and would have to be determined if the pipe is suitable for a hydropower installation in future studies.
The available flows released through the outlet of the reservoir were obtained from the WID. The available flow for hydropower generation is seasonal and occurs during the irrigation season assumed to be from May 15 to September 15. The minimum flow is 75 cfs, and the maximum flow is 250 cfs. The minimum flows occur early and late in the irrigation season, and the maximum flows occur during July and August. On average, 200 cfs is released throughout the irrigation season. The design flow was estimated to be the average flow or 200 cfs. The turbine can handle the variable flow rates fairly efficiently. Daily flow data should be obtained in future studies to accurately assess the energy generation of the hydropower facility. For this analysis, the following flow characteristics were assumed:
| Month | Average Monthly Flow |
| May | 75 cfs |
| June | 175 cfs |
| July | 225 cfs |
| August | 225 cfs |
| September | 100 cfs |
Utility Connection
The proposed hydropower facility is in a rural but fairly developed area. Several residences are within close proximity to the proposed site, and a major electrical transmission line is approximately 1 ¼ miles away. Smaller distribution electrical lines cross the proposed project site. The capacity of the distribution line is unknown but was assumed to be the location of interconnect.
Political and Environmental Concerns
The proposed site is on the outlet of the Wheatland Reservoir Number 1 in a rural area where agriculture is the driving industry. The reservoir is primarily used for irrigation but also provides recreation use. The nearest residence is approximately one-half of a mile away. Noise from the turbine is not anticipated to would impact nearby residences. The primary purpose of the reservoir is for irrigation, and the WID would continue to operate the reservoir as they historically have. Since the hydro turbine would be at an existing embankment and flows are already seasonal, the environmental impact associated with hydro would be very minimal. Fish and wildlife mitigation would not be required, and the federal permitting process would be streamlined and take minimal effort.
Generation and Turbine Selection
The Bureau of Reclamation’s Hydropower Assessment Tool was used to estimate capacity and energy generation of the proposed hydropower facility. Based on an average flow of 200 cfs and an average net head of 27 feet, the plant would have a design capacity of 482 kW and generate 1,018 MWh of energy annually. The head and flow conditions indicate the turbine would likely be a Kaplan. A cross flow turbine may be an option; however, the design flow would be on the high end of a cross flow turbine. The following tables show the plant generation summary.
| Plant Generation Summary | |
| Plant Design Capacity (kW) | 482 |
| Number of Data | 365 |
| Data Years | 1.00 |
| Total Data Period Energy (kWh) | 1,018,000 |
| Average Plant Capacity (kW) | 119 |
| Plant Peak Capacity (kW) | 482 |
| Plant Factor | 0.246 |
| Plant Monthly Generation | |||
| Month | Days with Data | Average Capacity (kW) | Average Energy (MWH) |
| January | 31 | 0 | 0 |
| February | 28 | 0 | 0 |
| March | 31 | 0 | 0 |
| April | 30 | 0 | 0 |
| May | 31 | 79 | 57 |
| June | 30 | 351 | 253 |
| July | 31 | 445 | 320 |
| August | 31 | 439 | 316 |
| September | 30 | 99 | 71 |
| October | 31 | 0 | 0 |
| November | 30 | 0 | 0 |
| December | 31 | 0 | 0 |
| Annual | 1,018 | ||
Economics
Plant costs were generalized and based on the generator output, Bureau of Reclamation’s cost index, Energy Electric Power Research Institute “Quantifying the Value of Hydropower in the Electric Grid: Plant Cost Elements,” and experience with similar projects. The cost estimate is conservative and should be estimated with more detail in future studies. For small, low-head hydro installations the Electric Power Research Institute indicates the range of turbine, generator, and controls could cost $1,200 to $1,400 per kW of output. This assessment assumed a cost of $1,400/kW or $675,000 for the turbine, generator, and controls. The civil infrastructure would consist of a pipeline bifurcation, short penstock, powerhouse and tailrace and was estimated to be 40 percent of the turbine and generator costs or $203,000. A summary of the total plant costs is shown below.
| Site Information | |
| Unit Capacity (MW) | 0.48 |
| Number of Units | 1 |
| Plant Capacity (MW) | 0.48 |
| Turbine Type | Kaplan |
| Design Head (ft) | 27 |
| Unit Speed (RPM) | 600 |
| Estimated Generation Voltage (KV) | 4.16 |
| Transmission Voltage (KV- 69,115) | 115 |
| T-Line Length (miles) | 0.00 |
| New Transformer | YES |
| Fish and Wildlife Mitigation (Yes/No) | 0.00 |
| Recreation Mitigation (Yes/No) | 0.00 |
| Historical & Archaeological (Yes/No) | 0.00 |
| Water Quality Monitoring (Yes/No) | 0.00 |
| Fish Passage Required (Yes/No) | 0.00 |
| State Sales Tax Rate ( percent) | 4.00 |
| Construction Year | 2014 |
| Total Direct Construction Cost | 1,206,724 |
| Civil Works | 203,550 |
| Turbine(s) | 295,275 |
| Generator(s) | 213,601 |
| Balance of Plant Mechanical | 59,055 |
| Balance of Plant Electrical | 74,760 |
| Transformer | 28,196 |
| T-Line | 0 |
| Contingency (20 percent) | 174,887 |
| Sales Taxes | 0 |
| Engineering and CM (15 percent) | 157,399 |
| Total Development Costs | 1,256,724 |
| Cost Escalation factor from 2010 | 1.1 |
| Licensing Cost | 50,000 |
| Total Direct Construction Cost | 1,206,724 |
| T-Line Right-of-Way | 0 |
| Fish & Wildlife Mitigation | 0 |
| Recreation Mitigation | 0 |
| Historical & Archeological | 0 |
| Water Quality Monitoring | 0 |
| Fish Passage | 0 |
| Annual O&M Expense | 16,566 |
| Fixed Annual O&M | 5,000 |
| Variable O&M | 5,000 |
| FERC Charges | 739 |
| Transmission / Interconnection | 1,000 |
| Insurance | 3,620 |
| Taxes | 0 |
| Management / Office / Overhead | 0 |
| Major Repairs Fund | 1,207 |
| Reclamation / Federal Admin | 0 |
It was assumed a loan would be secured for the total development costs of $1,256,724. This amount was amortized at 4 percent interest over 30 years resulting in an annual loan payment of $72,638. Including O&M costs of $16,566, the total annual expenses was estimated to be $89,204. Irrigation districts typically are not able to subsidize hydropower projects; therefore, the revenue from power generation should nearly cash flow the project from year one of operation. For this proposed project the energy would need to be sold at $0.085/kWh to cash flow the project from the first year of operation. At this rate, the project would have a simple payback period of 18 years.
Conclusions and Recommendations
Based on the assumptions listed above, the project feasibility is marginal. An avoided rate of $0.085/kWh is not out of the realm of possibility but is higher than current typical rates. Current avoided rates are typically around $0.04/kWh. This does not mean a more detailed analysis should not be completed. Without too much effort, more detailed head and flow rates can be estimated, and cost estimates could be specific to the project area instead of using generalized costs. The cost index used for this analysis tends to be conservative, and actual quotes from suppliers should be used to better estimate construction costs. It is recommended to use daily average flow rates throughout a typical irrigation season and investigate whether supplemental flows can be sent through the turbine to increase energy generation. A field survey of the available head should also be completed. This information can then be used to obtain specific turbine efficiency curves and a better estimate of plant capacity, and energy generation can be completed. It is recommended that a more detailed study be completed to assess the feasibility of this project. The following table shows the results of the preliminary analysis.
| Results – Wheatland Res No. 1 – Wheatland Irrigation District | ||
| Data Set | 1 | years |
| Max Head | 39 | ft |
| Min Head | 20 | ft |
| Max Flow | 250 | cfs |
| Min Flow | 75 | cfs |
| Turbine Selection Analysis | ||
| Selected Turbine Type | Kaplan | |
| Selected Design Head | 27 | ft |
| Maximum Turbine Flow | 250 | cfs |
| Generator Speed | 600 | rpm |
| Max Head Limit | 33.8 | ft |
| Min Head Limit | 17.5 | ft |
| Max Flow Limit | 250 | cfs |
| Min Flow Limit | 50 | cfs |
| Power Generation Analysis | ||
| Installed Capacity | 482 | kW |
| Plant Factor | 0.25 | |
| Projected Monthly Production | ||
| January | 0 | MWH |
| February | 0 | MWH |
| March | 0 | MWH |
| April | 0 | MWH |
| May | 57 | MWH |
| June | 253 | MWH |
| July | 320 | MWH |
| August | 316 | MWH |
| September | 71 | MWH |
| October | 0 | MWH |
| November | 0 | MWH |
| December | 0 | MWH |
| Annual production | 1,018 | MWH |
| Benefit/Cost Analysis | ||
| Projected expenditure to implement project | ||
| Total Construction Cost | $ 1,256,724 | |
| Annual O&M Cost | $ 16,566 | |
| Projected Total Cost over 50-year period (present worth) | $ 1,442,788 | |
| Projected revenue after implementation of project | ||
| Power generation income for 2014 to 2060 | $ 3,762,126 | |
| Projected Total Revenue over 50-year period | $ 1,335,893 | |
| Benefit/Cost Ratio | 0.93 | |
| Internal Rate of Return | 3.9 percent | |
| Installed Cost $ per kW | $ 2,605 | |
