Submitted to: Journal of Energy Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/1999
Publication Date: N/A
Citation: Panda, R.K., Clark, R.N. 1999. Stochastic study of windpumps with reservoir in southern high plains. Journal of Energy Engineering. 125(3):79-93.
Interpretive Summary: Historical hourly wind speed and water table data along with performance data for wind pumps were used to predict water availability for irrigation. Random probability analysis procedures were used to determine the most predominate wind speed range and estimate the volume of water available for irrigation. Results showed that the electrical wind pump would produce four times as much water as a mechanical wind pump and was capable of lifting water from a greater depth. The risk of emptying the storage reservoir was compared to reservoir size (cost of larger reservoir) and it was determined that one could afford to build a bigger reservoir when economic returns were higher. The methodology used in this analysis could be used to evaluate the feasibility and economics of wind-powered irrigation in any region.
Technical Abstract: Hourly wind speed data for 11 years (1983-93), historical ground water table data, and performance test results under varying conditions for two mechanical and one electrical windpump were used at Bushland, TX, to evolve major recommendations pertaining to wind-powered irrigation management. Stochastic analysis of hourly wind speed data showed that the average daily ywind speed lie most frequently in the range of 5.5 to 6 m/s; the upper and lower limits being 16 m/s and 4.5 m/s, respectively. This is conducive to most of the wind energy conversion systems manufactured today. The discharge of the electrical windpump was more than four times higher than the mechanical windpumps at high wind speeds. The performance of the electrical windpump was also much better at high operating head (60m) than at low operating heads under high wind regimes, showing its suitability for ground water pumping in the Southern High Plains. Stochastic estimation of fdaily windpump discharge revealed that pumping rates are high in the sprin and autumn seasons, favouring irrigation of winter wheat crop. The trend of variation in unit reservoir capacity, under different levels of daily demand and risk, shows that wind-powered irrigation systems with high risk can be adopted under higher economic return conditions. Though the results obtained in the study are applicable mainly to the Southern High Plains of the U.S., the methodology developed will have general applicability.