Submitted to: Irrigation Associations Exposition and Technical Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/2/2005
Publication Date: 11/6/2005
Citation: Trout, T.J., Gartung, J.L. 2005. Energy use in micro-irrigation. Irrigation Assocation Exposition and Technical Conference Proceedings. Proc. Nov 6-8, pp 62-76. Interpretive Summary: Electrical energy in California is expensive and in short supply. Irrigation water pumping is a major user of energy. Micro-irrigation is potentially a low pressure and energy method to apply irrigation water. A survey of 312 micro-irrigation systems in California showed that many systems operate at higher pressures than is necessary. We estimate that 60% of the systems could reduce system pressures by 15 psi, which would save about $25 per acre per year in energy costs and 220 Gigwatt-hrs/yr of electrical energy statewide. It will often be economical for designers and growers to design or modify systems to reduce pressure requirements and energy use.
Technical Abstract: Micro-irrigation systems can operate with low pressure. Micro-irrigation emitters require only 7 - 20 psi. Cleaning and delivering the water to the emitters on flat fields typically requires an additional 15 psi. A survey of 312 California micro-irrigation systems showed that 60% of the systems exceed these pressures, and 25% exceed by over 10 psi. Pressure could be reduced by an average of 15 psi in 60% of the systems. Pressure was lost at the filter station, in the distribution system, at pressure regulators, in the lateral inlets, and at the emitters. Higher pressure is required to irrigate undulating land. Reducing system pressure by 15 psi in a system could save about $25 per acre per year in electricity costs, and reducing pressure by 15 psi for 60% of the 1.7 million acres of micro-irrigation in California would save 220 Gigawatt-hrs/yr of energy and 90 Megawatts of peak load. It will often be economical to invest more in the system to save pressure and energy costs, but energy-saving changes may decrease system flexibility and simplicity or increase risk of system failures.