Investigating Different Strategies to Reduce Energy Consumption in Saleh Abad Irrigation Network

Today, the dependency between energy consumption and water use has become an important issue in pressurized irrigation networks. In addition to the problem of water scarcity, rising energy costs are also a challenge for the agricultural sector. The objective of this study was to investigate different strategies to reduce energy consumption in the pressurized irrigation network of Saleh Abad.

For this purpose, firstly, minor changes affecting energy consumption including change in diameter of lateral pipe were evaluated. In this level, evaluated scenarios were lateral pipe diameters in mm 63 and 75. Hydraulic analysis of irrigation network was calculated using WaterGems software and energy consumption in different pumping stations was calculated using energy audit. In the second level of evaluation, four scenarios were defined to reduce energy consumption in the irrigation networks by structural changes in the irrigation network based on energy audit strategies, critical point control, network sectoring and pumping station management. The scenarios were (i) network sectoring without changing the main canal line, (ii) change of main canal line to pipe line, (iii) implementation a new first pipe line for a part of the network that is irrigated by gravity water, and (iv) elimination of the secondary pumping station by increasing the primary pumping station head. In the scenarios i, ii and iii, the part of the irrigation network lands was determined that could be irrigated without the need for a secondary pumping station. In this scenarios, the energy saving was calculated in a new condition by varying the type or number of pumps in secondary pumping stations to provide upstream discharge and head requirements.

The results showed that according to the topographic conditions of the network, changing the diameter of the laterals had no effect on saving energy. Also, the results showed that by network sectoring and applying scenarios(i), (ii), and (iv), the irrigated area without the need for a secondary pumping station were 610.8, 1591.5 and 1621.8 hectares, the energy saving in secondary pumping station were 14.6, 46.1 and 47.4% and the total energy consumed in network were 3.9, 12.4 and 12.7%, respectively. In the scenario iv, the primary pumping station was optimized. The result indicated that if the pumps type of the primary pumping station were changed and the water reservoir was implemented in higher level, it would be possible to eliminate the secondary pumping stations. In this case, the total area network (2820 ha) was irrigated without the secondary pump station and the energy saving was 8.46%.

The results of this study showed that changing the diameter of the lateral pipe had no significant effect on the energy consumption of the network. Also, the results showed that network sectoring and changes in main pipeline, it is possible to save up to 3121 MWh in the annual energy consumption of the network. Therefore, it is suggested that, network sectoring based on the input pressure of hydrants and the use of gravity, in the design of irrigation and drainage networks, considered as an effective solution to reduce energy consumption.