Optimal Pumping Scheduling for Complex Irrigation Water Distribution Systems

The establishment of an optimal pumping schedule is a cost-free, efficient measure that is easily adopted to reduce energy costs. This paper proposes an optimal pumping scheduling model for complex irrigation water distribution systems (WDS) for the case in which head and efficiency are independent of flow rate. The proposed model utilizes a simplified pumping scheme and a determinist linear programming (LP) optimization algorithm. A robust and versatile software application was also developed that is useful for WDS managers in adopting optimal pumping scheduling decisions for a specific electricity tariff structure and to satisfy all system performance constraints. The model also provides the option of testing and comparing different alternative electricity tariffs and allows managers to select the most cost-effective tariff for their system. The model is applied to a real WDS located in the province of Almería in southeastern Spain. The optimal pumping scheduling during an entire year is obtained for several alternative tariffs using real data on irrigation demands, pumping efficiencies, energy prices, and tariffs for the analyzed year. The most efficient electricity tariff is also obtained for that year. Finally, the actual management strategies in the studied year are compared with the optimal strategies provided by the model. Although the system managers chose an appropriate tariff for their system, the use of this optimization tool would have provided significant savings to their energy bills, exceeding 20% of the total energy costs.