Optimal Water Management in Agro-Industrial Districts: An Energy Hub’s Case Study in the Southeast of Spain

Jerónimo Ramos-Teodoro,Lidia Roca,Francisco Rodríguez,Juan D Gil,Manuel Berenguel

doi:10.3390/pr9020333

Abstract

In this work, the optimal management of the water grid belonging to a pilot agro-industrial district, based on greenhouse cultivation, is analyzed. Different water supply plants are considered in the district, some of them using renewable energies as power sources, i.e., a solar thermal desalination plant and a nanofiltration facility powered up by a photovoltaic field. Moreover, the trade with the water public utility network is also taken into account. As demanding agents, a greenhouse and an office building are contemplated. Due to the different water necessities, demand profiles, and the heterogeneous nature of the different plants considered as supplier agents, the management of the whole plant is not trivial. In this way, an algorithm based on the energy hubs approach, which takes into account economic terms and the optimal use of the available resources in its formulation, is proposed for the pilot district with a cropping area of 616 m2. Simulation results are provided in order to evidence the benefits of the proposed technique in two cases: Case 1 considers the flexible operation of the desalination plant, whereas in Case 2 the working conditions are forced to equal the plant’s maximum capacity (Case 2). A flexible operation results in a weekly improvement of 4.68% in profit, an optimized use of the desalination plant, and a reduction of the consumption of water from the public grid by 58.1%.

Highlights

Climate change has a great impact on the water supply sector of many regions worldwide, such as in southern Europe, where the hydrological stress is expected to shortly increase due to this phenomenon and some areas are already facing serious water problems [1]
The analysis presented in the following subsections consists of a comparison between the operation of the energy hub (EH), over a week in March 2014, under two different conditions placed on the desalination plant: Case 1 considers the operation point, in terms of the desalinized flow of water (Do,3 ), as a decision variable; whereas in Case 2 that variable is constrained to force that the plant work at its maximum capacity whenever it is activated, which is representative of what a human operator would do
This paper compares two cases of water management where the operation of a desalination plant is constrained to work to a manual operation mode, in contrast to its flexible use, in which the amount of distilled flow is adapted to the consumption needs

Summary

Introduction

Climate change has a great impact on the water supply sector of many regions worldwide, such as in southern Europe, where the hydrological stress is expected to shortly increase due to this phenomenon and some areas are already facing serious water problems [1] One of these is the province of Almería (southeast of Spain), which is identified as one of the driest regions in the continent, but has one of the largest agricultural production systems. The main driving force of the economy in this province is agriculture, with around 30,000 ha of greenhouse crop production [2] The development of this industry has been tied, for a long time, to the depletion of freshwater reservoirs (despite the efficient management of this resource that has been performed in this sector [3]). The current panorama in Almería can be visualized as a distributed water network composed of (i) producers, based on traditional (wells and water public utility network) and non-traditional sources (desalination facilities and other non-conventional systems), and (ii) consumers, such as industries related to agriculture and greenhouses

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