Elsevier

Energy

Volume 55, 15 June 2013, Pages 1084-1093
Energy

Energy consumption for crop irrigation in a semiarid climate (south-eastern Spain)

https://doi.org/10.1016/j.energy.2013.03.034Get rights and content

Highlights

  • Energy for extraction water accounts for 71–82% total energy consumption.

  • Desalinated brackish water is the highest energy consumption source (1.4 kWh m−3).

  • Average energy consumed for irrigation in SE of Spain was 1.17 kWh m−3.

Abstract

This paper analyses the water-energy nexus in irrigation districts (IDs) under the semi-arid conditions of south-eastern Spain. Three IDs supplied by different water sources and subjected to water scarcity over time were studied throughout a 10-year period (2002–2011). A set of performance indicators was selected to characterise water and energy relationships at three management levels: basin, irrigation district, and farm. Basin level was the largest energy consumer, representing 71–82% of the annual total consumption, which ranged from 0.95 to 1.55 kWh m−3. Basin energy consumption increased depending on the water source as follows: surface water, recycled water, groundwater, external water transfer, and desalinated brackish water. ID level involved 12–15% of the annual total consumption. The highest values were attained in periods of water scarcity, when the available sources were those with higher energy requirements. ID modernisation resulted in slight decreases in energy consumption at that level. At farm level, energy consumption was lacking when farmers took advantage of the pressure head in the ID distribution network, whereas it was from 0 to 0.19 kWh m−3 when the available pressure head was lost. Finally, water and energy productivities by the main crops were analysed.

Introduction

Water is a critical natural resource upon which all social and economic activities and ecosystem functions depend. Agriculture accounts for 70% of all water withdrawal by the combined agricultural, municipal and industrial sectors in the world, with crop irrigation being the prevailing use. Irrigated agriculture plays a crucial role in the global food production system, accounting for more than 40% of the world's production on less than 20% of the cultivated land. Irrigated crop yields are about 2.7 times higher than those of rainfed farming at worldwide scale [1]. In Spain, the role of irrigation is even higher since the agriculture sector uses approximately 75% of the total water resources [2]; about 60% of total production comes from just 20% of cropland that is irrigated [3]; and irrigated crops yields are about six times those of rainfed farming [4].

Water and energy are coupled in an intimate way. Many technical processes of harnessing, extracting, and producing energy utilise water, and energy is also required to make use of water at every phase of its extraction, distribution and usage processes [5]. This interdependence, which is often referred to as the ‘water–energy nexus’, has been increasingly highlighted as an important issue for future planning and strategic policy considerations [6]. Moreover, water scarcity is forcing nations to use non-traditional water sources such as desalinated and recycled water; choices that need to be sensitive to the environmental impacts of the required electricity [1].

Global energy demands are expected to grow by as much as 55% by 2030, according to the International Energy Agency [7]. The water–energy nexus is one of the reasons for this, since water is becoming scarce, not only in arid and drought prone areas but also in regions where rainfall is abundant, and new water sources with higher energy requirements should be incorporated to the supply systems. Thus, the embodied energy associated with water provision and the environmental impacts associated with water supply are also increasing with growing water scarcity [8].

The current importance of crop irrigation in total water consumption makes it clear that the sustainable use of water is a priority for agriculture in water stressed regions. To comply with this statement, Spanish irrigation systems have experienced profound transformations in the last decades, including a modernisation process since 2002 aimed to improve management performance and water use efficiency. As a result, while water consumption per hectare was reduced by 21% between 1950 and 2008, energy demand increased by 657% [3]. Therefore, although the amount of water diverted for irrigation to farms has been considerably reduced, the energy for pumping pressurised systems is much greater now compared to the gravity-fed systems used previously. Consequently, from now on it is necessary to manage energy resources more efficiently to control the increasing energy demand for crop irrigation [9].

At farm level, the concept of productivity can be defined as the production per unit input, and it is focused on limiting factors such as water and energy. Several productivity indicators have been suggested to analyse water use performance for irrigation [10], [11]. Other studies have stressed the need to study the energy consumption and energy output of different fruit and vegetable crops [12], [13], [14], some of them extrapolating the productivity concept to take into account the water–energy nexus and to analyse its footprint in irrigated crop production [15]. Indicators that capture the combined effect of water and energy inputs for measuring the potential environmental impacts of crop production have also been proposed [16].

This work is focused on the analysis of the interdependence between water and energy consumption in pressurised distribution and irrigation systems under the semi-arid conditions of south-eastern Spain. The study assesses energy consumption for irrigation throughout a 10-year period, particularising for different management levels and locations in the study area. The quantification of water and energy use in the Mediterranean region is interesting for planners and managers in water agencies and collective irrigation associations, especially if irrigation district modernisation processes and different water scarcity intensities have occurred throughout the study period. The results can also be useful for formulating recommendations for rationalising water and energy use in irrigated crop production.

Section snippets

Materials and methods

The methodology for developing this study was structured into several steps. First a suitable set of indicators for characterising the relationship between the water and energy use was selected. Next, the value of these indicators was calculated throughout a 10-year study period (2002–2011) in three irrigation districts (IDs) under the semi-arid conditions of south-eastern Spain. To calculate the performance indicators it was necessary to obtain data by: (a) consulting the manager and the

Water and energy consumption

Table 3 presents the average value and the variation range for the study period of the specific energy (EacVs) consumed in each management level and ID. EacVs in the basin level was considered as the addition of energy consumption weighted according to the percentage of water supplied from each source shown in Table 2.

Conclusions

Different water management levels are involved in providing water for crop irrigation. The right analysis of energy use at each management level is required in order to know the real value of energy performance indicators in crop production, as well as for making local or regional comparative analysis (benchmarking). There are three management levels that are involved in the water supply for irrigation in south-eastern Spain: basin, irrigation district (ID), and farm.

From the present work it

Acknowledgements

The authors acknowledge the European Community's Seventh Framework Research Programme for the financial support of this study through the grant agreement n. 245159 project SIRRIMED (Sustainable use of IRRIgation water in the MEDiterranean region, FP7-KBBE-2009-1-2-03, www.sirrimed.org). The collaboration of the staff of “Comunidad de Regantes del Campo de Cartagena”, “Comunidad de Regantes de Miraflores” and “Comunidad de Regantes del Transvase Tajo-Segura Comarca de Calasparra Cieza” and

References (38)

  • M.A. Moreno et al.

    Energy efficiency of pressurised irrigation networks managed on-demand and under a rotation schedule

    Biosyst Eng

    (2010)
  • M.A. Kahlown et al.

    Water use efficiency and economic feasibility of growing rice and wheat with sprinkler irrigation in the Indus Basin of Pakistan

    Agric Water Manage

    (2007)
  • R. Lal

    Carbon emission from farm operations

    Environ Int

    (2004)
  • F. Hernández-Sancho et al.

    Economic valuation of environmental benefits from wastewater treatment process: an empirical approach for Spain

    Sci Total Environ

    (2010)
  • A.K. Plappally et al.

    Energy requirements for water production, treatment, end use, reclamation, and disposal

    Renew Sust Energy Rev

    (2012)
  • WWAP (World Water Assessment Programme)

    The United Nations world water development report 4: managing water under uncertainty and risk

    (2012)
  • INE (Instituto Nacional de Estadística). Survey on water supply and sewerage. http://www.ine.es [accessed June...
  • J. Corominas

    Agua y Energía en el riego en la época de la Sostenibilidad

    Ingeniería del Agua

    (2010)
  • FENACORE (Federación Nacional de Comunidades de Regantes)

    Spanish irrigators communities and its nationals federations

    (1999)
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