Sustainable management of pressurized irrigation networks by improving the efficiency of water and energy use

In the last decades, irrigated agriculture has undergone a significant expansion, increasing the requirements of a natural and essential resource for the activity development, such as water. This resource is increasingly precious and competition for its use tends to be more intense in the economic sectors. This competition intensifies the need to submit to irrigation, especially in arid and semi-arid areas, a process of modernization by improving their technological level and ensure sustainability of the agricultural sector as a whole. The Spanish government has approved two plans for improving irrigation, National Irrigation Plan (NIP) horizon 2005 and NIP horizon 2008, both of them mainly consisted of promoting the canal lining, pressurized irrigation networks and new automation technologies to improve management in the irrigated areas. This plan has improved water use efficiency, but the new pressurized irrigation networks require large amounts of energy for pumping water. Therefore, energy costs have risen sharply after the modernization, being aggravated by an exponential increment of energy unit prize and compromising the profitability of the sector. In the interests of sustainability and in a context of climate change, where evapotranspiration rate increases water resources decreases, due to the increase of the greenhouse gas (GHG) directly emissions or indirectly caused by the combustion of non-renewable resources, have increased the need to improve efficiency of both resources. This document consists of seven sections. The first one provides an introduction and frame work in which the present PhD thesis is developed. The specific objectives to achieve the main objective of improving the sustainable management of water and energy use are defined in sections 2. Studies to achieve the proposed objectives are developed in sections 3, 4, 5 and 6 correspond to publications in scientific journals included in the database of the Science Citation Index (SCI) Section 3 contains a first study in which the water and energy use was evaluated in Fuente Palmera irrigation district. To this end, the protocol for energy audits, proposed by IDAE, was adopted and applied and which concluded that this irrigation district is high energy consumer. The impact of organizing farmers in irrigation turns, as improvement measure, was outlined and evaluated resulting a potential energy savings of 12 %...La agricultura de regadío ha sufrido una importante expansión en las últimas décadas, incrementándose así los requerimientos de un recurso natural y esencial para el desarrollo de la actividad, como es el agua. Este recurso es cada vez más preciado y la competencia en los diferentes sectores económicos por su uso tiende a ser más intensa. Esta competencia agudiza la necesidad de someter a los regadíos, principalmente en zonas áridas y semiáridas, a un proceso de modernización que mediante la mejora de su nivel tecnológico asegure su sostenibilidad y la del sector agrario en su conjunto. El Gobierno español ha aprobado varios planes para la mejora del regadío, Plan Nacional de Regadíos (PNR) horizonte 2005 y PNR horizonte 2008 que consistieron principalmente en la instalación de redes a presión en las zonas regables y la incorporación de nuevas tecnologías de automatización para mejorar su gestión. Dichos planes han conseguido mejorar la eficiencia en el uso del agua, sin embargo las nuevas redes a presión requieren elevados consumos de energía. Los costes energéticos que debe soportar el sector han crecido bruscamente tras la modernización, siendo agravados por un contexto de incremento exponencial del precio unitario de la energía y comprometiendo la rentabilidad del sector. En aras de la sostenibilidad y en un contexto de cambio climático, donde aumentan las tasas de evapotranspiración y disminuyen los recursos hídricos motivados por el incremento de las emisiones de gases de efecto invernadero, causados directa o indirectamente por la combustión de recursos no renovables, surge la necesidad de mejorar la eficiencia del uso de ambos recursos. Este documento consta de siete apartados. El primero de ellos proporciona una introducción y define el marco en el que se desarrolla la tesis doctoral. Los objetivos específicos para alcanzar el objetivo principal de mejorar la gestión sostenible de los recursos agua y energía, son definidos en el apartado 2. Los estudios realizados para la consecución de los objetivos propuestos se desarrollan en los apartados 3, 4, 5 y 6 y corresponden con publicaciones íntegras en revistas científicas incluidas en la base de datos del Science Citation Index (SCI) El apartado 3 contiene un primer estudio en el que se caracteriza el uso del agua y la energía en la zona regable de Fuente Palmera. Con este fin,..

The role of energy audits in irrigated areas: the case of �Fuente Palmera� irrigation district (Spain)

In recent years, energy consumption for irrigation has grown rapidly. Actually, nowadays energy represents a significant percentage on the total water costs in irrigation districts using energy to pressurize water. With the aim of improving energy efficiency in the Fuente Palmera irrigation district, was applied the protocol for conducting energy audits in irrigation districts developed by Spanish Institute for Diversification and Energy Savings (IDAE). The irrigated area organized in two independent sectors according to a homogeneous elevation criterion is analyzed and simulated. The potential energy savings derived from this measure was evaluated. For this purpose, a model based on the hydraulic simulator EPANET has been carried out. Its energy demand was estimated in 1,360 kWh ha�1 and its overall energy efficiency in 56%. The district was globally classified in group C (normal). Results show potential energy savings of up to 12% were obtained when the network was divided in sectors and farmers organized in two irrigation shifts. Further energy savings could be achieved by improving the hydraulic structures, such as the pumping station or the network layout and dimensions

Assessing the potential of solar energy in pressurized irrigation networks. The case of Bembézar MI irrigation district (Spain)

The high energy requirements and the rising costs highlight the need to reduce the energy dependence of the irrigation sector. Alternative management strategies have been developed to reduce the energy consumption of the irrigated areas and to improve the efficiency in the water and energy use. In addition, the renewable energy sources are starting to be considered as an alternative to reduce energy costs with smaller environmental impacts. In this work, a new methodology, that combines sectoring as energy saving measure and solar energy, is developed. Thus, it reduces the energy requirements and the dependence on conventional energy resources. This methodology is applied to the irrigation district of Bembézar Margen Izquierda (Córdoba, Spain). The results show that organizing the network in two irrigation sectors, annual potential energy savings of 30.8% were achieved. Therefore, this measure reduces the annual energy bill in 30.4% without major investments. Then, a 2.1 MW photovoltaic would supply energy to the sector with higher energy consumption. However, conventional energy would be required (with an annual cost of � 33.6 ha�1) when solar energy is not available or it is not enough to supply the demanded flows. Both measures together would reduce the energy costs in 71.7% and the greenhouse gases emissions in 70.5%. The total investment would be Me 2.8 but with a payback period of 8 years. At present, solar energy is a technically and economically viable alternative, which offers both economic and environmental benefit