The Dynamics of the Water-Electricity Nexus:How water availability affects electricity generation and its water consumption

Water is needed for electricity generation, for example, for hydropower plants or cooling water for thermal power plants. Freshwater is a scarce resource that will become increasingly scarce in the future as competition intensifies. It is, therefore, essential to map water-electricity relationships. This thesis first analyzes the existing literature on the water-electricity nexus and, subsequently, the temporal and spatial dynamics of electricity supply in Ecuador, which is a model for the global electricity supply. Only a few publications dominate the literature, especially publications from the last century for the U.S. so that new publications receive insufficient attention. The dissertation further shows that even in a wet country like Ecuador, fluctuations in water availability limit the production of hydropower plants, so that less electricity is produced for a few months. In the event of water shortages in the Pacific basin, hydropower plants in the Amazon take over. In the event of production loss in the Amazon basin, thermal power plants are used. These changes in electricity generation cause temporal and spatial changes in the water footprint (WF). When water availability is limited, water-efficient technologies are applied, decreasing the WF. Hydropower plants with a large water storage capacity also have variation in their WF due to the relationship of water availability, climate, and power planning. The assessment of the dynamics of the water-electricity system is essential for determining the best electricity mix with the lowest water consumption. This insight is also crucial for other countries

The monthly dynamics of blue water footprints and electricity generation of four types of hydropower plants in Ecuador

Water evaporates from reservoirs of hydropower plants (HPPs), often in significant volumes. Reservoir evaporation is a dynamic phenomenon depending on climate, varying size of open water surfaces (OWS), and electricity production. Due to a lack of data and methods to estimate the OWS's size variation, previous studies assessed HPPs water footprints (WFs) considering static OWSs acknowledging the uncertainty of this omission. This study estimates WFs of HPPs, considering dynamic OWSs for four plant types in Ecuador, Flooded lakes, and Flooded rivers, with dam heights lower or higher than their Gross Static Head (GSH). It quantifies OWSs size variation using a Digital Elevation Model and GSH data, assessing OWS evaporation, effects on electricity production and WFs. There are large differences among the evaporation of HPPs when OWS size variations are considered. HPP operation, geographical features, and climate determine temporal differences. Flooded lake HPPs have relatively large WFs. Flooded River HPPs, with dam heights below their GSH, have the smallest WFs, but water storage capacity is limited. Static area approaches underestimated annual WFs by 10% (Flooded Lake HPPs) to 80% (Flooded River HPPs). Earlier studies showed effects of HPPs on water from a water management perspective, suggesting that less water-intensive HPP technologies are favorable, or that other water-efficient electricity-generating technologies, like solar or wind, should replace HPPs. This study also included the electricity perspective, indicating that energy management and water storage are important factors for WFs. The most water-effective technology cannot fulfill current electricity production due to a lack of storage options. The system dynamics analysis indicates that aiming for small WFs is not always the best option from an energy and water perspective

Burning water, overview of the contribution of arjen hoekstra to the water energy nexus

This paper gives an overview of the contribution of water footprint (WF) studies on water for energy relationships. It first explains why water is needed for energy, gives an overview of important water energy studies until 2009, shows the contribution of Hoekstra’s work on WF of energy generation, and indicates how this contribution has supported new research. Finally, it provides knowledge gaps that are relevant for future studies. Energy source categories are: 1. biofuels from sugar, starch and oil crops; 2. cellulosic feedstocks; 3. biofuels from algae; 4. firewood; 5. hydropower and 6. various sources of energy including electricity, heat and transport fuels. Especially category 1, 3, 4, 5 and to a lesser extent 2 have relatively large WFs. This is because the energy source derives from agriculture or forestry, which has a large water use (1,2,4), or has large water use due to evaporation from open water surfaces (3,5). WFs for these categories can be calculated using the WF tool. Category 6 includes fossil fuels and renewables, such as photovoltaics and wind energy and has relatively small WFs. However, information needs to be derived from industry

The water, energy, and land footprint of tilapia aquaculture in Mexico, a comparison of the footprints of fish and meat

In the food-energy-water (FEW) nexus, livestock has a dominant place. It is generally considered as water, energy and land-intensive. Aquaculture could provide additional animal protein and contribute to meeting the food demand. However, aquaculture requires natural resources and causes freshwater pollution due to aquafeed, fertilizer, and hormone use. This study assesses the sustainability of aquaculture using the indicators water footprint (WF), energy footprint (EF) and land footprint (LF), comparing results with livestock. It uses extensive, semi-intensive and intensive Tilapia aquaculture in Mexico as a case study including broodstock, breeding, fattening, processing, and transportation phases. Tilapia production in intensive aquaculture has the largest footprints. Blue WFs are smallest in semi-intensive systems; green WFs, EFs and LFs are smallest for extensive systems. For protein, tilapia from intensive systems has the largest WF (126 l/g protein), beef (51 l/g), pork (33 l/g) and poultry (14 l/g) have smaller WFs. EFs per unit of protein or nutritional energy fall in the range of values for beef, poultry and pork. LFs of Tilapia (m2/kg) are larger than LFs of poultry but fall in the range of beef and pork. Per unit of nutritional energy EFs are similar to EFs for beef but larger than EFs of poultry and pork. From a FEW nexus perspective, it is not more sustainable to replace livestock with Tilapia. Tilapia requires more freshwater than beef, pork and poultry and pollutes larger amounts of water. For energy and land, Tilapia is not the better choice, because footprints are comparableS

Grey Water Footprint of Thermal Power Plants in Ecuador

Thermal power plants require water for their cooling system. Water availability is a limiting factor for electricity generation. The water footprint is a tool used to quantify water appropriation. Its blue component quantifies the volumetric water consumption by the cooling system, while the grey component can quantify the effect of the cooling water discharge in the water body. Several authors have estimated the blue water footprint of the cooling system, but only a few have assessed how the discharged water may affect the water body\u27s temperature. This paper assessed the thermal pollution produced by three Ecuadorian thermal power plants by estimating their grey water footprint. Results show that the grey water footprint can be up to three orders of magnitude larger than the blue water footprint of the plants, implying that the water bodies must have at least that volume of water to buffer the possible thermal pollution

4to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

Este volumen acoge la memoria académica de la Cuarta edición del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2017, desarrollado entre el 29 de noviembre y el 1 de diciembre de 2017 y organizado por la Universidad Politécnica Salesiana (UPS) en su sede de Guayaquil. El Congreso ofreció un espacio para la presentación, difusión e intercambio de importantes investigaciones nacionales e internacionales ante la comunidad universitaria que se dio cita en el encuentro. El uso de herramientas tecnológicas para la gestión de los trabajos de investigación como la plataforma Open Conference Systems y la web de presentación del Congreso http://citis.blog.ups.edu.ec/, hicieron de CITIS 2017 un verdadero referente entre los congresos que se desarrollaron en el país. La preocupación de nuestra Universidad, de presentar espacios que ayuden a generar nuevos y mejores cambios en la dimensión humana y social de nuestro entorno, hace que se persiga en cada edición del evento la presentación de trabajos con calidad creciente en cuanto a su producción científica. Quienes estuvimos al frente de la organización, dejamos plasmado en estas memorias académicas el intenso y prolífico trabajo de los días de realización del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad al alcance de todos y todas

Ecuador: Public Policies and Strategies in energy

Ecuador has been, and will continue to be for a while, an oil-based economy. Since the discovery, and afterwards extraction of the oil in the Ecuadorian territory, the country has depended economically of the exploitation and the exports of these non-renewable good. However, the country had taken impressive measures to change its dependence of fossil fuels and nowadays is trying to exploit renewable resources. In this chapter, the policies and strategies implemented by the government are analysed.El Ecuador ha sido y será por algún tiempo más un Estado que basa la mayoría de su economía en el sector energético. Desde el descubrimiento y la posterior extracción de petróleo en el territorio ecuatoriano, el país ha dependido económicamente de la explotación y exportación de este bien no renovable

An integrative approach to the Carbon Capture and Storage (CCS) technologies inside a Water-Energy Nexus Framework

The energy sector is a major source of the anthropogenic CO2 emissions. Therefore, the sector’s de-carbonization is imperative if we intend to curb the progression of Climate Change. Carbon Capture and Storage (CCS) was created in an attempt to reduce the carbon footprint of energy production. Nonetheless, literature shows that water consumption of electricity production nearly doubles when CCS technologies are applied. Those large footprints give an idea of the technology’s impact in the Water-Energy nexus. In this paper we quantify the Water-Energy-Nexus relations for CCS in the EU-28 using a Top-Down system’s approach. We: 1) elaborate the country’s inventory of water availability and consumption, 2) define the system and two indicators to be used, 3) assess specialized literature for quantify those indicators. Results suggest that water availability is not an issue for CCS, but the additional volume in the consumption could create an important impact on the countries’ infrastructure