Ecuador
Numerical Simulation of Solid Oxide Fuel Cells Comparing Different Electrochemical Kinetics
Mar 2021
Publication
Solid oxide fuel cells (SOFCs) produce electricity with high electrical efficiency and fuel flexibility without pollution for example CO2 NOx SOx and particles. Still numerous issues hindered the large‐scale commercialization of fuel cell at a large scale such as fuel storage mechanical failure catalytic degradation electrode poisoning from fuel and air for example lifetime in relation to cost. Computational fluid dynamics (CFD) couples various physical fields which is vital to reduce the redundant workload required for SOFC development. Modeling of SOFCs includes the coupling of charge transfer electrochemical reactions fluid flow energy transport and species transport. The Butler‐Volmer equation is frequently used to describe the coupling of electrochemical reactions with current density. The most frequently used is the activation‐ and diffusion‐controlled Butler‐Volmer equation. Three different electrode reaction models are examined in the study which is named case 1 case 2 and case 3 respectively. Case 1 is activation controlled while cases 2 and 3 are diffusion‐controlled which take the concentration of redox species into account. It is shown that case 1 gives the highest reaction rate followed by case 2 and case 3. Case 3 gives the lowest reaction rate and thus has a much lower current density and temperature. The change of activation overpotential does not follow the change of current density and temperature at the interface of the anode and electrolyte and interface of cathode and electrolyte which demonstrates the non‐linearity of the model. This study provides a reference to build electrochemical models of SOFCs and gives a deep understanding of the involved electrochemistry.
Opportunities for Low-carbon Generation and Storage Technologies to Decarbonise the Future Power System
Feb 2023
Publication
Alternatives to cope with the challenges of high shares of renewable electricity in power systems have been addressed from different approaches such as energy storage and low-carbon technologies. However no model has previously considered integrating these technologies under stability requirements and different climate conditions. In this study we include this approach to analyse the role of new technologies to decarbonise the power system. The Spanish power system is modelled to provide insights for future applications in other regions. After including storage and low-carbon technologies (currently available and under development) batteries and hydrogen fuel cells have low penetration and the derived emission reduction is negligible in all scenarios. Compressed air storage would have a limited role in the short term but its performance improves in the long term. Flexible generation technologies based on hydrogen turbines and long-duration storage would allow the greatest decarbonisation providing stability and covering up to 11–14 % of demand in the short and long term. The hydrogen storage requirement is equivalent to 18 days of average demand (well below the theoretical storage potential in the region). When these solutions are considered decarbonising the electricity system (achieving Paris targets) is possible without a significant increase in system costs (< € 114/MWh).
Design and Development of a Catalytic Fixed-Bed Reactor for Gasification of Banana Biomass in Hydrogen Production
Apr 2022
Publication
Hydrogen produced from biomass is an alternative energy source to fossil fuels. In this study hydrogen production by gasification of the banana plant is proposed. A fixed-bed catalytic reactor was designed considering fluidization conditions and a height/diameter ratio of 3/1. Experimentation was carried out under the following conditions: 368 ◦C atmospheric pressure 11.75 g of residual mass of the banana (pseudo-stem) an average particle diameter of 1.84 mm and superheated water vapor as a gasifying agent. Gasification reactions were performed using a catalyzed and uncatalyzed medium to compare the effectiveness of each case. The catalyst was Ni/Al2O3 synthesized by coprecipitation. The gas mixture produced from the reaction was continuously condensed to form a two-phase liquid–gas system. The synthesis gas was passed through a silica gel filter and analyzed online by gas chromatography. To conclude the results of this study show production of 178 mg of synthesis gas for every 1 g of biomass and the selectivity of hydrogen to be 51.8 mol% when a Ni 2.5% w/w catalyst was used. The amount of CO2 was halved and CO was reduced from 3.87% to 0% in molar percentage. Lastly a simulation of the distribution of temperatures inside the furnace was developed; the modeled behavior is in agreement with experimental observations.
Assessing the Feasibility of Hydrogen and Electric Buses for Urban Public Transportation using Rooftop Integrated Photovoltaic Energy in Cuenca Ecuador
Jul 2023
Publication
A main restriction of renewables from intermittent sources is the mismatch between energy resource availability and energy requirements especially when extensive power plants are producing at their highest potential causing huge energy surpluses. In these cases excess power must be stored or curtailed. One alternative is increasing urban solar potential which could be integrated to feed electric buses directly or alternatively through hydrogen (H2 ) as an energy vector. H2 from renewable electricity can be stored and used directly or through fuel cells. This study aims to determine the H2 capability that could be achieved when integrating large-scale photovoltaic (PV) generation in urban areas. This analysis was carried out by determining the PV energy potentially generated by installing PV in Cuenca City downtown (Ecuador). Cuenca is in the process of adopting renewal of the public transport vehicle fleet introducing a new model with an electric tram main network combined with “clean type buses”. The conventional diesel urban transport could be replaced establishing a required vehicle fleet of 475 buses spread over 29 routes emitting 112 tons of CO2 and burning 11175 gallons of diesel daily. Between the main findings we concluded that the electricity that could be produced in the total roof area exceeds the actual demand in the study area by 5.5 times. Taking into account the energy surplus it was determined that the available PV power will cover from 97% to 127% of the total demand necessary to mobilize the city bus fleet. The novelty of this work is the proposal of a combined methodology to find the potential to feed urban transport with urban solar power in cities close to the equatorial line.
Performance Analysis of Hybrid Solar/H2/Battery Renewable Energy System for Residential Electrification
Mar 2019
Publication
Due to the privileged location of Ecuador in terms of solar radiation the analysis and use of renewable energy system (RES) using solar energy has been of great interest during the last years. At the same time the supply support of RES in terms of direct current (DC) can be faced by using fuel cell (FC) systems which can give to the systems fully autonomy from fossil fuels. The aim of this paper is to propose the design of a hybrid photovoltaic-fuel cell-battery (PV-FC-B) system to supply the required electrical energy for residential use in the city of Guayaquil. The feasibility analysis constitutive elements of the system and adjusted variables are computed and presented using a computational tool. The results evidence that this system is not economically viable since the cost of energy (COE) in Ecuador is low compared to the COE of the proposed system. However a more detailed analysis considering the inherent benefits of no emission of pollutant gases is required to have a complete outlook.
A Review of Gas Phase Inhibition of Gaseous Hydrogen Embrittlement in Pipeline Steels
Feb 2024
Publication
The addition of small amounts of certain gases such as O2 CO and SO2 may mitigate hydrogen embrittlement in high-pressure gas transmission pipelines that transport hydrogen. To practically implement such inhibition in gas transmission pipelines a comprehensive understanding and quantification of this effect are essential. This review examines the impact of various added gases to hydrogen including typical odorants on gaseous hydrogen embrittlement of steels and evaluates their inhibition effectiveness. O2 CO and SO2 were found to be effective inhibitors of hydrogen embrittlement. Yet the results in the literature have not always been consistent partly because of the diverse range of mechanical tests and their parameters. The absence of systematic studies hinders the evaluation of the feasibility of using gas phase inhibitors for controlling gaseous hydrogen embrittlement. A method to quantify the effectiveness of gas phase inhibition is proposed using gas phase permeation studies.
Analysis for the Implementation of Surplus Hydropower for Green Hydrogen Production in Ecuador
Dec 2024
Publication
This study investigates the feasibility of utilizing surplus hydropower from Ecuador’s major hydroelectric plants to produce green hydrogen a clean energy source that can be used to meet a large percentage of energy needs. Given Ecuador’s significant hydropower infrastructure this approach leverages untapped energy resources for hydrogen production with potential impacts on decarbonization strategies. A Pareto analysis identified five key hydroelectric plants that contribute the most to the national surplus. Using historical data from 2019 to 2023 a stochastic model was applied to estimate future surplus availability through 2030. The findings indicate that although Ecuador’s surplus hydropower peaked in 2021 the general trend shows a decline suggesting an urgent need to capitalize on these resources efficiently. The results indicate a projected annual surplus of hydroelectric energy in Ecuador ranging from 7475 to 3445 GWh over the next five years which could be utilized for green hydrogen production. Ecuador thus has promising potential to become a green hydrogen producer enhancing both regional energy security and carbon reduction goals. The reduction in energy availability for hydrogen production is attributed to the increasing energy demand and variable climatic conditions.
Laboratory Studies on Underground H2 Storage: Bibliometric Analysis and Review of Current Knowledge
Dec 2024
Publication
: The global demand for energy and the need to mitigate climate change require a shift from traditional fossil fuels to sustainable and renewable energy alternatives. Hydrogen is recognized as a significant component for achieving a carbon-neutral economy. This comprehensive review examines the underground hydrogen storage and particularly laboratory-scale studies related to rock– hydrogen interaction exploring current knowledge. Using bibliometric analysis of data from the Scopus and Web of Science databases this study reveals an exponential increase in scientific publications post-2015 which accounts for approximately 85.26% of total research output in this field and the relevance of laboratory experiments to understand the physicochemical interactions of hydrogen with geological formations. Processes in underground hydrogen storage are controlled by a set of multi-scale parameters including solid properties (permeability porosity composition and geomechanical properties) and fluid properties (liquid and gas density viscosity etc.) together with fluid–fluid and solid–fluid interactions (controlled by solubility wettability chemical reactions etc.). Laboratory experiments aim to characterize these parameters and their evolution simulating real-world storage conditions to enhance the reliability and applicability of findings. The review emphasizes the need to expand research efforts globally to comprehensively address the currently existing issues and knowledge gaps.
Green Hydrogen Production—Fidelity in Simulation Models for Technical–Economic Analysis
Nov 2024
Publication
Green hydrogen production is a sustainable energy solution with great potential offering advantages such as adaptability storage capacity and ease of transport. However there are challenges such as high energy consumption production costs demand and regulation which hinder its largescale adoption. This study explores the role of simulation models in optimizing the technical and economic aspects of green hydrogen production. The proposed system which integrates photovoltaic and energy storage technologies significantly reduces the grid dependency of the electrolyzer achieving an energy self-consumption of 64 kWh per kilogram of hydrogen produced. By replacing the high-fidelity model of the electrolyzer with a reduced-order model it is possible to minimize the computational effort and simulation times for different step configurations. These findings offer relevant information to improve the economic viability and energy efficiency in green hydrogen production. This facilitates decision-making at a local level by implementing strategies to achieve a sustainable energy transition.
Integration of Water Electrolysis Facilities in Power Grids: A Case Study in Northern Germany
Mar 2022
Publication
This work presents a study of the effects that integration of electrolysis facilities for Power-to-X processes have on the power grid. The novel simulation setup combines a high-resolution grid optimization model and a detailed scheduling model for alkaline water electrolysis. The utilization and congestion of power lines in northern Germany is investigated by setting different installed capacities and production strategies of the electrolysis facility. For electrolysis capacities up to 300 MW (~50 ktH2/a) local impacts on the grid are observed while higher capacities cause supra-regional impacts. Thereby impacts are defined as deviations from the average line utilization greater than 5%. In addition the minimum line congestion is determined to coincide with the dailyconstrained production strategy of the electrolysis facility. Our result show a good compromise for the integrated grid-facility operation with minimum production cost and reduced impact on the grid.
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