Tidal Energy Potential in the Center Zone of the Colombian Pacific Coast

Introduction: Tidal energy is evidencing interest worldwide because it can be accurately estimated due to the cyclical behavior of the tides. This energy can be extracted from differences in sea level height through the use of gates and turbines of a reservoir (tidal power plant), or extracted from tidal currents through a grid of reversible horizontal axis microturbines as proposed in this study. Thus, the Colombian Pacific region has the opportunity to implement microturbines in strategic areas with the challenge of optimizing them to extract energy with local tidal heights up to 4 m and current velocities up to 1.5 m/s. Objective: Calculate the energy potentials from tidal currents in the central zone of the Colombian Pacific coast obtained through hydrodynamic modeling (Delft3D) validated it with in situ information. Methodology: The present study starts from level 1 of technological development (Technology Readiness Levels, TRL) till reaching the TRL 2. Then, the research performed a documentary review of national and international experiences related to tidal energy, evidencing the great opportunity that Colombia has to take advantage of this type of energy and join to the growing international interest in the development of clean and renewable energies. In addition, this study characterized the tidal heights and did calculations of energy potentials from tidal currents in the Colombian Pacific derived from hydrodynamic modeling (Delft3D) validated with measured in situ data. The results of this study encourage the application of these technologies in Colombia and represents a contribution to the fulfillment of the UN sustainable development objectives (Affordable and non-polluting energy, SDG 7). Results: From the 4 analysis points, the point B (Buenaventura) registered the highest accumulated potential for electricity generation per month (31,546.56 Wh / month). The maximum tidal heights at points A, B, C and D during 2018 were 1.88 m. Furthermore, the mean velocity range at points A, B, C and D was 0.28 m/s to 0.54 m/s, and the maximum velocity for these points were 0.54 m/s, 0.49 m/s, 0.31 m/s and 0.28 m/s respectively. Then, by means of 5 tidal microturbines with a reversible horizontal axis of 1 m sweep area for the point of highest potential (B), it is possible to generate electrical energy to meet the electrical consumption of a house, and with 544 microturbines the consumption of 99 houses. The tidal farm (544 microturbines) would require an area of 2079.36 m2 (e.g. 45.6 m x 45.6 m) and an average depth of 5 m; these requirements are feasible to be met because of the study area characteristics. Conclusions: This research determined the tidal energy potential in the central zone of the Colombian Pacific for 4 points of interest, (A, B, C and D) and the highest potentials were found in points A and B located in Bahía Málaga and Buenaventura respectively. In addition, the minimum velocities, the duration of these and the diurnal tidal regime (12 h) were analyzed, and it was found that points A and B showed the lowest times (1 h and 2 h) of minimum velocity, evidencing a capacity of daily electricity generation of 22 h and 20 h respectively. In consideration of the obtained results, this research shows the opportunity to perform studies for promoting the development of reversible horizontal-axis microturbines for the exploitation of tidal energy. The generated energy could be supplied to communities with access difficulties to the electricity distribution network, what would reduce poverty and the emission of Greenhouse Gases (GHG) due to the burning of fossil and plant-based fuels (firewood).   Conclusions: It was determined that the tidal energy potential in the central zone of the Colombian Pacific for 4 points of interest, (A, B, C and D) and the highest potentials were found in points A and B located in Bahía Málaga and Buenaventura respectively. In consideration of the results obtained, this research shows the opportunity performe studies for promoting the development of microturbines for electricity generation from tidal energy. The generated energy would supply to communities with difficulties in accessing the networks of electricity distribution, thus reducing poverty and the emission of Greenhouse Gases (GHG) due to the burning of fossil fuels and of vegetable origin (firewood).Introducción: La energía de las mareas está evidenciando un interés a nivel mundial porque se puede estimar con precisión debido al comportamiento cíclico de las mareas. Esta energía puede extraerse de las diferencias en la altura del nivel del mar mediante el uso de compuertas y turbinas de un embalse (planta de energía mareomotriz), o extraerse de las corrientes de marea a través de una red de microturbinas reversibles de eje horizontal como se propone en este estudio. Así, la región del Pacífico colombiano tiene la oportunidad de implementar microturbinas en áreas estratégicas con el desafío de optimizarlas para extraer energía con alturas de marea locales de hasta 4 m y velocidades de corriente de hasta 1.5 m/s. Objetivo: Calcular los potenciales energéticos de las corrientes de marea en la zona central de la costa pacífica colombiana obtenidos mediante modelado hidrodinámico (Delft3D) validado con información in situ. Metodología: El presente estudio parte del nivel 1 de desarrollo tecnológico (Niveles de desarrollo tecnológico, TRL en inglés) hasta llegar a TRL 2. Luego, la investigación realizó una revisión documental de experiencias nacionales e internacionales relacionadas con la energía mareomotriz, evidenciando la gran oportunidad que tiene Colombia para aprovechar este tipo de energía y sumarnos al creciente interés internacional por el desarrollo de energías limpias y renovables. Además, este estudio caracterizó las alturas de las mareas y realizó cálculos de potenciales energéticos a partir de corrientes de marea en el Pacífico colombiano derivados de modelos hidrodinámicos (Delft3D) validados con datos medidos in situ. Los resultados de este estudio incentivan la aplicación de estas tecnologías en Colombia y representan un aporte al cumplimiento de los Objetivos de Desarrollo Sostenible de la ONU (Energía asequible y no contaminante, ODS 7). Resultados: De los 4 puntos de análisis, el punto B (Buenaventura) registró el mayor potencial acumulado de generación eléctrica por mes (31,546.56 Wh/mes). Las alturas máximas de marea en los puntos A, B, C y D durante 2018 fueron de 1.88 m. Además, el rango de velocidad media en los puntos A, B, C y D fue de 0.28 m/s a 0.54 m/s, y la velocidad máxima para estos puntos fue de 0.54 m/s, 0.49 m/s, 0.31 m/s y 0.28 m/s respectivamente. Luego, mediante 5 microturbinas mareales con eje horizontal reversible de 1 m de área de barrido para el punto de mayor potencial (B), es posible generar energía eléctrica para cubrir el consumo eléctrico de una casa, y con 544 microturbinas el consumo de 99 casas. La granja de mareas (544 microturbinas) requeriría un área de 2079.36 m2 (por ejemplo, 45.6 m x 45.6 m) y una profundidad media de 5 m; estos requisitos son factibles de cumplir debido a las características del área de estudio. Conclusiones: Esta investigación determinó el potencial energético de las mareas en la zona central del Pacífico colombiano para 4 puntos de interés, (A, B, C y D) y los mayores potenciales se encontraron en los puntos A y B ubicados en Bahía Málaga y Buenaventura respectivamente. Además, se analizaron las velocidades mínimas, la duración de estas y el régimen de mareas diurno (12 h), y se encontró que los puntos A y B mostraron los tiempos más bajos (1 h y 2 h) de velocidad mínima, evidenciando una capacidad de generación eléctrica diaria de 22 h y 20 h respectivamente. En consideración a los resultados obtenidos, esta investigación muestra la oportunidad de realizar estudios para promover el desarrollo de microturbinas reversibles de eje horizontal para el aprovechamiento de la energía mareomotriz. La energía generada podría ser suministrada a comunidades con dificultades de acceso a la red de distribución eléctrica, lo que reduciría la pobreza y la emisión de Gases de Efecto Invernadero (GEI) por la quema de combustibles fósiles y vegetales (leña)

Identificación de la influencia de las variaciones convectivas en la generación de cargas transitorias y su efecto hidromecánico en las estructuras Offshore

La investigación identifica y explica el origen de cargas hidrodinámicas transitorias que afectan a las estructuras Offshore. Se aporta conocimiento en oceanografía para comprender los procesos físicos que generan las cargas del área estudio, y en dinámica estructural para analizar los efectos de las cargas transitorias. Mediante modelación física, numérica y mediciones en campo se estudió la hidromecánica de una turbina de viento fija y una flotante. Adicionalmente, se proponen métodos de modelamiento (numéricos, estadísticos y heurísticos) de parámetros océano atmosféricos, y recomendaciones de diseño de estructuras offshore. Por último, esta investigación incentiva el desarrollo de la ingeniería Offshore en Colombia para el aprovechamiento de energía y recursos costa afuera

Aplicación de O3 y O3/H2O2 como postratamiento del efluente de un reactor anaerobio de flujo horizontal y biomasa inmovilizada de flujo horizontal (RAFABI) tratando aguas residuales hospitalarias.

Introduction: In recent years, the "emerging pollutants" in urban, industrial, and surface water bodies have called the attention worldwide.  In many cases, these substances correspond to pollutants that have not been yet regulated by the environmental authorities. Hospitals are considered the main source of these contaminants as a result of different activities.  However, there is no consensus about the appropriate treatments for removing this kind of pollutants in the wastewaters; independent conventional biological processes do not reach the desirable values of discharge limits. Advanced oxidation processes (AOP) are known as an appropriate technology, not only to improve the biodegradability of recalcitrant compounds, but also to contribute to the removal of certain substances that are difficult to treat during the biological process.   Objective: Thus, this study evaluated the application of O3z and O3 /H2O2 to the effluent of an anaerobic horizontal flow reactor and immobilized biomass (HAIB). Methodology: The oxidizers were applied in a lab-scale batch borosilicate glass reactor. The reaction time was 60 min and samples were taken at intervals of 15 min. Parameters such as absorbance at UV254, biodegradability ratio expressed as COD/BOD5, and color as VIS436 were measured. All samples were analyzed in duplicate. Results. The results showed that the application of Ozone and O3/H2O2 results in an increase in the biodegradability of 25% and 67% respectively. Concerning color, an efficiency of 85 % for Ozone and 100 % for O3 /H2O2 was observed. Besides, the AOPs applied also showed their effectiveness in removing aromatic organics, removing 40 to 50% of UV254. Conclusions: Finally, it is important to mention that the application of advanced oxidation processes as a post-treatment of anaerobic effluents increases biodegradability mainly due to the transformation suffered by recalcitrant compounds.Introducción: En los últimos años, se ha incrementado la atención a la presencia de “contaminantes emergentes” en aguas residuales urbanas, industriales y cuerpos de agua superficial. En la mayoría de los casos, estas sustancias, corresponden a contaminantes que aún no ha sido reglamentados a nivel nacional por las autoridades ambientales. Los hospitales son considerados como la mayor fuente de estos compuestos, resultado de diferentes actividades. No existe en la actualidad un consenso sobre cuál o cuáles son los tratamientos adecuados para tratar las aguas residuales que contienen estos compuestos. En general, los procesos biológicos convencionales por sí solos no alcanzan a cumplir con los valores de los límites de descarga, siendo necesario aplicar postratamientos como los procesos de oxidación avanzada (POA), conocidos como una tecnología apropiada no sólo por aumentar la biodegradabilidad de los compuestos recalcitrantes, sino también por contribuir con la remoción de ciertas sustancias que son difíciles de tratar en un proceso biológico. Objetivo: Por tal razón, en este estudio se evaluó la aplicación de Ozono (O3) y O3/H2O2 al efluente de un reactor anaerobio de flujo horizontal y biomasa inmovilizada (RAFABI).   Metodología: Los oxidantes fueron aplicados en un reactor de vidrio de borosilicato tipo batch en escala de laboratorio. El tiempo de reacción fue de 60 min y se tomaron muestras a intervalos de 15 min. Para evaluar el desempeño del tratamiento se midieron parámetros tales como la absorbancia a una longitud de onda de UV254, la relación de biodegradabilidad expresada como DQO/DBO5, y el color como VIS436. Todas las muestras fueron analizadas por duplicado. Resultados: Los resultados mostraron que la aplicación de O3 y O3/H2O2 produjeron un incremento en la biodegradabilidad del 25% y del 67% respectivamente.  En relación con el color, se observó una eficiencia del 85 % para el Ozono y el 100 % para el O3/H2O2.  Adicionalmente, los dos POA aplicados también mostraron ser efectivos para remover orgánicos aromáticos medidos como UV254, para lo cual se obtuvieron remociones entre el 40 y 50% de UV254.  Conclusiones: Finalmente, es importante mencionar que la aplicación de procesos de oxidación avanzada como postratamiento de efluentes anaerobios, aumentan la biodegradabilidad principalmente por la transformación que sufren los compuestos recalcitrantes

Wind and power density data of strategic offshore locations in the Colombian Caribbean coast

The high potential of wind speed in the Colombian Caribbean coast is an opportunity to develop offshore wind energy technology. This article contains the wind speed and wind power density in four strategic locations in Colombia (Cartagena, Barranquilla, Santa Marta and La Guajira) at different elevations. The dataset from this study is related to the research paper “Renewables energies in Colombia and the opportunity for the offshore wind technology published in Journal of Cleaner Production (Rueda-Bayona et al.) [1]. Reading and processing numerous files stored in databases could be challenging because it demands software programming to do so, what could difficult the access to valuable data for the community. Also, high compressed files such as NetCDF formats demand specialised software which is not easy obtaining and utilising because it requires skills in a programming language. Then, this study used the NARR-NOAA database [2] and generated local wind and power density data stored in Excel sheets to ease their utilisation

Selection of jonswap spectra parameters during water-depth and sea-state transitions

The design of marine structures requires the simulation of wave parameters that consider sea-state and water-depth transitions. Proper selection of the model coefficients (e.g., alpha and gamma of the JONSWAP spectra) is then required, because of the wave-hydrodynamic nonlinearities during these ocean processes. Therefore, the model coefficient selection should be tested using a nonlinear analysis to assess the effect of the selected spectra coefficients over the modeled wave parameters. The present study performed a design of experiment (DOE)-analysis of variance (ANOVA) and probability analysis to assess the effect of alpha and gamma parameters over the significant wave height (Hs) and peak period (Tp) during sea-state and water-depth transitions. The DOE-ANOVA demonstrated for the mean and extreme wave states of the study area that alpha and gamma parameters positively affect the Hs behavior in deep and intermediate waters. Furthermore, the standardized effects of alpha and gamma over the Tp during extreme wave states suggest quadruplets of wave-wave interactions. The joint and normal probability distributions of alpha and gamma for extreme and normal waves showed a Gaussian distribution, allowing identification of specific alpha and gamma values for the JONSWAP spectra model. The selected alpha and gamma parameters were then validated through the comparison of the modeled Hs (JONSWAP) against other local studies. Considering its relevance in design strategies for offshore structures, this research contributed to the understanding of the nonlinear effects of alpha and gamma parameters over the Hs and Tp during variations of water depth and wave states, easing the selection of the model coefficients

Modeling wind speed with a long-term horizon and high-time interval with a hybrid fourier-neural network model

The limited availability of local climatological stations and the limitations to predict the wind speed (WS) accurately are significant barriers to the expansion of wind energy (WE) projects worldwide. A methodology to forecast accurately the WS at the local scale can be used to overcome these barriers. This study proposes a methodology to forecast the WS with high-resolution and long-term horizons, which combines a Fourier model and a nonlinear autoregressive network (NAR). Given the nonlinearities of the WS variations, a NAR model is used to forecast the WS based on the variability identified with the Fourier analysis. The NAR modelled successfully 1.7 years of windspeed with 3 hours of the time interval, what may be considered the longest forecasting horizon with high resolution at the moment

Performance of an Upflow anaerobic sludge blanket reactor for hospitals’ wastewaters treatment in Colombia: A preliminary study.

Las aguas residuales hospitalarias son consideradas peligrosas y dañinas para el medio ambiente y la salud pública, lo que exige la utilización de sistemas de tratamiento adecuados para controlar los contaminantes en ellas. Este estudio evaluó el desempeño de un reactor anaerobio de manto de lodos y flujo ascendente (UASB) para tratar aguas residuales hospitalarias reales. El reactor operó durante 145 días variando los valores de la carga orgánica volumétrica (COV). Los resultados mostraron que para valores medios de carga de 0.950 Kg DQO / m3.d la eficiencia de remoción de materia orgánica fue 59 ± 14%, sin embargo, el proceso fue inestable y mostró una baja producción de gas metano. Como resultado, esta investigación encontró que el reactor convencional tipo UASB no es una tecnología de tratamiento confiable y adecuada para el tratamiento de materia orgánica presente en las aguas residuales de los hospitales.  The hospitals’ wastewater is considered harmful to the environment and public health, which demands the utilization of proper treatment systems to manage the pollutants in them. This study evaluated the performance of an anaerobic reactor Upflow Sludge Blanket (UASB) to treat real hospitals’ wastewater (HWW). The reactor operated for 145 days with variations of the amount of organic load rate (OLR). The results showed that for mean organic load rate (OLR) of 0.950 Kg COD / m3.d the removal efficiency of organic matter was 59 ± 14%, however, the process was unstable and showed low methane gas production. As a result, this research found that UASB standard systems are not reliable and proper treatment technologies y for treating organic pollutants of hospitals’ wastewater

Application of O3 and O3 /H2O2 for post-treatment of horizontal-flow anaerobic immobilized biomass (HAIB) effluent, treating hospital wastewater.

Introduction: In recent years, the "emerging pollutants" in urban, industrial, and surface water bodies have called the attention worldwide.  In many cases, these substances correspond to pollutants that have not been yet regulated by the environmental authorities. Hospitals are considered the main source of these contaminants as a result of different activities.  However, there is no consensus about the appropriate treatments for removing this kind of pollutants in the wastewaters; independent conventional biological processes do not reach the desirable values of discharge limits. Advanced oxidation processes (AOP) are known as an appropriate technology, not only to improve the biodegradability of recalcitrant compounds, but also to contribute to the removal of certain substances that are difficult to treat during the biological process.   Objective: Thus, this study evaluated the application of O3z and O3 /H2O2 to the effluent of an anaerobic horizontal flow reactor and immobilized biomass (HAIB). Methodology: The oxidizers were applied in a lab-scale batch borosilicate glass reactor. The reaction time was 60 min and samples were taken at intervals of 15 min. Parameters such as absorbance at UV254, biodegradability ratio expressed as COD/BOD5, and color as VIS436 were measured. All samples were analyzed in duplicate. Results. The results showed that the application of Ozone and O3/H2O2 results in an increase in the biodegradability of 25% and 67% respectively. Concerning color, an efficiency of 85 % for Ozone and 100 % for O3 /H2O2 was observed. Besides, the AOPs applied also showed their effectiveness in removing aromatic organics, removing 40 to 50% of UV254. Conclusions: Finally, it is important to mention that the application of advanced oxidation processes as a post-treatment of anaerobic effluents increases biodegradability mainly due to the transformation suffered by recalcitrant compounds

Assessing the biofuel – transport nexus. The case of the sugar industry in cuba

Cuba currently faces a limited availability of transportation to support the development needs of the country. Transport availability is mostly limited because of fuel shortage. Moreover, Cuba has an important production of sugarcane, with a significant potential to further increase its production. Using sugarcane-based bioethanol is a significant opportunity for sugarcane producer countries. There are different raw materials available in the sugar industry to produce bioethanol. Therefore, there are different scenarios to increase the production of sugarcane and energy cane, to increase bioethanol production. In this study, two scenarios of sugarcane and energy cane production were considered, from which there are eight possible scenarios of bioethanol production. These bioethanol production scenarios were matched with three transport scenarios, including a business-as-usual scenario, a scenario considering the use of bioethanol blends in standard gasoline and diesel engines, and the and introduction of vehicles running on high ethanol blends or pure bioethanol (i.e flexible fuel vehicles, and ethanol buses and trucks). In total, the production of sugarcane-based bioethanol might support from 4 to 58% of the yearly demand for transport energy in the transport scenarios. Additionally, the use of bioethanol as a transport fuel can potentially reduce transport-related greenhouse gas emissions by an estimated 3–30%

Factors Affecting the Electricity Consumption and Productivity of the Lead Acid Battery Formation Process. The Case of a Battery Plant in Colombia

This study identifies the main factors affecting the electricity efficiency and productivity of the lead acid battery formation process. A representative sample of 12,286 battery formation processes, developed between June 2014 and June 2015, were used in a statistic analysis. As a result, an energy performance indicator was developed to assess the electricity consumption of battery formation. Given that there are several formation circuits in the formation area, an energy performance indicator was developed for each circuit. The influence of the operational practices, operational teams, workings shift starting time and technical condition of the circuits were analyzed. The influence of the operational practices and the technical conditions of the formation circuits were identified as the main factors affecting the productivity and the electricity consumption. These factors cause a time waste, affecting productivity between 2% and 5%, and increasing the electricity consumption. As a result it is recommended to improve maintenance and operational practices towards higher productivity and electricity efficiency