901 resultados para Marine Current Energy


Relevância:

90.00% 90.00%

Publicador:

Resumo:

Low-voltage and high-current switching delay characteristics of a simple triggered vacuum gap (TVG) are described using lead zirconate titanate as the dielectric material in the auxiliary gap. This TVG has superior performance at high currents (up to 14 kA was studied) with regard to delay, reliable firing and extended life as compared to the one using either supramica or silicon carbide. The total delay consists of three intervals: to break down the auxiliary gap, to propagate the trigger plasma and to break down the main gap. The data on the influence of the various parameters like the trigger voltage, current, energy and the main circuit energy are given. It has been found that the delay due to the first two intervals is small compared to the third.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The MaRINET FP7 project aims to build a synergy in the European marine renewable energy development infrastructure network, involving a total of 28 partners across the union. Its scope extends from small to large scale testing, in both tank and field. The main activities of the project are to standardize test procedures, to provide centralized free access for European technology developers, and to innovate for improving test infrastructures and techniques.
Two years to the end of the project, this paper presents an update of the work being carried in this last part. It focuses on research objectives identified to be current challenges for industrial development. They are distributed in 6 topics. On the one hand are issues directly related to one of the 3 types of energy scoped in the project: wave, tidal, and offshore wind. On the other hand, collaborative effort is drawn on aspects that are common to those technologies: electrical components, environmental monitoring, and dedicated moorings.
Theory and validation of new test techniques are presented, for example in the case of non-intrusive wave measurements. This is done in coordination with extensive experimental analysis of the phenomena implying tests, such as nonlinearities in moorings.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Politicians, industry and the public generally accept the need for energy consumption to be cut to deliver climate change mitigation measures essential for us to avoid climate disaster. For non-domestic fuel users current energy policy has attempted to drive this through rational economic responses to energy cost pressures. This reliance on voluntary action has created an “Energy Inconsistency”, that is a marked difference between energy opportunities that have been proven technically viable, financially rational and retrofit feasible and those actually adopted. Other factors must therefore be involved to influence what appear to be simple carbon and cost saving opportunities. This paper presents a new approach to energy efficiency and consumption in non-domestic buildings, viewing attitudes and behaviours of building owners and users as the key driver of energy consumption. A new framework is proposed as a method to examine the impact of building ownership on the users’ and owners’ abilities to improve energy efficiency and consumption and identify opportunities to overcome the barriers inherent in these ownership structures.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Grass-based diets are of increasing social-economic importance in dairy cattle farming, but their low supply of glucogenic nutrients may limit the production of milk. Current evaluation systems that assess the energy supply and requirements are based on metabolisable energy (ME) or net energy (NE). These systems do not consider the characteristics of the energy delivering nutrients. In contrast, mechanistic models take into account the site of digestion, the type of nutrient absorbed and the type of nutrient required for production of milk constituents, and may therefore give a better prediction of supply and requirement of nutrients. The objective of the present study is to compare the ability of three energy evaluation systems, viz. the Dutch NE system, the agricultural and food research council (AFRC) ME system, and the feed into milk (FIM) ME system, and of a mechanistic model based on Dijkstra et al. [Simulation of digestion in cattle fed sugar cane: prediction of nutrient supply for milk production with locally available supplements. J. Agric. Sci., Cambridge 127, 247-60] and Mills et al. [A mechanistic model of whole-tract digestion and methanogenesis in the lactating dairy cow: model development, evaluation and application. J. Anim. Sci. 79, 1584-97] to predict the feed value of grass-based diets for milk production. The dataset for evaluation consists of 41 treatments of grass-based diets (at least 0.75 g ryegrass/g diet on DM basis). For each model, the predicted energy or nutrient supply, based on observed intake, was compared with predicted requirement based on observed performance. Assessment of the error of energy or nutrient supply relative to requirement is made by calculation of mean square prediction error (MSPE) and by concordance correlation coefficient (CCC). All energy evaluation systems predicted energy requirement to be lower (6-11%) than energy supply. The root MSPE (expressed as a proportion of the supply) was lowest for the mechanistic model (0.061), followed by the Dutch NE system (0.082), FIM ME system (0.097) and AFRCME system(0.118). For the energy evaluation systems, the error due to overall bias of prediction dominated the MSPE, whereas for the mechanistic model, proportionally 0.76 of MSPE was due to random variation. CCC analysis confirmed the higher accuracy and precision of the mechanistic model compared with energy evaluation systems. The error of prediction was positively related to grass protein content for the Dutch NE system, and was also positively related to grass DMI level for all models. In conclusion, current energy evaluation systems overestimate energy supply relative to energy requirement on grass-based diets for dairy cattle. The mechanistic model predicted glucogenic nutrients to limit performance of dairy cattle on grass-based diets, and proved to be more accurate and precise than the energy systems. The mechanistic model could be improved by allowing glucose maintenance and utilization requirements parameters to be variable. (C) 2007 Elsevier B.V. All rights reserved.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The current energy requirements system used in the United Kingdom for lactating dairy cows utilizes key parameters such as metabolizable energy intake (MEI) at maintenance (MEm), the efficiency of utilization of MEI for 1) maintenance, 2) milk production (k(l)), 3) growth (k(g)), and the efficiency of utilization of body stores for milk production (k(t)). Traditionally, these have been determined using linear regression methods to analyze energy balance data from calorimetry experiments. Many studies have highlighted a number of concerns over current energy feeding systems particularly in relation to these key parameters, and the linear models used for analyzing. Therefore, a database containing 652 dairy cow observations was assembled from calorimetry studies in the United Kingdom. Five functions for analyzing energy balance data were considered: straight line, two diminishing returns functions, (the Mitscherlich and the rectangular hyperbola), and two sigmoidal functions (the logistic and the Gompertz). Meta-analysis of the data was conducted to estimate k(g) and k(t). Values of 0.83 to 0.86 and 0.66 to 0.69 were obtained for k(g) and k(t) using all the functions (with standard errors of 0.028 and 0.027), respectively, which were considerably different from previous reports of 0.60 to 0.75 for k(g) and 0.82 to 0.84 for k(t). Using the estimated values of k(g) and k(t), the data were corrected to allow for body tissue changes. Based on the definition of k(l) as the derivative of the ratio of milk energy derived from MEI to MEI directed towards milk production, MEm and k(l) were determined. Meta-analysis of the pooled data showed that the average k(l) ranged from 0.50 to 0.58 and MEm ranged between 0.34 and 0.64 MJ/kg of BW0.75 per day. Although the constrained Mitscherlich fitted the data as good as the straight line, more observations at high energy intakes (above 2.4 MJ/kg of BW0.75 per day) are required to determine conclusively whether milk energy is related to MEI linearly or not.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The growing dependence on electricity for economic growth in all countries prompts the need to manage current resources for future sustainability. In today’s world, greater emphasis is placed on energy conservation for energy security and for the development of every economy. However, for some countries understanding the basic drivers to such achievements is farfetched. The research presented in this paper investigates the electricity generation and access potential for Botswana. In addition detailed documentation and 13 years energy consumption and generation trends are investigated. Using questionnaires and empirical studies the energy demand for the entire nation was estimated. From the research it was established that current energy generation trends account for 38- 39% of the country’s population with access to electricity. Considering the percentage rate of sector energy demand, the proposed total installed capacity of 1332 MW, would not meet the country's energy demand at 100% access. The likely consequence of the lack of adequate supply would cumulate to significant increase of imports and/or load shedding to meet demand.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The current energy systems within Curaçao depend primarily on high cost, imported fossil fuels, and typically constitute power sectors that are characterized by small, inefficient generation plants which result in high energy prices. As a consequence of its dependence on external fuel supplies, Curaçao is extremely vulnerable to international oil price shocks, which can impact on economic planning and foreign direct investment within their industrial sectors. The ability of the successive governments to source capital for economic stimulation and social investment is therefore significantly challenging. Additionally, there is over-dependence on two of the most climate-sensitive economic sectors, namely the tourism and fisheries sectors, but the vulnerabilities of the country to the effects of climate change make adaptation difficult and costly. It is within this context that this report focuses on identification of the fiscal and regulatory barriers to implementation of energy efficiency and renewable energy technologies in Curaçao with a view of making recommendations for removal of these barriers. Consultations with key Government officials, the private sector as well as civil society were conducted to obtain information and data on the energy sector in the country. Desktop research was also conducted to supplement the information gathered from the consultations. The major result of the assessment is that Curaçao is at an early stage in the definition of its energy sector. Despite some infrastructural legacies of the pre-independence era, as well as a number of recent developments including the modernization and expansion of its windfarms and completion of a modern Electricity Policy, there are still a number of important institutional and policy gaps within the energy sector in Curaçao. The most significant deficiency is the absence of a ministry or Government agency with portfolio responsibility for the energy sector as a whole; this has: limited the degree to which the activities of energy sector stakeholders are coordinated and retarded the development and implementation of a comprehensive national energy policy. The absence of an energy policy, which provides the framework for energy planning, increases investor risk. Also, the lack of political continuity that has emanated from the frequent changes in Government administrations is a concern among stakeholders and has served to reduce investor confidence in particular, and market confidence in general.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Background Energy Policy is one of the main drivers of Transport Policy. A number of strategies to reduce current energy consumption trends in the transport sector have been designed over the last decades. They include fuel taxes, more efficient technologies and changing travel behavior through demand regulation. But energy market has a high degree of uncertainty and the effectiveness of those policy options should be assessed. Methods A scenario based assessment methodology has been developed in the frame of the EU project STEPS. It provides an integrated view of Energy efficiency, environment, social and competitiveness impacts of the different strategies. It has been applied at European level and to five specific Regions. Concluding remarks The results are quite site specific dependent. However they show that regulation measures appear to be more effective than new technology investments. Higher energy prices could produce on their turn a deterioration of competitiveness and a threat for social goals.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

El actual contexto de fabricación, con incrementos en los precios de la energía, una creciente preocupación medioambiental y cambios continuos en los comportamientos de los consumidores, fomenta que los responsables prioricen la fabricación respetuosa con el medioambiente. El paradigma del Internet de las Cosas (IoT) promete incrementar la visibilidad y la atención prestada al consumo de energía gracias tanto a sensores como a medidores inteligentes en los niveles de máquina y de línea de producción. En consecuencia es posible y sencillo obtener datos de consumo de energía en tiempo real proveniente de los procesos de fabricación, pero además es posible analizarlos para incrementar su importancia en la toma de decisiones. Esta tesis pretende investigar cómo utilizar la adopción del Internet de las Cosas en el nivel de planta de producción, en procesos discretos, para incrementar la capacidad de uso de la información proveniente tanto de la energía como de la eficiencia energética. Para alcanzar este objetivo general, la investigación se ha dividido en cuatro sub-objetivos y la misma se ha desarrollado a lo largo de cuatro fases principales (en adelante estudios). El primer estudio de esta tesis, que se apoya sobre una revisión bibliográfica comprehensiva y sobre las aportaciones de expertos, define prácticas de gestión de la producción que son energéticamente eficientes y que se apoyan de un modo preeminente en la tecnología IoT. Este primer estudio también detalla los beneficios esperables al adoptar estas prácticas de gestión. Además, propugna un marco de referencia para permitir la integración de los datos que sobre el consumo energético se obtienen en el marco de las plataformas y sistemas de información de la compañía. Esto se lleva a cabo con el objetivo último de remarcar cómo estos datos pueden ser utilizados para apalancar decisiones en los niveles de procesos tanto tácticos como operativos. Segundo, considerando los precios de la energía como variables en el mercado intradiario y la disponibilidad de información detallada sobre el estado de las máquinas desde el punto de vista de consumo energético, el segundo estudio propone un modelo matemático para minimizar los costes del consumo de energía para la programación de asignaciones de una única máquina que deba atender a varios procesos de producción. Este modelo permite la toma de decisiones en el nivel de máquina para determinar los instantes de lanzamiento de cada trabajo de producción, los tiempos muertos, cuándo la máquina debe ser puesta en un estado de apagada, el momento adecuado para rearrancar, y para pararse, etc. Así, este modelo habilita al responsable de producción de implementar el esquema de producción menos costoso para cada turno de producción. En el tercer estudio esta investigación proporciona una metodología para ayudar a los responsables a implementar IoT en el nivel de los sistemas productivos. Se incluye un análisis del estado en que se encuentran los sistemas de gestión de energía y de producción en la factoría, así como también se proporcionan recomendaciones sobre procedimientos para implementar IoT para capturar y analizar los datos de consumo. Esta metodología ha sido validada en un estudio piloto, donde algunos indicadores clave de rendimiento (KPIs) han sido empleados para determinar la eficiencia energética. En el cuarto estudio el objetivo es introducir una vía para obtener visibilidad y relevancia a diferentes niveles de la energía consumida en los procesos de producción. El método propuesto permite que las factorías con procesos de producción discretos puedan determinar la energía consumida, el CO2 emitido o el coste de la energía consumida ya sea en cualquiera de los niveles: operación, producto o la orden de fabricación completa, siempre considerando las diferentes fuentes de energía y las fluctuaciones en los precios de la misma. Los resultados muestran que decisiones y prácticas de gestión para conseguir sistemas de producción energéticamente eficientes son posibles en virtud del Internet de las Cosas. También, con los resultados de esta tesis los responsables de la gestión energética en las compañías pueden plantearse una aproximación a la utilización del IoT desde un punto de vista de la obtención de beneficios, abordando aquellas prácticas de gestión energética que se encuentran más próximas al nivel de madurez de la factoría, a sus objetivos, al tipo de producción que desarrolla, etc. Así mismo esta tesis muestra que es posible obtener reducciones significativas de coste simplemente evitando los períodos de pico diario en el precio de la misma. Además la tesis permite identificar cómo el nivel de monitorización del consumo energético (es decir al nivel de máquina), el intervalo temporal, y el nivel del análisis de los datos son factores determinantes a la hora de localizar oportunidades para mejorar la eficiencia energética. Adicionalmente, la integración de datos de consumo energético en tiempo real con datos de producción (cuando existen altos niveles de estandarización en los procesos productivos y sus datos) es esencial para permitir que las factorías detallen la energía efectivamente consumida, su coste y CO2 emitido durante la producción de un producto o componente. Esto permite obtener una valiosa información a los gestores en el nivel decisor de la factoría así como a los consumidores y reguladores. ABSTRACT In today‘s manufacturing scenario, rising energy prices, increasing ecological awareness, and changing consumer behaviors are driving decision makers to prioritize green manufacturing. The Internet of Things (IoT) paradigm promises to increase the visibility and awareness of energy consumption, thanks to smart sensors and smart meters at the machine and production line level. Consequently, real-time energy consumption data from the manufacturing processes can be easily collected and then analyzed, to improve energy-aware decision-making. This thesis aims to investigate how to utilize the adoption of the Internet of Things at shop floor level to increase energy–awareness and the energy efficiency of discrete production processes. In order to achieve the main research goal, the research is divided into four sub-objectives, and is accomplished during four main phases (i.e., studies). In the first study, by relying on a comprehensive literature review and on experts‘ insights, the thesis defines energy-efficient production management practices that are enhanced and enabled by IoT technology. The first study also explains the benefits that can be obtained by adopting such management practices. Furthermore, it presents a framework to support the integration of gathered energy data into a company‘s information technology tools and platforms, which is done with the ultimate goal of highlighting how operational and tactical decision-making processes could leverage such data in order to improve energy efficiency. Considering the variable energy prices in one day, along with the availability of detailed machine status energy data, the second study proposes a mathematical model to minimize energy consumption costs for single machine production scheduling during production processes. This model works by making decisions at the machine level to determine the launch times for job processing, idle time, when the machine must be shut down, ―turning on‖ time, and ―turning off‖ time. This model enables the operations manager to implement the least expensive production schedule during a production shift. In the third study, the research provides a methodology to help managers implement the IoT at the production system level; it includes an analysis of current energy management and production systems at the factory, and recommends procedures for implementing the IoT to collect and analyze energy data. The methodology has been validated by a pilot study, where energy KPIs have been used to evaluate energy efficiency. In the fourth study, the goal is to introduce a way to achieve multi-level awareness of the energy consumed during production processes. The proposed method enables discrete factories to specify energy consumption, CO2 emissions, and the cost of the energy consumed at operation, production and order levels, while considering energy sources and fluctuations in energy prices. The results show that energy-efficient production management practices and decisions can be enhanced and enabled by the IoT. With the outcomes of the thesis, energy managers can approach the IoT adoption in a benefit-driven way, by addressing energy management practices that are close to the maturity level of the factory, target, production type, etc. The thesis also shows that significant reductions in energy costs can be achieved by avoiding high-energy price periods in a day. Furthermore, the thesis determines the level of monitoring energy consumption (i.e., machine level), the interval time, and the level of energy data analysis, which are all important factors involved in finding opportunities to improve energy efficiency. Eventually, integrating real-time energy data with production data (when there are high levels of production process standardization data) is essential to enable factories to specify the amount and cost of energy consumed, as well as the CO2 emitted while producing a product, providing valuable information to decision makers at the factory level as well as to consumers and regulators.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Es bien conocido por todos que la Primera Revolución Industrial, que tuvo su inicio en la segunda mitad del Siglo XVIII, conllevó un aumento del uso de los recursos energéticos que no se ha detenido para llegar a los niveles de desarrollo tecnológico, industrial y de calidad de vida, de los que se dispone en la actualidad. A simple vista podría intuirse que para disponer de un mayor nivel tecnológico, industrial, de confort, etc. sea necesario un mayor consumo de energía primaria. La actual generación de energía está principalmente basada en el procesamiento de los diversos compuestos del carbono (hidrocarburos, gases y productos derivados del petróleo), que son contaminantes y además, se agotan. Desde hace unas pocas décadas, la humanidad ha sido consciente que es necesario generar energía a partir de fuentes de origen renovable, y que además resulten menos contaminantes. Así, en la actualidad, se ha llegado a un estado de desarrollo avanzado para la explotación de diversas fuentes de energías como la eólica, a la vez que se comienza a mirar con realismo la posibilidad de explotación de diversas energías de origen marino. Se considera que las energías renovables procedentes de los océanos que se encuentran más desarrolladas tecnológicamente hablando, sin tener en cuenta la energía eólica fuera costa (offshore), son la denominada energía undimotriz o de las olas y la energía de las corrientes marinas, no necesariamente en este orden. El trabajo propuesto en esta Tesis se centra en este último recurso energético y, aunque no se dispone todavía de ningún dispositivo en fase de explotación comercial, la concepción, diseño y desarrollo de dispositivos para la extracción de energía de las corrientes, y su evolución, han sido relativamente rápidos e importantes en estos últimos años. Existen ya diferentes dispositivos en fase de pruebas con resultados muy prometedores. Aunque los dispositivos actuales se encuentran limitados a la explotación energética en zonas de poca profundidad, los diferentes estudios del recurso indican la necesidad de explotar corrientes marinas a mayores profundidades, para lo que se están desarrollando actualmente dispositivos, cuya evolución en lo que a sistemas de fondeo se refiere, está siendo muy parecida a la que se ha producido en los parques eólicos fuera costa, similar a su vez, a la evolución llevada a cabo en las plataformas oceánicas para la explotación de recursos petrolíferos (denominados oil & gas) que se extraen de profundidades cada vez mayores. Las soluciones tecnológicas que resulten válidas han de ser también económicamente viables, y en la actualidad se requiere todavía reducir costos en todas las fases de instalación, explotación y mantenimiento de estos dispositivos, sea cual sea su profundidad de operación. Uno de los focos de estudio para abaratar los costes de explotación en general, pasa por abaratar y reducir los costes en las maniobras necesarias de inmersión (de la superficie del mar a la profundidad de operación) y emersión (de la profundidad de operación a la superficie del mar) de estos dispositivos, para llevar a cabo tareas de mantenimiento in situ, en el mar, y sin necesidad de buques especializados ni de su transporte a tierra. En esta Tesis se propone, en primer lugar, un método para evaluar el ciclo de vida de diversos dispositivos de aprovechamiento de las corrientes marinas. Se evidencia que el coste de la energía así generada sigue siendo no plenamente competitivo, por lo que se requiere avanzar en el abaratamiento de costes, principalmente en la instalación y en su mantenimiento. Para ello se propone como novedad principal, introducir sistemas de control en lazo cerrado para realizar maniobras de instalación y mantenimiento de forma automática. También se aporta un modelo dinámico original y muy sencillo para dispositivos bajo estos movimientos de emersión/inmersión, a partir del cual se han desarrollado los algoritmos de control para el propósito mencionado, que no es otro sino automatizar en todo lo posible las maniobras completas. Los algoritmos de control propuestos han sido validados mediante simulación. Se proponen trayectorias de referencia de movimiento suaves (smooth) similares a las utilizadas en robótica. Estos movimientos de cambios de profundidad en lazo cerrado, combinados con secuencias de movimientos en bucle abierto para cuando el dispositivo interacciona en la superficie libre, han dado lugar a nuevas maniobras completas de instalación y mantenimiento que se presentan en esta Tesis, diferentes a las actuales. Finalmente, y como justificación de la viabilidad económica del método novedoso aportado, se ha realizado un estudio comparativo de los costes de la tecnología propuesta, frente a la tecnología actual. Este nuevo sistema de maniobras automáticas implica un ciclo de vida diferente para los dispositivos de aprovechamiento de la energía de las corrientes, ciclo que se cuantifica a partir de un dispositivo base que ha sido modificado y adaptado para la nueva tecnología propuesta, demostrando su viabilidad tanto técnica como económica. ABSTRACT It’s well known that the First Industrial Revolution started in the second half of the eighteenth century, carried the increasing of the use of energy resource which have not been stopped until reach the present technology, industrial evolution and daily life quality. On the surface, it can be known intuitively that a higher consumption of primary energy resource is demanded for benefiting from a higher technological industrial and daily life level. Today, the generation of energy is mainly based in the processing of carbon products (hydrocarbons, gases and petroleum products) which are pollutants, and additionally, are depleted. From a few decades ago, the humanity is aware the energy should be obtained from renewable resources, which besides, should be cleaner. So, at the present, a technical develop has been gained to exploit several energy source, as wind energy, and, at the same time, the extraction of the marine energy starts to seem as a reality. The renewable marine energies considered more advanced and technically developed, without keeping in mind, the offshore wind energy, are the wave energy and the tidal current energy, not necessarily in that order. This Thesis is focused in this last energy resource, and, although, any device is under commercial operation, the concept, design and develop of this type of devices to extract the tidal current energy and their evolution has been comparatively fast and important the last years. There are several devices under test with promising results. Even through the current devices are limited to lower depth areas, the several studies of the tidal energy resource suggest the need to exploit the marine current at greater depths to what is being developed devices, where their evolution in the anchoring system is being very similar to the evolution performed in the offshore wind farms, which is at the same time, similar to the evolution in the oil and gas exploitation which are extracted to greatest depths. Viable technical solutions should be also viable economically and nowadays the cost in all phases of the project (installation, maintenance and operation) should be decreased whatever the operation depth is. One focus of study to lower the operation cost is the cost decreasing of immersion manoeuvring operations (from sea surface to the operation depth) and immersion manoeuvring operations (from operation depth to the sea surface), therefore the maintenance operations can be performed on – site, in the sea, and no specialized vessels are required to transport the devices from the sea to shore. In this dissertation, firstly is proposed a method to evaluate the life cycle of the tidal energy current devices. It is proved the energy generated by these devices is not fully competitive; therefore, the cost falling is mainly an objective in the installation and the maintenance operations. For that, it is proposed as main novelty, the using of closed loop control systems to perform the automatic installation and manoeuvring operations. It is also contributed with an original and simple dynamic model and for controlling the immersion/emersion movements of these devices, from which the control algorithms are developed in order to automate as much as possible the complete manoeuvring. The control algorithms proposed has been validated by simulations. Reference paths with smooth movements, similar which are used in robotics, are suggested. These movements to change the depth using closed loop control, combined with the sequences in open loop movements when the device is in free surface, have been development for a new complete manoeuvring to installation and maintenance operations which are advanced in this Thesis and they are different to the present manoeuvrings. Finally and as justification of the economic viability of this original method, a comparative cost study between the technology proposed and the current technology is performed. This new automatic manoeuvring system involves a different life cycle for the tidal energy current devices, cycle that is quantified from a base device which has been modified and adapted for the new proposed technology, showing the technical and economic viability.