Rural electrification has long been the most important topic on the development agenda of many countries. The needs for power supplies to rural areas increased significantly in the past decades. Extending electricity grids to rural areas is of a very high initial cost and is not viable economically. Micro hydroelectric power plants provide a good economical solution, which is also environmentally very friendly. The current study concentrates on selecting and optimizing a suitable cross-flow micro-turbine to be used in micro hydroelectric power plants. Cross-flow turbines are in general of simple structure, low cost, easy to fabricate and of modest efficiency. The main purpose of the present work is to optimize the performance of a selected turbine by establishing the optimal turbine’s design parameters. A complete analysis of the internal flow, which is of turbulent, two-phase and three dimensional in nature, was undertaken by simulating it using various CFD simulation codes. This study reports on the flow simulation using ANSYS CFX with a two-phase flow model, water-air free surface model and shear stress transport (SST) turbulence model. Prediction velocity and pressure fields of inside the turbine are, subsequently, used to characterize the turbine performance for different geometric parameters including the number of runner blades, the angle of attack, the ratio of inner to outer diameter, the nozzle profile, the blade profile, the nozzle throat width, the nozzle to runner blades width and the runner blades width to outer runner diameter. The results revealed the highly complex nature of the flow and provided a very good insight to the flow structure and performance optimization parameters.

The thesis numerically explores the use and behavior of Active Hydraulic Devices (AHDs), creating a new capability to simulate and control a pipe system’s transient performance. Automatic control valves are the first type of AHDs studied in this research. Due to the challenges inherent in the design of a pressure relief valve (PRV), the general principles of PRV use and selection are studied along with the system’s response to the PRV parameters. A new application of PID (proportional, integral and derivative) control valve is envisioned that combines a remote sensor at the upstream end of a pipeline to create a non- or semi- reflective boundary at the downstream end. Case studies show that, with such a boundary, the reflection and resonance of pressure waves within the pipeline are sometimes eliminated and invariably limited. The second type of AHDs studied in this research is the governed hydro turbine, the most complicated hydraulic component in terms of transient analysis and waterhammer control. A complete numerical model is developed for the turbine installations in either urban water networks or conventional hydropower generation systems. Using the model, transient simulations for several realistic hydro projects are presented along with various transient control measures.

Adaptive management (AM) is a systematic process that regards management and policy decisions as experiments or treatments. This iterative process is relatively simple and intuitive, leading to widespread uptake and application of these principles. Popularity of AM results in the process being routinely inserted into strategies or plans without full recognition of the commitment and paradigm shift in management that it represents. This case study involved evaluation of Manitoba Hydro’s Environmental Protection Program during construction of the Bipole III transmission line and its use of AM. Researching the program’s functionality spanned three construction seasons using document review, employee interviews and site visits. The program was evaluated according to what current literature identifies as elements of successful AM. Monitoring and Innovative activities provided strong examples of AM principles while other areas such as communication face challenges. The recommendations pursue a more active approach to AM and continual improvement of environmental protection performance. / February 2017

Nos últimos leilões de energia promovidos pelo Governo projetos eólicos foram protagonistas, sendo a fonte com maior número de projetos cadastrados e vencedores. Nessa perspectiva, que de fato tem fomentado o interesse, tanto por empreendedores como por agentes do setor elétrico, pelo entendimento dos fatores de risco que podem influenciar o retorno financeiro dos investidores que encontraram nesta fonte uma alternativa interessante para diversificar seu portfólio de projetos. Diante desta oportunidade, este trabalho tem como objetivo desenvolver uma metodologia para reconstrução de séries históricas de geração eólica possibilitando estudos energéticos de complementariedade entre fontes. Esta dissertação possibilitou a avaliação da complementariedade energética entre os recursos eólicos e hídricos. Por meio da análise da correlação entre séries de geração de energia eólica e hídrica, foi possível identificar o benefício energético existente na formação de um portfólio hidro-eólico. A complementariedade entre a energia eólica e hidráulica possibilita que geradores que possuam portfolio com ambas as fontes compartilhem a exposição dos riscos relacionados à sazonalidade dos ventos, beneficiando diretamente o mercado consumidor com diminuição dos custos na geração. / In recent energy auctions, held by the government wind projects were protagonists, being the source with the highest number of registered and winning projects. From this perspective, which in fact has stimulated interest, both as investors by electrical sector agents, by understanding the risk factors that may influence the financial returns to investors who have found this an interesting alternative source to diversify its project portfolio. Considering this opportunity, this work aims to develop a methodology for reconstruction historical series of wind generation enabling studies of complementarity between energy sources. This work has enabled an evaluation of complementarity between wind and hydro generation. By analyzing, the correlation between wind and hydro series was possible to identify the energetic benefit in a composition of a hydro-wind portfolio. The complementarity between wind and hydropower enables generators in the same portfolio share risks related to exposure due to seasonality of winds, directly benefiting the market with lower generations costs, driven by increased competition resulting from the participation of wind power in all segments of marketing.

L'adaptation des villes au changement climatique constitue un enjeu majeur des politiques d’aménagement. Promouvoir l'intégration des infrastructures vertes et bleues dans l'environnement urbain entant que stratégies d'adaptation implique ainsi de comprendre leurs impacts sur les bilans en eau et en énergie. Un modèle hydro microclimatique,TEB-Hydro, a préalablement été développé en tenant compte du couplage détaillé des deux bilans. Cependant, des études récentes ont mis en cause la représentation des processus hydrologiques en sous-sol urbain. Ainsi, ce travail de thèse consiste à améliorer la composante hydrologique du modèle (drainage de l’eau du sol par les réseaux, écoulements souterrains vertical et latéral). Après calage,une évaluation hydrologique est réalisée sur deux bassins versants urbains de Nantes. Dans les deux cas, le calage fait ressortir la même configuration de simulation, malgré des morphologies différentes, ce qui est encourageant pour des applications du modèle en projection climatique. L’évaluation hydrologique met en avant les paramètres clés du modèle et démontre une amélioration du processus de l’infiltration de l’eau du sol dans le réseau d’assainissement. L’évaluation hydro-énergétique du modèle démontre une représentation satisfaisante des flux de chaleur sensible et latente. Le fonctionnement du modèle vis-à-vis de l’évapotranspiration est discuté via le prisme de la végétation et de la morphologie urbaine. Une première application de TEB-Hydro en contexte de changement climatique permet d’évaluer une méthode statistique existante de désagrégation et soulève la problématique de la représentation de la dynamique pluviométrique dans ce contexte. / Adapting growing cities to climate change is a major challenge in planning policy. Promoting the integration of green and blue infrastructures in the urban environment as adaptation strategies implies understanding their impacts on both the urban hydrological and energy balance. A hydro-microclimate model,TEB-Hydro, was developed previously, taking into account detailed coupling between the two balances. However, first model evaluation studies on different urban catchments have questioned the representation of the hydrological processes in the urban subsoil. This PhD work consists of performing new developments on the models hydrological component (soil-water drainage by sewer networks, vertical and lateral subsoil flows). After calibration a hydrological evaluation is performed on two urban catchments in Nantes. In both cases, the calibration brings out the same simulation configuration, despite different catchment related properties. This is encouraging for applying the model on climate projection. The hydrological evaluation highlights the model key parameters as well as shows improvements concerning sewer soilwater infiltration processes. In addition, a hydro-energetic evaluation shows a satisfactory representation of sensible and latent heat fluxes. The model operation vis-à vis evapotranspiration processes is discussed through vegetation and urban morphology. A first application of TEB-Hydro in climate change context enables evaluating an existing statistical disaggregation method as well as raises the problematic in representing rainfall dynamics for climate projection purposes.

The Hydro Muscle is a soft linear actuator which utilizes hydraulic pressure and elastic properties of its core for actuation. The Hydro Muscle has been recruited to actuate bio-inspired robot systems using a classic set point tracking feedback control system. A more efficient method is to develop a model-based control system which uses a dynamic model of the Hydro Muscle. The dynamic behavior of the Hydro Muscle which describes the relation between the forces exerted to the resultant motion can be studied with the help of a dynamic viscoelastic model. A dynamic viscoelastic model defines the force exerted by the Hydro Muscle as a function of the hydraulic pressure, the tensile expansion of the Hydro Muscle and the rate of its tensile expansion. Multivariable linear regression is employed to generate a model to relate fluid pressure, tensile expansion, and the rate of tensile expansion to the force exerted by the Hydro Muscle. The developed model can be utilized to implement a model-based control algorithm for the force control of individual joints. This model-based control design could be extended to systems involving multiple Hydro Muscles to allow for a modular control system. The design and test of multi-fiber Hydro Muscle actuated biologically inspired ankle is considered to study control strategies for multi-fiber system. A set-point tracking control algorithm with a proportional differential controller is used to minimize the tracking error. Modular force variation with sequential recruitment of Hydro Muscle is studied.

Vegetation stabilises slopes via both mechanical reinforcement (through root anchorage) and hydrologic reinforcement (through transpiration-induced soil matric suction). However, relatively little is known about the effectiveness of different plant species in stabilising soil slopes via the two reinforcing mechanisms, and so decisions on species selection are seldom made with optimisation of slope reinforcement in mind. In this thesis, a comprehensive testing programme including laboratory, glasshouse and field experiments is designed and implemented, with the aim to quantify and investigate the transpiration-induced hydrologic reinforcement and root biomechanical properties during the early plant establishment of selected woody species, widespread under European temperate climate. Ten species native to Europe (Buxus sempervirens L.; Corylus avellana L.; Crataegus monogyna Jacq.; Cytisus scoparius (L.) Link; Euonymus europaeus L.; Ilex aquifolium L.; Ligustrum vulgare L.; Prunus spinosa L.; Salix viminalis L. and Ulex europaeus L.) were investigated in a glasshouse experiment to understand any relation of transpiration induced hydrologic reinforcement with above- and below-ground plant traits (e.g. specific leaf area; root length density). The ten species showed large differences in terms of water uptake, which translated to significant differences in matric suction and soil strength. Species with the largest water uptake increased soil strength more than ten times that in fallow soil. Specific leaf area, root length density and root:shoot ratio were best correlated with the induced hydrologic reinforcement provided by the ten tested species. These results supplied essential species information for designing the subsequent experiments. Based on the previous findings, three representative yet contrasting species (Corylus avellana, Ilex aquifolim and Ulex europaeus) were selected and planted in 1-m soil columns to investigate the effects of season (i.e. summer vs winter), plant functional type (i.e. deciduous vs evergreen) and soil depth on the magnitude and distribution of transpiration-induced matric suction and the associated soil strength gain. Evergreens could slowly induce matric suction and hence potentially stabilise soil during winter. However, there were very large differences between the tested evergreens (I. aquifolium and U. europaeus). Indeed, only U. europaeus provided matric suction and soil strength gain along the entire depth-profile because of its fast growth (above- and below-ground). A full-scale field experiment was also performed to provide ground-truth data on the extent of variation in hydrologic reinforcement among species, hence validating the glasshouse results obtained in the first two studies. The two-year field experiment yielded a similar ranking to the glasshouse experiments in terms of the species ability to rapidly develop matric suction and soil strength. In particular, the evergreen U. europaeus induced large matric suction (e.g. ≥ 70 kPa at 0.5 m depth) even during the early establishment period. Furthermore, this field research highlighted the greater (compared to other tested species) temporal effectiveness of U. europaeus, which was able to provide matric suction on the slope from early spring to late autumn. The greater ability of U. europaeus in inducing and preserving matric suction can be attributed to its large water uptake, which supports its fast growth, as well as to the notable interception loss provided by its canopy. Therefore, U. europaeus can represent a very suitable species for slope stabilisation under the temperate climate context. Root biomechanical properties, including tensile strength and Young's modulus, were investigated in the laboratory for the same ten species. The results highlighted a large variability in the tensile strength-diameter relations during the early stage establishment of plants, especially in thin roots with diameter ranging from 0.4 to 2.0 mm. The root tensile strength-diameter relationships highlighted three different trends. The common negative power relation between root tensile strength and diameter existed only for two out of the ten tested species (i.e. E. europaeus and U. europaeus). B. sempervirens, I. aquifolium and P. spinosa showed a slight increase in tensile strength with increasing root diameter. C. avellana, C. monogyna and L. vulgare consistently showed an initial increase in root tensile strength with increasing root diameter, reaching peak strength between 1.0 and 2.5 mm diameter. Beyond the peak strength, a reduction in strength was observed with increasing root dimeter. These bimodal trends might be partially explained by the differences in the development stage of root primary and secondary structures. Root moisture content can be one of the factors inducing the observed large variability in root tensile strength. Therefore, the last part of this thesis assessed the effects of root drying on the root biomechanical properties of U. europaeus. Root strength and stiffness showed an abrupt increase when root water content dropped below 0.5 g g-1. The strength increase can be explained by the reduction in root diameter and by changes in root properties induced by the root water potential drop. Moreover, root water loss and root strength gain were diameter-dependent because of the relatively larger evaporative surface per volume of thin roots.

Nos últimos leilões de energia promovidos pelo Governo projetos eólicos foram protagonistas, sendo a fonte com maior número de projetos cadastrados e vencedores. Nessa perspectiva, que de fato tem fomentado o interesse, tanto por empreendedores como por agentes do setor elétrico, pelo entendimento dos fatores de risco que podem influenciar o retorno financeiro dos investidores que encontraram nesta fonte uma alternativa interessante para diversificar seu portfólio de projetos. Diante desta oportunidade, este trabalho tem como objetivo desenvolver uma metodologia para reconstrução de séries históricas de geração eólica possibilitando estudos energéticos de complementariedade entre fontes. Esta dissertação possibilitou a avaliação da complementariedade energética entre os recursos eólicos e hídricos. Por meio da análise da correlação entre séries de geração de energia eólica e hídrica, foi possível identificar o benefício energético existente na formação de um portfólio hidro-eólico. A complementariedade entre a energia eólica e hidráulica possibilita que geradores que possuam portfolio com ambas as fontes compartilhem a exposição dos riscos relacionados à sazonalidade dos ventos, beneficiando diretamente o mercado consumidor com diminuição dos custos na geração. / In recent energy auctions, held by the government wind projects were protagonists, being the source with the highest number of registered and winning projects. From this perspective, which in fact has stimulated interest, both as investors by electrical sector agents, by understanding the risk factors that may influence the financial returns to investors who have found this an interesting alternative source to diversify its project portfolio. Considering this opportunity, this work aims to develop a methodology for reconstruction historical series of wind generation enabling studies of complementarity between energy sources. This work has enabled an evaluation of complementarity between wind and hydro generation. By analyzing, the correlation between wind and hydro series was possible to identify the energetic benefit in a composition of a hydro-wind portfolio. The complementarity between wind and hydropower enables generators in the same portfolio share risks related to exposure due to seasonality of winds, directly benefiting the market with lower generations costs, driven by increased competition resulting from the participation of wind power in all segments of marketing.

Hydro power can be defined as converting the energy of flowing water into useful mechanical power by a turbine or water wheel. A micro hydro system typically has an electrical generation capacity of less than 100 kilo watts. These systems are usually constructed to supply power to individuals or groups of individuals who are independent of the power supply grid. The scope of this project is to outline the principles of micro hydro and to document the design process of a micro hydro site. This will include the measurements, calculations, and methods performed in a feasibility study for a potential site. The desired outcome of the project is to develop a viable solution to gain energy independence at a remote site owned by the author.

<p>The heating of the solar corona has been investigated during four of decades and several mechanisms able to produce heating have been proposed. It has until now not been possible to produce quantitative estimates that would establish any of these heating mechanism as the most important in the solar corona. In order to investigate which heating mechanism is the most important, a more detailed approach is needed.</p><p>In this thesis, the heating problem is approached ”ab initio”, using well observed facts and including realistic physics in a 3D magneto-hydrodynamic simulation of a small part of the solar atmosphere. The ”engine” of the heating mechanism is the solar photospheric velocity field, that braids the magnetic field into a configuration where energy has to be dissipated. The initial magnetic field is taken from an observation of a typical magnetic active region scaled down to fit inside the computational domain. The driving velocity field is generated by an algorithm that reproduces the statistical and geometrical fingerprints of solar granulation. Using a standard model atmosphere as the thermal initial condition, the simulation goes through a short startup phase, where the initial thermal stratification is quickly forgotten, after which the simulation stabilizes in statistical equilibrium. In this state, the magnetic field is able to dissipate the same amount of energy as is estimated to be lost through radiation, which is the main energy loss mechanism in the solar corona.</p><p>The simulation produces heating that is intermittent on the smallest resolved scales and hot loops similar to those observed through narrow band filters in the ultra violet. Other observed characteristics of the heating are reproduced, as well as a coronal temperature of roughly one million K. Because of the ab initio approach, the amount of heating produced in these simulations represents a lower limit to coronal heating and the conclusion is that such heating of the corona is unavoidable.</p>