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>

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. 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. 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.

Global environmental concerns associated with conventional energy generation have led to the rapid growth of wind energy applications in electric power systems. Growing demand for electrical energy and concerns associated with limited reserves of fossil fuels are also responsible for the development and increase in wind energy utilization. Many jurisdictions around the world have set high wind penetration targets in their energy generation mix.<p> The contribution of wind farms to the overall system reliability is limited by the uncertainty in power output from the highly variable energy source. High wind penetration can lead to high risk levels in power system reliability and stability. In order to maintain the system stability, wind energy dispatch is usually restricted and energy storage is considered to smooth out the fluctuations and improve supply continuity. The research work presented in this thesis is focused on developing reliability models for evaluating the benefits associated with wind power and energy storage in electric power generating systems. An interactive method using a sequential Monte Carlo simulation technique that incorporates wind farm and energy storage operating strategies is developed and employed in this research. Different operating strategies are compared and the resulting benefits are evaluated. Important system impacts on the reliability benefits from wind power and energy storage are illustrated. Hydro facilities with energy storage capability can alleviate the impact of wind power fluctuations and also contribute to system adequacy. A simulation technique for an energy limited hydro plant and wind farm coordination is developed considering the chronological variation in the wind, water and the energy demand. The IEEE four-state model is incorporated in the developed technique to recognize the intermittent operation of hydro units. Quantitative assessment of reliability benefits from effective utilization of wind and water resources are conducted through a range of sensitivity studies. The information provided and the examples illustrated in this thesis should prove useful to power system planners and wind developers to assess the reliability benefit from utilizing wind energy and energy storage and the coordination between wind and hydro power in electric power systems.

The ruins of the La Colle Falls Hydro Dam encompass two very distinct topographies: the physical landscape of the vast Canadian Northwest, and the complex emotional terrain of the urban mythology of the city of Prince Albert, Saskatchewan. In 1912 the city embarked on the ambitious project, building a dam and shipping lock on the North Saskatchewan River to supply the city with cheap and plentiful hydroelectric power and create a navigable inland shipping route from Winnipeg to Edmonton. The people of the community believed that it was poised to become a new commercial centre of the west, a key manufacturing and industrial metropolis. Instead, the project became an enormous and ruinous financial debacle that embarrassed the residents and crippled the urban growth of the city for nearly a century. Its failure, and the consequent suffering it brought permeate local legend to this day. The solution to this negative residual memory exists in the hydro dam’s own genesis: the spiritual and functional significance of the North Saskatchewan River as a site of traditional Aboriginal healing and a crucial regional amenity. Unable to bridle the waters of the North Saskatchewan, the dam instead comprises a dramatic visual testimony to the effects of an enormous work of construction on the panoramic Saskatchewan landscape, and an ideal setting to address the interface of man, structure, and the human body in the natural world. This thesis uses the ruins of the dam as a physical armature on which to construct a spa complex, an architectural insertion that will complete the dam, and present a positive alternative ending to its story. The spa is viewed as a place of intimate physical contact and remedial personal reflection that acknowledges the dramatic landscapes surrounding it, engages the senses, and simultaneously heals the bodies of the patrons while reconciling the latent negative historical memory of the original hydro dam project.

Ce mémoire procède à une analyse des avantages et des coûts, pour l'ensemble du Québec, d'un contrat à partage de risques établi sur une période de vingt-cinq ans entre une aluminerie et Hydro-Québec qui lui octroie une quantité substantielle d'électricité à faible tarif. L'hypothèse émise est que si ce contrat n'est pas renouvelé en 2014, l'aluminerie transfère sa production hors du Québec. Alors, la province subirait des pertes associées à l'arrêt de la production, mais en contrepartie, un bloc d'énergie deviendrait disponible pour le marché extérieur de plus en plus lucratif. Le modèle est basé sur des données publiées portant sur les ententes existantes et sur les alumineries du Québec. L'intérêt de l'évaluation est accentué par le contexte du marché de l'électricité. Le coût d'opportunité de la ressource grandit pendant que la demande interne et externe pour l'énergie est toujours en croissance. D'abord, un modèle caractérise les avantages pour la société québécoise que procure l'utilisation, pour la production d'aluminium, d'un bloc d'énergie de 5 Térawattheures. Cette valeur équivaut au produit marginal de l'électricité. C'est le coût éventuel du non-renouvellement du contrat. Ensuite, il est calculé le montant qui serait obtenu si ce même bloc d'électricité était alloué à l'exportation et si les revenus étaient réinvestis au Québec par la suite. Ce sont les bénéfices reliés au non-renouvellement du contrat. Une fois actualisée, la valeur des bénéfices soustraite de celle des coûts donne l'ordre de grandeur des pertes subies par l'ensemble de la société découlant de ces ententes. Elles sont évaluées entre 3 et 6 milliards de dollars. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Contrats à partage de risques, Hydro-Québec, Électricité, Aluminerie, Valeur ajoutée, Analyse avantages/coûts, Actualisation.

The ruins of the La Colle Falls Hydro Dam encompass two very distinct topographies: the physical landscape of the vast Canadian Northwest, and the complex emotional terrain of the urban mythology of the city of Prince Albert, Saskatchewan. In 1912 the city embarked on the ambitious project, building a dam and shipping lock on the North Saskatchewan River to supply the city with cheap and plentiful hydroelectric power and create a navigable inland shipping route from Winnipeg to Edmonton. The people of the community believed that it was poised to become a new commercial centre of the west, a key manufacturing and industrial metropolis. Instead, the project became an enormous and ruinous financial debacle that embarrassed the residents and crippled the urban growth of the city for nearly a century. Its failure, and the consequent suffering it brought permeate local legend to this day. The solution to this negative residual memory exists in the hydro dam’s own genesis: the spiritual and functional significance of the North Saskatchewan River as a site of traditional Aboriginal healing and a crucial regional amenity. Unable to bridle the waters of the North Saskatchewan, the dam instead comprises a dramatic visual testimony to the effects of an enormous work of construction on the panoramic Saskatchewan landscape, and an ideal setting to address the interface of man, structure, and the human body in the natural world. This thesis uses the ruins of the dam as a physical armature on which to construct a spa complex, an architectural insertion that will complete the dam, and present a positive alternative ending to its story. The spa is viewed as a place of intimate physical contact and remedial personal reflection that acknowledges the dramatic landscapes surrounding it, engages the senses, and simultaneously heals the bodies of the patrons while reconciling the latent negative historical memory of the original hydro dam project.

Global environmental concerns associated with conventional energy generation have led to the rapid growth of wind energy applications in electric power systems. Growing demand for electrical energy and concerns associated with limited reserves of fossil fuels are also responsible for the development and increase in wind energy utilization. Many jurisdictions around the world have set high wind penetration targets in their energy generation mix.<p> The contribution of wind farms to the overall system reliability is limited by the uncertainty in power output from the highly variable energy source. High wind penetration can lead to high risk levels in power system reliability and stability. In order to maintain the system stability, wind energy dispatch is usually restricted and energy storage is considered to smooth out the fluctuations and improve supply continuity. The research work presented in this thesis is focused on developing reliability models for evaluating the benefits associated with wind power and energy storage in electric power generating systems. An interactive method using a sequential Monte Carlo simulation technique that incorporates wind farm and energy storage operating strategies is developed and employed in this research. Different operating strategies are compared and the resulting benefits are evaluated. Important system impacts on the reliability benefits from wind power and energy storage are illustrated. Hydro facilities with energy storage capability can alleviate the impact of wind power fluctuations and also contribute to system adequacy. A simulation technique for an energy limited hydro plant and wind farm coordination is developed considering the chronological variation in the wind, water and the energy demand. The IEEE four-state model is incorporated in the developed technique to recognize the intermittent operation of hydro units. Quantitative assessment of reliability benefits from effective utilization of wind and water resources are conducted through a range of sensitivity studies. The information provided and the examples illustrated in this thesis should prove useful to power system planners and wind developers to assess the reliability benefit from utilizing wind energy and energy storage and the coordination between wind and hydro power in electric power systems.