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Energy is an essential factor regarding the economic development and for providing a high standard of living to the population of any country. Because energy is produced mainly using classic fuels (coal, oil and gas) for a few decades there are signals regarding their exhaustion. Therefore, mankind should concern more about finding viable alternatives to replace the classical fuels. This way the use of nuclear fuels appeared, then the force of the wind, of the tides and of the photovoltaic cells. However, there are still enough energy resources for further growth of the global energy production. The great consumers are both the major energy producers, only their hierarchy has changed and changes over time. The paper presents all these countries, and also Romania, including its specific developments in recent years.

[Paper in French] The European public policy in favor of the biodiesel consumption is highly debated. Available estimates of the induced land use changes conclude that this policy is inefficient to reduce emissions of GreenHouse Gas. We show that the crop yield evolutions in these estimates are significantly lower than the observed and expected evolutions. This difference is directly related to biased calibration choice of behavioral parameters. We show using the GTAP-BIO framework that a consistent calibration of these parameters leads to a strong reduction (by around 80% in the long run) of the land use changes and induced emissions.

This work focuses on the refinement of sea-states spectral characterisation in the frame of the development of wave energy converters (WECs). Until now, this characterisation has been limited to the consideration of basic global parameters such as the significant wave height and mean wave period. The present work namely underlines - thanks to simplified numerical models - that such a description is not sufficient to account for the performance of WECs, for they still exhibit a large variability in terms of mean production while wave energy and period are fixed. It is therefore needed to refine this description by introducing new wave characteristics, such as the wave groupiness, which is itself related to the sea-state's spectral bandwidth. The classical - spectral - approaches, allowing a statistical analysis of wave groups along with other works in the literature, permit to draw a set of relevant spectral parameters. The sensitivity of simplified offshore WEC models (linear in the frequency domain) to these parameters is then observed. The question of deterministic mean power estimation - namely in the case of non-linear models - is also raised, for it is also related somehow to the bandwidth of the wave field. A sea-state is actually made of a superimposition of various wave systems (as swells and wind-sea). It is then possible to refine even more its description, namely through the multi-system approach. The latter enables indeed to track in time and space the wave systems independently of each other. An algorithm for the automatic spatiotemporal analysis is proposed and illustrated to this end. Lastly, the influence of such description refinements (wave groupiness and multi-system approach) is observed at several locations (Portugal, North Sea, California) by considering various WEC models (linear axi-symmetric heaving devices, 3D SEAREV with non-linear hydrodynamics): in all cases, it is shown that both extended descriptions allow for a better characterisation of the mean WEC performance at both short and long term. Ces travaux portent sur la caractérisation spectrale des états de mer dans le cadre du développement de systèmes récupérateurs de l'énergie des vagues (SREVs). Jusqu'alors, cette caractérisation s'est limitée à des paramètres globaux basiques tels que la hauteur significative et la période moyenne des vagues. Les présents travaux soulignent notamment, à l'aide de modèles simplifiés, que cette description est insuffisante car un SREV montre encore une grande variabilité en termes de production moyenne, ces deux paramètres étant fixés par ailleurs. On s'intéresse donc à raffiner cette description en considérant des caractéristiques de vagues nouvelles, comme le groupement de vagues, lui-même lié à la largeur de bande de l'état de mer. Les approches classiques - spectrales - sur l'étude descriptive des groupes de vagues et la littérature permettent de dégager un certain nombre de paramètres spectraux. On observe ensuite la sensibilité de modèles de SREVs offshore simplifiés (modèles fréquentiels linéaires) à ces paramètres de largeur globale. La question de l'estimation déterministe de performance moyenne (dans le cas de convertisseurs non-linéaires) est également abordée, étant elle-même liée à cette caractéristique. Un état de mer étant constitué de plusieurs systèmes de vagues (houles, mer de vent), il est encore possible de raffiner sa description grâce à une approche multisystème. Celle-ci permet en outre de suivre ces systèmes indépendamment dans le temps et l'espace. Un algorithme d'analyse spatio-temporelle est proposé et illustré à cet égard. Enfin, l'influence de ces raffinements est observée en différents sites (Portugal, Mer du Nord, Californie) sur des cas de SREVs divers (systèmes axi-symétriques linéaires, SEAREV 3D d'hydrodynamique non-linéaire), et montre que dans tous les cas, le raffinement apporté permet de mieux caractériser la production à court et long terme de ces dispositifs.

Climate change will affect agricultural production conditions, which will translate in impacts on yield and cost of production for Quebec farmers. This would likely affect the relative competitive position of Quebec in North America. Using the Delphi technique and partial budgets, climate change scenarios for the 2050 period were elaborated and their impact on relative competitiveness assessed for Quebec and its competitors in North America. Results indicate that Quebec competitive position would improve due to more favorable conditions for corn and apple production and due to worsen conditions for the competitors in maple syrup production.

info:eu-repo/semantics/published

The factsheets describe 13 electricity supply alternatives that could contribute to the Swiss electricity mix in 2035: (1) three hydropower types, including large dams, large run-of-river, and small hydropower; (2) five new renewable technologies—solar cells (photovoltaics), wind, deep geothermal, woody biomass, and biogas; (3) nuclear power; (4) waste incineration and large natural gas power; (5) net electricity import from abroad (net on the annual basis); and (6) electricity savings and efficiency improvements to reduce the electricity demand. Each technology, its current status, resource potential, and environmental, health, and economic impacts were described qualitatively and quantitatively. The impacts included climate change (CO2equiv); local air pollution (PM10equiv; SOx and NOx); water, landscape, and land use (m2 of land use); flora and fauna; accidental impacts, resource use, and waste (kWh of nonrenewable energy used for 1 kWh of electricity); electricity costs (rappen (Rp.) per kWh); and electricity supply reliability. The impacts were assessed using data from literature, prioritizing the Swiss-specific data as much as possible and including qualitative explanations for non-experts. The factsheets are accompanied by a glossary and a supplementary overview table that applied a five-color indicator system to reflect the severity of impacts across technologies. The factsheets were developed for an informed citizen panel study in July 2017 in Switzerland, described in the following publication: Volken, S.; Xexakis, G.; Trutnevyte, E. Perspectives of Informed Citizen Panel on Low-Carbon Electricity Portfolios in Switzerland and Longer-Term Evaluation of Informational Materials. Environmental Science & Technology 2018 52 (20), 11478-11489, DOI: 10.1021/acs.est.8b01265

Renewable and available in abundance, incident solar radiation is an ideal candidate for energy production. The development of nanostructured coatings for the improve- ment of technologies that convert solar energy into heat and electricity opens interesting new perspectives for the future. This PhD thesis presents an approach based on iterative cycles for the development and optimisation of such materials with a view to industrial scale production. Two ap- plications are investigated : chromium-free black selective coatings for durable thermal solar absorbers and orange coloured interferential filters for photovoltaic collectors with a view to their architectural integration. The first part of this work describes in detail the different production stages of the black selective coating from the preparation of the solutions to the manufacturing of a prototype. According to our study, the optimal coating for stainless steel tubes with a length of two meters is composed of a superposition of thin layers of Cu-Co-Mn-O//Cu- Co-Mn-Si-O//Si-O applied through sol-gel technology and annealed by an innovative induction heating process for which a patent request has been filed. The nanocomposite coating has the advantage of combining the optical properties αsol = 0.93 and εth = 0.12 with durability properties that make it eligible for possible industrialisation. The second part of the thesis describes the production of orange coloured interferen- tial filters applied on photovoltaic collectors through magnetron sputtering, a process for which another patent application has been filed. The obtained samples meet the expectations of the market with regard to such a product with a relative performance reduction of 10 to 15% in comparison with an identical collector without a filter. An in- dustrial prototype of 1190 mm x 412 mm has been produced and is being characterised at the moment these lines are written.

Nowadays most of the decisions in the field of energy supply lead to an increased use of renewable energy resources. Such decisions imply several consequences for instance in electrical power generation. Indeed, replacing conventional energy sources by more stochastic ones has many impacts on the energy ressources managment. Guaranteeing an uninterrupted power flow to the consumer tends to be harder due to sudden changes of the power balance. A response can be found in adding several storage units within the power grid. As a matter of fact, energy storage systems have received a growing interest in the last few years. Consequently, the use of energy storage systems involves and requires fast energy transfers such as during the charge of a battery. This latter issue is the key point of the present work whose focus will be set on intermittent energy sources, which are thightly linked with the use of energy storage devices. First of all, several tools will be developed in order to characterize the energy transfer between two energy sources. These ones will highlight efficiency of powering several kind of loads. In order to solve the issues related to conventional power supplies, the focus will be set on systems made of several types of energy sources — or hybrid systems. The degrees of freedom of such solutions will be underlined and a classification of hybrid systems will be proposed. In order to illustrate the use of hybrid power supplies, an example will be studied and its sizing will be emphasized. Within that specific case, a fast energy transfer will be investigated. Being given the high level of sollicitation of energy storage units, this energy transfer turns out to be the key point of the development. In order to generalize the comments on the fast energy transfer, the scope will be set on the power supply of intermittent loads. Several solutions for the power supply of such loads will be commented. A new approach with embedded storage will be proposed for powering highly intermittent loads at low frequency. This system will be investigated and modelled during the last part of this work. An experimental validation of a two-stage power supply with embedded storage will be set up. This latter will interface a low power source with a high power load. Although this connexion seems to be impossible, the experimental set-up will demonstrate that the two-stage power supply allows interfacing such systems. Finally, a power amplification ratio will be introduced, which illustrates the capability of the system to generate a much higher power than its power supply is able to provide.

The detailed analysis of energy consumption requires a global approach to behaviour and individual action registers. This makes it possible to investigate the question between the different spheres of activity of people, from housing to habitat and from habitat to travel. This thesis aims to analyze, through the creation of a lifestyle variable, to what extent these explain the coherence between practices and values of individuals, and whether they allow a better approach to energy consumption between the two sectors of housing and mobility. Our questioning led to the construction of a typology of respondents based on the activities carried out and their values. Our methodology is based on an ad-hoc survey carried out at the end of 2013 among 2191 French households. The questionnaires provide us with information on the activities carried out, mobility behaviour and associated energy consumption. These elements are complemented by a series of more specific questions about the values and aspirations of respondents. First, we have shown that the relevance of using the lifestyle variable for analyzing energy consumption can be observed at a disaggregated level. We found significant differences in consumption between individuals and their lifestyles through mobility patterns and modes of travel, as well as the uses and types of energy used at home. To understand these differences, we analyzed in detail how individualâ s energy consumption is spatially distributed according to their lifestyle, showing mechanisms of compensation, cumulation and independence between spaces. Each lifestyle has its own pattern of consumption, influenced by socio-demographic and spatial variables. Our second questioning concerns the relationship between lifestyle and the living environment of individuals and the consequences on energy consumption. First, through residential congruence, we show that lifestyle has a concrete influence on residential choice. Secondly, we demonstrate that residential dissonance, contrary to congruence, is conditioned by the positioning of individuals in the lifecycle as well as the technical offer of the territory. We highlight the fact that these discordances generate effects of over-consumption of energy, either in the home or during mobility, due to frustration with unrealized residential aspirations. In order to go beyond the unique use of density in analyzing the role of lifestyle and living environment on people's energy consumption, we have created territories with functional, structural and sensitive attributes. While individuals show very different consumptions according to the inhabited territory, lifestyles hardly directly related to consumptions. The same is true of housing, since we see the major role played by the type of housing, the surface area and age of buildings on energy consumption in the home rather than that of lifestyles. However, the latter influence the possession of equipment. We thus show that lifestyle, the position in the lifecycle, the technical offer of the territory conditions the choice of a living environment and generally the "consumption space" of individuals. We note that the choice of a specific living environment conditions the practice of certain activities and can influence residential aspirations already anchored in individuals. It is this recursive relationship between lifestyle and living environment that will condition the volumes and forms of energy consumed on a daily basis.