• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 5
  • 5
  • 5
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Sustainable Future for Wind Energy in Sweden

Øvereng, Aurora January 2018 (has links)
The 2040 governmental goal of 100 % renewable electricity in Sweden means that there will be a shift in electricity production and a phasing out of nuclear power. This nuclear power has to be replaced by some other source. Wind power is a viable alternative, thanks to its reliability and the abundance of wind in Sweden. However, wind power production requires a large amount of land and carries the risk of disrupting the landscape. Wind energy is therefore often difficult to develop, and when developed it is often in rural areas where it disturbs as few people as possible. This study presents an alternative to rural exploitation, it investigates whether it is possible to produce sufficient wind power to satisfy urban demand within 20 000 meters of the 20 largest cities in Sweden. Firstly, the criteria for areas where wind power can be developed were synthesised. Secondly a numerical model was used to simulate energy demand in TWh considering the future growth in demand and the phasing out of nuclear power. The demand for wind power was then translated into correlating area in km2. Finally, a GIS analysis was conducted to estimate the extent of area suitable for wind power development based on the criteria above and within a 20 000m perimeter from the 20 largest cities in Sweden. The analysis showed that only 35 % of the required area for wind power development fulfilled the criteria within the given perimeter. From the GIS analysis only 940.73 km2 was found to be suitable. From the numerical model, the results showed that for it to be sufficient, there would have to be at least 2687.1 km2 suitable land. The conclusion from this study is that in order to phase out the nuclear power, the majority of the wind power has to be located in the rural areas.
2

The development and modeling of an ethanol production biocatalytic system with cell retention

Mokomele, Thapelo 12 1900 (has links)
Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: See PDF for abstract. / AFRIKKANSE OPSOMMING: Sien PDF vir die opsomming.
3

Ensinando produção sustentável de energia elétrica por meio de jogos didáticos em sala de aula

Sato, Alino Massaiuqui January 2017 (has links)
Orientador: Prof. Dr. Nelson Studart / Dissertação (mestrado) - Universidade Federal do ABC, Mestrado Nacional Profissional em Ensino de Física - MNPEF, 2017. / Esta dissertação aborda o ensino da produção sustentável de energia elétrica por meio de jogos didáticos. Trata-se um tema de grande relevância para a formação do cidadão, contribuindo para a conscientização da necessidade de combater o aquecimento global. À medida que a população aumenta, o consumo de energia elétrica também e torna-se imperiosa a utilização de fontes primárias de energia limpa. A geração de energia elétrica renovável aproveita os recursos dos ventos, do sol, do mar e dos materiais orgânicos, convertendo-os em energia elétrica. O trabalho foi fundamentado na teoria de aprendizagem baseada em jogos discutida por Wallon, Huizinga e Chateau, apresentado na forma de uma sequência de ensino aplicada aos alunos de Física do 3º ano do Ensino Médio em uma escola pública da cidade de Cotia ¿SP. Como estratégia didática e para fixação de conteúdo, foram aplicados em sala de aula dois jogos pedagógicos: um jogo de tabuleiro tipo trilhas e um jogo de cartas super-trunfo. Os jogos e sua aplicação em sala de aula constituem o produto educacional descrito nessa dissertação. O uso dos jogos despertou o interesse e motivou os alunos para apreender o tema proposto de forma divertida e diferente das aulas tradicionais de Física. / This dissertation addresses the teaching of the sustainable production of electrical energy through didactic games. This issue is of great relevance for the formation of the citizen, contributing to the awareness of the need to combat global warming. As the population grows, so does the consumption of electricity and primary sources of clean energy become imperative. The generation of renewable electric energy takes advantage of the resources of the winds, the sun, the sea and the organic materials converting into electric energy. The work was based on the theory of game-based learning discussed by Wallon, Huizinga and Chateau, presented in the form of a teaching sequence applied to physics students of the 3rd year of a public High School in the city of Cotia -SP. As a didactic strategy for content retention, two pedagogical games were applied in the classroom: a board game and a super-trump card game. The games and their application in the classroom constitute the educational product described in this dissertation. The use of the games aroused interest and motivated the students to apprehend the proposed theme in a fun and different way from the traditional classes of Physics.
4

Description et analyse du fonctionnement énergétique des espaces bâtis. Mises en œuvre systémique du bilan carbone associé. Application à l'Éco Ferme de Vincendo et au territoire de Mayotte / Description and analysis of energy functioning of built spaces. Systemic implementation of the associated carbon footprint. Application to the Vincendo Eco Farm and the territory of Mayotte

Nidhoimi, El-Assad 19 July 2018 (has links)
Dans un contexte où les tensions liées aux ressources énergétiques fossiles sont de plus en plus vives, concevoir une nouvelle manière d'appréhender le contexte énergétique est devenu essentiel. Les moyens de production et de consommation énergétiques habituels ont montré leur limite avec l'apparition de nouveau type de pollution pour différents secteurs. Dans ce rapport de thèse, nous nous sommes essentiellement axés sur le secteur de l'électricité en proposant un outil, d'aide à la décision, pour simuler la consommation électrique ainsi que la production électrique à partir des énergies renouvelables (EnR). La simulation de la consommation électrique permet d'avoir des informations à différents échelles d'observation en s'appuyant sur une démarche systémique et typologique, qui permet de calculer le bilan carbone associé à cette consommation ainsi que son coût annuel. Par la suite, cette consommation a été analysée à l'échelle horaire afin de pouvoir là mettre en relation avec des fichiers de production pour effectuer un pilotage au niveau de la courbe de charge. Ce pilotage a pour but de lisser les pics au niveau de la courbe de charge. Les premiers résultats analytiques obtenus à l'aide des outils développés montrent qu'il est possible de réduire l'appel au réseau électrique normal à un certain niveau en fonction des dimensionnements des systèmes de production EnR et du stockage. Ainsi que de pouvoir limité les coûts d'investissement au juste nécessaire, c'est-à-dire avoir un prix le moins cher possible, grâce à une optimisation du système EnR. / In a context where the tensions linked to fossil energy resources are increasing, design a new way of understanding the energy context has become essential. The usual means of energy production and consumption have shown their limit with the appearance of new types of pollution for different sectors. In this thesis, we mainly focused on the electricity sector by proposing a tool to simulate electricity consumption and electricity production from renewable energies (RES). Simulation of electricity consumption allows having information on different observation scales based on a systemic and typological approach, according to which the associated carbon footprint to this consumption is being calculated as well as its annual cost. Subsequently, this consumption was analyzed at the hourly scale, which is to relate it to the production files in order to control the load curve. This control aims to smooth down the peaks of the load curve. The first analytical results, obtained by using the developed tools, show that it is possible to reduce the use of the normal electrical network to a certain level according to the dimensions of the RES production systems and storage.
5

Stochastic Modeling of Electricity Prices and the Impact on Balancing Power Investments / Stokastisk modellering av elpriser och effekten på investeringar i balanskraft

Ruthberg, Richard, Wogenius, Sebastian January 2016 (has links)
Introducing more intermittent renewable energy sources in the energy system makes the role of balancing power more important. Furthermore, an increased infeed from intermittent renewable energy sources also has the effect of creating lower and more volatile electricity prices. Hence, investing in balancing power is prone to high risks with respect to expected profits, which is why a good representation of electricity prices is vital in order to motivate future investments. We propose a stochastic multi-factor model to be used for simulating the long-run dynamics of electricity prices as input to investment valuation of power generation assets. In particular, the proposed model is used to assess the impact of electricity price dynamics on investment decisions with respect to balancing power generation, where a combined heat and power plant is studied in detail. Since the main goal of the framework is to create a long-term representation of electricity prices so that the distributional characteristics of electricity prices are maintained, commonly cited as seasonality, mean reversion and spikes, the model is evaluated in terms of yearly duration which describes the distribution of electricity prices over time. The core aspects of the framework are derived from the mean-reverting Pilipovic model of commodity prices, but where we extend the assumptions in a multi-factor framework by adding a functional link to the supply- and demand for power as well as outdoor temperature. On average, using the proposed model as a way to represent future prices yields a maximum 9 percent overand underprediction of duration respectively, a result far better than those obtained by simpler models such as a seasonal profile or mean estimates which do not incorporate the full characteristics of electricity prices. Using the different aspects of the model, we show that variations of electricity prices have a large impact on the investment decision with respect to balancing power. The realized value of the flexibility to produce electricity in a combined heat and power plant is calculated, which yields a valuation close to historical realized values. Compared with simpler models, this is a significant improvement. Finally, we show that by including characteristics such as non-constant volatility and spiky behavior in investment decisions, the expected value of balancing power generators, such as combined heat and power plants, increases. / I takt med att fler intermittenta förnyelsebara energikällor tillför el i dagens energisystem, blir också balanskraftens roll i dessa system allt viktigare. Vidare så har en ökning av andelen intermittenta förnyelsebara energikällor även effekten att de bidrar till lägre men också mer volatila elpriser. Därmed är även investeringar i balanskraft kopplade till stora risker med avseende på förväntade vinster, vilket gör att en god representation av elpriser är central vid investeringsbeslut. Vi föreslår en stokastisk flerfaktormodell för att simulera den långsiktiga dynamiken i elpriser som bas för värdering av generatortillgångar. Mer specifikt används modellen till att utvärdera effekten av elprisers dynamik på investeringsbeslut med avseende på balanskraft, där ett kraftvärmeverk studeras i detalj. Eftersom huvudmålet med ramverket är att skapa en långsiktig representation av elpriser så att deras fördelningsmässiga karakteristika bevaras, vilket i litteraturen citeras som regression mot medelvärde, säsongsvariationer, hög volatilitet och spikar, så utvärderas modellen i termer av årlig prisvaraktighet som beskriver fördelningen av elpriser över tid. Kärnan i ramverket utgår från Pilipovic-modellen av råvarupriser, men där vi utvecklar antaganden i ett flerfaktorramverk genom att lägga till en länkfunktion till tillgång- och efterfrågan på el samt utomhustemperatur. Vid användande av modellen som ett sätt att representera framtida priser, fås en maximal över- och underprediktion av prisvaraktighet om 9 procent, ett resultat som är bättre än det som ges av enklare modellering såsom säsongsprofiler eller enkla medelvärdesestimat som inte tar hänsyn till elprisernas fulla karakteristika. Till sist visar vi med modellens olika komponenter att variationer i elpriser, och därmed antaganden som används i långsiktig modellering, har stor betydelse med avseende på investeringsbeslut i balanskraft. Det realiserade värdet av flexibiliteten att producera el för ett kraftvärmeverk beräknas, vilket ger en värdering nära faktiska realiserade värden baserade på historiska priser och som enklare modeller inte kan konkurrera med. Slutligen visar detta också att inkluderandet av icke-konstant volatilitet och spikkarakteristika i investeringsbeslut ger ett högre förväntat värde av tillgångar som kan producera balanskraft, såsom kraftvärmeverk.

Page generated in 0.1225 seconds