• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 82
  • 39
  • 10
  • 8
  • 6
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 172
  • 172
  • 58
  • 29
  • 28
  • 16
  • 16
  • 16
  • 15
  • 15
  • 15
  • 14
  • 14
  • 14
  • 13
  • 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.
21

Overall CO2 efficiency assessment for a low carbon energy system

Zheng, Zhanghua January 2014 (has links)
Decarbonization of the power sector is of great importance for the transition to a sustainable and low-carbon world economy. Estimating carbon efficiency in the power sector is a key step to grasp the impact of demand-side usage changes and evaluate their potential environmental benefits. In order to quantify the environmental benefits of demand-side usage changes, Average Emission Factor (AEF) and Marginal Emission Factor (MEF) have been proposed in the electrical power sector. AEF is defined as the ratio of the total CO2 emitted in the system to the total electricity generated. It is an effective factor for reporting on CO2 emissions at system level and on an average basis, but the current AEF model lacks clarity on the factors actually affecting the estimation. MEF is defined as the incremental change in carbon emissions as a result of a change in demand. However, previous MEF assessments did not consider key technical limitations, such as ramp-rate constraint for generators and network constraints, and carbon trading mechanisms. This thesis improves the estimation for both AEF and MEF and key achievements can be summarized as: 1). A novel model of estimating AEF, with its application to GB, US and China’s electricity system. 2). Improvement on conventional MEF model by considering ramp-rate constraint in dispatch order. 3). Sensitivity studies on MEF using current fuel prices and future fuel prices. 4). A new model of estimating MEF considering both the utilization level of generators and the carbon costs when determining the dispatch order. 5). The effect of power network on MEF estimation, with a comparison of congested scenarios and non-congested scenario.
22

Grön IT -Vad krävs av Scania InfoMate för att bli en Grön IT leverantör? / Green IT -What does it take for Scania InfoMate to become a Green IT solution provider?

Kristiansson, Emelie January 2009 (has links)
This master thesis was performed at InfoMate which is the IT organisation within Scania CVAB. Scania is a global company with operations in Europe, Latin America, Asia, Africa andAustralia. Scania is the world’s third largest manufacturer of heavy trucks and heavy bussegment. InfoMate’s mission is to provide the global business activities with IT solutions thatsupport the core activity. Scania InfoMate is represented in Sweden, France, Holland andLatin America with totally 650 employees.The objective for this thesis is to evaluate the environmental work within InfoMate andpropose improvements. The thesis explains how a green approach of IT can increaseprofitability of the company. Green IT doesn’t only consist of taking responsibility of theenvironmental change; it is as much about decreased cost, increased efficiency and anenhanced image.Green IT is much about reducing energy consumption. The thesis makes it clear that it alreadyexist an ongoing work with this within InfoMate but with the economical approach as thedriving force. Mainly is it the increment in the number of virtualized servers that hasdecreased the energy consumption per server. However, there is a great potential to dosubstantial improvements. An important part of the environmental work is to engage theemployees by education, as well as connect the environmental policy of Scania to InfoMate,and make it visible to one and all within the IT organisation. Last but not the least, it isimportant to do measurements and follow up how the environmental work proceeds and whatit results in, in a motivation purpose. It is also important to visualise what needs to focus on,to make the work more uniform and goal-oriented. / Uppsatsnivå: D
23

ANÁLISE DO TRANSPORTE INTERMODAL DA SOJA DESTINADA À EXPORTAÇÃO, CONSIDERANDO OS CUSTOS DE EMISSÕES DE CO2 NO BRASIL

Zaluski, Patrícia Regina da Silva 08 February 2018 (has links)
Submitted by admin tede (tede@pucgoias.edu.br) on 2018-08-23T14:48:51Z No. of bitstreams: 1 Patrícia Regina da Silva Zaluski.pdf: 1284798 bytes, checksum: 2ae114d5a9bdb1ae65916591abc56a0d (MD5) / Made available in DSpace on 2018-08-23T14:48:51Z (GMT). No. of bitstreams: 1 Patrícia Regina da Silva Zaluski.pdf: 1284798 bytes, checksum: 2ae114d5a9bdb1ae65916591abc56a0d (MD5) Previous issue date: 2018-02-08 / The traditional logistics seeks reduction of costs with greater efficiency in the service, attending to the dimensions of performance speed, flexibility and cost. When the sustainability theme is inserted into logistics management, there are emerging analyzes of atmospheric CO2 emissions and their cost impacts on transportation modes. In this context, the main objective of this research was to analyze the efficiency of the modal arrangements of the outflow of soybeans produced in Brazil for export, and CO2 emissions for an intermodal transport network of soybeans exported in Brazil. The emission estimate was calculated based on the adapted formula of ANTT (2014a; 2014b) reports, which followed methodologies presented by the IPCC and MCTI (2010). The method consists in the estimation of emissions by consumption factor of diesel oil, considering the tonnage transported in TKU. The results obtained show the best export routes for soybeans, considering freight costs and CO2 emissions. The Brazilian logistics infrastructure needs investments in the construction of new terminals, in order to favor the use of intermodality. The road mode still has lower logistics costs and holds greater supply and availability in the market, in contrast, intermodality has the best performance in reducing emissions. / A logística tradicional busca redução de custos com maior eficiência no serviço, atendendo às dimensões de desempenho velocidade, flexibilidade e custo. Quando o tema sustentabilidade é inserido à gestão logística, emergem análises sobre as emissões atmosféricas de CO2 e seus impactos em termos de custos nos modais de transporte. Nesse contexto, o objetivo central desta pesquisa foi analisar a eficiência dos arranjos modais de escoamento da soja produzida no Brasil destinada à exportação, e de emissões de CO2 para uma rede de transporte intermodal da soja de exportação no Brasil. A estimativa de emissões foi calculada com base na fórmula adaptada de relatórios da ANTT (2014a; 2014b), que seguiu metodologias apresentadas pelo IPCC e MCTI (2010). O método consiste na estimação de emissões por fator de consumo de óleo diesel, considerando a tonelagem transportada em TKU. Os resultados obtidos apresentam as melhores rotas de escoamento da soja de exportação, considerando os custos de frete e emissões de CO2. A infraestrutura logística brasileira carece de investimentos na construção de novos terminais, de modo a favorecer o uso da intermodalidade. O modo rodoviário ainda possui menores custos logísticos e detém maior oferta e disponibilidade no mercado, em contrapartida, a intermodalidade possui os melhores desempenhos em redução de emissões.
24

Emissions for Sale : The Ethics of Emissions Trading

Paulsson, Fredrik January 2003 (has links)
<p>International regulations target a global reduction of carbon dioxide (CO2) emissions through the allocation of national reduction targets and the definition of mechanisms to achieve these targets. One of these mechanisms is international emissions trading, these trading programs have been the targets of widespread criticism since they were introduced into the policy-making arena. The point of departure in this study has been that the trading raises questions about morality, since it implies signals, which legitimates pollution. The main purpose with this study has been to find out if emissions trading systems can be morally justified with the method of wide reflective equilibrium. From the study it was found that the moral intuition; it is wrong to pollute the environment, and perform activities, which legitimates pollution, finds support from the different theories within environmental ethics and Kantian ethics. But, it was also found that there are a number of background theories, such as neo-classical economic thinking, liberalism, and utilitarianism, that supports the notion of emissions trading. The paper argues that even though the concept of CO2-emissions trading raises moral questions it can be morally defended on the basis of rationality. When the theory about specification is applied to the concept of emissions trading it is possible to reach a situation were a wide reflective equilibrium is achieved.</p>
25

Desiccant Cooling Analysis : <em>Simulation software, energy, cost and environmentalanalysis of desiccant cooling system</em>

Artieda Urrutia, Juan January 2010 (has links)
<p>Desiccant cooling is a technology that, based on a open psychrometric cycle, is able to provide cooling using heat as the main energy carrier. This technology uses a considerably smaller amount of electricity than refrigerators based on the vapor-compression cycle, which is an electricity driven cycle. Electricity is often more expensive than other types of energy and has CO<sub>2</sub> emissions associated with its generation , so desiccant cooling has the potential of achieving both economic and environmental benefits.</p><p>In addition to this, the heat the desiccant cooling cycle needs to work can be supplied at relative low temperatures, so it can use heat coming from the district heating grid, from a solar collector or even waste heat coming from industries.</p><p>The system which will be studied in this report is a desiccant cooling system based on the model designed by the company Munters AB. The systems relies on several components: a desiccant rotor, a rotary heat exchanger two evaporative humidifiers and two heating coils. It is a flexible system that is able to provide cooling in summer and heat during winter.</p><p>This study performs a deep economic and environmental analysis of the desiccant cooling systems, comparing it with traditional vapor compression based systems:</p><p>In order to achieve this objective a user-friendly software was created, called the DCSS – Desiccant Cooling Simulation Software – that simulates the operation of the system during a year and performs automatically all the necessary calculations.</p><p>This study demonstrates that economic savings up to 54% percent can be achieved in the running costs of desiccant cooling systems when compared to traditional compressor cooling systems, and  reductions up to39% in the CO<sub>2</sub> emissions. It also demonstrates that desiccant cooling is more appropriate in dry climate zones with low latent heat generation gains.</p><p>In addition to that, the DSCC software created will help further studies about the physical, economic and environmental feasibility of installing desiccant cooling systems in different locations.</p>
26

Swedish industrial and energy supply measures in a European system perspective

Trygg, Louise January 2006 (has links)
A common electricity market in Europe will in all probability lead to a levelling out of the electricity price, which implies that Swedish consumers will face higher electricity prices with a European structure. This new market situation will force industry and energy suppliers to take new essential measures as actors in a deregulated European electricity market. In this thesis it is shown how over 30 Swedish small and medium-sized industries can reduce their use of electricity by about 50%. When scaling up the result to include all Swedish industry, the measures will lead to a significant reduction in global CO2 emissions, and a situation where Sweden will have a net export of electricity. Changing industrial energy use towards increased use of district heating will consequently affect the local energy suppliers. As a local energy supplier invests in CHP and co-operates on heat with an industry that has altered its energy use, the system cost will be halved. Considering higher European electricity prices, the benefits will be even higher with possibilities to reduce global emission with over 350%. In Sweden where district heating is very well established, heat driven absorption technology is especially favourable since it will lead to cost effective electricity production and increased utilization time for a CHP plant. Vapour compression chillers have been compared with heat driven absorption cooling for a local energy utility with a district cooling network and for industries in a Swedish municipality with CHP. The results show that the higher the share of absorption technology is, in comparison to compression chillers, the lower the production cost will be for producing cooling. This thesis illustrates measures for Swedish industry and energy suppliers in a fully deregulated European electricity market that will shift the energy systems in the direction of cost-effectiveness and resource effectiveness. The thesis also shows that the benefits of the measures will increase even more when accounting with electricity prices with a higher European structures. To methodically change the use of electricity would be an economical way to increase the competitiveness of Swedish plant in relation to other European plants. Taking advantage of these particularly Swedish conditions will contribute to the creation of lean resource systems, and as a result help the whole EU region to meet its commitment under the Kyoto Protocol. Altering industrial energy use towards less electricity and energy dependence will be a competitive alternative to new electricity production and help secure energy supply in the European Union.
27

System studies of forest-based biomass gasification

Wetterlund, Elisabeth January 2012 (has links)
Bioenergy will play an important role in reaching the EU targets for renewable energy. Sweden, with abundant forest resources and a well-established forest industry, has a key position regarding modern biomass use. Biomass gasification (BMG) offers several advantages compared to biomass combustion-based processes, the most prominent being the possibility for downstream conversion to motor fuels (biofuels), and the potential for higher electrical efficiency if used for electricity generation in a biomass integrated gasification combined cycle (BIGCC). BMG-based processes in general have a considerable surplus of heat, which facilitates integration with district heating or industrial processes. In this thesis integration of large-scale BMG, for biofuel or electricity production, with other parts of the energy system is analysed. Focus is on forest-based biomass, with the analysis including techno-economic aspects as well as considerations regarding effects on global fossil CO2 emissions. The analysis has been done using two approaches – bottom-up with detailed case studies of BMG integrated with local systems, and top-down with BMG studied on a European scale. The results show that BMG-based biofuel or electricity production can constitute economically interesting alternatives for integration with district heating or pulp and paper production. However, due to uncertainties concerning future energy market conditions and due to the large capital commitment of investment in BMG technology, forceful economic support policies will be needed if BMG is a desired route for the future energy system, unless oil and electricity prices are high enough to provide sufficient incentives for BMG-based biofuel or electricity production. While BMG-based biofuel production could make integration with either district heating or pulp and paper production economically attractive, BIGCC shows considerably more promise if integrated with pulp and paper production than with district heating. Bioenergy use is often considered CO2-neutral, because uptake in growing plants is assumed to fully balance the CO2 released when the biomass is combusted. As one of the alternatives in this thesis, biomass is viewed as limited. This means that increased use of bioenergy in one part of the energy system limits the amount of biomass available for other applications, thus increasing the CO2 emissions for those applications. The results show that when such marginal effects of increased biomass use are acknowledged, the CO2 mitigation potential for BMG-based biofuel production becomes highly uncertain. In fact, most of the BMG-based biofuel cases studied in this thesis would lead to an increase rather than the desired decrease of global CO2 emissions, when considering biomass as limited. / Bioenergi spelar en viktig roll för att nå EU:s mål för förnybar energi. Sverige har med sina goda skogstillgångar och sin väletablerade skogsindustri en nyckelposition vad gäller modern bioenergianvändning. Förgasning av biomassa har flera fördelar jämfört med förbränningsbaserade processer - i synnerhet möjligheten att konvertera lågvärdiga råvaror till exempelvis fordonsdrivmedel. Används gasen istället för elproduktion kan en högre verkningsgrad nås om gasen används i en kombicykel, jämfört med i en konventionell ångturbincykel. De förgasningsbaserade processerna har i allmänhet ett betydande överskott av värme, vilket möjliggör integrering med fjärrvärmesystem eller industriella processer. I denna avhandling analyseras integrering av storskalig biomassaförgasning för drivmedelseller elproduktion, med andra delar av energisystemet. Skogsbaserad biomassa är i fokus och analysen behandlar såväl teknoekonomiska aspekter, som effekter på globala fossila CO2-utsläpp. Forskningen har gjorts på två olika systemnivåer - dels i form av detaljerade fallstudier av biomassaförgasning integrerat med lokala svenska system, dels i form av systemstudier på europeisk nivå. Resultaten visar att förgasningsbaserad biodrivmedels- eller elproduktion kan komma att utgöra ekonomiskt intressanta alternativ för integrering med fjärrvärme eller massa- och papperstillverkning. På grund av osäkerheter i fråga om framtida energimarknadsförhållanden och på grund av de höga kapitalkostnaderna som investering i förgasningsanläggningar innebär, kommer kraftfulla ekonomiska styrmedel krävas om biomassaförgasning är en önskad utvecklingsväg för framtidens energisystem, såvida inte olje- och elpriserna är höga nog att i sig skapa tillräckliga incitament. Medan förgasningsbaserad drivmedelsproduktion kan vara ekonomiskt attraktivt att integrera med såväl fjärrvärme som med massa- och papperstillverkning, framstår förgasningsbaserad elproduktion som betydligt mer lovande vid integrering med massa- och papperstillverkning. Användning av bioenergi anses ofta vara CO2-neutralt, eftersom upptaget av CO2 i växande biomassa antas balansera den CO2 som frigörs när biomassan förbränns. Som ett av alternativen i denna avhandling ses biomassa som begränsad, vilket innebär att ökad användning av bioenergi i en del av energisystemet begränsar den tillgängliga mängden biomassa för andra användare, vilket leder till ökade CO2-utsläpp för dessa. Resultaten visar att när hänsyn tas till denna typ av marginella effekter av ökad biomassaanvändning, blir potentialen för minskade globala CO2-utsläpp med hjälp av förgasningsbaserade tillämpningar mycket osäker. I själva verket skulle de flesta av de förgasningsbaserade drivmedel som studerats i denna avhandling leda till en utsläppsökning, snarare än den önskade minskningen.
28

Possibilities and consequences of deregulation of the European electricity market for connection of heat sparse areas to district heating systems

Amiri, Shahnaz, Moshfegh, Bahram January 2010 (has links)
The objective of the study is to analyse the conditions for connection of residential buildings in heat sparse areas to district heating systems in order to increase electricity production in municipal combined heat and power plants. The European electricity market has been assumed to be fully deregulated. The relation between connection of heat sparse areas, increased electricity and heat production as well as electricity prices, fuel prices and emissions rights is investigated. The results of the study show that there is potential to expand the district heating market to areas with lower heat concentrations in the cities of Gavle, Sandviken and Borlange in Sweden, with both economic and environmental benefits. The expansion provides a substantial heat demand of approximately 181 GWh/year, which results in an electricity power production of approximately 43 GWh/year. Since the detached and stand-alone houses in the studied heat sparse areas have been heated either by oil boiler or by direct electricity, connection to district heating also provides a substantial reduction in emissions of CO2. The largest reductions in CO2 emissions are found to be 211 ktonnes/year assuming coal-fired condensing power as marginal electricity production. Connection of heat sparse areas to district heating decrease the system costs and provide a profitability by approximately 22 million EURO/year for the studied municipalities if the price of electricity is at a European level, i.e. 110 EURO/MWh. Sensitivity analysis shows, among other things, that a strong relation exists between the price of electricity and the profitability of connecting heat sparse areas to district heating systems. / Original Publication:Shahnaz Amiri and Bahram Moshfegh, Possibilities and consequences of deregulation of the European electricity market for connection of heat sparse areas to district heating systems, 2010, Applied Energy, (87), 7, 2401-2410.http://dx.doi.org/10.1016/j.apenergy.2010.02.002Copyright: Elsevier Science B.V., Amsterdam.http://www.elsevier.com/
29

Emissions for Sale : The Ethics of Emissions Trading

Paulsson, Fredrik January 2003 (has links)
International regulations target a global reduction of carbon dioxide (CO2) emissions through the allocation of national reduction targets and the definition of mechanisms to achieve these targets. One of these mechanisms is international emissions trading, these trading programs have been the targets of widespread criticism since they were introduced into the policy-making arena. The point of departure in this study has been that the trading raises questions about morality, since it implies signals, which legitimates pollution. The main purpose with this study has been to find out if emissions trading systems can be morally justified with the method of wide reflective equilibrium. From the study it was found that the moral intuition; it is wrong to pollute the environment, and perform activities, which legitimates pollution, finds support from the different theories within environmental ethics and Kantian ethics. But, it was also found that there are a number of background theories, such as neo-classical economic thinking, liberalism, and utilitarianism, that supports the notion of emissions trading. The paper argues that even though the concept of CO2-emissions trading raises moral questions it can be morally defended on the basis of rationality. When the theory about specification is applied to the concept of emissions trading it is possible to reach a situation were a wide reflective equilibrium is achieved.
30

Desiccant Cooling Analysis : Simulation software, energy, cost and environmentalanalysis of desiccant cooling system

Artieda Urrutia, Juan January 2010 (has links)
Desiccant cooling is a technology that, based on a open psychrometric cycle, is able to provide cooling using heat as the main energy carrier. This technology uses a considerably smaller amount of electricity than refrigerators based on the vapor-compression cycle, which is an electricity driven cycle. Electricity is often more expensive than other types of energy and has CO2 emissions associated with its generation , so desiccant cooling has the potential of achieving both economic and environmental benefits. In addition to this, the heat the desiccant cooling cycle needs to work can be supplied at relative low temperatures, so it can use heat coming from the district heating grid, from a solar collector or even waste heat coming from industries. The system which will be studied in this report is a desiccant cooling system based on the model designed by the company Munters AB. The systems relies on several components: a desiccant rotor, a rotary heat exchanger two evaporative humidifiers and two heating coils. It is a flexible system that is able to provide cooling in summer and heat during winter. This study performs a deep economic and environmental analysis of the desiccant cooling systems, comparing it with traditional vapor compression based systems: In order to achieve this objective a user-friendly software was created, called the DCSS – Desiccant Cooling Simulation Software – that simulates the operation of the system during a year and performs automatically all the necessary calculations. This study demonstrates that economic savings up to 54% percent can be achieved in the running costs of desiccant cooling systems when compared to traditional compressor cooling systems, and  reductions up to39% in the CO2 emissions. It also demonstrates that desiccant cooling is more appropriate in dry climate zones with low latent heat generation gains. In addition to that, the DSCC software created will help further studies about the physical, economic and environmental feasibility of installing desiccant cooling systems in different locations.

Page generated in 0.09 seconds