Orientador: Marcor Julio Rider Flores / Banca: Sergio Azevedo de Oliveira / Banca: Roberto Cayetano Lotero / Resumo: Esta dissertação de mestrado discute sobre o investimento em capacidade de transmissão em mercados elétricos competitivos e sua relação com o investimento em capacidade de geração. O principal problema que surge ao descentralizar os investimentos são as externalidades, devido à dependência entre os custos de oportunidade da capacidade transmissão e geração. As externalidades são distorções nomercado que se apresentam quando as decisões de um agente afetam o bem-estar de outro agente, porém não vice-versa. Em presença de externalidades não é válido afirmar que a solução descentralizada seja igual ao resultado centralizado (ótimo de Pareto). Para solucionar este problema deve-se implementar um processo descentralizado através de esquemas regulatórios. Logo, é proposto um modelo binível que procura o ótimo de Pareto e serve como referência para implementação de esquemas regulatórios que permitam avaliar os investimentos em capacidade de transmissão e geração em um mercado competitivo. O modelo binível proposto é transformado em um problema de programação linear inteira mista, usando a teoria de dualidade e técnicas de linearização. O modelo proposto foi implementado em AMPL e solucionado usando o solver comercial CPLEX. Finalmente, são apresentados os resultados obtidos para dois sistemas testes e um sistema real / Abstract: This dissertation discusses about the investing in transmission capacity in competitive electricity markets and its relation with the investing in generation capacity. Since opportunity costs of transmission and generation capacity are dependent, externalities arise when the investments decisions are decentralized. Externalities are present whenever a decision of a certain agent affects another agent's welfare but not vice versa. In presence of externalities, the decentralized outcome does not lead to a Pareto optimal solution. In order to overcome this problem, the Pareto optimal solution should be found, and set in the market by means of regulation. Moreover, a bi-level multistage model is proposed, which finds the Pareto optimal solution. This solution can be used as reference for the implementation of regulatory mechanisms that asses the investments in transmission and generation capacity. The proposed bi-level model is transformed into a mixed integer linear problem using duality theory and linearization techniques. Finally, the proposed model is implemented in AMPL and solved using CPLEX; results for several study cases are presented / Mestre

Thesis (Master of Engineering in Electrical Engineering))--Cape Peninsula University of Technology, 2018. / Industry, which forms the lifeblood of South Africa’s economy, is under threat as a result of increased electricity pricing and unstable supply. Wheeling of energy, which is a method to transport electricity generated from an Independent Power Producer (IPP) to an industrial consumer via the utility’s network, could potentially address this problem. Unlike South Africa’s electricity landscape, which is highly regulated and monopolized by Eskom, most developed countries have deregulated their electricity market, which has led to greater competition for electricity supply. This thesis, presents an evaluation of the economic viability and technical concerns arising from third party transportation of energy between an IPP and an industrial consumer. IPP’s are able to generate electricity from various renewable distributed generation (DG) sources, which are often physically removed from the load. In practice, electricity could be generated by an IPP and connected to a nearby Main Transmission Substation (MTS) in a region with high solar, wind or hydropower resources and sold to off-takers a few hundred kilometres away. Using two software simulation packages, technical and economic analysis have been conducted based on load data from two industrial sites, to determine the viability of wheeling energy between an IPP and off-taker. The viability will be evaluated based on levelized cost of electricity (LCOE); net present cost (NPC); DG technology; distance from the load; available renewable resources; impact on voltage profile, fault contribution, thermal loading of the equipment and power loss. The results from both case studies show that the impact of DG on the voltage profile is negligible. The greatest impact on voltage profile was found to be at the site closest to the load. Asynchronous and synchronous generators have a greater fault contribution than inverter-based DG. The fault contribution is proportional to the distance from the load. Overall, thermal loading of lines increased marginally, but decreased based on distances from the load. Power loss on short lines is negligible but there is a significant loss on the line between the load and DG based on the distance from the load. Electricity generated from wind power is the most viable based on LCOE and NPC. For larger wind systems, as illustrated by the second case study, grid parity has already been reached. Wheeling of wind energy has already proven to be an economically viable option. According to future cost projection, large scale solar energy will become viable by 2019. The concept of wheeling energy between an IPP and off-taker has technical and economic merit. Wheeling charges are perceived to be high, but this is not the case as wheeling tariffs consist of standard network charges. In the future, renewable energy will continue to mature based on technology and cost. Solar energy, including lithium-ion battery back-up technology, looks promising based on future cost projections. Deregulation of the electricity market holds the key to the successful implementation of energy wheeling as it will open the market up for greater competition.

The last decade has delivered rapid structural change to the Australian electricity sector. The common conceptualisation of the sector's restructuring has been narrowly based around sector-specific regulatory change and the creation of a national electricity market. This thesis argues that such a focus provides an incomplete and inaccurate explanation of the transformation. Three closely interrelated layers of policies and actions embodying the precepts of neoliberalism, and implemented by the state, have driven the sector's transformation. These policies and actions transcend 'electricity-centric' policies and encompass policies which have become systemic to the Australian public sector as well as a third layer which has transformed the prevailing industrial paradigm across all industry sectors. The drivers of the electricity sector's restructuring -- and the outcomes and beneficiaries arising -- form the core research focus of this thesis. The research task is addressed by using the analytical framework of the French theory of r??gulation. The analysis reveals that the electricity sector has been Australia's second largest contributor of privatisation proceeds, remains dominated by government ownership and has falling levels of foreign ownership. Higher relative wage levels and union membership are also evident as have been job losses and substantial real price increases for households whereas those for business have generally fallen. The purported 'reform' centrepiece, the national electricity market, was found to be increasingly uncompetitive due to its own regulatory regime and market manipulation by government-owned companies. In addition, the sector exhibits a heightened precariousness: an unprecedented financial vulnerability arising from a strong appetite for debt and derivatives and exacerbated by payments to government owners not by new investment in generation capacity; increasing tensions between the nation-state and local-state concerning the national electricity market and compromises with labour; and an exposure to political and financial risks from the sector's global integration. The clear winners from the sector's restructuring are the owners of capital and the state, particularly the local-state, although the sustainability of this situation is questionable. The analysis also generates a number of propositions about the application of r??gulation theory to sector-based research.

Abstract not available

Abstract not available

<p>Arvika Fjärrvärme AB, a district heating company from Arvika, today cover 74 % of their total energy production with biofuel wich runs a 16 MW bioler giving process water at saturated liquid state.</p><p>In recent years Vaporel AB has introduced a new tecnique that gives an external generation of steam after boilers. The concept is built on an adiabatic pressure drop of the saturated liquid in a so called Flashbox which makes a small part of the liquid to evaporate. The generated steam is lead into a turbine where electricity is in a conventional manner.</p><p>The purpose with this rapport was to do a basic study for the specific system at Arvika where it’s possible to see the potential production of electricity that follows an installation of a flasbox.</p><p>The final goal was to introduce an economic analysis of a flashox installation at given conditions.</p><p>To reach our goals we have created a model in Excel where we used the given conditions at Arvika Fjärrvärme to do our calculations. The model has been tested at three different states, of process water returning to potboiler, to be able to decide the optimal operation for the system at present.</p><p>The studies have resulted in a pressure of the processwater at 14,5 bar (at) and a pressuredrop to 9,5 bar (at) in the flashbox. The condenser pressure is set to 0,5 bar (at) what is equal to 81 ˚C. Energy to the district heating net is produced in the condenser and heat exchanger.</p><p>The result of our calculations clearly shows that to reach the highest turbine-efficiency as possible and gain the largest profit the highest process-waterflow possible should be used.</p><p>That means 70 kg/s after present conditions.</p><p>At the highest boiler efficiency the turbine will produce 694 kW. At this state the water that returns to the boiler will be at temperature 148 ˚C (14, 5 bar).</p><p>Totally during a year the production of electric energy could reach 2, 47 GWh/year. The energy used by the pumps will increase with 0,21 GWh over the year at that state.</p><p>Included all economic factors this will generate a profit of 0, 97 million (SEK)/year.</p><p>To make an installation of a flashbox system more profitable an increased generation of electricity have to be made. This could be done by an installation of new pumps to be able to run the process-water at a larger flow to increase the amount of steam made in the flashbox.</p> / <p>Arvika fjärrvärme producerar idag 74% av sitt värmeunderlag via en hetvattenpanna som drivs med biobränsle och har en maxeffekt på 16 MW.</p><p>På senare år har företaget Vaporel AB introducerat en ny teknik på marknaden som ger en extern ångproduktion efter hetvattenpannor.</p><p>Konceptet är byggt på en trycksänkning som medför att delar av det mättade vattnet förångas efter att ha letts in i en så kallad flashbox. Efter flashboxen äntrar ångan en turbin där el produceras på konventionellt vis.</p><p>Syftet med denna rapport har varit att ta fram en grundläggande studie för Arvikas specifika system där det är möjligt att se den potentiella elproduktionen vid en flashboxinstallation.</p><p>Det slutgiltiga målet med rapporten har varit att kunna presentera en lönsamhetsbedömning för en flashboxinstallation vid givna driftfall.</p><p>För att kunna uppfylla uppsatta mål har en Excelmodell konstruerats där beräkningar utförts efter givna förutsättningar, detta utefter tre olika driftfall för att kunna fastställa den mest optimala driften för systemet i dagsläget.</p><p>Studierna har lett fram till att vi har kunnat fastställa ett maximalt tryck efter pannan på 14,5 bar (at) samt en trycksänkning över flashboxen till 9,5 bar. Kondensortryck efter turbinen har satts till 0,5 bar(a) vilket ger en kondensations temperatur motsvarande 81 ˚C. Energi till att värma fjärrvärmevattnet tas via kondensorn samt en värmeväxlare.</p><p>Resultatet av våra beräkningar visar tydligt att vi för att nå en så hög turbineffekt som möjligt och därmed en större lönsamhet skall ha ett så högt processvattenflöde som tillåts, enligt dagens förutsättningar 70 l/s.</p><p>Vid högsta panneffekten kommer turbinen att ge 694 kW, enligt Excelmodellen, vid en returtemperatur till pannan satt till 148 ˚C.</p><p>Sammanlagt under året, med Arvikas varaktighetsdiagram som grund, kommer vi att kunna producera 2,47 GWh el/år varav pumparna kommer att kräva 0,21 GWh el extra per år.</p><p>Med alla ekonomiska faktorer inräknade så kommer detta att ge en vinstkalkyl på 0,97 miljoner /år.</p><p>För att kunna göra dessa installationer lönsamma krävs att vi ökar elproduktionen och därmed den årliga vinsten, detta skulle kunna göras i och med installation av nya pumpar för att uppnå ett större flöde i pannkretsen.</p><p>Vidare bör en studie göras för att bedöma lönsamheten gällande en ombyggnad av rökgaskondenseringen för att kunna klara en större effekt och därmed kunna använda högre returtemperaturer till biopannan. Detta skulle generera ett högre genomsnittligt flöde över året.</p>

University of Macau / Faculty of Science and Technology / Department of Electrical and Computer Engineering

Arvika Fjärrvärme AB, a district heating company from Arvika, today cover 74 % of their total energy production with biofuel wich runs a 16 MW bioler giving process water at saturated liquid state. In recent years Vaporel AB has introduced a new tecnique that gives an external generation of steam after boilers. The concept is built on an adiabatic pressure drop of the saturated liquid in a so called Flashbox which makes a small part of the liquid to evaporate. The generated steam is lead into a turbine where electricity is in a conventional manner. The purpose with this rapport was to do a basic study for the specific system at Arvika where it’s possible to see the potential production of electricity that follows an installation of a flasbox. The final goal was to introduce an economic analysis of a flashox installation at given conditions. To reach our goals we have created a model in Excel where we used the given conditions at Arvika Fjärrvärme to do our calculations. The model has been tested at three different states, of process water returning to potboiler, to be able to decide the optimal operation for the system at present. The studies have resulted in a pressure of the processwater at 14,5 bar (at) and a pressuredrop to 9,5 bar (at) in the flashbox. The condenser pressure is set to 0,5 bar (at) what is equal to 81 ˚C. Energy to the district heating net is produced in the condenser and heat exchanger. The result of our calculations clearly shows that to reach the highest turbine-efficiency as possible and gain the largest profit the highest process-waterflow possible should be used. That means 70 kg/s after present conditions. At the highest boiler efficiency the turbine will produce 694 kW. At this state the water that returns to the boiler will be at temperature 148 ˚C (14, 5 bar). Totally during a year the production of electric energy could reach 2, 47 GWh/year. The energy used by the pumps will increase with 0,21 GWh over the year at that state. Included all economic factors this will generate a profit of 0, 97 million (SEK)/year. To make an installation of a flashbox system more profitable an increased generation of electricity have to be made. This could be done by an installation of new pumps to be able to run the process-water at a larger flow to increase the amount of steam made in the flashbox. / Arvika fjärrvärme producerar idag 74% av sitt värmeunderlag via en hetvattenpanna som drivs med biobränsle och har en maxeffekt på 16 MW. På senare år har företaget Vaporel AB introducerat en ny teknik på marknaden som ger en extern ångproduktion efter hetvattenpannor. Konceptet är byggt på en trycksänkning som medför att delar av det mättade vattnet förångas efter att ha letts in i en så kallad flashbox. Efter flashboxen äntrar ångan en turbin där el produceras på konventionellt vis. Syftet med denna rapport har varit att ta fram en grundläggande studie för Arvikas specifika system där det är möjligt att se den potentiella elproduktionen vid en flashboxinstallation. Det slutgiltiga målet med rapporten har varit att kunna presentera en lönsamhetsbedömning för en flashboxinstallation vid givna driftfall. För att kunna uppfylla uppsatta mål har en Excelmodell konstruerats där beräkningar utförts efter givna förutsättningar, detta utefter tre olika driftfall för att kunna fastställa den mest optimala driften för systemet i dagsläget. Studierna har lett fram till att vi har kunnat fastställa ett maximalt tryck efter pannan på 14,5 bar (at) samt en trycksänkning över flashboxen till 9,5 bar. Kondensortryck efter turbinen har satts till 0,5 bar(a) vilket ger en kondensations temperatur motsvarande 81 ˚C. Energi till att värma fjärrvärmevattnet tas via kondensorn samt en värmeväxlare. Resultatet av våra beräkningar visar tydligt att vi för att nå en så hög turbineffekt som möjligt och därmed en större lönsamhet skall ha ett så högt processvattenflöde som tillåts, enligt dagens förutsättningar 70 l/s. Vid högsta panneffekten kommer turbinen att ge 694 kW, enligt Excelmodellen, vid en returtemperatur till pannan satt till 148 ˚C. Sammanlagt under året, med Arvikas varaktighetsdiagram som grund, kommer vi att kunna producera 2,47 GWh el/år varav pumparna kommer att kräva 0,21 GWh el extra per år. Med alla ekonomiska faktorer inräknade så kommer detta att ge en vinstkalkyl på 0,97 miljoner /år. För att kunna göra dessa installationer lönsamma krävs att vi ökar elproduktionen och därmed den årliga vinsten, detta skulle kunna göras i och med installation av nya pumpar för att uppnå ett större flöde i pannkretsen. Vidare bör en studie göras för att bedöma lönsamheten gällande en ombyggnad av rökgaskondenseringen för att kunna klara en större effekt och därmed kunna använda högre returtemperaturer till biopannan. Detta skulle generera ett högre genomsnittligt flöde över året.

Low-temperature fuel cells (LTFC) such as phosphoric acid fuel cells (PAFC) and proton exchange membrane fuel cells (PEMFC) are a promising electrochemical energy system for the conversion of hydrogen to electricity. Many challenges must be overcome before commercialization is possible. This dissertation focuses on the degradation of carbon catalyst supports and PEMFC water management. Kinetic studies are presented on the structure-reactivity relationship including an in-depth study of commercially available and model carbons. A mechanism and numerical model of the electrochemical oxidation of graphene-based carbon is proposed to explain longstanding questions. Three mechanisms are concluded to contribute to the current decay commonly observed during electrochemical oxidation: mass loss, reversible passive oxide formation, and irreversible oxide formation. Water uptake and electro-osmosis are investigated to improve the understanding and aid modeling of water transport in PEMFCs below 0 °C. The implication of an electro-osmotic drag coefficient less than unity is discussed in terms of proton transport mechanisms. Capillary pressure saturation relations are presented for carbon fiber paper which can both be used as gas-diffusion layers in PEMFCs. Boundary and scanning curves for imbibition and drainage are measured to further understanding of the hysteresis observed during PEMFC operation.

Originally presented as the author's Thesis--Technische Universität Hamburg, 2007. / Includes bibliographical references.