Carbon capture and storage in the power sector of Portugal and Spain

Tese de mestrado integrado em Engenharia da Energia e do Ambiente, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2011Portugal e Espanha são ainda caracterizados por uma forte dependência nos combustíveis fósseis. No ano de 2007, cerca de 67% da produção eléctrica total em Portugal foi gerada por centrais convencionais baseadas em combustíveis fósseis. Devido a esta forte dependência nos combustíveis fósseis, verificada quer no sector energético português, quer no espanhol, as emissões de CO2 resultantes assumem valores elevados. De forma a ser possível limitar as alterações climáticas a um nível aceitável, minimizando o seu impacto, torna-se necessário definir o cap do aumento da temperatura a 2 graus Celsius, em relação ao nível pré-industrial. A fim de alcançar este ambicioso objectivo, as emissões de dióxido de carbono nos países industrializados, incluindo Portugal e Espanha, têm de ser reduzidas em pelo menos 80% até 2050. As alterações necessárias incluem um aumento acentuado da produção energética com base em fontes renováveis, rigorosas medidas para a eficiência energética e a introdução de tecnologias CCS para centrais de carvão e de gás. O objectivo do presente estudo foi analisar a necessidade bem como a viabilidade técnica e económica das tecnologias CCS no sector energético em Portugal e Espanha, de forma a descarbonizar o sector de energia Ibérico até ao ano de 2050. Para o efeito, as LPS (Large Point Sources) de dióxido de carbono dos sectores energéticos, e possíveis formas de armazenamento de CO2 foram identificadas e uma análise de correspondência fonte-dreno foi efectuada pelo mapeamento das fontes de LPS e potenciais sumidouros geológicos, e analise da proximidade de fontes e sumidouros. Da mesma forma, o potencial económico futuro de RES para a produção de electricidade foi identificado. Nesse âmbito, dois cenários diferentes foram analisados. No primeiro cenário, 60% da produção eléctrica será proveniente de fontes energéticas renováveis enquanto os restantes 40% em igual proporção de centrais de carvão e de gás baseadas em tecnologias CCS. No segundo cenário considera-se 80% RES e 20% CCS. Para Espanha, em ambos os cenários, considera-se uma taxa de 10% de produção energética nuclear. Na parte final da tese, foram analisados os parâmetros económicos para tecnologias de produção energética diversas e calculados os Levelized Costs of Electricity Generation (LCOE) até 2050. Como os resultados demonstram, o preco break-even para os certificados de CO2 será cerca de 25€/t de forma a tornar as centrais de carvão baseadas em CCS economicamente viáveis. No caso das centrais de gás, o preço break-even assume valores de aproximadamente 83€/t.Portugal and Spain are still relying heavily in fossil fuels. In the year 2007 around 64% of Portugal’s and 61% of Spain’s total electricity generation was provided by conventional, fossil-fuel based power plants. Due to the high dependency of Portugal’s and Spain’s power sector on fossil fuels, the related CO2 emissions of this sector are very high. To limit climate change to an acceptable level, where its consequences are limited to a minimum, it is necessary to define the cap in temperature increase with 2-degree Celsius, compared to pre-industrial level. To reach this ambitious target, carbon dioxide emissions of industrialized countries, including Portugal and Spain, have to be reduced by at least 80% by 2050. These changes will include a sharp increase in electricity generation out of renewable energy sources, strict energy efficiency measures and the induction of CCS technologies for coal- and gasfired power plants. The objective of the following study was to analyze the necessity and technical and economical viability of CCS systems for Portugal’s and Spain’s power sector, in order to decarbonize the Iberian power sector by 2050. For that purpose the carbon dioxide LPS (large point sources) of the power sectors and possible storage sides for CO2 were identified and a source-sink matching analysis was performed by mapping the LPS sources and potential geological sinks to analyze the proximity of sources and sinks. Furthermore the future economic potential of RES for electricity production was identified. For that two different scenarios were developed. In a first scenario 60% of electricity generation will be covered by RES and the remaining 40% in even shares by CCS based coal- and gasfired power plants. The second scenario assumes 80% RES and 20% CCS. For Spain in both scenarios nuclear power generation is considered with a share of 10%. In the last part of the thesis the economical parameters for different power generation technologies were analyzed and the Levelized Cost of Electricity Generation (LCOE) by 2050 calculated. As the results show, the break-even price for CO2 certificates will be around 25 €/t in order to make coal based CCS power plants economical viable. For gas-fired power plants the break-even price is around 83 €/t

Ultra-low switching current density in all-amorphous W-Hf / CoFeB / TaOx films

We study current-induced deterministic magnetization switching and domain wall motion via polar Kerr microscopy in all-amorphous W$_{66}$Hf$_{34}$/CoFeB/TaO$_\text{x}$ with perpendicular magnetic anisotropy and large spin Hall angle. Investigations of magnetization switching as a function of in-plane assist field and current pulse-width yield switching current densities as low as $3\times 10^{9}$ A/m$^2$. We accredit this low switching current density to a low depinning current density, which was obtained from measurements of domain wall displacements upon current injection. This correlation is verified by investigations of a Ta/CoFeB/MgO/Ta reference sample, which showed critical current densities of at least one order of magnitude larger, respectively.Comment: 9 pages, 8 figure

Quantum simulation of the spin-boson model with a microwave circuit

We consider superconducting circuits for the purpose of simulating the spin-boson model. The spin-boson model consists of a single two-level system coupled to bosonic modes. In most cases, the model is considered in a limit where the bosonic modes are sufficiently dense to form a continuous spectral bath. A very well known case is the ohmic bath, where the density of states grows linearly with the frequency. In the limit of weak coupling or large temperature, this problem can be solved numerically. If the coupling is strong, the bosonic modes can become sufficiently excited to make a classical simulation impossible. Here, we discuss how a quantum simulation of this problem can be performed by coupling a superconducting qubit to a set of microwave resonators. We demonstrate a possible implementation of a continuous spectral bath with individual bath resonators coupling strongly to the qubit. Applying a microwave drive scheme potentially allows us to access the strong-coupling regime of the spin-boson model. We discuss how the resulting spin relaxation dynamics with different initialization conditions can be probed by standard qubit-readout techniques from circuit quantum electrodynamics.Comment: 23 pages, 10 figure

Gauge dependences of higher-order corrections to NMSSM Higgs boson masses and the charged Higgs Decay H±→W±hi{H^{\pm } \rightarrow W^\pm h_{i}}

In this paper we compute the electroweak corrections to the charged Higgs boson decay into a W boson and a neutral Higgs boson in the CP-conserving NMSSM. We calculate the process in a general R ξ Rξ gauge and investigate the dependence of the loop-corrected decay width on the gauge parameter ξ ξ . The gauge dependence arises from the mixing of different loop orders. Phenomenology requires the inclusion of mass and mixing corrections to the external Higgs bosons in order to match the experimentally measured mass values. As a result, we move away from a strict one-loop calculation and consequently mix orders in perturbation theory. Moreover, determination of the loop-corrected masses in an iterative procedure also results in the mixing of different loop orders. Gauge dependence then arises from the mismatch with tree-level Goldstone boson couplings that are applied in the loop calculation, and from the gauge dependence of the loop-corrected masses themselves. We find that the gauge dependence is significant

Welche landwirtschaftlichen Anbausysteme fördern das Bodenleben?

In einem weltweit einmaligen Langzeit-Feldexperiment in der Nähe von Basel werden seit 1978 biologische und konventionelle Anbauweisen in einer 7-jährigen Fruchtfolge miteinander verglichen. Die Landbausysteme wirken sich unterschiedlich auf das Bodenleben aus. Vor allem die biologischen Verfahren fördern die Menge, die Aktivität und die Diversität von Bodenlebewesen. Mit der Entwicklung neuer Methoden sind weitere Erkenntnisgewinne möglich geworden

Pseudoscalar MSSM Higgs Production at NLO SUSY-QCD

One of the most important mechanisms at the Large Hadron Collider (LHC) for the production of the pseudoscalar Higgs boson of the Minimal Supersymmetric Standard Model (MSSM) is the loop-induced gluon fusion process gg → A. The higher-order QCD corrections have been obtained a long time ago and turned out to be large. However, the genuine supersymmetric (SUSY–)QCD corrections have been obtained only in the limit of large SUSY particle masses so far. We describe our calculation of the next-to-leading-order (NLO) SUSY-QCD results with full mass dependence and present numerical results for a few representative benchmark points. We also address the treatment of the effective top and bottom Yukawa couplings, in the case of heavy SUSY particles, in terms of effective low-energy theories where the heavy degrees of freedom have been decoupled. Furthermore, we include a discussion of the relation between the SUSY-QCD corrections that we have computed and the Adler-Bardeen theorem for the axial anomaly. In addition, we apply our results to the gluonic and photonic pseudoscalar Higgs decays A → gg, γγ at NLO

Digital Quantum Simulation, Trotter Errors, and Quantum Chaos of the Kicked Top

This work aims at giving Trotter errors in digital quantum simulation (DQS) of collective spin systems an interpretation in terms of quantum chaos of the kicked top. In particular, for DQS of such systems, regular dynamics of the kicked top ensures convergence of the Trotterized time evolution, while chaos in the top, which sets in above a sharp threshold value of the Trotter step size, corresponds to the proliferation of Trotter errors. We show the possibility to analyze this phenomenology in a wide variety of experimental realizations of the kicked top, ranging from single atomic spins to trapped-ion quantum simulators which implement DQS of all-to-all interacting spin-1/2 systems. These platforms thus enable in-depth studies of Trotter errors and their relation to signatures of quantum chaos, including the growth of out-of-time-ordered correlators.Comment: 20 pages, 6 figure

Evaluation of environmental sampling methods for detection of Staphylococcus aureus on fomites

We evaluated a variety of methods to recover S. aureus from inanimate surfaces. Two contact agar plates and three swab sampling methods were tested on porous and non-porous surfaces and bar soap. The cost and ease of use of each method was also evaluated. S. aureus was recovered using all methods on both porous and non-porous surfaces. S. aureus could not be detected on three of four brands of soap