Doctoral School

Reading date: 28/10/2026

• GARATACHEA SOLÉ, ROGER: Domestic and Transboundary Air Pollution across European countries: health impacts and policy implications
  
  Author: GARATACHEA SOLÉ, ROGER
  Programme: DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Normal
  Deposit date: 07/09/2026
  Reading date: 28/10/2026
  Reading time: 11:00
  Reading place: UPC, Campus NordBuilding C1. Classroom: 002C/Jordi Girona, 1-308034 Barcelona
  Thesis director: PEREZ GARCIA-PANDO, CARLOS | JORBA CASELLAS, ORIOL
  Thesis abstract: Air pollution remains a major environmental and public health problem in Europe, despite decades of regulation and substantial improvements in air quality. Fine particulate matter (PM2.5) and tropospheric ozone (O3) remain two of the most harmful air pollutants. Their formation, transport, and impacts are shaped by complex interactions between local emissions, transboundary pollution, natural sources, atmospheric chemistry, and meteorology. This complexity makes it difficult to determine which sources are responsible for observed pollution levels.This thesis studies the geographical origins of O3 and both geographical and sectoral origins of PM2.5 across Europe, evaluating their implications for health impacts and air-quality governance. Using the CALIOPE regional air-quality modeling system, a tagging approach is applied to quantify domestic, transboundary, maritime, and hemispheric contributions to O3 concentrations and associated short-term mortality. For PM2.5, a perturbation-based approach combined with an observation-constrained methodology is used to quantify source contributions and their related short-term mortality impacts, which are further disaggregated by economic sector and natural sources. The thesis also assesses the feasibility of achieving the revised European Ambient Air Quality Directive PM2.5 standards by 2030 under both current legislation (CLE) and maximum feasible reduction (MFR) pathways.The findings indicate that European air pollution is strongly shaped by sources beyond the jurisdiction in which exposure occurs. For O3, hemispheric and transboundary contributions represent major components of surface concentrations across Europe, underscoring the importance of long-range transport. Consequently, the health impacts related to O3 are also largely driven by imported pollution, which accounts for 88% of all O3-attributable deaths in Europe. However, during high-ozone episodes, local and regional contributions become more relevant, suggesting that domestic and nearby emission reductions can be particularly important under peak O3 levels. For PM2.5, short-term mortality impacts are also strongly influenced by cross-border transport and by the sectoral composition of emissions. Anthropogenic emissions accounted for 55% of PM2.5-attributable deaths, with 35% of this anthropogenic burden resulting from cross-border transport within Europe. Residential combustion emerges as the main anthropogenic source, although agriculture, road transport, industry, and power generation can also make important contributions depending on the region and season.The PM2.5 compliance analysis shows that projected emission reductions are expected to substantially improve air quality by 2030, but important governance challenges will remain. CLE would enable many European air-quality zones to meet the revised PM2.5 limit values, with further improvements under MFR. However, a large share of zones reaching compliance under CLE reductions remain cooperation-dependent, requiring emission reductions in foreign countries rather than domestic action alone. Excluding natural-source contributions further increases attainment, highlighting the role of sources that are not fully controllable through national mitigation policies. These results show that remaining non-compliance reflects not only insufficient domestic action, but also transboundary dependencies, natural contributions, and the limitations of national policy instruments.Overall, this thesis demonstrates that source-resolved modelling is crucial to understand air quality results, estimate health impacts, and design effective compliance strategies. Achieving European air-quality standards will require not only ambitious emission reductions, but also coordinated international action and regulatory frameworks that explicitly account for the transboundary nature of atmospheric pollution.
  

• SOLÉ LLOVERAS, JORDI: Methods for Assessing Radiated Electromagnetic Emissions In Situ. Application to Photovoltaic Systems
  
  Author: SOLÉ LLOVERAS, JORDI
  Programme: DOCTORAL DEGREE IN ELECTRONIC ENGINEERING
  Department: Department of Electronic Engineering (EEL)
  Mode: Normal
  Deposit date: 17/09/2026
  Reading date: 28/10/2026
  Reading time: 10:30
  Reading place: Aula de Graus C4-002, campus nord UPC
  Thesis director: AZPÚRUA AUYANET, MARCO AURELIO | SILVA MARTINEZ, FERNANDO
  Thesis abstract: The increasing deployment of large electrical systems, renewable energy plants and power electronic installations is creating new challenges for electromagnetic compatibility assessment. Many of these systems cannot be tested in conventional EMC laboratories because they are too large, too powerful, too distributed or too dependent on their final installation conditions. As a result, radiated electromagnetic emissions must often be assessed in situ, under real operating conditions and in uncontrolled electromagnetic environments. In these scenarios, the measurement problem is no longer limited to comparing a spectrum with a limit.This thesis develops and validates methods for assessing radiated electromagnetic emissions in situ, with photovoltaic systems as the main application case. The work proposes a structured measurement methodology covering the complete assessment process, from planning and characterization of the electromagnetic environment to the selection of measurement axes and points, emissions assessment and interpretation of results. Ambient noise is addressed as one of the most frequent and difficult challenges in practical in situ radiated emission assessments. Since the measured spectrum may contain contributions from both the equipment under test and external electromagnetic sources, the interpretation process must distinguish emissions generated by the installation from those associated with the surrounding electromagnetic environment. To support this interpretation, several complementary strategies are experimentally validated, including closer distance measurements, conducted RF current measurements, reduced RBW analysis, amplitude probability distribution analysis, etc.The thesis also addresses one of the most critical open issues in practical in situ assessments: the application of radiated emission limits when the measurement distance differs from the reference distance defined by the standard. It is shown that the conversion should be applied to the emission limit rather than to the measured field level, avoiding an unintended relaxation of the permissible level. Specific H-field distance conversion factors below 30 MHz are derived from analytical equations, numerical simulations and experimental validation, and are simplified into practical expressions and tables suitable for direct use in measurement procedures and standardization documents. For E-field emissions above 30 MHz, the classical inverse distance relation is justified and its limitations are quantified.The thesis results are applied to three real photovoltaic installations with different characteristics and measurement constraints. These campaigns demonstrate the applicability of the proposed methodology under real operating conditions and show the practical difficulties associated with in situ radiated emission assessment. The results show that robust conclusions require the use of complementary techniques to determine if an installation is prone to generate interferences.Beyond the experimental validation, the thesis has been transferred to scientific publications, industrial EMC assessment activities and standardization work. The proposed methodology, the ambient noise interpretation and the H-field distance conversion factors have been presented and discussed in technical committees involved in the development of future EMC standards. Therefore, this thesis provides not only an academic and scientific contribution, but also a practical technical reference for engineers, stakeholders and technical committees involved in the application and future development of EMC standards.
  

Reading date: 29/10/2026

• CABRERA REDONDO, ÓSCAR: From Optimisation to Artificial Intelligence Solutions for Modern Power Systems
  
  Author: CABRERA REDONDO, ÓSCAR
  Programme: DOCTORAL DEGREE IN ELECTRICAL ENGINEERING
  Department: Department of Electrical Engineering (DEE)
  Mode: Normal
  Deposit date: 30/09/2026
  Reading date: 29/10/2026
  Reading time: 10:00
  Reading place: ETSEIB - UPC
  Thesis director: ARAGÜÉS PEÑALBA, MÒNICA
  Thesis abstract: Modern power systems are being transformed by decarbonisation, renewable generation, distributed energy resources, electrification, digitalisation, and the participation of new agents. These changes increase operational complexity and require faster, adaptive, and distributed decision-making tools. In this context, optimisation provides the structure to enforce physical and operational constraints, while artificial intelligence contributes prediction, approximation, adaptation, and privacy-preserving learning capabilities.This thesis investigates the transition from optimisation-based formulations towards artificial-intelligence-assisted solutions for modern power systems through three contributions at grid, community, and user levels. At the grid level, a physics-informed graph-based Lagrangian neural network is proposed for direct current optimal power flow approximation. By combining a graph neural network with an augmented Lagrangian loss, the model improves physical consistency under limited training. The approach is evaluated on benchmark electrical networks from 3 to 118 buses, including normal and stressed variants. Under normal conditions, the mean equality-constraint residual is reduced from 0.0219 p.u. to 0.0137 p.u., corresponding to a 37.44% improvement over a purely data-driven graph neural network, while achieving average speed-ups of 94 and 15 times over a widely used nonlinear optimisation solver under normal and extreme conditions, respectively.At the community level, the thesis analyses the smart operation of local energy communities under organisational and operational constraints. The results show that collective self-consumption can create substantial aggregate value, but that user composition and allocation rules strongly influence benefit distribution. In the evaluated case studies, configurations with 50% of users owning private photovoltaic generation reach the highest average total savings, 97.42€, while surplus reallocation increases total savings by up to 45.14€. However, fairness-aware mechanisms remain necessary to reduce negative individual outcomes.At the user level, the thesis proposes personalised federated learning strategies for household electricity demand forecasting. The proposed model-based clustering approaches improve personalisation without centralising private smart meter data. Compared with conventional federated learning, FedEC and FedKM reduce the mean squared error by 0.27% and 0.67%, respectively, with FedKM achieving the lowest aggregate error among the personalised methods considered.Overall, this thesis shows that optimisation and artificial intelligence are complementary components of modern power systems. Their responsible integration requires methods that are accurate, efficient, physics-aware, regulation-aware, and user-centred.
  

• DIAZ MOTTA, ARMANDO: Large Scale Wind-Powered Offshore Ammonia Production
  
  Author: DIAZ MOTTA, ARMANDO
  Programme: DOCTORAL DEGREE IN ELECTRICAL ENGINEERING
  Department: Department of Electrical Engineering (DEE)
  Mode: Normal
  Deposit date: 30/07/2026
  Reading date: 29/10/2026
  Reading time: 12:00
  Reading place: Aula 28.8 Sala Conferències - ETSEIB-UPC
  Thesis director: DÍAZ GONZÁLEZ, FRANCISCO | VILLA ARRIETA, MANUEL RICARDO
  Thesis abstract: Hydrogen and renewable ammonia can support the decarbonization of sectors where direct electrification is not feasible, with green ammonia serving as a hydrogen carrier between renewable production areas and distant demand centers.Among the large-scale pathways proposed in recent years, green ammonia production based on renewable electricity and water electrolysis has attracted increasing attention. However, limited attention has been given to the long-term feasibility of off-grid offshore ammonia production based on SOEC electrolysis and powered entirely by offshore wind. This thesis specifically addresses this knowledge gap by investigating whether large-scale, off-grid offshore green ammonia production based on solid oxide electrolysis (SOEC), a Haber-Bosch synthesis loop (HB), and offshore wind power can become a feasible pathway by 2050.This research aims to assess the technical and long-term economic feasibility of offshore wind-based ammonia production. To this end, the thesis combines a state-of-the-art assessment with a thermodynamic steady-state model of a 3 000 tpd SOEC-Haber-Bosch ammonia plant and an integrated pseudo-dynamic framework that couples the plant, offshore wind generation, battery storage, and hydrogen buffer storage. This framework includes an economic model and a capacity optimization algorithm to minimize the levelized cost of ammonia (LCOA). The pseudo-dynamic model simulates flexible plant operation over an extended load range under site-specific wind conditions. Three offshore locations with high-quality wind resources, namely La Guajira (Colombia), the North Sea (Denmark), and the Gulf of Roses (Spain), are assessed in this thesis. The results show that, at steady state and full load, the plant requires 1 030 MW and reaches an overall efficiency of 63% on an LHV-NH3 basis, while the SOEC electrolyzer achieves 87% on an LHV-H2 basis. The Haber-Bosch loop supplies 57% of the thermal power required for feedwater evaporation in the electrolysis process. Under partial-load operation, the SOEC unit reaches minimum loads of 61% and 72% for steam conversion scenarios of 70% and 85%, respectively, with stack temperature variations within ±30 °C. Under offshore operating conditions, the overall efficiency reaches 60%, and the plant capacity factor reaches 80% at the best-performing site, about 10% below that of a conventional grid-connected ammonia plant.Regarding economic feasibility, the results indicate that La Guajira and the North Sea could achieve the lowest levelized cost of ammonia by 2050, at 472 and 436 USD t-1, respectively, whereas the Gulf of Roses remains less competitive at around 720 USD t-1.A comparison across the selected sites further shows that inflexible Haber-Bosch operation, i.e., operation at 100% load, results in only marginal production cost differences relative to flexible operation over the 10-100% load range, but increases Haber-Bosch hot-standby events, revealing a trade-off between operational stability and storage requirements.The thesis provides a techno-economic assessment framework for offshore green ammonia production, while also supporting the capacity planning of offshore renewable resources. Furthermore, the results indicate that SOEC-based offshore ammonia could become cost-competitive by 2050, provided that costs decline for floating wind and solid oxide electrolysis, and that exogenous factors such as supportive market conditions and favorable policy frameworks emerge.
  

• MUKHOPADHYAY, SHRODDHA: Nonlinear optics at the nanoscale: harmonic generation in resonant metasurfaces
  
  Author: MUKHOPADHYAY, SHRODDHA
  Programme: DOCTORAL DEGREE IN COMPUTATIONAL AND APPLIED PHYSICS
  Department: Department of Physics (FIS)
  Mode: Normal
  Deposit date: 30/09/2026
  Reading date: 29/10/2026
  Reading time: 15:30
  Reading place: Sala de conferencias, planta baja, edificio TR1, Calle Colon 1, Campus Terrassa
  Thesis director: COJOCARU, CRINA MARIA | TRULL SILVESTRE, JOSE FRANCISCO
  Thesis abstract: This thesis aims to contribute to two important research areas in photonics: nonlinear optics and nanophotonics (in particular metasurfaces).These interconnected fields underpin the development of next‑generation nonlinear nanophotonic devices. As modern photonic technologies increasingly rely on nanomaterials, their reduced dimensionality gives rise to new physical regimes, and we require refined theoretical tools and experimental strategies to understand and harness the behavior of sub‑wavelength structures. The work integrates concepts from nonlinear optics, condensed‑matter physics, and nanophotonics. While nonlinear optics was historically explored in bulk crystals under phase-matching conditions, recent advances in nanofabrication have shifted the focus toward nanoscale platforms where light–matter interactions are dominated by strong confinement, surface effects, and nonlocal corrections. In this regime, under ultrafast and intense light excitation, traditional bulk descriptions of nonlinear polarization are insufficient, and microscopic models become necessary. The Maxwell-hydrodynamic theoretical framework used throughout this thesis fulfills this need for a unified description. This theoretical foundation is complemented by nonlinear simulations performed using FDTD and FEM numerical methods. Experimentally, the thesis implements table-top optical setups for high-precision measurements of the efficiencies of the nonlinear harmonic generation processes, and their enhancements in the abovementioned material platforms. In this regards, we reach detection deep into the UV, a limit of far field optical measurements, as well as report two and three orders of magnitude enhancements in the harmonics generated, direct implications of resonant light localization in investigated metasurfaces.Within this framework, this thesis examines harmonic generation in two representative classes of nanomaterials: ultrathin films of semiconductors and metals, and their corresponding one‑ and two‑dimensional periodic metasurfaces. Although the geometries and fabrication strategies differ across these systems, their nonlinear optical response can be interpreted and validated using our combined experimental-theoretical methodology, which applies seamlessly across the different materials and geometries investigated. This consistent approach across disparate platforms has been a guiding principle of the work, as it enables a systematic understanding of how free and bound electrons, surface contributions, and nonlocal effects jointly shape nonlinear emission at the nanoscale.A major component of the work is the study of resonant metasurfaces in plasmonic, dielectric and hybrid-plasmonic platforms, understanding of the material properties at the nanoscale along with the strong electromagnetic field enhancement to compensate for the reduced interaction volume at the nanoscale. How these resonances arise, how they hybridize, and how they shape nonlinear emission has been central to the progression of this work. The interplay between material dispersion, geometry, and electromagnetic coupling has revealed a rich landscape of phenomena that bridge classical and emerging regimes of nanophotonics. By unifying nonlinear optical theory with nanoscale material physics, this work provides a foundation for the design and optimization of nonlinear metasurfaces, compact frequency converters, and emerging quantum photonic platforms. The results demonstrate that ultrathin films and nonlinear metasurfaces are not simply miniaturized versions of bulk materials, but fundamentally distinct systems governed by additional physical mechanisms that dominate at nanometric scales. By integrating theory, simulation, and experiment, this work provides both conceptual clarity and practical methodologies for understanding and engineering nonlinear processes in next‑generation nanophotonic devices.