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- 3D Magnetic Inversion in Angola: Serra da Neve Alkaline Complex and Jamba Itabirites case studiesPublication . Machadinho, Ana; Represas, Patricia; Alves, Daniela; Cordeiro, Domingos; Carvalho, João; Lopes, R.; Caessa, Paulo; Pereira, L. F; Osório, A.ABSTRACT: Demanding and speculative economies make it imperative to search for new areas of mineral exploration. Angola’s geological diversity presents an enormous potential for mineral resources. This potential can be assessed by applying different methods, such as geophysical prospecting, to discover new potential targets of areas to explore. For many years, the magnetic method has been successfully used in mineral exploration. In this work we apply a 3D magnetic inversion technique to aeromagnetic data in two different study areas. The Serra da Neve alkaline complex (SNAC) represents a potential source for rare earth elements (REE) and the Jamba itabirites provides metallic mineral deposits with iron and gold mineralizations. In both case studies, whether concerning alkaline intrusions or itabirites deposits, their magnetic properties are characterized by strong magnetic anomalies clearly delineated on magnetic anomaly maps. The high magnetic susceptibility (k) contrast between these target structures and the host rocks allowed us to obtain a coherent three-dimensional geometry for the SNAC structures and the itabirites deposits. The magnetic inversion technique also provided magnetic vector inversion (MVI)susceptibility values estimation for constituent lithologies, as well as the shape and size of the studied structures and deposits. The results demonstrate the effectiveness of the magnetic method for the detection and characterization of target areas, offering an innovative technique to identify potential areas in mineral resources exploration.
- Contribution to the development of a new value chain in the marine renewable energy sectorPublication . Fontes, Margarida; Simões, Teresa; Estanqueiro, Ana; Nieto, Felix; Tsami, MariaABSTRACT: As part of the commitments made in the NECP2030 for Portugal, an increase in wind capacity is planned, including an additional 10.4 GW onshore and 2 GW offshore. In this sense, it is necessary to assess the conditions for the creation of a new industrial value chain that will accelerate this development and offer attractive conditions for the involvement of the industrial sector, providing conditions for the objectives recommended in the NECP 2030 to be met. Projects OffshorePlan - Planning for the Use of Offshore Renewable Energies in Portugal, and OceanTrans - Ocean energy technologies transformative potential analyzed the relevant socio-economic component for this sector, namely the process of creating a new industrial value chain to support the development of marine renewable energies. As part of this research, a questionnaire survey was conducted targeting companies in sectors with complementary skills and resources, directly or indirectly related to the development of projects in this area. The questionnaire yielded 114 responses from companies already active and 182 from companies willing to become involved in the future. The results allowed us to obtain a global view of the actual and potential involvement of the industrial sector, as well as to gain some insight into how companies view the requirements to operate in this area and the main barriers to their performance. This article presents the main findings obtained in the scope of this research and discusses their contribution to the advancement of the marine renewable energy sector and, as such, to the development of offshore wind energy in Portugal.
- Enhanced borohydride oxidation kinetics with Au@MOF-808 nanocomposite electrocatalysts with ultra-low Au loadingPublication . Belhaj, Ines; Becker, J. Alexander; Viana, Alexandre M.; Gusmão, Filipe M. B.; Chaves, Miguel; Pereira, Eulália; Sljukic, Biljana; Balula, Salete S.; Silva, Luis Cunha; Santos, Diogo M. F.ABSTRACT: The highly stable metal-organic framework (MOF) composed of[Zr6O4(mu 3-OH)4(OH)6(H2O)6(BTC)2]& sdot;nH2O units (MOF-808) was modified by incorporating gold (Au) nanoparticles and functional groups to enhance electrocatalytic activity for the borohydride oxidation reaction (BOR). Three composite materials (Au@MOF-808, Au@MOF-808-NH2, and Au@MOF-808-SH) were prepared by the incorporation of Au in structurally related MOFs, MOF-808, MOF-808-NH2, and MOF-808-SH, respectively. These composite materials were evaluated as anodic electrocatalysts for BOR in alkaline media using cyclic voltammetry and chronoamperometry. Among the prepared materials, Au@MOF-808-NH2 exhibited the highest BOR activity, with an apparent activation energy of 15.3 kJ mol-1, a reaction order of 0.6, an anodic charge transfer coefficient of 0.63, and a number of exchanged electrons of 4.4. The latter was significantly below the theoretical eight-electron value, indicating the presence of alternative reaction pathways. Notably, this material achieved a high mass-specific BOR peak current of 4.23 A mu gAu-1, demonstrating outstanding electrocatalytic efficiency despite the ultralow noble metal loading. These results underscore the potential of Au@MOF-808-NH2 as a cost-effective and scalable anodic electrocatalyst for high-performance direct borohydride fuel cells.
- Evaluation of occupational exposure to flour dust and additives in a milling industryPublication . Matos, Maria Luísa; Cardoso, Ricardo TeixeiraABSTRACT: This study aimed to assess an environmental risk in a workstation: the occupational exposure of workers to flour dust, and mixtures of flour dust with additives in the cereal milling industry. The purpose was to understand how exposure to flour dust, and mixtures of flour dust with additives affects the health of workers. In the facilities of the milling company where this study was carried out, there is an area where workers are particularly exposed to flour dust and mixtures of flour dust with additives involved. Therefore, one of the main objectives of this study was to evaluate if these workers were subjected to occupational health hazards during their working hours, due to the contact with suspended flour dust in their workstations, focusing special attention to this area, whenever possible. A sampling of particles suspended in the air was carried out, in order to perform a quantitative analysis. Suction pumps were used, placed on workers, who work in three different workstations, to make a quantitative comparison. An average concentration (a.c.) of 17.27 mg/m3 was obtained in the workstation of the preparation of mixtures, an a. c. of 1.35 mg/m3 and one of 2.25 mg/m3 in the bagging workstation – for plain flour and for added flour, respectively. It was found that all values obtained exceed the Exposure Limit Value proposed by the Standard NP 1796:2014, which presents a value calculated as a weighted average of 0.5 mg/m3. Mitigation with the use of personal protective equipment (PPE), FFP3 type masks, is enough to protect workers.
- Exploring the offshore wind and wave generation complementarity in Portugal for a sustainable and resilient power systemPublication . Couto, António; Justino, Paulo Alexandre; Costa, Paula Silva; Simões, Teresa; Estanqueiro, AnaABSTRACT: Exploring variable energy sources generation complementarity can, among several benefits, help in the reduction of the negative impacts of variability from individual sources, and lower the system’s flexibility requirements. This study focuses on the complementarity between offshore wind and wave energy aiming to identify its overall value to the power system. Using Portugal as a case study, this work examines two offshore regions of the Plan for the Allocation of Offshore Renewable Energy in Portugal using standard approaches to assess the level of complementarity. The findings show a clear seasonal mismatch in the summer between wind and wave energy, which supports their complementary nature and helps smooth out seasonal fluctuations in offshore renewable generation. The results indicate that wave energy brings value to diversifying the offshore energy mix. When compared with onshore renewable generation, the combined use of offshore wind and wave power significantly enhances the stability of energy supply, reduces extreme events, which can contribute to decrease the need for additional system flexibility in future nearly 100% renewable-based power systems.
- Novel approach to location planning of hydrogen refueling stations: How market drivers and existing infrastructure impact the hydrogen economyPublication . Espinha, Maria; Portillo, Juan C. C.; Simoes, Sofia; Barbosa, Juliana PachecoABSTRACT: This study aims to present a novel methodology to assess future potential location of hydrogen refueling stations (HRS), involving geospatial and levelized costs of hydrogen (LCOH) analyses. This methodology entails five stages and was developed and applied to mainland Portugal. It can be used in other regions or countries. In this study, a total of 708 potential locations for different HRS were identified and studied for five scenarios. The results indicate that LCOH varies between a minimum of 6.5 €/kg H and a maximum of 11.2 €/kg H. Moreover, 3 574 routes were analyzed considering four hydrogen production sites and the five scenarios, of which 2 395, or 67% of the routes, have a LCOH of between 6 - 9 €/kg H. The main conclusions of the study indicate that there are significant regional disparities in Portugal and that the adoption of hydrogen as an alternative fuel still presents challenges, especially in regions with limited hydrogen refueling infrastructure. The uneven distribution of hydrogen infrastructure and the high associated costs are likely to further exacerbate these economic and technological disparities. Addressing these imbalances requires the development of regional strategies that encourage, for example, hydrogen production in remote and underserved regions.
- Renewable Energy Production in the Mediterranean: Exploring the Potential for Offshore Wind DevelopmentPublication . Simões, Teresa; Tsami, Maria; Nieto, Felix; Huvaj, NejanABSTRACT: This study presents an overview of the current state of the Maritime Spatial Planning among the Mediterranean countries, explores the previous studies on evaluating the offshore wind potential of the Mediterranean region along with the criteria for suitable site selection. Based on a review of the current state of offshore renewable energy, the potential locations offshore wind will be explored for the Mediterranean coastline case study area. The research concludes with a set of critical considerations related to the need for proper synergies establishment among different stakeholders and for cultivating social acceptance and community engagement. The analysis aims to support decision-makers evaluating the potential of the Mediterranean coastal area in supporting the energy transition goal.
- Satellite-based offshore wind data close to the coast: comparison with onshore meteorological mast records and microscale CFD simulationsPublication . Álvarez, Antonio J.; Snæbjörnsson, Jónas Þór; Couto, António; Simões, Teresa; Poozesh, Poorya; Félix, NietoABSTRACT: Satellite observation of environmental phenomena is becoming increasingly accurate, complementing pre-existing measurement techniques. In this work, the offshore wind field recorded by Sentinel-1 on February 6th, 2021, close to the Southwestern Iceland coast is compared with the anemometric measurements provided by a relatively dense network of weather stations in the Reykjanes peninsula and microscale CFD simulations that use the Hvassahraun weather station data to approximate wind velocity and direction in offshore locations. The three methodologies show a good agreement in the 10-minute velocity magnitudes for the set of considered offshore locations, while the 10-minute mean wind direction shows certain scattering, although with a consistent prevalence of Eastern wind directions, in agreement with the anemometric data. The results show obvious complementarities among the three approaches, suggesting further studies to improve accuracy, especially for capturing local effects impacting wind magnitude and directionality.
- Unit Sizing and Feasibility Analysis of Green Hydrogen Storage Utilizing Excess Energy for Energy IslandsPublication . Koca, Kemal; Dursun, Erkan; Bekçi, Eyüp; Uçar, Suat; AKPOLAT, Alper Nabi; Tsami, Maria; Simões, Teresa; Tesch, Luana; AKSÖZ, Ahmet; Borg, Ruben PaulABSTRACT: This study examines whether green hydrogen production using combined wind and solar energy on Marmara Island can meet the island's electricity demand and fuel the fuel needs of a hydrogen-powered ferry. A hybrid system consisting of a 10 MW wind farm, a 3 MW solar PV system, and a PEM electrolyzer sized to meet the island's hydrogen demand was modeled for the island, located in the southwestern Sea of Marmara. The hydrogen production potential, energy flows, and techno-economic performance were evaluated using HOMER-Pro 3.18.4 version. According to the simulation results, the hybrid system generates approximately 62.6 GWh of electricity annually, achieving an 82.8% renewable energy share. A significant portion of the produced energy is transferred to the electrolyzer, producing approximately 729 tons of green hydrogen annually. The economic analysis demonstrates that the system is financially viable, with a net present cost of USD 61.53 million and a levelized energy cost of USD 0.175/kWh. Additionally, the design has the potential to reduce approximately 2637 tons of CO2 emissions over a 25-year period. The results demonstrate that integrating renewable energy sources with hydrogen production can provide a cost-effective and low-carbon solution for isolated communities such as islands, strengthening energy independence and supporting sustainable transportation options. It has been demonstrated that hydrogen produced by PEM electrolyzers powered by excess energy from the hybrid system could provide a reliable fuel source for hydrogen-fueled ferries operating between Marmara Island and the mainland. Overall, the findings indicate that pairing renewable energy generation with hydrogen production offers a realistic pathway for islands seeking cleaner transportation options and greater energy independence.