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Publications

2024

Stochastic optimization framework for hybridization of existing offshore wind farms with wave energy and floating photovoltaic systems

Authors
Kazemi-Robati, E; Silva, B; Bessa, RJ;

Publication
JOURNAL OF CLEANER PRODUCTION

Abstract
Due to the complementarity of renewable energy sources, there has been a focus on technology hybridization in recent years. In the area of hybrid offshore power plants, the current research projects mostly focus on the combinational implementation of wind, solar, and wave energy technologies. Accordingly, considering the already existing offshore wind farms, there is the potential for the implementation of hybrid power plants by adding wave energy converters and floating photovoltaics. In this work, a stochastic sizing model is developed for the hybridization of existing offshore wind farms using wave energy converters and floating photovoltaics considering the export cable capacity limitation. The problem is modeled from an investor perspective to maximize the economic profits of the hybridization, while the costs and revenues regarding the existing units and the export cable are excluded. Furthermore, to tackle the uncertainties of renewable energy generation, as well as the energy price, a scenario generation method based on copula theory is proposed to consider the dependency structure between the different random variables. Altogether, the hybridization study is modeled in a mixed integer linear programming optimization framework considering the net present value of the project as the objective function. The results showed that hybrid-sources-based energy generation provided the highest economic profit in the studied cases in the different geographical locations. Furthermore, the technical specifications of the farms have also been considerably improved providing more stable energy generation, guaranteeing a minimum level of power in a high share of the time, and with a better utilization of the capacity of the cable while the curtailment of energy is maintained within the acceptable range.

2024

Aquacom: A Multimodal Underwater Wireless Communications Manager for Enhanced Performance

Authors
Moreira, G; Loureiro, JP; Teixeira, FB; Campos, R;

Publication
2024 IEEE 22ND MEDITERRANEAN ELECTROTECHNICAL CONFERENCE, MELECON 2024

Abstract
Underwater wireless communications play a significant role in the Blue Economy, supporting the operations of sensing platforms like Autonomous Surface Vehicles (ASVs) and Autonomous Underwater Vehicles (AUVs). These platforms require reliable and fast communications to transmit the extensive data gathered without surfacing. Yet, the ocean poses challenges to signal propagation, restricting communications to high bitrate at short ranges via optical and RF, or low bitrate at long distances using acoustic communications. This paper introduces Aquacom, a multimodal manager for underwater communications that integrates acoustic, RF, and optical communnications, ensuring seamless handover between technologies and link aggregation to enhance network performance. Upon validation in freshwater tank lab tests, Aquacom demonstrated the capability for switching interfaces without data loss and effective link aggregation through the simultaneous use of multiple wireless interfaces.

2024

Unsupervised and interpretable discrimination of lithium-bearing minerals with Raman spectroscopy imaging

Authors
Guimaraes, D; Monteiro, C; Teixeira, J; Lopes, T; Capela, D; Dias, F; Lima, A; Jorge, PAS; Silva, NA;

Publication
HELIYON

Abstract
As lithium-bearing minerals become critical raw materials for the field of energy storage and advanced technologies, the development of tools to accurately identify and differentiate these minerals is becoming essential for efficient resource exploration, mining, and processing. Conventional methods for identifying ore minerals often depend on the subjective observation skills of experts, which can lead to errors, or on expensive and time-consuming techniques such as Inductively Coupled Plasma Mass Spectrometry (ICP-MS) or Optical Emission Spectroscopy (ICPOES). More recently, Raman Spectroscopy (RS) has emerged as a powerful tool for characterizing and identifying minerals due to its ability to provide detailed molecular information. This technique excels in scenarios where minerals have similar elemental content, such as petalite and spodumene, by offering distinct vibrational information that allows for clear differentiation between such minerals. Considering this case study and its particular relevance to the lithium- mining industry, this manuscript reports the development of an unsupervised methodology for lithium-mineral identification based on Raman Imaging. The deployed machine-learning solution provides accurate and interpretable results using the specific bands expected for each mineral. Furthermore, its robustness is tested with additional blind samples, providing insights into the unique spectral signatures and analytical features that enable reliable mineral identification.

2024

PEExcel: A fast one-stop-shop Assessment and Simulation framework for Positive Energy Districts

Authors
Schneider, S; Drexel, R; Zelger, T; Baptista, J;

Publication
BauSim Conference Proceedings - Proceedings of BauSim 2024: 10th Conference of IBPSA-Germany and Austria

Abstract

2024

Practical tools for measuring and monitoring sustainable innovation

Authors
Guimarães, C; Santos, JD; Almeida, F;

Publication
Innovation and Green Development

Abstract
Organizations assume a key role in the goal of achieving sustainable development and are influential elements on the path to sustainability. Allied with competitiveness, today, there is also a strategy based on sustainability, anchored in the concept of responsibility, minimizing the potential negative effects of our actions through innovative products, services, processes, and models. Measuring and monitoring these efforts is currently a challenge for organizations. This study adopts a mixed methods approach to address this challenge and identifies 13 tools and 16 dimensions that are central elements in the process of measuring and monitoring sustainable innovation. The findings indicate that the dimensions related to social and governance components are the most relevant in sustainable innovation, while inclusion and entrepreneurship are dimensions that are not highly valued by these tools. © 2024 The Authors

2024

UAV Visual and Thermographic Power Line Detection Using Deep Learning

Authors
Santos, T; Cunha, T; Dias, A; Moreira, AP; Almeida, J;

Publication
SENSORS

Abstract
Inspecting and maintaining power lines is essential for ensuring the safety, reliability, and efficiency of electrical infrastructure. This process involves regular assessment to identify hazards such as damaged wires, corrosion, or vegetation encroachment, followed by timely maintenance to prevent accidents and power outages. By conducting routine inspections and maintenance, utilities can comply with regulations, enhance operational efficiency, and extend the lifespan of power lines and equipment. Unmanned Aerial Vehicles (UAVs) can play a relevant role in this process by increasing efficiency through rapid coverage of large areas and access to difficult-to-reach locations, enhanced safety by minimizing risks to personnel in hazardous environments, and cost-effectiveness compared to traditional methods. UAVs equipped with sensors such as visual and thermographic cameras enable the accurate collection of high-resolution data, facilitating early detection of defects and other potential issues. To ensure the safety of the autonomous inspection process, UAVs must be capable of performing onboard processing, particularly for detection of power lines and obstacles. In this paper, we address the development of a deep learning approach with YOLOv8 for power line detection based on visual and thermographic images. The developed solution was validated with a UAV during a power line inspection mission, obtaining mAP@0.5 results of over 90.5% on visible images and over 96.9% on thermographic images.

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