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In recent years, seaports have faced increasing pressure to transition towards a low-carbon and more sustainable energy model. In this context, the exploitation of the local wave energy resource may appear as a promising alternative. Therefore, the objective of this work is to present a methodology to select the best WEC-site combination to supply the energy demands of ports. To illustrate this methodology, the Port of Leixões (Portugal) is used as a case study. For the selection of wave energy sites in port areas, the methodology proposes a detailed spatial characterisation of both the wave resource and marine uses. For the area of study, having considered the main marine uses (sediment disposal, biodiversity, aquaculture, recreational and navigation), two exploitable wave energy sites (Areas I and II) with average annual energy resources of 24 and 17 kWm−1, respectively, were found. Next, the methodology proposes a techno-economic optimisation of WECs, based on the local wave conditions of Areas I and II, to minimise their associated Levelised Cost of Energy (LCoE). The results obtained confirm the effectiveness of the methodology, with the novel oCECO device, appearing as the most feasible option (with an LCoE of EUR 387.6/MWh) to exploit the wave potential in the surrounding areas of the port.

This paper discusses a disruptive approach to wave energy conversion, based on a hybrid solution: the E-Motions wave energy converter with integrated triboelectric nanogenerators. To demonstrate it, a physical modelling study was carried out with nine E-Motions sub-variants, which were based on three original hull designs (half-cylinder (HC), half-sphere (HS) and trapezoidal prism (TP)). A unidirectional lateral tribo-device was incorporated within the E-Motions’ hull during the experiments. The physical models were subjected to eight irregular sea-states from a reference study on the Portuguese coastline. Results point towards a significant hydrodynamic roll response, with peaks of up to 40 °/m. Three peaks were observed for the surge motions, associated with slow drifting at low frequencies. The response bandwidth of the HC sub-variants was affected by the varying PTO mass-damping values. By comparison, such response was generally maintained for all HS sub-variants and improved for the TP sub-variants, due to ballast positioning adjustments. Maximum power ratios ranged between 0.015 kW/m3 and 0.030 kW/m3. The TENGs demonstrated an average open-circuit voltage and power per kilogram ratio of up to 85 V and 18 mW/kg, respectively, whilst exhibiting an evolution highly dependent upon wave excitation, surge excursions and roll oscillations. Thus, TENGs enable redundant dual-mode wave energy conversion alongside E-Motions, which can power supporting equipment with negligible influence on platform hydrodynamics.

Harnessing and using marine renewable energy at seaports is a promising solution to put these energy-intensive infrastructures on the right track to energy self-sufficiency and environmental sustainability, reducing their carbon footprint. This paper presents a summary of the main conclusions and achievements of a recently concluded R&D project that encompassed the experimental study of an innovative hybrid wave energy converter integrated into a case-study rubble-mound breakwater in the Port of Leixões, Portugal. It also describes the prospective studies planned in two ongoing projects, PORTOS – Ports Towards Energy Self-Sufficiency and WEC4Ports – A hybrid Wave Energy Converter for Ports, intended to further develop and assess this promising technology. It has been demonstrated that its wave-to-wire efficiency and annual energy production are 27.3% and 35.0 MWh/m per year, respectively, for the case-study location. Hence, a 240 m long device could provide more than half of the port’s electricity consumption, which vows for the device’s potential. Moreover, the impact of its integration into the case-study breakwater showed that it leads to a 50% reduction of overtopping discharges over the structure, and no significant effects on the structure’s wave reflection, although the stability of the toe berm blocks was negatively impacted. Overall, the conclusions obtained are favourable to the integration of this technology into rubble-mound breakwaters. Notwithstanding, further research is still needed, namely in terms of wave forces acting upon the structure, important for the assessment of the functional performance and lifecycle readiness of the technology, and the use of PTO control strategies. This is being addressed in PORTOS and WEC4Ports projects.

Coastal zone management plans need to consider scenarios of coastline evolution and associated uncertainties. In this paper, the main causes of shoreline retreat and coastal erosion (natural and anthropogenic) in the north coast of Portugal are discussed. The importance of increasing knowledge on coastal dynamics to improve long-term predictions of coastline changes is highlighted since it is essential to establish proper management tools. It is also shown that the Portuguese coastal ecosystems are not resilient enough to extreme events and that the Portuguese coastal zone, like very many others worldwide, and will be severely affected by the effects of climate change. It is concluded that extreme events need to be properly characterized and their impacts assessed since they have important implications in terms of uses of either the coastal zone or the coastal waters. Without that analysis, coastal management plans will be lacking technical and scientific information and data that could help decision-makers define the best strategies to control erosion levels and the impact of extreme events related to climate change effects. Finally, a detailed assessment of the coastline evolution was performed for the new Caminha-Espinho coastal management program, for the time horizons 2050 and 2100, based on historical data. The methodology used for the evaluation of the rates of shoreline change, hazard mapping and definition of set-back lines is presented. Selected examples are given to demonstrate the potential of this methodology in supporting the development of coastal zone management plans, but also to highlight the limitations and uncertainties linked to the complexity of the phenomena under analysis.

Em resposta à solicitação da empresa Cabelte, S.A., sito na Rua de Espírito Santo, Arcozelo, 4410-420 Vila Nova de Gaia - Portugal, o Instituto de Hidráulica e Recursos Hídricos (IHRH) da Faculdade de Engenharia da Universidade do Porto (FEUP) elaborou o presente Relatório relativo à medição de Níveis Hidrostáticos (NHE) em duas Captações da Cabelte, S.A., Arcozelo - Vila Nova de Gaia, tendo como referência os elementos fornecidos, conhecidos e medidos à data deste relatório. Este estudo tem como objetivos: · Observação dos NHE em duas captações de águas existentes nos terrenos da empresa Cabelte, S.A., sito na Rua de Espírito Santo, Arcozelo, 4410-420 Vila Nova de Gaia; · Medições, com recurso a duas sondas de nível, dos NHE em duas captações (adiante identificadas por Furo 1 Central Norte e Furo 2 Central Sul) situadas nos terrenos da empresa Cabelte, S.A; · Neste documento é apresentada a metodologia seguida na realização dos trabalhos de campo, os equipamentos utilizados e os resultados obtidos com base nas medições efetuadas. O estudo foi coordenado pelo Prof. Francisco Taveira Pinto, Professor Catedrático da FEUP e pelo Prof. Joaquim Góis, Professor Auxiliar da FEUP

The buckling tendency of an offshore pipeline buried in a liquefiable soil aggravates under earthquake situations. Moreover, to understand the upheaval displacement behavior of an offshore pipeline under dynamic loading, it is crucial to understand the variation of liquefaction potential within the soil bed. Thus, in the present study, the variation of the liquefaction potential within the soil body and its effect on the pipeline upheaval displacement (u) and post-shake uplift resistance (Vup) is investigated using a finite element package called PLAXIS 2D. The study was performed for different seismic and soil conditions. To define the soil, two advanced constitutive models are used. The static stages are modelled with the ‘Hardening Soil Model with small strain’ (HSS model), while the dynamic stage is modelled with the PM4Sand model. Moreover, the problem is defined as a 2d plane strain problem. The pipe is considered to be covered with Nevada sand. Several parameters such as a sand-density index (Dr), pipe embedment depth (H), seismic frequency (f) and amplitude are varied to study the variation of the soil liquefaction potential, the pipe upheaval buckling and the post-shake uplift resistance. The model is validated with past studies and a considerable match is obtained. The liquefaction potential is shown using the shadings of a user-defined parameter called a pore water pressure ratio (ru). Moreover, the variation of pipe upheaval displacement (u) and pipe uplift resistance (Vup) are shown using various plots. Thus, it is observed that the liquefaction potential is reduced with an increase in the frequency and the amplitude of the seismic signal. Moreover, the peak upheaval buckling, and the duration of earthquake loading to reach the peak upheaval buckling, decreased with an increase in the earthquake signal frequency. Again, the variation of post-peak uplift resistance of the buried pipeline with the pipe embedment depth is observed to be independent of the signal parameters. However, the variation of uplift resistance of the pipeline with the soil relative density is influenced by the signal parameters.

Layout optimization of wave energy offshore parks is a challenging task, as it encompasses various design objectives and constraints attributed to the complex hydrodynamic interactions. The wave energy converter (WEC) park performance is affected by local environment and device characteristics. To solve this challenge, advanced numerical algorithms, including artificial intelligence, have been applied to a wide range of case studies. Nevertheless, this process remains incomplete, which keeps it as a pertinent research topic in the field of WEC development. The present paper provides an overview of the current state and research trends of offshore WEC park layout optimization. To analyze the state-of-the-art, the paper targets the last decades' research on this topic, summarizing the studies, addressing the optimization objective and the employed methods and separating them according to the corresponding technique. The review showed that the results strongly depend on the methodologies applied. Furthermore, a preferential use of computational intelligence techniques has been observed in recent years. (c) 2022 Elsevier Ltd

Assessing the evolution of the performance of water supply and sanitation services is essential to monitor progress towards the universalization of water services, as specified by the Sustainable Development Goal 6 of Agenda 2030, adopted by United Nations member countries. Brazil, a developing country with a continental size and geographical diversity, will face significant challenges to achieve this goal. The main objective of this paper is to evaluate the evolution of productivity of water supply and sanitation services in Brazilian municipalities in the period 2012-2019. The analysis also explores whether water services' performance is balanced across the country, with a specific analysis of performance at the macroregion level. From a methodological perspective, this research evaluates productivity change over time using a Malmquist Productivity Index estimated with a metafrontier, satisfying the circularity property. It also develops a pseudo Malmquist index that compares productivity levels across macro-regions. The results revealed a productivity loss of approximately 4% at the national level, with an unequal profile across the macro-regions. The Southeast municipalities stand out for exhibiting, on average, higher productivity levels than the South and Northeast municipalities.

This work was partially supported by the project PORTOS—Ports Towards Energy SelfSufficiency, with the reference EAPA_784/2018 and co-financed by the Interreg Atlantic Area Program through the European Regional Development Fund, and by the OCEANERA-NET COFUND project WEC4Ports—A hybrid Wave Energy Converter for Ports, with the reference OCEANERA/0004/2019, under the frame of FCT. This work was funded by the project ATLANTIDA (NORTE-01-0145-FEDER000040), supported by the North Portugal Regional Operational Programme (NORTE2020), under the PORTUGAL 2020 Partnership Agreement and through the European Regional Development Fund (ERDF).

Em resposta à solicitação da Cabelte, Cabos Eléctricos e Telefónicos, S.A., sito na Avenida da Indústria, nº 380 e 382 Ribeirão - V.N. de Famalicão - Portugal, o Instituto de Hidráulica e Recursos Hídricos (IHRH) da Faculdade de Engenharia da Universidade do Porto (FEUP) elaborou este Relatório Final relativo à medição de a Níveis Hidrostáticos (NHE) em Captações da Cabelte, S.A., Ribeirão - Famalicão, desenvolvido tendo como referência os elementos fornecidos, conhecidos e medidos até à data. Este estudo tem como objetivos: * Observação dos NHE em duas captações de águas existentes nos terrenos da empresa Cabelte, Cabos Elétricos e Telefónicos, S.A., sito na Av. da Indústria, 380 e 382, Bragadela, 4760-706 Ribeirão (Famalicão); * Medições, com recurso a duas sondas de nível, dos NHE em duas captações (adiante identificadas por P18 e P19) situadas nos terrenos da empresa Cabelte, Cabos Elétricos e Telefónicos, S.A. * Neste documento é apresentada a metodologia seguida na realização dos trabalhos de campo, os equipamentos utilizados e os resultados obtidos com base nas medições efetuadas. O estudo foi coordenado pelo Prof. Francisco Taveira Pinto, Professor Catedrático da FEUP e pelo Prof. Joaquim Góis, Professor Auxiliar da FEUP.

The combined exploitation of wave and offshore wind energy resources is expected to improve the cost competitiveness of the wave energy industry as a result of shared capital and operational costs. In this context, the objective of this work is to explore the potential benefits of co-locating CECO, an innovative wave energy converter, with the commercial WindFloat Atlantic wind farm, located on the northern coast of Portugal. For this purpose, the performance of the combined farm was assessed in terms of energy production, power smoothing and levelised cost of energy (LCoE). Overall, the co-located farm would increase the annual energy production by approximately 19% in comparison with the stand-alone wind farm. However, the benefits in terms of power output smoothing would be negligible due to the strong seasonal behaviour of the wave resource in the area of study. Finally, the LCoE of the co-located farm would be drastically reduced in comparison with the stand-alone wave farm, presenting a value of 0.115 per USD/kWh, which is similar to the levels of the offshore wind industry as of five years ago. Consequently, it becomes apparent that CECO could progress more rapidly towards commercialisation when combined with offshore wind farms.

Buckling is a crucial phenomenon to be considered in offshore pipelines and is dependent on the resistance of the surrounding soil, which depends on the diameter of the pipe (D) and embedment depth (H). In this study, the behaviour of the failure mechanisms and the capacity factors are investigated for a practical range of embedment depth (H) and diameter of offshore pipelines (D), using Indian coastal clay properties. A 2D plane-strain model was created using a finite element package PLAXIS 2D validated against previous studies. The immediate breakaway and no breakaway conditions are analyzed. The capacity factors are observed to increase with increasing embedment depth, up to a peak value and remain constant for further increase in embedment depth. The capacity factors are observed to be decreasing with increasing pipeline diameter. The failure mechanisms are shown using displacement contour diagrams and stress contours.

This study proposes a benchmarking approach to assess water supply and sanitation services' performance in Brazilian municipalities from an integrated perspective of efficiency and access. The regional differences and the impact of the governance models adopted by different municipalities (local public entities, regional public entities, and private entities) on efficiency levels are also explored. The results revealed significant heterogeneity in the efficiency levels of Brazilian municipalities, as the average efficiency score is relatively low (45%). The Southeast and Center-west regions stand out both in terms of efficiency and access dimensions. There is evidence that municipalities with services provided by local public entities have higher efficiency than those with regional providers. On the other hand, efficiency differences between municipalities with public and private providers are statistically significant. Finally, regulatory strategies are suggested based on the outcome of the integrated analysis. (c) 2021 Elsevier Ltd

Numerical models are valuable tools to provide information on wave-structure interaction processes that are difficult to measure in a physical model. The current level of accuracy of numerical models is relatively high but an adequate validation to establish the models' empirical parameters is required to ensure a correct representation of the phenomena to be investigated. To this end, a "trial and error" approach is typically adopted, potentially resulting in a large number of simulations. In this study, a methodology based on Artificial Neural Networks (ANN) is presented, to obtain the optimal combination of values for the empirical coefficients that characterize the porous media in a VARANS-VOF model for predicting mean overtopping discharges. From an initial reduced set of simulations, input and output data are obtained for the training of the ANN. The ANN is then used to estimate the best values for the combination of coefficients that describe the three breakwater layers (armour, filter, and core), which are subsequently applied in the numerical model. The method was successfully applied to a set of laboratory experiments aimed at obtaining overtopping discharges for a Single-Layer Cube armoured breakwater. It resulted in a large reduction of computational effort when compared to the simulation of all possible combinations of values. (c) 2021 Elsevier Ltd

O benchmarking é uma ferramenta fundamental para a gestão dos serviços de abastecimento de água e drenagem de águas residuais, que permite identificar as melhores práticas bem como apontar a ineficiência dos serviços. Sob este aspeto, a análise contextual desempenha um importante papel uma vez que auxilia o investigador a perceber os fatores que afetam o desempenho dos serviços. Neste estudo implementou-se uma abordagem nãoparamétrica baseada em DEA para calcular a eficiência dos serviços de abastecimento de água e de drenagem de águas residuais em uma amostra de 448 municípios brasileiros. Os resultados identificaram um grande potencial de melhoria nos serviços e revelaram também a grande heterogeneidade no ambiente em que esses serviços são prestados. A análise contextual mostrou que as regiões Centro-Oeste e Sudeste do país têm os serviços mais eficientes, enquanto a região Nordeste apresenta a maior ineficiência. Para além disso, verificou-se ainda que as entidades gestoras com administração local são mais eficientes que as com administração regional. Por fim, encontrou-se evidências de que as entidades gestoras privadas apresentam eficiência ligeiramente mais elevadas que as entidades públicas.

Scour protections are a key component of bottom-fixed foundations, namely in gravity based foundations, jacket structures and monopiles commonly used for offshore wind turbines, oil and gas production units and more recently in wave or tidal energy platforms. The cost of the scour protection represents a considerable portion of the capital, operation and maintenance expenditures of the overall investment. Therefore, both the industry and the scientific community devote many studies and research projects focused on its cost-benefit optimisation. In addition, the rising concern of climate change effects and need for lifetime extension of offshore platforms coupled with repowering activities represent new challenges to the design of these elements, which are typically designed to last 25 years, with or without re-filling operations. The ORACLE project has been focused on design optimisation of scour protections in marine environment, by means of improved reliability under long-term conditions. This project includes the physical modelling of optimised dynamic and wide-graded scour protections and the probabilistic assessment and quantification of safety. The present work provides a brief overview of the most recent results of ORACLE. Latest results include the early developments of a new methodology to analyse bathymetric profiles and to compute the damage number and a probabilistic methodology to optimise the median stone diameter of the armour layer.

A Praia do Carneiro, situada na frente marítima do Porto, a norte do molhe de Felgueiras, encontra-se relativamente exposta à agitação marítima, que provoca, em situações de tempestade, o galgamento do muro marginal da Avenida D. Carlos e ainda a remoção de areias. Face a estes problemas e com o objetivo de mitigar os riscos existentes, a Consulmar Lda projetou uma nova intervenção de proteção costeira constituída por cinco quebramares destacados, que consiste numa reformulação de uma primeira proposta para o local, cujo funcionamento hidráulico-estrutural se revelou insatisfatório. O presente estudo incluiu a construção de um modelo físico da Praia do Carneiro e áreas adjacentes com o objetivo de analisar de uma forma qualitativa as erosões localizadas que se desenvolvem junto às estruturas e, quantitativamente, a eficácia do campo de cinco quebramares destacados na redução dos níveis de agitação a sotamar do mesmo. O trabalho permitiu observar a formação e desenvolvimento de erosões localizadas junto aos quebramares nos locais onde não havia afloramentos rochosos na fundação, sem que estas provocassem a instabilidade dos mesmos. Além disso, os quebramares de taludes, construídos com enrocamento ou por blocos cúbicos Antifer, não foram capazes de resistir às condições de agitação marítima mais energéticas, para os níveis de água mais elevados. No entanto, os resultados obtidos permitiram concluir que os cinco quebramares destacados reduzem satisfatoriamente os níveis de agitação a sotamar.

A Praia das Pastoras, na cidade do Porto, é, por vezes, sujeita a fenómenos de galgamento dos muros que a limitam anterior e lateralmente, tanto pelas ondas como pela areia que estas arrastam. Estes galgamentos ocorrem durante situações extremas de agitação marítima, quando se poderá verificar também algum fenómeno de sobrelevação do nível médio da água no canal constituído pelos dois molhes, sendo mais relevantes em situações de preia-mar de águas vivas. O presente estudo em modelo físico teve por objetivo analisar a eficácia de uma solução preliminar projetada tendo em vista a melhoria das condições existentes no que concerne à diminuição dos galgamentos do muro de separação entre a praia e a marginal, bem como a estabilidade da própria estrutura. Foi possível concluir que a estrutura de taludes proposta era estável, mesmo para as condições hidrodinâmicas extremas previstas para o local, no entanto a sua eficácia na atenuação dos níveis de agitação marítima a sotamar e dos galgalmentos ficou aquém das espectativas, sobretudo para os níveis de água mais elevados e para as condições de agitação marítima mais extremas. Com base nos resultados obtidos, sugere-se a adoção de uma solução mais dissipativa da energia das ondas, nomeadamente através de uma colocação irregular dos blocos no manto resistente do quebramar, assim como a colocação do quebramar de proteção numa posição mais exterior, de forma a dissipar a energia das ondas ainda antes de estas entrarem no canal delimitado pelos dois molhes.

Wave overtopping is a critical aspect to take into consideration when designing a coastal structure. An adequate crest geometry (a combination of height and width) is required to maintain the required acceptable safety levels for the population and infrastructure behind the structure. This paper presents the wave overtopping results of laboratory experiments for single-layer cube (SLC) armoured breakwaters with a regular placement pattern. The experiments considered different incident wave conditions and two armour layer porosities, 29% and 33%. Mean wave overtopping discharges obtained were generally higher than the ones observed in previous experiments for the same armour configuration. Available methods shown some limitations in predicting the measured overtopping discharges suggesting the relevance of other factors. It is observed that, by including the ratio of wavelength to the armour crest width in an alternative overtopping formula, the mean flow rate predictions are improved. It was also found that mean overtopping discharges increase by 16-42% due to a decrease in armour porosity with negligible differences in reflection coefficients. A different initial seed number in the wave generation series can lead to differences in wave overtopping discharges up to a factor of two. This work aims to contribute to the knowledge of wave overtopping in SLC armoured breakwaters considering the limited available information for this type of armour configuration. (c) 2021 Elsevier B.V.

The offshore wind is the sector of marine renewable energy with the highest commercial development at present. The margin to optimise offshore wind foundations is considerable, thus attracting both the scientific and the industrial community. Due to the complexity of the marine environment, the foundation of an offshore wind turbine represents a considerable portion of the overall investment. An important part of the foundation’s costs relates to the scour protections, which prevent scour effects that can lead the structure to reach the ultimate and service limit states. Presently, the advances in scour protections design and its optimisation for marine environments face many challenges, and the latest findings are often bounded by stakeholder’s strict confidential policies. Therefore, this paper provides a broad overview of the latest improvements acquired on this topic, which would otherwise be difficult to obtain by the scientific and general professional community. In addition, this paper summarises the key challenges and recent advances related to offshore wind turbine scour protections. Knowledge gaps, recent findings and prospective research goals are critically analysed, including the study of potential synergies with other marine renewable energy technologies, as wave and tidal energy. This research shows that scour protections are a field of study quite challenging and still with numerous questions to be answered. Thus, optimisation of scour protections in the marine environment represents a meaningful opportunity to further increase the competitiveness of marine renewable energies.