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In this study, projections and current status of municipal solid waste generation worldwide and its collection, final destination, and waste-to-energy technologies are reviewed. Firstly, an overview of waste generation worldwide is presented comparing income levels and the material composition of residues in several regions. This paper focused on contrasting Brazil and Portugal in terms of waste production and its management from generation to disposal or treatment. Furthermore, it is presented a summary of leading waste-to-energy technologies such as incineration, anaerobic digestion, gasification, pyrolysis, co-combustion, co-gasification, among others. Technical aspects of these thermo-chemical, biological, and physic-chemical processes for the production of biofuels such as biogas, syngas, biodiesel, and hydrogen-enriched gases are presented. Additionally, current aspects of the waste-to-energy market are exposed regarding the major players, investments, and expectations for the future of this activity with the elaboration of SWOT analyses. Finally, a review of greenhouse gases emissions worldwide is presented, specifically from Brazil and Portugal, as well as some consequences of these pollutant gases on the society and the environment and which are the main technologies for carbon dioxide capturing and sequestration as promising solutions for lower pollutant gases concentration in the atmosphere. This review paper aims to provide information for the management of municipal solid waste in Brazil and Portugal considering the mutual objective of meeting sustainable development goals. [ABSTRACT FROM AUTHOR]

This paper seeks to identify promising sites and technologies, in Portugal, for co-located wave energy conversion and offshore aquaculture, whilst providing benchmark implementation references and guidelines to researchers. Accordingly, two case study sites are considered for deployment of five wave energy devices and up to six aquaculture species. A thorough analysis in terms of power ratios, efficiency, redundancy, species viability, device survivability and costs is performed, seeking to find viable co-located solutions. It is found that the Wave Dragon device yields the most promising energy demand coverage and energy output (5 226 to 6 817 MWh/year). Nevertheless, it may require rescaling towards optimal operation, while the OCECO 4 excels in terms of capacity factor (0.24–0.29) and default adaptation to the deployment sites. The WaveRoller® has the lowest single-unit cost (125 €/MWh) but requires up to nine units to cover all the energy demand targets. Larger wave farms are required for the BBDB and AquaBuOY, albeit with potentially greater economies of scale and single-unit redundancy. These sites also enable cultivation of most of the considered species, even under ideal conditions. Lastly, it is recommended that the devices enter survivability mode at a significant wave height threshold of 5.5 m. • Co-located potential of wave energy harvesting and offshore aquaculture in Portugal. • 5 WECs co-located with 3 + 3 aquaculture species in two deployment sites. • Estimation of energy/power ratios, efficiency, redundancy and species viability. • Wave Dragon stands-out on energy coverage, WaveRoller® on costs and OCECO on capacity factor. • 6/6 and 4/6 viable species for Figueira da Foz (2 ideal) and Sines (3 ideal) sites. [ABSTRACT FROM AUTHOR]

The paper aims to develop a decision tool for planning offshore wind farm locations, combining multi-criteria decision analysis and geographic information systems. This method considers several technological, environmental, social, and economic criteria. The criteria are used as evaluation factors and constraints to rank the identified potential locations through an Analytic Hierarchy Process. During the evaluation of the available areas, a pairwise comparison is used in which a group of experts determines the weights. Sensitivity and consensus analyses evaluate the results robustness. The methodology is developed for a case study in the Atlantic coastal areas of Portugal, Spain, and France. The results show the potential of this tool to support the planners in the designation of regions for floating wind farm development. [ABSTRACT FROM AUTHOR]

Islands have the potential to be precursors in the transition to clean energy, by adopting new technologies and applying innovative solutions that can serve as showcases at an international level. This paper is a contribution towards understating the importance of community engagement on energy transition processes. It covers multiple aspects of a green transition process, including technical, environmental, social, and economic issues. Starting by a participatory diagnosis process, the community of a small island located in Portugal (Culatra Island, Algarve), was challenged to lead the transition process and define different pillars of energy transition. The process brought together local authorities, academia, citizens and companies. Using practical examples, it is shown how the community is succeeding in tailoring new technological solutions for a green transition, according with the specific needs of the island, as expressed by the islanders themselves, including batteries, electric vehicles, retrofitting of homes, or heat pumps, which, when combined, could lay the foundations for the creation of a Renewable Energy Community and leverage socioeconomic benefits. •The vision is to create an island' energy community based on participatory economy. •Energy generation, revenues and internal rate of return are presented. •The energy layout plant can generate 35% of the total energy consumed in the island. •There is a potential to the island become autonomous in terms of energy production. • Adjusting consumption to generation can be achieved through demand response. [ABSTRACT FROM AUTHOR]

The non-stationary and stochastic nature of wind power reveals itself a difficult task to forecast and manage. In this context, with the continuous increment of wind farms and their capacity production in Portugal, there is an increasing need to develop new forecasting tools with enhanced capabilities. On the one hand, it is crucial to achieve higher accuracy and less uncertainty in the predictions. On the other hand, the computational burden should be kept low to enable fast operational decisions. Hence, this paper proposes a new hybrid evolutionary-adaptive methodology for wind power forecasting in the short-term, successfully combining mutual information, wavelet transform, evolutionary particle swarm optimization, and the adaptive neuro-fuzzy inference system. The strength of this paper is the integration of already existing models and algorithms, which jointly show an advancement over present state of the art. The results obtained show a significant improvement over previously reported methodologies. [ABSTRACT FROM AUTHOR]

Hydrokinetic energy has been mainly studied in areas where the principal driver of the current is the tide. However, in certain areas river discharges play also a principal role. The exploitation of the hydrokinetic resource in such areas has its own peculiarities, dictated by the combined influence of the two driving agents. The objective of this paper is to investigate the exploitation of hydrokinetic energy in the Miño Estuary, the largest estuary in NW Spain and N Portugal, with a focus on the site-specific performance of hydrokinetic energy converters (HECs) and its intra-annual variability. A state-of-the-art hydrodynamics numerical model is implemented and successfully validated based on field data. A third-generation HEC—to be more specific, the new Smart Freestream Turbine (SFT)—is considered, and its performance at the location with the greatest potential is assessed by means of: (i) site-specific efficiency, (ii) availability factor, and (iii) capacity factor. We find that, whereas the site-specific efficiency does not vary significantly, the availability and capacity factors do experience substantial intra-annual (seasonal) variability. In summer and autumn, river discharges are low, and the tide dominates the hydrokinetic resource. In contrast, during winter and spring, the river discharges significantly contribute to the resource, leading to a considerable increase in the availability and capacity factors. More generally, the results imply that in areas subject to combined fluvial and tidal influences the performance of HECs may depart significantly from that in tide-dominated areas, and this departure must be carefully weighed in assessing a project. • Hydrokinetic resource under influence of tide and river discharges is investigated. • River discharges induce a pronounced seasonal variability in the hydrokinetic resource. • The hydrokinetic resource is controlled to a large extent by the hydrological regime. • River discharges lead to a considerable increase in the performance during winter. [ABSTRACT FROM AUTHOR]

When planning wind farms it is important to optimize the layout to increase production and reduce costs. In this paper we minimize the levelized cost of energy (LCOE) for a floating wind farm using wind data in an area around Porto Santo in Portugal. We use ensemble based optimization (EnOpt), which is frequently applied in the geophysical community to find optimal controls of oil reservoirs. EnOpt is usually used for unconstrained optimization problems or for problems with simple constraints, for example upper and lower bounds on the optimization variables. Here we consider a layout problem with many constraints on the distances between turbines. To handle the constraints, we use an extension of EnOpt called EPF-EnOpt, in which the constrained problem is replaced by a series of unconstrained problems with increasing penalty terms. We compare the performance of this method with EnOpt with a fixed penalty term, and with a deterministic gradient method. All the tested methods reduce the LCOE, but EPF-EnOpt gives better results than both a single run of EnOpt with a fixed penalty term and the deterministic gradient method, and at a lower computational cost than using the gradient method. We also consider the problem of maximizing the annual energy production without taking into account any costs. EPF-EnOpt performs the best also for this problem. • Layout optimization for a floating offshore wind farm. • Minimization of levelized cost of energy and maximization of annual energy production. • Optimization problem with many constraints on the distances between turbines. • Use of ensemble optimization (EnOpt and EPF-EnOpt) to reduce the computational cost. • Constraints handled by increasing penalty terms in EPF-EnOpt. [ABSTRACT FROM AUTHOR]

Short-term photovoltaic (PV) power forecasting is essential for integrating renewable energy sources into the grid as it provides accurate and timely information on the expected output of PV systems. Deep learning (DL) networks have shown promising results in this area, but depending on the weather conditions and the particularities of each PV system, different DL architectures may perform best. This paper proposes a meta-learning method to improve one-hour-ahead deterministic forecasts of PV systems by dynamically blending the base forecasts of multiple DL models to learn under what conditions each model performs best. Four base models of different long short-term memory architectures are used to produce PV production forecasts without using numerical weather predictions, with the objective to enhance the generalizability of the proposed solution. The accuracy of the meta-learner is evaluated using three rooftop PV systems in Lisbon, Portugal. Results indicate that different base models perform best at different PV plants, and meta-learning can improve accuracy by up to 5% over the most accurate base model per plant and up to 4.5% over the equal-weighted combination of the base forecasts. These improvements are statistically significant and even larger during peak production hours. • Four LSTM models for hour-ahead PV production forecasting. • A meta-learning model to optimally blend the forecasts of the four LSTM models. • Focus on NWP independent approaches, resulting in faster and more reliable models. • Evaluation on three PV plants located in Portugal using representative benchmarks. [ABSTRACT FROM AUTHOR]

Abstract A new era of cleaner distributed generators, like wind and solar, dispersed along the distribution network are gaining great importance and contributing to the environment and political goals. However, the variability and intermittency of those generators pose new complexities and challenges to the network planning. This research paper proposes an innovative stochastic methodology to deal with the expansion planning of large distribution networks in a smart grid context with high penetration of distributed renewable energy sources and considering the seasonal impact. Also, new power lines locations and types, the size and the location of energy storage systems are considered in the optimization. A distribution network with 180 buses located in Portugal considering high distributed generators penetration is used to illustrate the application of the proposed methodology. The results demonstrate the advantage of the stochastic model when compared with a deterministic formulation, avoiding the need for larger investments in new lines and energy storage systems. Highlights • Seasonal and daily periods impact effect in the long-term DN expansion planning. • Two-stage stochastic model in a smart grid context with high RES penetration. • Optimal ESS size and location and optimal type and location of new lines. • Optimal investment expansion planning. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with the protection of wind energy systems against the indirect effects of lightning. As wind energy is gaining increasing importance throughout the world, lightning damages involving wind energy systems have come to be regarded with more attention. Nevertheless, there are still very few studies in Portugal regarding lightning protection of wind energy systems using models of the Electro-Magnetic Transients Program (EMTP). Hence, a new case study is presented in this paper, based on a wind turbine with an interconnecting transformer, considering that lightning strikes the soil near the tower at a distance such that galvanic coupling occurs through the grounding electrode. Computer simulations obtained by using EMTP-RV are presented and conclusions are duly drawn. [Copyright &y& Elsevier]

Abstract: This paper presents a refined description of the wave climate observed in a Portuguese location for marine energy projects. The data used in this case study were derived from 3-month in situ measurements carried out using three directional buoys that have been deployed simultaneously – yet independently (various buoy types and water depths) – on the Atlantic coast in the neighbourhood of Figueira da Foz. Two ways of reporting the statistics were adopted. In the first one, each recorded sea state was summarized as a set of global parameters accounting for energy, mean frequency and direction, spectral bandwidth and directional spreading related to the main ongoing wave field considered as unimodal. In the second one, each sea state has been decomposed into its own wave components – swells and wind-sea – which are characterised separately and individually by the same set of parameters as previously. Besides the adopted data processing techniques and the illustration of such thorough wave climate description modes, the paper also addresses the advantages and limits of each adopted parameterization in the frame of simultaneous and independent in situ wave measurements. [Copyright &y& Elsevier]

This paper investigates the spatial characteristics of wind speed statistics in oceanic areas of Portugal. The main goal is to apply a regionalization method to define statistically homogeneous regions and then analyze the probabilistic moments, the wind power density, percentiles and extreme values within each region. The Regional Frequency Analysis based on L-moments was implemented using five years of atmospheric simulations. The domain convers latitudes 36.0ºN to 42.2ºN and longitudes 11.0ºW to 7.2ºW, with resolution of 0.081° X 0.097° and 6 h. The investigation using the L-moment ratios resulted in four regions: north (1), center (2), southwest (3) and south (4) of Portugal. A discussion about the potential associated with each region, in terms of the wind energy available and the extreme events severity, enriches the final analyses. Region 1 has the benefit of the highest mean wind power density, equal to 909 W / m 2 , but it presented the most extreme winds with return value of 25.4 m/s for the return period of 20 years. It was observed that extreme winds are reduced moving south, together with the wind power densities, which are analyzed in detail. The spatial and regional characteristics of wind power densities and extreme values are deeply explored. [ABSTRACT FROM AUTHOR]

Abstract: In Portugal, there is a critical need for architects to incorporate energy-conscious strategies on the process of refurbishment design. Passive design technology is still widely unknown or misused by Architects, to a large extent because information on these issues is scarce, mostly referring to foreign climatic and building contexts. There is also a great need for user-friendly tools, like the LT method, particularly for demonstrating and validating its use in the Portuguese context. This paper presents the LT-Portugal software, which is an energy design tool that can quickly assess the energy use (lighting, cooling, ventilation and heating) and thermal comfort implications of design options – both in existing projects and also to inform design decisions. Despite the complexity of the analysis, the LT method is easy to use and to apply to a range of situations. It is thus an ideal to assess refurbishment strategies, to which it has been applied before, and to make comparisons between various refurbishment options. [Copyright &y& Elsevier]

Abstract: This paper addresses the importance of the probabilistic analysis in determining the wave energy potential to support the design of electrical generators for wave energy conversion. The irregular activity of ocean waves induces variable frequencies and amplitudes of operation for point absorbers electrical generators, which may lead to the construction of inefficient electrical machines. Applying probabilistic models to describe the ocean wave''s behavior allows the determination of the values most likely to be sampled for ocean-state parameters. Knowing these values, the most expected ocean wave potential can be determined and a proper device design can be performed. This work also refers to the importance of using the joint probability models instead of the marginal ones. Seven locations at the Portuguese coast are evaluated in order to determine their wave energy resource potential. [Copyright &y& Elsevier]

Abstract: This paper proposes artificial neural networks in combination with wavelet transform for short-term wind power forecasting in Portugal. The increased integration of wind power into the electric grid, as nowadays occurs in Portugal, poses new challenges due to its intermittency and volatility. Hence, good forecasting tools play a key role in tackling these challenges. Results from a real-world case study are presented. A comparison is carried out, taking into account the results obtained with other approaches. Finally, conclusions are duly drawn. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the study of the impact of energy absorption by wave farms on the nearshore wave climate and, in special, the influence of the incident wave conditions and the number and position of the wave farms, on the nearshore wave characteristics is studied and discussed. The study was applied to the maritime zone at the West coast off Portugal, namely in front of São Pedro de Moel, where it is foreseen the deployment of offshore wave energy prototypes and farms between the 30m and 90m bathymetric lines, with an area of 320Km2. In this study the REFDIF model was adapted in order to model the energy extraction by wave farms. Three different sinusoidal incident wave conditions were considered. Five different wave farm configurations, varying the position of the wave farm, its number and the width of the navigation channels at each wave farm were analysed. The results for each configuration in terms of the change of the wave characteristics (wave height and wave direction) at the nearshore are presented, compared and discussed for three representative wave conditions. [Copyright &y& Elsevier]

Abstract: The present paper focuses on the issue of thermal comfort adaptive criteria and its relevance to the implementation of passive design strategies, in the context of a field work carried out in Portugal. This field work involved monitoring and questionnaires in office buildings existing in Lisbon, as well as other types of buildings, such as homes for the elderly and educational buildings, during summer, winter and mid-season. [Copyright &y& Elsevier]

Abstract: This paper presents a general overview on the subject of sustainable building and urban design in Portugal – within the Southern-European context. It focuses on its evolution, the most striking aspects, present needs and future trends. Various case studies are presented, including the integration of renewable energy systems at urban and building scale. [Copyright &y& Elsevier]