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The growing search for alternative energy sources is not only due to the present shortage of non-renewable energy sources, but also due to their negative environmental impacts. Therefore, a lot of attention is drawn to the use of biomass as a renewable energy source. However, using biomass in its natural state has not proven to be an efficient technique, giving rise to a wide range of processing treatments that enhance the properties of biomass as an energy source. Torrefaction is a thermal process that enhances the properties of biomass through its thermal decomposition at temperatures between 200 and 300 °C. The torrefaction process is defined by several parameters, which also have impacts on the final quality of the torrefied biomass. The final quality is measured by considering parameters, such as humidity, heating value (HV), and grindability. Studies have focused on maximizing the torrefied biomass’ quality using the best possible combination for the different parameters. The main objective of this article is to present new information regarding the conventional torrefaction process, as well as study the innovative techniques that have been in development for the improvement of the torrefied biomass qualities. With this study, conclusions were made regarding the importance of torrefaction in the energy field, after considering the economic status of this renewable resource. The importance of the torrefaction parameters on the final properties of torrefied biomass was also highly considered, as well as the importance of the reactor scales for the definition of ideal protocols.

East Lisbon is being exposed to large-scale urban regeneration processes, where luxury residential projects and mixed-use spatial developments are already underway. Thus, it is a living laboratory for “smart”, “creative” and “green” projects, as well as related urban public space interventions. Braço de Prata is an urban space overlooked by developers, being surrounded by obsolete industrial buildings. Concerning the recent interest in international investments in brownfield regeneration and greenfield developments, it represents an attractive urban terrain as a post-industrial working-class neighbourhood, where “smart” and “green” suggest transforming space so that both new and old residents can live and work together and share public space regardless of analysis on their environmental recognitions. The aim of this paper is to present an empirical evaluation model that examines the possible impacts of environmental negligence through the reorganisation of the physical and social fabric. The analyses focus on dwellers’ moral understanding of their changing environment as site-specific domains to address the unique conditions that affect transiently defined presumptions about the collective needs. Taking an evaluative approach in the Braço de Prata case, this paper demonstrates the specific socio-ecological implications of urban inequality in post-industrial neighbourhoods that could be threatened by new decisions, both through urban planning approaches and instruments.

Abstract Accurate knowledge of tidal turbine impacts on the far-field hydrodynamic conditions, which extend from 3 to 20 diameters downstream the turbine, is essential for the estimation of tidal resource, farm layout design and environmental impact. For this purpose, tidal turbine operation is modelled within coastal models, as enhanced bottom friction, or momentum sinks. In Delft3D-FLOW, a state-of-the-art coastal model, turbine operation is usually represented via momentum losses, using the Porous Plate tool. However, the Porous Plate tool presents significant limitations to accurately represent energy extraction and geometry of tidal turbines. Recently, a new tool (Actuator Disc) based on the Momentum Actuator Disc Theory (MADT) was developed in Delft3D-FLOW, overcoming the aforementioned limitations and showing excellent results against laboratory data. The aim of this work is to compare the behaviour of the Actuator Disc and Porous Plate on the far-field hydrodynamics. Overall, significant differences were found, with the Porous Plate significantly underestimating the impact on instantaneous and residual flow velocities and turbulence conditions, when the turbine operates at its rated power. Consequently, MADT appears as the best alternative to investigate the far-field hydrodynamic impacts of tidal turbine operation and previous research based on the Porous Plate tool should be revisited.

Abstract Scenedesmus obliquus biomass was used as a feedstock for comparing the biological production of hydrogen by two different types of anaerobic cultures: a heat-treated mixed culture from a wastewater treatment plant and Clostridium butyricum DSM 10702. The influence of the incubation temperature and the carbon source composition were evaluated in order to select the best production profile according to the characteristics of the microalgal biomass. C. butyricum showed a clear preference for monomeric sugars and starch, the latter being the major storage compound in microalgae. The highest H 2 production reached by this strain from starch was 468 mL/g, whereas the mixed culture incubated at 37 °C (LE37) produced 241 mL/g. When the mixed culture was incubated at 58 °C (LE58), a significant increase in the H 2 production occurred when xylose and xylan were used as carbon and energy source. The highest H 2 yield reached by the LE37 culture or in co-culture with C. butyricum was 1.52 and 2.01 mol/mol of glucose equivalents, respectively. However, the ratio H 2 /CO 2 (v/v) of the biogas produced in both cases was always lower than the one produced by the pure strain. In kinetic assays, C. butyricum attained 153.9 mL H 2 /L h from S. obliquus biomass within the first 24 h of incubation, with a H 2 yield of 2.74 mol/mol of glucose equivalents. H 2 production was accompanied mainly by acetate and butyrate as co-products. In summary, C. butyricum demonstrated a clear supremacy for third generation bioH 2 production from S. obliquus biomass.

Abstract High power pseudocapacitors are extremely relevant to answer specific needs in the current energy transition arena and to implement an efficient renewable energy society. However, literature shows that are still open gaps concerning improvement of their energy density at high power, conversion efficiency, cost and cycle life. Electrodes based on active transition metal compounds, and in particular metal sulphides, evidence high potential to meet these objectives. This work discusses the dependence on the synthesis route of the charge storage mechanism of manganese sulphide-based materials and relates the pseudocapacitive response of these electrodes with their polycrystalline nature. Results reveal that a manganese oxy-sulphide mixture can achieve a high specific capacitance of 231 F.g−1 at 0.5 A/g in a 0.65 V active window. These values represent a 31.5 % increase compared to pure rambergite, γ-MnS, and 436 % compared to pure hausmannite Mn3O4 prepared under the same conditions. Moreover, the results show that manganese oxy-sulphide electrodes are characterized by good charge retention (73%), and superior long term capacity retention (above 86%) after 5000 cycles, evidencing potential for high power energy storage applications.

This paper explores how market and regulatory factors affect stakeholders' investments in smart grid projects in Europe. Distribution System Operators (DSOs), universities, and technology manufacturers are leading investors, with a cumulative 2286 M€ financed since 2002. Statistical tests were conducted on these groups' investments in smart grid projects in the EU-28, Norway, and Switzerland from 2008-2015, to evaluate the influence of the following factors on investment: the level of distribution sector concentration, the regulatory mechanism in place, and the existence of innovation stimulus mechanisms. The level of distribution sector concentration did not significantly influence investments by these three groups. Market-minded stakeholders, such as DSOs and technology manufacturers, invested more in countries that employed hybrid, incentive, or innovation-stimulus mechanisms; meanwhile, collaborative knowledge-seeking institutions, such as universities, were not swayed by these factors. Taking these findings into consideration will help policy makers design adequate incentives for stakeholders.

The sustainability assessment methodology has to be demonstrated in order to become the tool in the engineering practice. This chapter is devoted to the attempt to evaluate the sustainability of energy systems and show how it can be used in the everyday engineering practice. Obviously, this type of approach has its limitation due to the lack of data for the serious consideration of the system. But it should be anticipated that these excises might serve as guidance for eventual future applications. Also, it should be emphasised that this type of methodology will become an useful tool only if it proves to be justified in the engineering practice.

Abstract Lighting simulation is a useful instrument in predicting lighting conditions in buildings. Modelers can use several matrix methods according to the buildings’ characteristics and the objectives of the analysis. However, it is unknown which methods are the most appropriate for lighting analysis of heritage buildings. The Joanina Library located in the University of Coimbra – a World Heritage building – was used to compare different matrix methods (2PH, 3PH, and 5PH) under several solar models (BRL, DISC, Perez, and Reindl) using Radiance-based simulations. On-site measurements (indoor and outdoor) were used to calculate each method’s accuracy under different solar models. The combination of the 2PH method with the DISC solar model presented the highest accuracy with an average MBEr and RMSEr of 2.8 % and 43.6 %, respectively. Therefore, the 2PH method was the best choice for the case study, even though the 3PH method may also be considered, especially for parametric studies of improving measures.