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Abstract. The concept of wake steering on wind farms for power maximization has gained significant popularity over the last decade. Recent field trials described in the literature not only demonstrate the real potential of wake steering on commercial wind farms but also show that wake steering does not yet consistently lead to an increase in energy production for all inflow conditions. Moreover, a recent survey among experts shows that validation of the concept currently remains the largest barrier to adoption. In response, this article presents the results of a field experiment investigating wake steering in three-turbine arrays at an onshore wind farm in Italy. This experiment was performed as part of the European CL-Windcon project. While important, this experiment excludes an analysis of the structural loads and focuses solely on the effects of wake steering on power production. The measurements show increases in power production of up to 35 % for two-turbine interactions and up to 16 % for three-turbine interactions. However, losses in power production are seen for various regions of wind directions too. In addition to the gains achieved through wake steering at downstream turbines, more interesting to note is that a significant share in gains is from the upstream turbines, showing an increased power production of the yawed turbine itself compared to baseline operation for some wind directions. Furthermore, the surrogate model, while capturing the general trends of wake interaction, lacks the details necessary to accurately represent the measurements. This article supports the notion that further research is necessary, notably on the topics of wind farm modeling and experiment design, before wake steering will lead to consistent energy gains on commercial wind farms.

Mathematical equations are developed to study thermal processes in a CPC collector with a flat one-sided absorber. An expression for the temperature of the heat transfer fluid as a function of the space-co-ordinate in the flow direction and the time dependent solar intensity is developed. The effects of various parameters on the thermal performance of such a CPC are studied. The selectively coated CPC with flat one-sided collector is more efficient than the black painted one with the same condition. The predicted results were also compared with the experimental results reported in the literature.

The transport sector needs to go through an extended process of decarbonisation to counter the threat of climate change. Unfortunately, the International Energy Agency forecasts an enormous growth in the number of cars and greenhouse gas emissions by 2050. Two issues can thus be identified: (1) the need for a new methodology that could evaluate the policy performances ex-ante and (2) the need for more effective policies. To help address these issues, we developed an Agent-Based Model called Mobility USA aimed at: (1) testing whether this could be an effective approach in analysing ex-ante policy implementation in the transport sector; and (2) evaluating the effects of alternative policy scenarios on commuting behaviours in the USA. Particularly, we tested the effects of two sets of policies, namely market-based and preference-change ones. The model results suggest that this type of agent-based approach will provide a useful tool for testing policy interventions and their effectiveness.

Nowadays, most countries of the world are implementing the transition to the low-carbon economy which implies the need to carry out a full-scale eco-modernization of the energy sector. Green energy may be identified as one of the core concerns of energy sector modernization as it allows a considerable decrease in emissions of harmful substances into the atmosphere. Therefore, nuclear and renewable energy may become key areas of global energy development in the near future, which is also in agreement with circular economy concepts. However, public opinion (and other controversial visions/aspects) is one of the barriers to their development. The purpose of this study is to analyze the relationship between attitudes towards nuclear and renewable energy in two countries: a EU country (Italy) and a non-EU country (Russia), considering the level of their development. The authors conducted a survey among residents regarding their attitude towards nuclear and renewable energy, as well as their attitude to the present energy policy. The cluster analysis technique was used to analyze the results. The obtained results confirmed the dependence between the level of development of nuclear and renewable energy and the public attitude towards it. The national energy policy also might influence public opinion on the development of nuclear or renewable energy. The authors identified public attitude as one of the key factors in the development of energy and the achievement of environmental and social sustainability.

The construction of a permeable thermoelement that uses heat fluxes carried by a gas or liquid is presented. A method for thermoelement design on the basis of mathematical optimal control theory and computer simulation techniques is described. The results of research into a permeable planar thermoelement fabricated from Bi-Te-Se-Sb semiconductor materials are presented. The data obtained demonstrate the possibility of obtaining the desired temperature range for the optimal conditions, with energy efficiency exceeding that of conventional thermoelements by 8% to 17%. The basic theoretical principles and computer simulation results have been confirmed experimentally.

Lipase‐catalyzed transesterification of triglycerides and alcohols to obtain biodiesel is an environmentally friendly and sustainable route for fuels production since, besides proceeding in mild reaction conditions, it allows for the use of low‐cost feedstocks that contain water and free fatty acids, for example non‐edible oils and waste oils. This review article reports recent advances in the field and focus in particular on a major issue in the enzymatic process, the inactivation of most lipases caused by methanol, the preferred acyl acceptor used for alcoholysis. The recent results about immobilization of enzymes on nano‐materials and the use of whole‐cell biocatalysts, as well as the use of cell‐surface display technologies and metabolic engineering strategies for microbial production of biodiesel are described. It is discussed also insight into the effects of methanol on lipases obtained by modeling approaches and report on studies aimed at mining novel alcohol stable enzymes or at improving robustness in existing ones by protein engineering.

This work presents a project of hi-tech and supergreen ‘nZEB casale’ in Italy. The ‘nZEB casale’ is located in Matera, in the south of Italy. The project concerns the renovation of a medieval ‘casale’, a group of rural houses for residential use. The shape of the new nZEB is in the style of old light-colored buildings, compact and with projections and shielding elements to reduce the summer thermal loads. The use of local and certified materials for the construction of buildings has resulted in a low environmental impact of buildings and an excellent winter and summer energy performance reaching the best energy class A4. Finally, this work presents an environmental protocol to be applied to nZEBs in order to take into account the other benefits of these constructions, as well as the energy benefits.

AbstractVineyard pruning is a potential lignocellulosic feedstock for bioethanol production from agricultural woody residues, due to its high sugar content and ready availability in whole Europe. Ethanol production from lignocellulosic biomass requires a pretreatment step and then enzymatic hydrolysis process to release sugars for fermentation to ethanol. In this work, alkaline pretreatment with NaOH on vineyard residues was investigated on laboratory scale. The raw material was firstly characterized in order to determine cellulose, hemicellulose and lignin content, using the standard laboratory analytical procedures for biomass analysis provided by the National Renewable Energy Laboratory (NREL). Then, based on Response Surface Methodology tool (RSM), a Box-Behnken model was chosen to define a design of experiments (DoE) in terms of the three independent variables that influence the process: the NaOH concentration, the reaction time and the temperature of the pretreatment process. According to the design, 15 samples of raw material were submitted to alkaline pretreatment and subsequent enzymatic hydrolysis and the glucose yield from whole process was calculated. The statistical optimization was carried out with Minitab 17 software, in order to determine the best operative pretreatment condition by maximizing the glucose yield from enzymatic hydrolysis.Results show that the best glucose yield was obtained at the highest sodium hydroxide concentration and temperature of the reaction; this condition allowed to achieve very significant glucose yield thanks to lignin removal performed with the pretreatment.