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Abstract This paper proposes a multi-criteria decision approach for sorting energy-efficiency initiatives, promoted by electric utilities, with or without public funds authorized by a regulator, or promoted by an independent energy agency, overcoming the limitations and drawbacks of cost–benefit analysis. The proposed approach is based on the ELECTRE-TRI multi-criteria method and allows the consideration of different kinds of impacts, although avoiding difficult measurements and unit conversions. The decision is based on all the significant effects of the initiative, both positive and negative, including ancillary effects often forgotten in cost–benefit analysis. The ELECTRE-TRI, as most multi-criteria methods, provides to the decision maker the ability of controlling the relevance each impact can have on the final decision in a transparent way. The decision support process encompasses a robustness analysis, which, together with a good documentation of the parameters supplied into the model, should support sound decisions. The models were tested with a set of real-world initiatives and compared with possible decisions based on cost–benefit analysis.

Are microalgae a potential energy source for biofuel production? This paper presents the laboratory results from a Nannochloropsis sp. microalga biorefinery for the production of oil, high-value pigments, and biohydrogen (bioH2). The energy consumption and CO2 emissions involved in the whole process (microalgae cultivation, harvest, dewater, mill, extraction and leftover biomass fermentation) were evaluated. An economic evaluation was also performed. Oil was obtained by soxhlet (SE) and supercritical fluid extraction (SFE). The bioH2 was produced by fermentation of the leftover biomass. The oil production pathway by SE shows the lowest value of energy consumption, 177-245 MJ/MJ(prod), and CO2 emissions, 13-15 kgCO(2)/MJ(prod). Despite consuming and emitting c.a. 20% more than the SE pathway, the oil obtained by SFE, proved to be more economically viable, with a cost of 365€/kg(oil) produced and simultaneously extracting high-value pigments. The bioH2 as co-product may be advantageous in terms of product yield or profit.

The effect of energy policies on the energy performance of residential properties/houses in nineteen Portuguese districts from 2014 to 2021 was investigated. A linear random-effects model regression was used as the method in this empirical investigation. The empirical results indicated that the income per capita has a negative effect on residential properties with high energy efficiency certificates (e.g., A+, A, and B) and a positive impact on residential properties with low energy efficiency certificates (e.g., C, D, E, and F); the codes and standards energy policies for energy efficiency have a positive effect on residential properties with high energy efficiency certificates (e.g., A, B, and B−) and residential properties with low energy efficiency certificates (e.g., C, D, E, and F); the fiscal and financial incentive policies for energy efficiency have a positive effect on residential properties with high energy efficiency certificates (e.g., A+, A, and B) and a negative effect on residential properties with B− energy certificate, and also a negative effect on residential properties with low energy efficiency certificates (e.g., C and D) and a positive effect on residential properties with an F energy certificate; the information and education policies of energy efficiency have a positive effect on residential properties with high energy efficiency certificates (e.g., A+, A, and B) and residential properties with low energy efficiency certificates (e.g., C, D, and E); and, finally, the consumer credit per capita has a positive effect on residential properties with high energy efficiency certificates (e.g., A+, A, and B) and a negative effect on residential properties with low energy efficiency certificates (e.g., C, D, and F), as well as a positive effect on residential properties with an F energy certificate.

Dissertação de Mestrado em Engenharia Eletrotécnica e de Computadores apresentada à Faculdade de Ciências e Tecnologia The evolution of society, its demographic growth, and its technological and economic development made electricity an essential good, causing the consumption of electricity to increase over the years, to guarantee these supply fossil fuels were used in its production an unsustainable option that has generated high levels of pollution and a climate crisis. To address these problems, the European Union established the European Directive 2018/2001. This directive allows renewable energy self-consumers to produce, consume, share, store and sell electricity, promoting various sustainable behaviors such as reducing energy bills, reducing CO2 emissions, combating energy poverty, and reducing the cost of energy—initial investment. This dissertation aims to develop different methodologies for defining the sharing coefficients of energy produced in a CER and to establish comparisons of their performance in the CER. The CER used as a case study in this dissertation is composed of two schools in Coimbra and the DEEC building. In a preliminary analysis of the consumption of each building, several simulations were carried out to find out which would be the best location of production in the CER, having that choice fell on school 1. Five methods were developed to define the coefficients of sharing the surplus energy produced by the CER by its members. In key 1, fixed coefficient, a fixed percentage of energy sharing is assigned, in key 2 the sharing coefficients are proportional to the consumption of each user, that is, members who have higher consumption receive a greater percentage of energy. Keys 3, 4, and 5 all have the same energy sharing philosophy, they follow a list of priorities, with energy sharing being done by serving the highest priorities until they run out of energy or all members of the list see their consumption needs. satisfied. According to the results obtained, it was possible to conclude that the best key or the most beneficial key for this particular CER would be key 3, as it generates less unused surplus energy and still has good equity, that is, it is energy effectively used annually by CER members, one member, in this case, uses 58% and another 42%.In short, to choose the distribution key that optimizes the sharing of surplus energy in a community, we must consider the community, since each key has its advantages and disadvantages, and its use varies according to the CER. A evolução da sociedade, o seu crescimento demográfico e o seu desenvolvimento tecnológico e económico, tornou a eletricidade um bem essencial, fazendo com que o consumo de energia elétrica aumentasse ao longo dos anos, para garantir esta oferta foram utilizados combustíveis fósseis na sua produção, uma opção não sustentável que gerou elevados níveis de poluição e uma crise climática. Para colmatar esses problemas a União Europeia estabeleceu a Diretiva Europeia 2018/2001. Essa diretiva permite aos autoconsumidores de energia renovável produzir, consumir, partilhar, armazenar e vender eletricidade, promovendo diversos comportamentos sustentáveis como redução na fatura energética, a redução das emissões de CO2, combate à pobreza energética e consequentemente a redução no custo do investimento inicial. A presente dissertação tem como objetivo desenvolver diversas metodologias de definição dos coeficientes de partilha de energia produzida numa CER e estabelecer comparações do seu desempenho na CER. A CER usada como estudo de caso nesta dissertação é composta por dois estabelecimentos escolares de Coimbra e pelo edifício do DEEC. Numa análise preliminar dos consumos de cada edifício, realizou-se várias simulações para descobrir qual seria a melhor localização da produção na CER, tendo essa escolha recaído na escola 1. Foram desenvolvidos cinco métodos para definição dos coeficientes de partilha da energia excedentária produzida pela CER pelos membros da mesma. Na chave 1, coeficiente fixo, é atribuída uma percentagem fixa de partilha de energia, na chave 2 os coeficientes de partilha são proporcionais ao consumo de cada utilizador, ou seja, membros que tenham maior consumo recebem uma maior percentagem de energia. Já as chaves 3, 4, 5 têm todas a mesma filosofia de partilha de energia, seguem uma lista de prioridades, sendo a partilha de energia feita servindo os mais prioritários até esgotar a energia ou todos os membros da lista vejam as suas necessidades de consumo satisfeitas. De acordo com os resultados obtidos foi possível concluir que a melhor chave ou a chave mais benéfica para esta a CER em particular seria a chave 3, por gerar menos energia excedentária não utilizada e mesmo assim ter uma boa equidade, ou seja, é a energia efetivamente utilizada anualmente pelos membros da CER, um membro, neste caso, utiliza 58% e outro 42%. Em suma, para se escolher a chave de repartição que otimiza a partilha da energia excedentária duma comunidade, devemos ter em consideração a comunidade, visto que, cada chave tem as suas vantagens e desvantagens e a sua utilização varia de acordo com a CER.

With sensor-based demand-controlled ventilation (SBDCV), the rate of ventilation is modulated over time based on the signals from indoor air pollutant or occupancy sensors. SBDCV offers two potential advantages: better control of indoor pollutant concentrations, and lower energy use and peak energy demand. Based on theoretical considerations and on a review of literature, SBDCV has the highest potential to be cost-effective in applications with the following characteristics: (a) a single or small number of pollutants dominate so that ventilation sufficient to control the concentration of the dominant pollutants provides effective control of all other pollutants; (b) large buildings or rooms with unpredictable temporally variable occupancy or pollutant emission; and (c) climates with high heating or cooling loads or locations with expensive energy. At present, most SBDCV systems are based on monitoring and control of carbon dioxide (CO2) concentrations. There is a limited number of well-documented case studies that quantify the energy savings and the cost-effectiveness of SBDCV. The case studies reviewed suggest that in appropriate applications, SBDCV produces significant energy savings with a payback period typically of a few years.

The present study seeks to select the most important articles and reviews from the Web of Science database that approached alternative fuels towards the decarbonization of the maritime sector. Through a systematic review methodology, a combination of keywords and manual refining found a contribution of 103 works worldwide, the European continent accounting for 57% of all publications. Twenty-two types of fuels were cited by the authors, liquefied natural gas (LNG), hydrogen, and biodiesel contributing to 49% of the mentions. Greenhouse gases, sulfur oxide, nitrogen oxide, and particulate matter reductions are some of the main advantages of cleaner sources if used by the vessels. Nevertheless, there is a lack of practical research on new standards, engine performance, cost, and regulations from the academy to direct more stakeholders towards low carbon intensity in the shipping sector.

Forest community connections are crucial to ensure forest stewardship and sustainability. We explored the potential of mushrooming to enable such connections in contexts where these connections have been historically broken, alienating local people from forests. Taking the case of the recent devolution of a community forest (baldios) in central Portugal to the local population, we present a five-year pilot project to rework mycology from a mushroom-centered approach to a mushroom-in-baldios approach. Mushrooms were used as an entry-point to connect the forest ecology with the challenges of governance and community building. The devised activities provided an opportunity for people inside and outside the local community to adventure into the woods and find out more about their socio-ecological history, develop communal and convivial relationships and engage in the responsible gathering of wild mushrooms. However, the hosting of mushroomers to know, value and engage with the community forest recovery has constantly worked against the enclosure of mushrooms to provide marketable forms of leisure. The outcome of these activities depends on the relationships established between mushrooms, mycologists, local administrators, commoners and poachers, all operating within a framework that favors the eradication of resources instead of long-term relationships that sustain places.

The article proposes a framework establishing a disaster resilience index applicable worldwide that accounts for differences between countries in terms of development and in terms of the relevance of several resilience dimensions. To achieve this index, countries were clustered using an indicator that reflected their performance according to the Sustainable Development Goals. For each cluster of countries, a Delphi process was used to obtain scores for every resilience dimension and sub-dimension that were then transformed into weights that varied from cluster to cluster to reflect differences in sustainable development. The article discusses the methodology that led to the quantification of the weights according to the Delphi process, as well as its results. The results highlighted the anticipated differences between different groups of countries, but also reflected cluster-specific features that should be accounted for when analyzing disaster resilience. The article also discusses different applications and possible improvements of the proposed framework based on comments collected during the Delphi process.