• Energy Research

Nowadays there is a growing concern with the environment and sustainability, which means that better methods, including pollutants analysis, with less consumption of materials, organic solvents, and energy, need to be developed. Considering the almost inexistent information about the topic, the main goal of this work was to compare the environmental impacts of two analytical methods, a traditional one based on liquid chromatography with fluorescence detection and a newly developed carbon paper sensor. The selected analyte was 17α-ethinylestradiol, which is a contaminant of emergent concern in aquatic ecosystems due to its endocrine disruptor behavior. The life cycle assessment data showed that the sensor detection presents an almost negligible environmental impact when compared with the extraction step (the same for both methods) and the liquid chromatographic determination (roughly 80 times higher than with the sensor). The sensor values for all categories of damage are below 3% of the total method impacts, i.e., 1.6, 1.9, 2.4, and 2.9% for resources, climate change, human health, and ecosystem quality. The extraction represents 98.1% of the sensor environmental impacts (and 99.6% of its life cycle costing) and 38.8% of the chromatographic method. This study evidences the need of developing and applying greener analytical (detection and extraction) strategies.

Application of zero valent iron nanoparticles is an innovative technology for ground water treatment and soil remediation. There are several methods to synthesise nano scale zero valent iron (nZVI), namely through bottom-up methods which consists on chemical reactions using strong reducing agents. In this work, the environmental impacts and costs were determined for two methods, namely the traditional one that uses sodium borohydride and the green method that uses extracts obtained from natural products. The consideration of environment and economic aspects in the earlier stages of the synthesis processes and in the development of new materials is of great importance since it can help to decide if alternative methods are promising and should be further developed aiming more sustainable processes. In this work, life cycle assessment (LCA) was used as an ecodesign strategy evaluating environmental performance of the two synthesis methods, identifying critical stages of the synthesis processes of nZVI. An economic evaluation and a sensitivity analysis considering a different scenario for electricity production were also performed. The results obtained in this study showed that the green synthesis method presents lower environmental impacts than the traditional one, roughly 50% lower in the first scenario. In the second scenario, environmental impact of green synthesis corresponds to 38% of the environmental impact of traditional synthesis. In the green method, the critical stage is the extraction process which is closely related to the electricity production. In the traditional method, the reactant use is the critical stage that is related to the production of sodium borohydride. The economic evaluation indicated that the traditional synthesis method is much more expensive than the green synthesis (roughly eight times higher). From the results obtained, it is possible to conclude that the green synthesis method presents lower environmental impacts in both scenarios and lower costs than the traditional synthesis.

Abstract Data of Portuguese wastewater treatment plants (WWTPs) were analyzed in order to compare their energy and environmental performances. Several absolute and ratio indicators were considered, namely, electricity consumption, CO2 emissions from electricity, biochemical oxygen demand removal and the corresponding ratio indicators where each of the previous amounts was divided by total volume treated. Groups for statistical analysis were established considering different factors (population equivalent, size, etc.) and Kruskal-Wallis test was applied to assess the effect of these factors on the indicators considered. Significant differences were found for population equivalent and size for the three absolute indicators.

Abstract Hydropower is one of the most traditional renewable energy source and a major contributor for renewable energy production in many countries. In Portugal it was the only renewable energy source for many years but nowadays wind presents similar production levels and for example in 2015 wind was the main source producing 45.5 % of the total renewable energy. However hydro energy will continue to be important in the renewable energy production and in this work ranking of nine models for hydro energy production with various numbers of parameters was done using adjusted R-squared and corrected Akaike information criterion (AICc).

Abstract Traditional approaches to protect environment usually rely on a legal framework that enforces measures and behaviors on organizations. However, to achieve sustainability it is necessary to apply other tools that need a stronger commitment from the organizations in the three pillars of sustainable development. The implementation of an Environmental Management System, being a voluntary instrument, can play an important role in the environmental pillar because it has a structured approach to manage environmental aspects of organizations. The new revisions of the two most important standards maintain the previous pattern. EMAS (Eco-Management and Audit Scheme) incorporates the requirements of ISO 14001:2015 while maintaining important additional requirements such as the Environmental Statement and the employee involvement. The new revision of ISO 14001 by emphasizing organizational environmental performance can be a significant opportunity to increase sustainability given the fact that this international standard is more widely implemented than EMAS.

The use of fossil fuels as the main source of energy for most countries has caused several negative environmental impacts, such as global warming and air pollution. Air pollution causes many health problems, causing social and economic negative effects. Worldwide efforts are being made to avoid global warming consequences through the establishment of international agreements that then lead to local policies adapted to the development of each signing nation. In addition, there is a depletion of nonrenewable resources which may be scarce or nonexistent in future generations. The preservation of resources, which is a common goal of the Circular Economy strategy and of sustainable development, is not being accomplished nowadays. In this work, the calculation of indicators and mathematical and statistical analysis were applied to clarify and evidence the trends, provide information for the decision-making process, and increase public awareness. The fact that European countries do not possess abundant reserves of fossil fuels will not change, but the results of this analysis can evolve in the future. In this work, fossil fuel energy consumption, fossil fuel depletion, and their relationship with other variables, such as energy dependence and share of renewable energy in gross final energy consumption, were analyzed for 29 European countries. Furthermore, it was possible to conclude that many European countries still depend heavily on fossil fuels. Significant differences were not found in what concerns gross inland consumption per capita when the Kruskal–Wallis test was applied. It was possible to estimate that by 2050 (considering Jazz scenario) it will only remain approximately 14% of oil proven reserves, 72% of coal proven reserves and 18% of gas proven reserves. Given the small reserves of European countries on fossil fuels, if they need to use them, they will fast disappear.

Energy and materials are increasingly important in industrialized countries, and they impact the economy, sustainability, and people’s future. The purpose of this work was to study the relationship between energy and the circular economy using methods such as Pearson’s correlation and a principal component analysis. Thus, 12 strong correlations were found, with 5 of them between the following relevant variables from two different subjects: the correlations of the raw material consumption, the domestic material consumption, and the material import dependency with the final energy consumption in transport (0.81, 0.92, and 0.81); the correlation of the circular material use rate with the final energy consumption in households (0.70); and the correlation of the material import dependency with the final energy consumption in industry (0.89). The time series forecast was only conclusive for the waste generated, showing that it will increase in the next 10 years.

Abstract Biodiesel has attracted considerable attention as a renewable, biodegradable, and nontoxic fuel and can contribute to solving the energy problems, significantly reducing the emission of gases which cause global warming. The first stage of this work was to simulate different alternative processes for producing biodiesel. The method used for the production of biodiesel is the transesterification of vegetable oils with an alcohol in the presence of a catalyst. The raw materials used were palm oils and waste cooking oil. The second stage was a life cycle analysis for all alternatives under study, followed by an economic analysis for the alternatives that present minor impacts and which are more promising from an economic point of view. Finally, we proceeded to compare the different alternatives from both the point of view of life cycle and economic analysis. The feasibility of all processes was proven and the biodiesel obtained had good specifications. From the standpoint of life cycle analysis, the best alternative was the process of alkaline catalysis with acid pre-treatment for waste cooking oil. The economic analysis was done to the previous mentioned process and to the process that uses raw virgin oils, methanol, and sodium hydroxide. This process has lower investment costs but the process of alkaline catalysis with acid pre-treatment, whose main raw material is waste oil, is much more profitable and has less environmental impacts.