Nidia Caetano | Instituto Politecnico do Porto (original) (raw)

Papers by Nidia Caetano

Environment, Development and Sustainability, May 31, 2018

This article presents and describes the LCA4Power tool, developed in this work to assess the pote... more This article presents and describes the LCA4Power tool, developed in this work to assess the potential environmental impacts, as, for example, the contribution to global warming, of electricity generation in continental Portugal, not considering the Madeira and Azores archipelagos. Based on a life cycle perspective, the tool considers the life cycles of various available technologies for producing electricity, on a cradle-to-gate perspective, excluding distribution and final use. It was implemented in MS Excel™ using emission factors obtained from the literature and other sources, instead of raw life cycle inventory data. The current version of the tool includes wind and hydroelectric power as renewable energy sources, and thermal and combined heat and power generation from fossil fuels as non-renewable energy sources. The combination of the aforementioned electricity generation technologies is responsible for more than 90% of the electricity generated in continental Portugal. Results were validated comparing the tool's predictions with data from other LCA studies of electricity production, showing a good agreement, in particular for the greenhouse gas emissions. As added value, this tool provides a user-friendly way of simulating the potential environmental impacts of different endogenous energy mixes in Portugal, thus support decision making and communication. Future developments of the tool will include other technologies for electricity generation and its application to support decision making through the analysis of future scenarios for electricity generation in Portugal.

The Electricity Journal, Oct 1, 2020

Abstract Portugal has made great progress in implementing renewable energy systems (RES) to use i... more Abstract Portugal has made great progress in implementing renewable energy systems (RES) to use its endogenous renewable resources. As the cost of renewable energy generation is decreasing, mainly for photovoltaic energy, a significant increase in its production is expected, in particular at the local and domestic levels. Yet, much investment and development is still needed to fulfil the goals for renewable energy generation defined by the Portuguese government and the European Union, in order to decarbonize energy generation and reduce energy dependence. Besides limitations in the installed capacity, the full potential of existing and future RES is not fulfilled, mainly due to imbalances in supply and demand, resulting from the varying climatic conditions and limited energy storage capacity. Although some investment was made in large scale Energy Storage Systems (ESS), especially pumped hydro, distributed energy storage (DES), in particular for stationary domestic storage appliances, have received little attention from decision makers. When properly defined, designed and implemented, they can contribute to increase the efficiency of existing and future RES and the capacity factor. Thus, in this work the questions regarding the implementation of DES are analysed. The main criteria that have to be considered when selecting the proper storage technology for DES are defined, taking into account information and data from current legislation and/or strategic plans and goals, and the technical and scientific literature, in order to support decision making and policy definition at different levels. The proposed application of the various criteria leads to the conclusion that for DES, electrochemical based ESS are the most adequate, among which Li ion batteries and redox flow batteries, particularly suited for local and/or household applications. The current policies sought out for Portugal are also examined in order to identify which aspects should be improved to promote and increase the relevance of DES in the Portuguese energy mix, and it is concluded that specific policies and support are needed to increase the relevance of decentralized electricity storage systems.

Energy Reports, Feb 1, 2020

Buildings are responsible for a significant part of the global energy consumption. Besides the ne... more Buildings are responsible for a significant part of the global energy consumption. Besides the need to improve their energy efficiency, new buildings also need to generate their own energy, preferably from renewable sources, to become more sustainable. As renewable energy generation is strongly dependent on the climatic conditions, energy storage must be considered when designing such a system. In this study, a cradle-to-grave life cycle assessment (LCA) study of a renewable energy generation system with a prototype Vanadium flow battery integrated in a Near Zero Energy Building (NZEB) is performed. A combined grid-connected PV and a solar thermal system generates the energy, and it was dimensioned to supply the annual energy needs of a household in Porto, Portugal considering the local climatic conditions. As an end of life scenario, it is assumed that the battery is dismantled and most of the materials are recycled. A functional unit of 1 kWh of supplied energy to the system was considered, and study results show that environmental impacts are reduced when the energy is produced onsite and the battery components are recycled or reused. A sensitivity analysis was conducted changing the household's geographic location.

Journal of Cleaner Production, Sep 1, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Energy Reports, Feb 1, 2020

Battery storage technologies have been showing great potential to address the vulnerability of re... more Battery storage technologies have been showing great potential to address the vulnerability of renewable electricity generation systems. Among the various options, vanadium redox flow batteries are one of the most promising in the energy storage market. In this work, a life cycle assessment of a 5 kW vanadium redox flow battery is performed on a cradle-to-gate approach with focus on the vanadium electrolytes, since they determine the battery's storage capacity and can be readjusted and reused indefinitely. The functional unit is 1 kWh stored by the battery. The initial results show that the environmental hotspots reside mainly in the structural and material components of the battery, evidencing the need for alternative or recycled materials, preferably produced locally. Since the quantity of electrolytes determine the amount of storable electricity, an analysis was conducted on the variation of the impacts with the increase of storage capacity. An alternative scenario with reused electrolytes was also performed. Results show that with the increase of storage capacity, the contribution of the electrolytes to the impacts decrease significantly by stored kWh. In the reused electrolytes scenario, impacts were reduced mainly for the Acidification and Mineral, fossil and renewable resource depletion categories.

Energy Reports, Feb 1, 2020

Microalgae have been reported as a promising alternative for biofuels production. However, the us... more Microalgae have been reported as a promising alternative for biofuels production. However, the use of microalgae for biofuels is still a challenge due to the intense energy use and the generation of a significant amount of biomass residues in the process. In order to analyze the environmental impacts of different technological processes for the production of biodiesel from microalgae, several studies have been published making use of the Life Cycle Assessment (LCA) methodology, which allows the recognition of the process bottlenecks and supports the identification of alternatives for a more efficient use of the feedstock. Therefore, in this study, a Life Cycle Inventory (LCI) is compiled, based on real pilot-scale process data, which was scaled-up to a microalgae biomass industrial plant for biofuel production. Values of energy, nutrients, water, and materials consumption are used to create an inventory of inputs and outputs for biomass cultivation and biodiesel production, in order to acquire data to conduct a complete LCA modeling in future studies. According to this model, to produce 1 kg of biodiesel it is necessary about 12 kg of dried algae biomass. This study supports the decision-making process in biofuel production to promote the development of sustainable pilot and large-scale algae-based industry, through the identification of critical factors. c

Energy Reports, Jun 1, 2022

Energy Reports, Feb 1, 2020

The growing impacts of climate change mainly due to the increasing emissions of GHG, especially c... more The growing impacts of climate change mainly due to the increasing emissions of GHG, especially carbon dioxide, has led to the development and implementation of specific strategies and policies to reduce them. Carbon capture and utilization (CCU) is currently seen as a good option, as it contributes to reduce the net carbon emissions and fulfil the goals of the Paris Agreement. This work analyses the economic potential of CO 2 biofixation by microalgae from the exhaust gas of a Portuguese Natural Gas Combined Cycle (NGCC) power plant. Literature and real operational data are used, collected from reports of Portuguese power generation companies. A preliminary design and economic analysis of the carbon biofixation system was done. Results show that, although requiring a very large investment, the process is economically viable. In further studies a more in depth approach and detailed project combined with a sensitivity analysis, and a comparison with the chemical based CO 2 fixation will be done.

CRC Press eBooks, Feb 14, 2022

RSC Advances, 2020

I am afraid that Theorem 14, as stated in p 496, is incorrect. The correct version of this theore... more I am afraid that Theorem 14, as stated in p 496, is incorrect. The correct version of this theorem is as follows: THEOREM 14. The following statements (1), (2) and (3) are equivalent and imply statement (4): (1) 4e(L(l/i),Co); (2) Σ* I a«k I N k-> 0 (n-+ oo) for every N > 1; (3) (i) sup w , fc \a nk \N k < oo for every N > 1, (ii) lim w a nk = 0 for every fixed k; (4) supJα^r->0 (n-+<*>). Proof. The equivalence of (1), (2) and (3) follows easily from Theorem 3 [3], Theorem 12 and Lemma 3. Now, since it has been shown in the original argument that (2) implies (4) the proof of the theorem is completed. We remark in passing that a generalized version of the first part of Theorem 14 has been proved recently (cf. C. G. Lascarides; Duality, matrix transformations and weak convergence in some classes of sequences generated by infinite matrices. Ph. D. Thesis, University of Lancaster, England (1971); Theorem 4.2.10). Finally, we notice a minor misprint in p. 489 line 8, where the inclusion c(p; 1) ~Z)c Q (p; 1) should be c(p; 1) czc o (p; 1).

Energy Reports, Feb 1, 2020

In spite of raising awareness of the environmental impacts associated to the production and utili... more In spite of raising awareness of the environmental impacts associated to the production and utilization of plastics, in many situations, the use of plastics is advantageous, and options are still unavailable or under development, representing an opportunity to develop more sustainable options, such as less energy intensive solutions. In this work, the LCA methodology is used to evaluate the environmental impacts of boxes, bowls and plates produced using Areca palm (Areca catechu) sheath, a waste material common in southern India. The inventory is a combination of primary data from a company in India, complemented with secondary data from the Ecoinvent v2.1 (Simapro V7.3). Results show that the main contributors to the potential environmental impact categories and the most energy intensive life cycle steps, are transportation, shipping and electricity generation. Carbon footprints of 1180, 1033 and 1090 kg CO 2 eq/ton were obtained for Areca boxes, plates and bowls, respectively. Plates made from Areca palm sheath have lower environmental impacts than plastic plates, except in the ozone layer depletion and terrestrial toxicity impact categories. c

Green chemistry and sustainable technology, 2017

This chapter presents an overview of the current state of the art concerning the application of l... more This chapter presents an overview of the current state of the art concerning the application of life cycle assessment (LCA) to assess and improve the environmental performance and sustainability of processes that use or are based on membrane technologies. A presentation of the LCA methodology is made, based on the current framework defined by the ISO Standard, focusing on the main aspects and how LCA can be applied to a given product or process system. A review of the available studies was done for membrane based or systems in which membranes have an important role, focusing in water treatment process, either for human and industrial application or wastewater treatment. The analysis shows that the application of LCA is still limited in membrane process, and more work still needs to be done, for example, taking into account the manufacture and final disposal/recycling of the membranes and their corresponding process modules, and to properly asses how membranes may increase the sustainability of existing processes by replacing existing technologies with larger environmental impact. As the need to evaluate the environmental impact and sustainability of new processes increases, the application of the LCA methodology will become more common both in process design and/or process operation.

Energy Procedia, Oct 1, 2018

District heating networks are commonly addressed in the literature as one of the most effective s... more District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.

Aquaculture, Nov 1, 2020

In either unicellular or multi-cellular form, microalgae are photosynthetic microorganisms, mainl... more In either unicellular or multi-cellular form, microalgae are photosynthetic microorganisms, mainly known for being part of the human diet in several world regions. More recently, they have been in the spotlight of researchers, not only because of their nutritional value, but also due to their high value-added components. This work reviews five microalgae genera: Dunaliella, Botryococcus, Chlamydomonas, Chlorella and Arthrospira, considered among the most promising for commercial biotechnological applications. The analysis shows that, although the research paradigms are generally shared among species, parameterization changes of culture environment and stress conditions, several applications can be envisaged for the cultivated species, which is discussed in this work. Besides, several applications in which these microalgae are being widely used, or are intended to be used, are analyzed and discussed. The potential applications depend on the type of metabolites found in each microalgae species, which is discussed in this work, giving examples of application and describing methods for their cultivation, harvesting and biomass processing. Thus, in addition to being used in human diet supplementation, microalgae can be used as ingredients for animal feed, medicines, cosmetics pigments, biofuels, bioplastics and biostimulants. 2. Brief presentation of the microalgae species Microalgae are classified into cyanobacteria (blue-green), rhodophytes (red algae), chlorophytes (green algae) and chromophytes (all other algae) (Mobin and Alam, 2017). Dunaliella, Botryococcus, Chlamydomonas and Chlorella are microalgae belonging to the phylum of chlorophytes that have different structural shapes. Chlorella has a spherical shape, as well as Dunaliella, however, this presents a change in its structural shape as the cells grow. Chlamydomonas and Botryococcus have oval shape, which depending on the species, may also present pyramidal shape. Arthrospira (Spirulina) are cyanobacteria with cylindrical trichome shape. As shown in Table 1, Botryococcus can reach the highest amount of

The European Project Semester (EPS) is a one-semester capstone project/internship programme offer... more The European Project Semester (EPS) is a one-semester capstone project/internship programme offered to engineering, product design and business undergraduates by 18 European engineering schools. EPS aims to prepare future engineers to think and act globally by adopting project-based learning and teamwork methodologies. The EPS@ISEP programmethe EPS programme provided by ISEP-the School of Engineering of the Polytechnic Institute of Porto-started in 2011 and has since welcomed 3rd and 4th year mobility students during the spring semester. In particular, sustainable development is a pervasive concern within EPS projects. It was in this context that, in 2012, a team of EPS@ISEP students decided to develop a water disinfection system. While the technical goal of the project was to design and develop a fluid disinfection system for removing bacteria, viruses and seaweeds, the overall objective was far more ambitious: to help students learn, develop and adopt sustainable practices for their future professional life. The system was intended to be a simple and effective solution for water treatment and recycling. At a larger scale, the project contributes to the preservation of the planet's fresh water resources and to the improvement of the population's health by eliminating harmful microorganisms from the water. This challenge was, by itself, motivational and exposed the team to new learning experiences. The team found several approaches for water treatment and, after a detailed analysis, decided to adopt Ultraviolet (UV) irradiation for the removal of microorganisms. This multidisciplinary real world problem drove the team during the semester. The team surveyed and compared different methods for water cleansing and recycling, chose one approach and, then, designed, built and tested the prototype. In addition, the students also addressed marketing, sustainability as well as the ethic and deontological issues regarding the proposed solution while developing crosscultural understanding, teamwork and communication skills. The project provided an excellent opportunity to foster the concept of sustainable development amongst students.

Chemical engineering transactions, 2016

Lipid Content and Productivity of Arthrospira platensis and Chlorella vulgaris under Mixotrophic ... more Lipid Content and Productivity of Arthrospira platensis and Chlorella vulgaris under Mixotrophic Conditions and Salinity Stress Teresa M. Mata*, António A. Martins, Octávio Oliveira, Sandra Oliveira, Adélio M. Mendes, Nídia S. Caetano a LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto (FEUP), R. Dr. Roberto Frias S/N, 4200-465 Porto, Portugal b Department of Environmental Engineering, Faculty of Natural Sciences, Engineering and Technology (FCNET), Oporto Lusophone University, R. Dr. Augusto Rosa, 24, 4000-098 Porto, Portugal c CIETI, Department of Chemical Engineering, School of Engineering (ISEP), Polytechnic Institute of Porto (IPP), R. Dr. António Bernardino de Almeida S/N, 4200-072 Porto, Portugal tmata@fe.up.pt

Chemical engineering transactions, 2016

Sustainability Evaluation of Biodiesel from Arthrospira platensis and Chlorella vulgaris under Mi... more Sustainability Evaluation of Biodiesel from Arthrospira platensis and Chlorella vulgaris under Mixotrophic Conditions and Salinity Stress António A. Martins*, Teresa M. Mata, Octávio Oliveira, Sandra Oliveira, Adélio M. Mendes, Nídia S. Caetano a LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto (FEUP), R. Dr. Roberto Frias S/N, 4200-465 Porto, Portugal b Department of Environmental Engineering, Faculty of Natural Sciences, Engineering and Technology (FCNET), Oporto Lusophone University, R. Dr. Augusto Rosa, 24, 4000-098 Porto, Portugal c CIETI, Department of Chemical Engineering, School of Engineering (ISEP), Polytechnic Institute of Porto (IPP), R. Dr. António Bernardino de Almeida S/N, 4200-072 Porto, Portugal tmata@fe.up.pt

Chemical engineering transactions, 2015

a LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of ... more a LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto (FEUP), R. Dr. Roberto Frias S/N, 4200-465 Porto, Portugal b Department of Chemical Engineering, School of Engineering (ISEP), Polytechnic Institute of Porto (IPP), R. Dr. António Bernardino de Almeida S/N, 4200-072 Porto, Portugal c Department of Environmental Engineering, Faculty of Natural Sciences, Engineering and Technology (FCNET), Oporto Lusophone University, R. Dr. Augusto Rosa, 24, 4000-098 Porto, Portugal tmata@fe.up.pt

Energy Reports, 2020

Industrial production and commercialization of biodiesel from microalgae have become a good alter... more Industrial production and commercialization of biodiesel from microalgae have become a good alternative to conventional feedstock. Microalgae show high growth rate and carbon sequestration and can be easily cultivate in fresh and/or marine water, using non-arable soil. This study aims to analyze the technical and economic feasibility of biodiesel production from Phaeodactylum tricornutum, using an algae biomass production scaled-up scenario, considering local reality prices and available technologies. The model assumes 80,000 m 3 of microalgae cultivation, in a set of bubble column photobioreactors installed on 15.247 ha of land, reaching a total of 1,811 tons of microalgae biomass and 171,705 L of biodiesel per year. The production cost estimated for microalgae biomass is 2.01 e kg −1 and for biodiesel is 0.33 e L −1. The ROI calculated for the project is 10% with a 10 years' payback time and an EBITDA of 588,139 e year −1. Despite the project's viability in the medium term, the cost of producing microalgae biodiesel remains high when compared to fossil fuels. Thus, unless greater technological maturity is achieved to make the process more economical, it will not be viable in the short term. c

Environment, Development and Sustainability, May 31, 2018

The Electricity Journal, Oct 1, 2020

Energy Reports, Feb 1, 2020

Journal of Cleaner Production, Sep 1, 2020

Energy Reports, Feb 1, 2020

Energy Reports, Jun 1, 2022

Energy Reports, Feb 1, 2020

CRC Press eBooks, Feb 14, 2022

RSC Advances, 2020

Energy Reports, Feb 1, 2020

Green chemistry and sustainable technology, 2017

Energy Procedia, Oct 1, 2018

Aquaculture, Nov 1, 2020

Chemical engineering transactions, 2016

Chemical engineering transactions, 2015

Energy Reports, 2020

Excessive fossil fuel consumption is driving the search for alternative energy production solutio... more Excessive fossil fuel consumption is driving the search for alternative energy production solutions and, in particular, for sustainable sources of energy such as microalgae, from which biodiesel, among other useful compounds, can be obtained. After producing the microalgae, they must be harvested and dried. Existing drying solutions consume too much energy and are, therefore, expensive and unsustainable. The goal of this EPS@ISEP Spring 2013 project was to develop a solar microalgae dryer for the microalgae laboratory of ISEP. A multinational team of five students from distinct fields of study was responsible for designing and building the solar microalgae dryer prototype. The prototype includes a control system to ensure that the microalgae are not destroyed during the drying process. The solar microalgae dryer works as a distiller, extracting the excess water from the microalgae suspension. This paper details the design steps, the building technologies, the ethical and sustainable concerns and compares the prototype with existing solutions. The proposed sustainable microalgae drying process is competitive as far as energy usage is concerned. Finally, the project contributed to increase the team’s sustainable development awareness, active learning and motivation.

This work aims to explore the production of biodiesel from oil extracted from spent coffee ground... more This work aims to explore the production of biodiesel from oil extracted from spent coffee grounds (SCG) via enzymatic catalysis with the Lipozymes RM IM, TL 100L and CALB L, in the presence of a co-solvent, and to optimize the reaction conditions. A three factors design of experiments was performed to evaluate the influence on the reaction performance of ethanol/oil molar ratio, enzyme concentration and reaction temperature. Oil was extracted from air dried SCG with hexane in a pilot solid/liquid extractor, resulting in 6.4{\%} (m/m oil) in dry SCG. The coffee oil was characterized for its kinematic viscosity (38.04 mm2/s), density (0.903 g/cm3), heating value (38 MJ/kg), iodine value (63 g I2/100 g oil), water content (0.1458{\%}), acid value (44.78 mg KOH/g oil), flash point (>120{\thinspace}{\textdegree}C) and triglyceride content (82.8{\%}). Based on the design of experiments, the best conditions for the transesterification reaction are 5:1 molar ratio of ethanol/oil, 4.5{\%} (m/m oil) of enzyme and 45{\thinspace}{\textdegree}C of temperature, resulting in an experimental yield of 96.7{\%}, with 87.6{\%} (m/m) of esters content. Additionally, it was studied the effect of water in the transesterification reaction, using ethanol at 92, 85 and 75{\%} (v/v). Results show that the best reaction yield (97.2{\%}) and esters content (92.1{\%}) were obtained using ethanol 92{\%}. Although the esters content of the biodiesel obtained from coffee oil does not accomplish the EN 14214:2009 requirements, it is promising as there is the possibility to blend the coffee oil with oil from other sources in order to meet the standard requirements.