• Energy Research

Milk and dairy products constitute an important ingredient in the human diet. Ultra-high temperature (UHT) milk is the main dairy product consumed in Portugal and its production entails large inputs of resources which derive on negative environmental effects such as nutrient enrichment of the ecosystem and climate change. In this study, Life Cycle Assessment (LCA) methodology was considered for the environmental assessment of packaged UHT milk produced in Portugal, including simple (whole, semi-skimmed and skimmed) and cocoa milk from a cradle-to-gate perspective and to identify the environmental hot spots. Results showed that the production of the raw milk in the dairy farm is the main hot spot in almost all the categories under assessment mainly due to the emissions from enteric fermentation, manure management and fertilisers production and application. Furthermore, on-site emissions derived from dairy factory are remarkable together with the packages and energy requirements production. The values reported in this study are in the range of other related papers. However, differences were also identified due to several reasons such as allocation approach, data sources, characterisation factors, farm management regimes and assumptions considered. Therefore, these aspects should be carefully addressed and sensitivity to the assumptions and uncertainty of the results should be evaluated.

Abstract In this paper, the Life Cycle Assessment (LCA) methodology is applied to Portuguese printing and writing paper in order to compare the environmental impact of the use of two kinds of fuels (heavy fuel oil and natural gas) in the pulp and paper production processes. The results of inventory analysis and impact assessment show that the pulp and paper production processes play an important role in almost all of the analysed parameters, which do not always result in an important contribution to the corresponding impact categories. The substitution of heavy fuel oil by natural gas in the pulp and paper production processes seems to be environmentally positive.

Social life cycle assessment of a bioelectricity system encompassing more than 400 processes within seven tiers of the supply chain.

An important aspect of sustainable development is the implementation of effective and sustainable waste management strategies. The present study focuses on a Life Cycle Assessment (LCA) approach to different waste management strategies for natural cork stoppers, namely incineration at a municipal solid waste incinerator, landfilling in a sanitary landfill, and recycling. In the literature, there are no LCA studies analyzing in detail the end-of-life stage of natural cork stoppers as well as other cork products. In addition, cork is usually treated as wood at the end-of-life stage. Thus, the outcome of this study can provide an important insight into this matter. The results showed that different management alternatives, namely incineration and recycling, could be chosen depending on the impact category considered. The former alternative presented the best environmental results in the impact categories of climate change, ozone depletion and acidification, while the latter for photochemical ozone formation and mineral and fossil resource depletion. The landfilling alternative did not present the best environmental performance in any of the impact categories. However, when the biogenic carbon dioxide emission was assessed for the climate change category, the landfilling alternative was found to be the most effective since most of the biogenic carbon would be permanently stored in the cork products and not emitted into the atmosphere. A sensitivity analysis was performed and the results showed that there are various parameters that can significantly influence the results (e.g., carbon content in cork and decay rate of cork in the landfill). Thus, LCA studies should include a detailed description concerning their assumptions when the end-of-life stage is included in the boundaries since they can influence the results, and furthermore, to facilitate the comparison of different end-of-life scenarios. The present study and the obtained results could be useful for the decision-making process concerning public solid waste policies and industrial strategies.

SummaryTo support effective urban policies aimed at decreasing the environmental impacts of cities, it is important to develop robust tools for accounting those impacts. Environmentally extended input‐output analysis (EEIOA) is among the most used tools for this purpose, allowing the quantification of both direct and indirect impacts. Life cycle assessment (LCA) is also a holistic and comprehensive tool that accounts for direct and indirect impacts—but its application to cities is still very recent. This study aims at applying EEIOA and LCA to the municipality of Aveiro (Portugal) in order to compare the outcomes of the two tools in terms of total impacts (climate change and fossil fuel depletion) and hotspots (sectors/products contributing most to the impacts), to identify limitations and advantages of the tools when applied to Aveiro, and to illustrate how LCA can be applied to cities. The total impacts estimated with LCA and EEIOA were similar and the hotspots were also the same: transports, food, construction, and electricity. However, the relative contribution of some sectors was very different in the two tools due to methodological differences mainly in system boundaries, type of activities or products considered in each sector, and geographical coverage of impact data. This study concludes that the analyzed tools can provide complementary results to support decision making concerning urban planning and management.

Abstract The ornamental earthenware ceramic manufacturing is typically a multifunctional system because several pieces with different dimensions and geometries are produced in the same mill, at the same time. Therefore, an allocation procedure is needed in order to quantify the share that each ornamental earthenware ceramic piece represents in the manufacturing total energy consumption and costs and greenhouse gas (GHG) emissions. The main aim of this study was to present a methodology to allocate to each piece the energy consumed in the ornamental earthenware ceramic manufacturing process. The methodology relies on mass, volume or number of pieces, depending on the type of energy and stage of manufacturing, and has been tested and validated in a real manufacturing context at an ornamental earthenware ceramic mill. Another objective of this study was the determination of the energy consumption and cost and the GHG emissions, per piece, of some pieces produced in the mill where the allocation methodology was applied, in order to identify improvement opportunities in the manufacturing process. The results show that the energy consumption and costs and the GHG emissions of the studied ceramic pieces are strongly dependent on its dimension, both in terms of mass and volume, and also on the piece susceptibility to crack and to experience deformations and imperfections. These results suggested some improvement measures to reduce the consumption of electricity, natural gas (in shaping and in the biscuit and glost firing cycles) and calcite used as raw material.

Purpose The dairy sector covers multiple activities related to milk production and treatment for alimentary uses. Different dairy products are available in the markets, with yoghurt being the second most important in terms of production. The goal of this study was to analyse from a cradle-to-grave approach the environmental impacts and energy balance derived from the yoghurt (solid, stirred and drinking yoghurts) manufacture process in a specific dairy factory processing 100 % Portuguese raw milk.

Abstract The market for insulation material is playing a crucial role in Europe's energy transformation, due to its influence on energy consumption in buildings. The introduction of renewable materials for thermal insulation is recent, and little is known so far about its environmental implications. This study analyses the environmental performance of a cork insulation board, made of agglomerated cork from forestry cork wastes, by means of cradle-to-gate Life Cycle Assessment methodology. The results indicate that the use of natural insulation materials does not necessarily imply a reduction of environmental impacts due to manufacturing processes with a low technological development. In this case, the most influential stage is the manufacturing stage, in which the board agglomeration and the cork trituration have the highest impacts. The most influential inputs are both the transport used during the life cycle and the large quantities of electricity and diesel in the manufacturing stage. Some strategies have been identified to reduce the environmental impact, such as promote the acquisition of local raw cork to reduce transportation from the manufacturer, improve the efficiency and productivity of manufacturing processes and improve the product design to help increase its market share. Moreover, the inclusion of biogenic carbon contained in forest-based building materials affects the Global Warming Potential results considerably. However, it is very important to consider how this biogenic carbon is calculated and how the product is managed after its lifetime.

The measurement of water consumption by trees is fundamental for detecting potential opportunities to mitigate water resource depletion. The water footprint (WF) is a tool to address the environmental effects related to water use, identifying ways to reduce overall water consumption. This work presents a review, updating the information on how WF is being addressed when applied to forest and orchard trees, identifying the methodological trends of the WF studies, and highlighting the main challenges that deserve further research for a consistent WF assessment of these trees. A sample with 43 publications selected based on keyword screening criteria was comprehensively reviewed, showing that most of the studies focus on orchard trees (mainly olive and citrus trees). The bulk of the studies only presented accounting or inventory results (i.e., water volumes consumed) and disregarded their sustainability or impact. This review highlights that a robust WF assessment of forest and orchard trees requires further research for harmonising the quantification of the green water scarcity footprint, and puts key challenges to the WF practitioners, such as the selection of the most adequate method to estimate ET considering trees specificities and climatic parameters, and the adoption of high spatial and temporal resolution for the WF assessment.