The environmental impacts derived from the urban water system of the municipality of Aveiro (Portugal) were analysed in this study using the Life Cycle Assessment (LCA) methodology. In addition, ...those stages and processes with the largest environmental impacts were identified and improvement scenarios were proposed. The entire water system was considered, including the following stages: water abstraction and treatment, water distribution, sewage collection, wastewater treatment and disposal, and water administration.
The results show that the stage of water abstraction and treatment was the most relevant for the majority of impact categories because most of the electricity consumption happened during this stage. For marine eutrophication and marine ecotoxicity, the stage of wastewater treatment and disposal alone carried almost the entire burden because of the release of nitrogen and phosphorus into the sea.
Electricity consumption and discharge of nutrients to the sea have been identified as the largest contributors to the environmental impacts. Therefore, scenarios focused on changing these burdens were assessed in order to prioritise those actions that would bring the greatest improvements. The proposed improvement actions could be a basis for the decision-making process regarding future investments towards environmental sustainability of the urban water system.
This study evaluates the environmental impacts associated with the production of eucalypt (Eucalyptus globulus Labill.) and maritime pine (Pinus pinaster Ait.) wood in Portugal. Life Cycle Assessment ...(LCA) methodology is used from cradle-to-gate. Three forest management scenarios, representative of different forest management intensities and logging equipment, were simulated for each species. Furthermore, a sensitivity analysis was performed to evaluate the influence of adopting different values for the wood productivity. The results obtained for each impact category show a relatively wide range of variation when different management scenarios and wood productivities are taken into account. The impacts, except for those in the category photochemical oxidant formation, are much smaller in the less intensive scenario (40–88%). The impacts of using chainsaws and adapted farm tractors in logging operations instead of harvesters and forwarders do not significantly differ (less than 11%), except for the impact category photochemical oxidant formation for which there are significant differences. For the same type of management scenario, the impacts of eucalypt wood production are larger than those estimated for maritime pine wood. The logging stage, as well as fertilization, especially with nitrogen-containing fertilizers, plays a major role in all the impact categories. More accurate impacts could be quantified using the methodology adopted in this study when the provenance of the wood and, consequently, the forest operation type and frequency, and associated consumption of fuels, lubricants and fertilizers, are known.
► The environmental impacts of eucalypt and maritime pine wood produced in Portugal are evaluated. ► The impacts are influenced by forest management scenarios and wood productivity. ► Logging operations and fertilization are the main hot spots.
The use of biomass pellets as fuel is emerging as a suitable alternative to fossil resources for mitigating climate change. A considerable number of articles have applied Life Cycle Assessment (LCA) ...to quantify and to compare the environmental performance of biomass pellets but a wide variation of results can be found in the literature. This work reviews 84 articles on LCA of biomass pellets, focusing on identifying trends in methodological choices and on understanding the influence of those choices on life cycle impacts, in particular global warming and non-renewable primary energy. Most of the reviewed articles assess woody pellets and most of the cradle-to-grave studies focus on heat generation. The methodological choices vary widely between articles with respect to approach (attributional or consequential), functional unit, system boundaries, procedure to deal with multifunctionality and allocation, biogenic carbon modelling, inclusion of greenhouse gases other than carbon dioxide, life cycle impact assessment method, impact categories, and presence of sensitivity analysis. The results for global warming and non-renewable primary energy were assessed, showing a correlation between them. Moreover, a high variability is found for global warming, with impacts ranging from −18 to 488 g CO2 eq/MJpellets. The main causes (technological features, assumptions, methodological choices) for this high variability are analysed and discussed.
•Comprehensive review of 84 LCA articles focusing on biomass pellets.•Articles often assess woody pellets as feedstock and heat generation as application.•LCA methodological choices present great differences between articles.•Correlation between global warming and non-renewable primary energy results.•Large variation in global warming impacts, from −18 to 488 g CO2 eq/MJpellets.
Currently there are several methodologies available for estimating the carbon footprint of products. In this study a comparison has been made between the outcomes and the implications of three ...different methodologies applied to office paper: (1) the ISO 14040/14044 standards limited to the analysis of greenhouse gas (GHG) emissions and the corresponding impact category global warming; (2) the PAS 2050; and (3) the Confederation of European Paper Industries (CEPI) framework. The carbon footprint of office paper from cradle-to-costumer is 4.64, 4.74 and 4.29
g
CO
2eq per A4 sheet according to, respectively, the ISO 14040/14044 standards, the PAS 2050 and the CEPI framework. The ISO 14040/14044 standard methodology allows the quantification of 98% of the total GHG emissions with the smallest effort in data collection. The major hot spots are the stages of eucalypt pulp and office paper production and chemical and fuel production for all methodologies. General methodologies such as those analysed in this study are not enough for the comparison of products. More specific rules, such as Product Category Rules, that limit the degree of freedom in the choice of the functional unit, system boundary, allocation rules, data quality, between others, should be developed.
► Comparison of carbon footprint calculation methodologies applied to office paper. ► Cradle-to-costumer study. ► The carbon footprint of one A4 sheet of office paper ranges from 4.29 to 4.74
g CO
2eq. ► General methodologies are not enough for the comparison of products. ► More specific rules, such as Product Category Rules, should be developed.
Recently, wood pellets have become a reliable and clean renewable fuel for residential heating, replacing fossil fuels and reducing greenhouse gas emissions. Wood pellets are normally produced in ...industrial pellet plants (centralised production), but decentralised small-scale local production also occurs.
This study applies Life Cycle Assessment (LCA) to quantify and compare the environmental profile of one centralised and two decentralised alternatives for wood pellet production for residential heating in Portugal: (1) industrial wood pellets production (centralised), (2) wood pellets production at sawmills (decentralised) and (3) wood pellets production at households (decentralised). System boundaries include the stages of forest management, wood pellet production, wood pellet distribution and wood pellet energetic conversion.
The impact results show that industrial pellet production ranks as the worst alternative, while pellet production at households has the best environmental profile for all the impact categories under study. However, the environmental impacts of pellet production at the sawmill do not differ greatly from those of the pellet production at households; they are 14 to 16% higher for global warming and fossil resources scarcity and 0.3 to 3% higher for the remaining impact categories. The worst environmental performance of the industrial pellet production alternative is mainly due to high electricity and diesel consumption during wood pellet production and the use of logging residues to generate heat for drying biomass feedstock.
A sensitivity analysis was performed to evaluate the influence of changing the distance travelled during the transport of packed pellets to stores and sawdust to households. The results show changes in the environmental performance ranking, highlighting that for short distances, both decentralised alternatives can be more sustainable from an environmental perspective than the centralised alternative, but for larger distances, the pellet production at households should be avoided.
Display omitted
•Centralised and decentralised pellets production alternatives are assessed.•Industrial pellet production ranks as the worst environmental alternative.•Pellets production at households has the best environmental profile.•Impacts of sawmill pellets do not differ greatly from those of households pellets production.•For short distances, decentralised production can be more sustainable than centralised.
Bioenergy is becoming increasingly important for agriculture. However, the use of first generation crops for biofuels and bioenergy production is controversial due to their competition with food and ...feed. The cultivation of three different energy crops – wheat, maize and triticale – for biomass in order to produce biogas in Lombardy, in the Po Valley (Italy), was evaluated in this study to quantify their environmental profiles and identify the best biomass source from an environmental perspective. The choice of these cropping systems was based on the fact that they are well-known and extensively cultivated for energy purposes in Italy. The standard framework of the Life Cycle Assessment (LCA) was followed in this study and detailed inventories for these crops were designed. The environmental profile was analysed in terms of abiotic depletion, acidification, eutrophication, global warming, ozone layer depletion, photochemical oxidants formation, human toxicity and ecotoxicity. In addition, an energy analysis was performed using the cumulative energy demand method. According to the results, the selection of the best biomass source depends on several factors such as the functional unit and biomass yield. Therefore, a sensitivity assessment was done in order to identify these differences. Moreover, the most critical processes throughout the life cycle of the cropping systems were identified and improvement alternatives were proposed, specifically for the mineral fertilization (one of the most important hot spots). Thus, different scenarios built on alternative nitrogen based fertilizers were assessed in detail and discussed, resulting in the identification that the use of calcium ammonium nitrate instead of urea should improve the environmental profile regardless of the energy crop. Finally, the combination of triticale or wheat with maize classes 300, 400 and 500 in rotation systems was done in order to achieve similar biomass yields, per ha, to the maize classes 600 and 700, which were also evaluated. The best results were obtained for maize classes 600 and 700 regardless of the functional unit considered in all the categories assessed except in GWP, where triticale with maize 400 and with maize 500 were the best options.
An Environmental Product Declaration (EPD) provides information on a product's environmental performance along its life cycle. This paper aims to contribute to the development of Product Category ...Rules (PCR) specific for ceramic bricks in order to support the establishment of a “cradle to grave” EPD. The methodology for developing the PCR takes into account ISO 14025, ISO 21930 and EN 15804, and the environmental profile is based on the Life Cycle Assessment (LCA) methodology. In this context, some core issues like product category definition, impact categories, indicators, cut-off criteria and allocation criteria are addressed. The selected impact categories for this study were: global warming, ozone layer depletion, photochemical oxidation, acidification, eutrophication, depletion of abiotic resources and respiratory inorganics. Indicators of energy and water consumption were also considered, as well as particle emissions to air. The results obtained from an LCA study on ceramic bricks produced in Portugal, to support the development of the PCR, show that the use of different fuels in the brick manufacturing stage has a significant effect in some impact categories. The use of petroleum coke generates higher impacts than natural gas or biomass. In general, the major environmental impacts occur in the brick manufacturing stage, mainly due to fuel usage in the firing operation. Particle emissions to air should be considered as an additional parameter in the EPD, being especially important when solid fuels are used. A sensitivity analysis of the cut-off criteria options was also conducted, which concluded that a 0.5% decrease in mass proved to be adequate for adoption, with a significant reduction in the effort required for data collection.
•PCR are important rules for the establishment of EPD that communicate environmental impacts.•A cut-off criterion of 0.5% in mass, proved to be adequate for reduction in data collection for an EPD.•Brick factories that operate with petroleum coke have higher environmental impacts.•Manufacturing stage, namely firing, has the highest potential for improving.
Moving towards a global bioeconomy can mitigate climate change and the depletion of fossil fuels. Within this context, this work applies a set of multi-criteria decision analysis (MCDA) tools to ...prioritise the selection of five alternative bioenergy systems for residential heating based on the combination of three commercial technologies (pellet, wood stove and traditional fireplace) and two different feedstocks (eucalypt and maritime pine species). Several combinations of MCDA methods and weighting approaches were compared to assess how much results can differ. Eight indicators were used for a sustainability assessment of the alternatives while four MCDA methods were applied for the prioritisation: Weighted Sum Method (WSM), Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), Elimination and Choice Expressing Reality (ELECTRE), and Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE). Regarding the sustainability performance indicators, the highest environmental impacts were calculated for the fireplace alternatives, and there was not a best environmental option. Also, no clear trend was found for the economic and social dimensions. The application of MCDA tools shows that wood stove alternatives have the best sustainability performance, in particular wood stove with combustion of maritime pine logs (highest scores in the ranking). Regarding the worst alternative, fireplaces with combustion of eucalypt logs ranked last in all MCDA rankings. Finally, a sensitivity analysis for the weighting of the performance indicators confirmed wood stoves with combustion of maritime pine logs as the leading alternative and the key role of the analysts within this type of MCDA studies.
The development of methods to assess the potential environmental impact of green water consumption in life cycle assessment has lagged behind those for blue water use, which are now routinely applied ...in industrial and policy-related studies. This represents a critical gap in the assessment of land-based production systems and the ability to inform policy related to the bio-economy. Combining satellite remote sensing and meteorological data sets, this study develops two new sets of spatially-differentiated and globally applicable characterisation factors (CFs) to assess the environmental impact of green water flows in LCA.
One set of CFs addresses the impact of shifts in water vapour flow by evapotranspiration on blue water availability (CFWS) and the other set of CFs addresses moisture recycling within a basin (CFWA). Furthermore, as an additional and optional step, these two indicators are combined into an aggregated green water scarcity indicator, representing the global variability of green water scarcity. The values obtained for CFWA show that there are significant changes in green water flows that were returned to the atmosphere in Alaska (covered by open shrublands) and in some central regions of China (covered by grasslands and barren or sparsely vegetated land), where precipitation levels are lower than 10 mm/yr. The results obtained for CFWS indicate that severe perturbations in surface blue water production occur, particularly in central regions of China (covered by grasslands), the southeast of Australia (covered by evergreen broadleaf forest) and in some central regions of the USA (covered by grassland and evergreen needleleaf forest).
The application of the green water scarcity CFs enables the evaluation of the potential environmental impact due to green water consumption by agricultural and forestry products, informing both technical and non-technical audiences and decision-makers for the purpose of strategic planning of land use and to identify green water protection measures.
Display omitted
•Development of global spatially differentiated green water scarcity CFs for LCA.•Potential impact of ET on blue water production and green water recycled into the basin.•CFWS and CFWA show high variability mostly in the northern hemisphere.•Uncertainty of CFWS and CFWA is high due to changes on green water availability to ET purposes.
This study evaluates direct and indirect environmental impacts associated with the consumption of goods and services by the households living in the municipality of Aveiro (Portugal) using ...environmentally extended input output (IO) analysis. The environmental impacts addressed are greenhouse gas (GHG) emissions and fossil fuel consumption. A methodology adapted to the specificities of the data available is proposed. This methodology relies on the Portuguese economic IO table, on GHG emission and fossil fuel consumption intensities, and on national household expenditure data downscaled to the urban level. This methodology could also be applied to other municipalities or cities for which data on local household expenditures are missing. This study also identifies the sectors with the largest impacts in order to prioritise strategies for reducing the impacts to move the municipality towards more sustainable consumption.
The estimated total GHG emissions in 2005 amounted to 26 kg CO2-eq./cap/day and the total fossil fuel consumption was 7.3 koe/cap/day. The sectors that contributed most for both indicators are “land transport and transport by pipelines”, “food, beverages and tobacco”, “construction” and “production, collection and distribution of electricity”. Therefore, improvement measures are proposed for these sectors in order to more effectively decrease the environmental impacts related with GHG emissions and fossil energy consumption of the municipality.
PDF
