The provision of an adequate network of urban infrastructures is essential to create clean and energy-efficient urban mobility systems. However, the urban infrastructure to support sustainable ...mobility can produce a substantial environmental burden if no life cycle environmental criteria are applied in its design and management. This paper demonstrates the potential to support energy-efficient and CO2-free pedestrian and electric bike (e-bike) mobility through the ecological design (eco-design) of urban elements. An eco-design approach is applied to reconceptualize a conventional pergola toward an eco-product (solar pergola). The solar pergola generates surplus photovoltaic electricity that provides a multifunctional character. According to the end-use of this energy, different scenarios are analyzed for robust decision-making.
The deployment of solar pergolas can contribute to save from 2,080kg to over 47,185kg of CO2 eq. and from 350,390MJ to over 692,760MJ eq. in 10 years, depending on the geographic emplacement (solar radiation and electricity grid system). These savings are equivalent to charging 2–9 e-bikes per day using clean energy.
Instead of maximizing infrastructure deployment to shift to environmentally friendly modes of mobility, the implementation of multifunctional urban elements represents a key area of action in the context of smart city development.
•Infrastructure eco-design is key to mitigate environmental impacts of urban mobility.•Solar pergolas can support pedestrian and e-bike mobility with no environmental cost.•Over 47 tons of CO2 and 692GJ can be avoided in 10 years per implemented pergola.•Each pergola can support daily charging of 2–9 e-bikes by supplying clean energy.•Multifunctional infrastructure is key to support sustainable multimodal mobility.
Summary
For many companies, the greenhouse gas (GHG) emissions associated with their purchased and consumed electricity form one of the largest contributions to the GHG emissions that result from ...their activities. Currently, hourly variations in electricity grid emissions are not considered by standard GHG accounting protocols, which apply a national grid emission factor (EF), potentially resulting in erred estimates for the GHG emissions. In this study, a method is developed that calculates GHG emissions based on real‐time data, and it is shown that the use of hourly electricity grid EFs can significantly improve the accuracy of the GHG emissions that are attributed to the purchased and consumed electricity of a company. A model analysis for the electricity delivered to the Spanish grid in 2012 reveals that, for companies operating during the day, GHG emissions calculated by the real‐time method are estimated to be up to 5% higher (and in some special cases up to 9% higher) than the emissions calculated by the conventional method in which a national grid EF is applied, whereas for companies operating during nightly hours, GHG emissions are estimated to be as low as 3% below the GHG emissions determined by the conventional method. A significant error can therefore occur in the organizational carbon footprint (CF) of a company and, consequently, also in the product CF. It is recommended that hourly EFs be developed for other countries and power grids.
► 3 LCAs were run comparing various CO2 capture technologies used in biogas upgrading. ► 2 Novel carbon mineralization processes and 6 marketed technologies were studied. ► Carbon mineralization is a ...viable approach for biogas upgrading. ► One carbon mineralization process has the lowest environment impact.
This article evaluates the life cycle assessment (LCA) of three biogas upgrading technologies. An in-depth study and evaluation was conducted on high pressure water scrubbing (HPWS), as well as alkaline with regeneration (AwR) and bottom ash upgrading (BABIU), which additionally offer carbon storage. AwR and BABIU are two novel technologies that utilize waste from municipal solid waste incinerators – namely bottom ash (BA) and air pollution control residues (APC) – and are able to store CO2 from biogas through accelerated carbonation processes. These are compared to high pressure water scrubbing (HPWS) which is a widely used technology in Europe. The AwR uses an alkaline solution to remove the CO2 and then the solution – rich in carbonate and bicarbonate ions – is regenerated through carbonation of APC. The BABIU process directly exposes the gas to the BA to remove and immediately store the CO2, again by carbonation. It was determined that the AwR process had an 84% higher impact in all LCA categories largely due to the energy intensive production of the alkaline reactants. The BABIU process had the lowest impact in most categories even when compared to five other CO2 capture technologies on the market. AwR and BABIU have a particularly low impact in the global warming potential category as a result of the immediate storage of the CO2. For AwR, it was determined that using NaOH instead of KOH improves its environmental performance by 34%. For the BABIU process the use of renewable energies would improve its impact since accounts for 55% of the impact.
An option for the agriculture and energy sectors in Chile is the cultivation of energy crops, but environmental studies are first needed in the framework of a sustainable national energy policy.
In ...this study, we used a cradle-to-farm gate Life Cycle Assessment (LCA) to compare environmental impacts and energy and water demand of rapeseed (
Brassica napus L.) and sunflower (
Helianthus annuus L.) in Chile, as potential oleaginous crops for first-generation biodiesel production. National agricultural data are used for the LCA inventory and process data of international databases are adapted to local conditions. The effect of field N
2O emissions and land use change is evaluated. The results indicate that, compared to sunflower, rapeseed production has a better environmental performance in 9 out of the 11 impact categories evaluated, and lower water consumption. The energy demand of rapeseed is 4.9
GJ/t seed, 30% less than that of sunflower. Mineral fertilizers cause the highest environmental impact in both crops. The analysis of the life cycle of fertilizers indicates that extraction of raw materials and its production are key stages. Attempts to reduce the environmental impact and energy requirement of both crops should be mainly associated with the evaluation of other types of fertilization. In addition, particularly for sunflower, low impact herbicides should be evaluated, seed yield improved and cultivation practices optimized. If the crops are produced on degraded grasslands, the greenhouse gas emissions may be reduced.
Summary
The environmental characterization of the charging infrastructure required to operate electric vehicles (EVs) is usually overlooked in the literature. Only rudimentary life cycle inventories ...of EV charging facilities are available. This lack of information is especially noticeable in environmental studies of the environmental performance of electric two‐wheelers (E2Ws), none of which have included an analysis of charging facilities, even though they constitute the most successful electric‐drive market in the world. This article focuses on characterizing the life cycle of the global warming potential (GWP) and primary energy demand (PED) of two conventional charging facility designs that are widely implemented for charging E2Ws in public spaces. The relative environmental relevance of charging facilities per kilowatt‐hour (kWh) supplied to E2Ws is determined by considering a range of use scenarios (variability in the service ratio) and the effect of upgrading the electricity mix to include more renewable energy sources. Savings of over 3 metric tons (tonnes) of carbon dioxide equivalent emissions and 56 equivalent gigajoules can be achieved by implementing an optimized charging facility design. The internalization of the relative environmental burden from the charging facility per kWh supplied to E2Ws can increase the GWP of E2Ws’ use phase from 1% to 20% and the PED from 1% to 13%. Although the article focuses on one particular case scenario, the research is intended to provide complementary criteria for further research on the life cycle management of electric mobility systems. Thus, a series of factors that can influence the environmental performance of EV charging networks at the macro scale are discussed.
Previous studies assessing the environmental impacts of drinking water supply networks have considered a bottom-up approach, analysing single case studies. This paper presents a top-down approach for ...the assessment of the operational phase of a water supply network. A representative sample of 50 cities was statistically analysed to find relations between different variables regarding electricity and water consumption linked with the environmental impacts of the network. The results show that some of the variables are clearly related to the relative energy consumption of the network. Such is the case for population size, where small municipalities have up to 14 times higher relative electricity consumption compared with medium-sized municipalities (1.15E-2 as opposed to 8.3E-4 kWh/m3 registered water km of network) due to case-specific factors such as a strong gradient between a water tank and the consumption point. Similarly, the cases showing low population density exhibit 7 times higher relative electricity consumption because of the longer distances that must be covered and the correlation between population density and size. The values found for greenhouse gas (GHG) emissions derived from the energy consumption are consistent with results from previous studies: on average, 5.53 kg of CO2 eq. emissions/inhabitant·year are released, but the variability is very high, ranging from 0.005 to 67.8 kg of CO2 eq. emissions/inhabitant·year. No clearly significant correlations were found between the relative water demand and variables such as seasonality or income per capita, which might indicate that water consumption depends on individual decisions of the population rather than on the variables assessed. Models for the estimation of water demand, length of network and electricity consumption were defined. However, the modelling of electricity consumption presented more difficulties because of its high variability. A protocol for data collection should be defined and implemented in the future to enable the analysis of more high quality case studies and for the definition of more accurate and reliable models.
•A sample of 50 water supply networks was statistically assessed.•The supply of water generates around 5.53 kg of CO2/inhabitant·year.•Small municipalities have larger relative electricity consumptions tan medium ones.•Water demand and length of network can be estimated from population.
The demand for sanitation infrastructures is increasing due to a rise in the urban population. To meet the need for wastewater collection, the construction of sewer networks must comply with a series ...of technical parameters that indicate whether a solution is feasible or not. Considering that this construction implies a series of environmental impacts, this study coupled a structural analysis of one linear metre of sewer constructive solutions with their life cycle impacts. Different pipe materials (concrete, polyvinylchloride (PVC) and high-density polyethylene (HDPE)) were combined with different trench designs and their environmental performance was assessed using Life Cycle Assessment (LCA). These solutions complied with technical parameters consisting of traffic loads and pavement conditions, among others. Concrete pipes embedded in granular matter result in fewer environmental impacts, such as Global Warming Potential or Cumulative Energy Demand. Further, re-using the excavated soil results in up to 80 % of environmental savings with respect to extracting new materials. Concerning traffic loads and pavement conditions, failures in plastic pipes could be avoided if these are embedded in concrete. Moreover, the environmental impacts of this solution are similar to those resulting from the substitution of pipes that do not comply with the mechanical requirements of the construction site. Therefore, proper planning is needed to provide cities with sewers that are resilient to time and external loads and reduce the urban environmental impacts.
Perchloroethylene (PCE) is one of the most important groundwater pollutants around the world. It is a suspected carcinogen and is believed to be recalcitrant to microbial degradation. We report here, ...for the first time, aerobic degradation of PCE by the white rot fungus, Trametes versicolor, to less hazardous products. Aerobic degradation rate of PCE was 0.20 and 0.28 nmol h-1 mg-1 dry weight of fungal biomass. Trichloroacetic acid (TCA) was identified as the main intermediate using 2-13C-PCE as the substrate. Chloride released and TCA produced were stoichiometric with PCE degradation. Our studies using 1-aminobenzotriazole (ABT), an inhibitor of cytochrome P-450, suggested that a cytochrome P-450 system may be involved in PCE degradation by T. versicolor. These results are of particular interest because TCA production from PCE has not been reported to date in bacteria or fungi.
•A method to couple circularity and environmental assessments is presented.•Urban agriculture as a case study to exemplify urban metabolism flows.•Material Circularity Indicator (MCI) shows ...limitations at system-level.•Combining the Linear Flow Index and LCA to reach the lowest possible value.•Further research is required to detect limitations in sector-specific assessments.
Local food production through urban agriculture (UA) is promoted as a means to make cities more sustainable. However, UA does not come free of environmental impacts. In this sense, optimizing urban resources through circular economy principles offers the opportunity to close loops and improve production systems, but an assessment of these systems through a combination of circularity and environmental tools is missing from the literature. The goal of our study is to analyse the environmental and circularity performance of applying circular strategies in UA systems. We use Life Cycle Assessment (LCA) and the Material Circularity Indicator (MCI) to assess the baseline scenario of a Mediterranean rooftop greenhouse and the application of 13 circular strategies. The results show that the MCI score for all strategies was biased by overweighting of the water subsystem in the mass balance. Based on this finding, we propose a series of modifications to the circularity assessment, calculating specific MCI scores for every subsystem before coupling them with environmental life cycle indicators. The outcome is a set of indicators that use the Linear Flow Index (LFI), where decreasing the values as much as possible will correspond to a decrease both in environmental impact and linearity of the system (the inverse of circularity). The use of these indicators provides a simple understanding of the circular and environmental performance of these systems while being fully adaptable. With these indicators, the uses of nutrient recirculation, struvite fertilizer or recycled materials were the best strategies to improve urban agriculture.
In the European Union, the building sector accounts for more than 40% of the total energy consumption and environmental impacts, representing the area with the greatest potential for intervention. In ...addition to the existing policies that promote energy efficiency in buildings, the embodied energy and the environmental impacts contained in the building materials should be considered. In the case of the construction of insulation façade systems, the environmental implications are different depending on the type of façade system, the insulation materials used and the location of the building. This article aims to provide all of this information for Spain, including not only the production of the components of the façade system but also the installation phase and the transport to the building site. The results show that the most impactful alternative is the ventilated façade combined with the most impactful insulation materials of stone wool and expanded polystyrene. Meanwhile, the most advisable façade in all of the climate zones is the external thermal insulation system combined with any type of insulation. The environmental impacts of insulation materials are very different. Moreover, it is recommended that further studies complete these results with the economic and social implications of the use and maintenance phases for robust decision-making.
•LCA comparison of insulation materials applied in façade systems has been developed.•The Spanish climate factor is introduced in the cradle-to-site LCA.•The most sustainable option is the external thermal insulation system with glass wool.•Stone wool represents 30–50% of impacts for all of the façade systems analysed.•The choice on the type of insulation material has great environmental implications.
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