Self-healing is a preventive maintenance technique developed to extend the service life of road pavements, accordingly, increasing their sustainability: energy consumption savings, lower emissions, and a decrease in the use of non-renewable resources. Microwave (MW) self-healing technology consists of heating the binder so it can flow and fill the cracks in the pavement. To promote and enhance this asphalt self-healing capacity, electrically conductive susceptible particles like steel slag can be added as aggregates in the asphalt mixture, and a combination of heat and re-compaction energy (thermomechanical treatment) can be applied to improve healing rates. However, one of the key issues is determining how to take full advantage of asphalt mixtures self-healing capacity to maximize the extended life span of asphalt pavements in order to avoid the use of a great number of non-renewable resources and energy in the rehabilitation of deteriorated pavements. Although some different factors that affect self-healing effectiveness are being studied, the optimal implementation conditions and moment to apply the MW treatment have yet to be determined. Hence, this paper aims to identify variables and establish an optimal implementation of the MW self-healing technology including steel slags and a thermomechanical treatment (MW heating and re-compaction). For this purpose, the influence of the implementation conditions, the moment of application, and the mixture design have been assessed by Life-Cycle Greenhouse Gas emissions, Cumulative Energy Demand, and cost evaluation. Results have shown that the optimal moment to apply the MW treatment would be around the half-life span of the asphalt pavement, being the most beneficial solution when applied over asphalt mixtures using steel slag as this allows reducing energy requirement during the MW application process and minimise costs.

Renewable energy and energy efficiency terms are the focus of policymakers to achieve a sustainable energy policy. The concept of sustainability has become a key element in the development of renewable technologies, so both quantitative and qualitative assessments are essential to consider the environmental and socioeconomic impacts. This study presents the results of applying different methodologies to assess the sustainability of the development of solar energy technologies, where the importance of this type of analysis is highlighted to support decision-makers.

Self-healing roads are a new generation of pavements whose materials are capable of recovering their original properties after having suffered breakages or failures. This innovative technology aims to reduce the consumption of natural resources and non-renewable energy in the whole life-cycle of roads, due to the potential achievement of increasing their lifespan compared to traditional maintenance operations. Several previous tests have demonstrated the possibility of achieving new asphalt mixtures that could be self-healing by means of microwaves or induction when the pavement reaches deterioration, so the traditional maintenance technique could be postponed. As self-healing technology is still under study, there is a lack of rigorous environmental and economic studies. This study presents the quantification of the advantages and shortcomings of this novel technique when compared to traditional rehabilitation activities, since it is currently one of the priority research lines for paving materials nowadays. Analyses have been done by the application of the Life Cycle Assessment methodology. Results show a clear influence of self-healing in the comparative environmental performance in the majority of the impact categories. In fact, climate change impact could be reduced up to 15%, while the acquisition of extra abiotic materials is reduced by 50%.

Upgraded metallurgical grade silicon (UMG-Si) for photovoltaic (PV) solar applications has been manufactured through the metallurgical route by means of the process developed by Ferrosolar. In an ambitious mass production test, performed in commercial solar cells and modules production lines, the silicon was proven to be appropriate for photovoltaics applications (Fornie ' s et al., 2019 Mass production test of solar cells and modules made of 100% umg silicon. 20.76% record efficiency. Energies 12), reaching, in a conventional production line, up to 20.76% of solar cell efficiency with multicrystalline cells made of 100% UMG silicon. In this paper we present more results from the mentioned massive test. Defect engineering is being applied to improve the bulk lifetime of the UMG wafers and to guide in the identification of the limiting defects in the material. Moreover, the modules produced with 100% UMG silicon solar cells were installed together with the modules produced in the same production line with polysilicon material to assess the degradation of the UMG silicon when compared to polysilicon. After 24 months of outdoor PV generation, the degradation, in terms of Performance Ratio at 25 degrees C (25PR) diminution, has been the same for both types of modules. Additionally, a Life Cycle Assessment (LCA) has been performed for this UMG silicon and state-of-the-art Siemens polysilicon to compare the environmental impact of both silicon feedstocks. The results presented in this paper; chemical analysis of wafers, defect engineering, low degradation, average efficiency and environmental assessment, lead to a complete study of UMG silicon, confirming its potential to be used as raw material for PV applications.

A sustainability assessment regarding the manufacturing process and the use of a new proton exchange membrane fuel cell (PEMFC), specially designed for portable hydrogen applications, is presented. The initial fuel cell prototype has been configured by taking into account exclusively technical issues. However, a life cycle analysis considering environmental and socioeconomic impacts is crucial to improve the model to develop a more sustainable product. From the environmental perspective, the durability of the system and its efficiency are key elements required to decrease the potential overall impacts. High electricity consumption for manufacturing requires a commitment to the use of renewable energies, due to the high current value of the projected impact of climate change (42.5 tonnes of CO2 eq). From the socioeconomic point of view, the dependence of imported components required for the synthesis of some materials displaces the effects of value added and employment in Spain, potentially concentrating the largest impact on countries such as Singapore, Japan and the UK, whereas the cell assembly would have a greater benefit for the country of fabrication. These results provide a basis for new research strategies since they can be considered standard values for improving future upgrades of the fuel cell in terms of sustainability.

Solar grade silicon (SoGSi) is a key material for the development of crystalline silicon photovoltaics (PV), which is expected to reach the tera-watt level in the next years and around 50TW in 2050. Upgraded metallurgical grade silicon (UMGSi) has already demonstrated to be a viable alternative to standard polysilicon in terms of cost and quality. This study presents the life cycle assessment (LCA) of UMG obtained by the FerroSolar process. Moreover, it shows the environmental impacts of PV modules and electricity generation based on this material. For this, an exhaustive review of the life cycle inventory (LCI) of PV value chain, from metallurgical grade silicon (MG-Si) down to electricity generation, has been carried out updating inputs for all processes. The Balance of System (BoS) has also been updated with current state of the art data for a fixed open ground large PV site (100 MWpk). Two different electricity mixes, with low and high carbon intensities, have been considered. The results reveal that for PV electricity generation using UMG-Si instead of polysilicon leads to an overall reduction of Climate change (CC) emissions of over 20%, along with an improvement of the Energy Payback Time (EPBT) of 25%, achieving significantly low values, 12 gCO2eq/kWhe and 0.52 years, respectively. Moreover, it is shown that UMG silicon feedstock is not the main contributor to the carbon and energy footprint of the produced electricity, leaving the first place to PV module manufacturing.

Building Integrated Photovoltaic (BIPV) systems have been increasingly used as a means to generate electricity on-site, and their diffusion will increase in the near future. The objective of this article is to carry out a sustainability assessment of a BIPV system installed in Turkey regarding the three pillars: environmental, economic and social potential impact, in order to develop different indicators. For the socioeconomic analysis, a Multiregional Input-Output (MRIO) method was used to estimate production of goods and services, value added creation and employment opportunities. For the environmental evaluation, an Environmental Footprint (EF) analysis was performed. The levelized electricity costs and the greenhouse gas emissions abatement costs were also calculated. Results showed that the socioeconomic effects are relevant, although only a 23% of these effects remain in Turkey. The environmental profile is also good in terms of climate change impacts, showing substantial reductions in greenhouse gas emissions compared to fossil fuel alternatives for electricity generation. Regarding the life cycle stages of the technology, the highest environmental impacts are produced in the PV manufacturing processes. The electricity produced is still more costly than fossil-based technologies and in the highest range of PV technologies, but greenhouse gases abatement costs are not so high when compared to other references.

Novel renewable energy technologies in the Middle East and North Africa region can be developed through microgeneration systems aiming to supply local energy demands in a sustainable way. In this study, we carried out a sustainability assessment combining two reputable methodologies which have been applied to a facility comprising a hybrid solar/biomass micro-cogeneration organic ranking cycle system located in Morocco. We first applied a multiregional input–output analysis where economic issues such as the production of goods and services generated in all project's phases, as well as the added value and employment created, are estimated. Then, environmental impacts were assessed through a life cycle assessment (LCA). In terms of socioeconomic analysis, the total production of goods and services shows a value of 1.18 €2015/kWh. The added value and employment creation were 0.56 €2015/kWh and 0.05 full-time employees/MWh, respectively. The levelized cost of electricity results in 0.218 €2015/kWh and the multiplier effect amounts to 2.26. The largest increase in sectorial output is produced in the Moroccan electricity sector and the largest job creation takes place in the agriculture sector from the biomass supply. Regarding environmental results, LCA shows a climate change potential of 11.8 g CO2 eq/kWhel, of which more than 70

Road surfaces are subject to wear and tear due to materials ageing, weathering and the action of road traffic. Periodic rehabilitation or reconstruction is needed in order to restore them. This manuscript presents an environmental assessment of a traditional road pavement rehabilitation technique (with hot mix asphalt) in Spain by means of a life cycle approach. The environmental footprint method was selected for presenting the results, which have a similar range as those obtained in earlier studies. Extraction of raw materials and the manufacturing of processed materials are the stages with the most environmental impacts. Therefore, the use of recycled asphalts in an adequate percentage is advisable for reducing the total environmental impact. This is the first complete study carried out in Spain. Its results could be used as a baseline for comparison with both newer restoration techniques and the use of advanced materials in the country.

A la hora de diseñar un producto realizado con materiales biodegradables, se deben tener en cuenta todos los impactos asociados a lo largo de su ciclo de vida. La mayoría de los Análisis de Ciclo de Vida (ACV) existentes sobre biopolímeros no se han ocupado de la categoría de impacto de uso del suelo. Dado que la fracción orgánica de los productos biodegradables proviene normalmente de residuos agrícolas, esta categoría surge como una cuestión medioambiental primordial debido a los impactos que producen los cultivos. En el caso de que los biopolímeros tuvieran un gran éxito en el mercado, probablemente surgiría la necesidad de plantar nuevos campos de cultivo para cubrir la demanda, causando así nuevos impactos medioambientales derivados del uso del suelo. En este estudio se hace una comparación de las metodologías disponibles para evaluar dichos impactos, empleando distintas fuentes de datos para su aplicación. Para ello se evalúa el impacto causado por una hectárea de cultivo de patatas en dos zonas de España con diferentes características: los bosques mediterráneos del Sistema Ibérico y los pastos de la región cantábrica. Los resultados vienen a mostrar que no se han desarrollado aún metodologías fiables para evaluar esta categoría de impacto.

Energy security is a wide-ranging term to encompass issues such as security of supply, reliability of infrastructures, affordability and environmental friendliness. This article develops a robust indicator the Renewable Energy Security Index, RESI- to enrich the body of knowledge associated with the presence of renewable energy technologies within national electricity prodtiction mixes. RESI is built by combining environmental life cycle assessment and techno-economic energy systems modelling. Spain and Norway are used as illustrative case studies for the prospective analysis of power generation from an energy security standpoint. In the Spanish case, with a diversified electricity production mix and a growing presence of renewable technologies, RESI favourably "evolves" from 0.36 at present to 0.65 in 2050 in a business-as-usual scenario, reaching higher values in a highly-restricted CO2 scenario. The Norwegian case study attains RESI values similar to 1 due to the leading role of renewable electricity (mainly hydropower) regarding both satisfaction of national demand and exportation of electricity surplus. A widespread use of RESI as a quantifiable energy security index of national power generation sectors is found to be feasible and practical for both analysts and energy policy-makers, covering a significant number of energy security aspects. (C) 2017 Elsevier Ltd. All rights reserved.

This paper presents a set of prospective LCA studies of electricity production technologies of the Spanish mix from 2014 to 2050. The projection of the power system has been done by using the TIMES-Spain energy model, in which two prospective scenarios have been implemented, a Business as Usual (BaU) and other with a target of 80% reduction in CO2 emissions by 2050 with respect to 2005 levels. Accordingly, projections of ten LCA impact categories have been obtained. Concerning the evolution of the electricity mix, the coal power plants retirement by 2020 has been observed in both scenarios. The main differences befall on the natural gas contribution, higher in the BaU scenario than in 80% scenario and connected to the Combined Heat and Power (CHP) plants usage. In addition, LCA categories selected show overall reductions in the long term reaching from 21% in Ozone Depletion to 85% in Acidification in the BaU scenario, and from 56% in Ecosystems to 87% in Acidification in the 80% scenario. However, Abiotic Depletion potential grows up to 5-times by 2050 due to the metal requirements of the solar photovoltaic technologies, significantly present in the mix. Likewise, the analysis of the endpoint categories (Human Health and Ecosystems) concludes that their evolution is much affected by the presence of the natural gas CHPs and, furthermore, existing fossil options are the main cause of damage by far. Hence a fossil-renewable transition is needed in terms of sustainability. In summary, it is recommended to use energy systems modelling frameworks to develop comprehensive prospective LCA studies.

When environmental impacts are expressed in terms of loss of welfare, using a monetary unit, external costs are obtained that can be easily used in a cost–benefit analysis or be internalized through the appropriate environmental policy instruments. The objective of this study was to assess, from an economic perspective, the environmental consequences of a palm biofuel obtained by means of oil hydrotreatment (HVO, hydrotreated vegetable oil) in Spanish refineries. Results were compared to two counterparts: a low-sulphur fossil diesel (<10 ppm) and another palm biofuel obtained in transesterification units (FAME, fatty acid methyl ester). The evaluation concluded that FAME and HVO would have a worse environmental performance when compared to diesel due to the increased emissions of nitrogen oxides, small particles (PM2.5) and ammonium. They cannot be offset by emission reductions than other pollutants present, such as sulphur dioxides and greenhouse gases. Nevertheless, results are highly dependent on the approach used to quantify the external costs of GHG emissions.

The indirect Land Use Change (iLUC) impacts of biofuels refer to the effects of additional emissions due to land-use changes triggered by the expansion of energy crops in response to increased biofuel demand. These emissions are mostly greenhouse gases (GHG), thus relevant to the climate change impact category. In order to address these effects, the European Commission (EC) has proposed the inclusion of feedstock type specific iLUC factors for different biofuel sources in the Renewable Energy Sources Directive 2009/28/EC (RED). The goal of this study is to quantify the indirect environmental impacts both in terms of global energy crop land area and the subsequent iLUC, if an additional demand of biofuel in Spain occurs, from a consequential approach. Results show a wide range of GHG emissions, in terms of CO2, of biodiesel and bioethanol from iLUC effects, strongly influenced by the place where the potential biofuel is produced. Based on our study, two main aspects -determine the iLUC effects: the dedicated energy crops that are used to produce biofuels and the different coproducts obtained along the biofuels production process. Therefore, contrary to the EC proposal for including a single factor by type of crop, the development of origin-dependent iLUC factors seems to be a more appropriate alternative based on the current assessment. Other aspects that might affect the results, such as crop rotation or field management, have been excluded from the analysis in this work.

The aim of this paper is to identify areas of potential improvement of the European Reference Life Cycle Database (ELCD) electricity datasets. The revision is based on the data quality indicators described by the International Life Cycle Data system (ILCD) Handbook, applied on sectorial basis. These indicators evaluate the technological, geographical and time-related representativeness of the dataset and the appropriateness in terms of completeness, precision and methodology. Results show that ELCD electricity datasets have a very good quality in general terms, nevertheless some findings and recommendations in order to improve the quality of Life-Cycle Inventories have been derived. Moreover, these results ensure the quality of the electricity-related datasets to any LCA practitioner, and provide insights related to the limitations and assumptions underlying in the datasets modelling. Giving this information, the LCA practitioner will be able to decide whether the use of the ELCD electricity datasets is appropriate based on the goal and scope of the analysis to be conducted. The methodological approach would be also useful for dataset developers and reviewers, in order to improve the overall Data Quality Requirements of databases.

Under the framework of the European Platform on Life Cycle Assessment, the European Reference Life-Cycle Database (ELCD - developed by the Joint Research Centre of the European Commission), provides core Life Cycle Inventory (LCI) data from front-running EU-level business associations and other sources. The ELCD contains energy-related data on power and fuels. This study describes the methods to be used for the quality analysis of energy data for European markets (available in third-party LC databases and from authoritative sources) that are, or could be, used in the context of the ELCD. The methodology was developed and tested on the energy datasets most relevant for the EU context, derived from GaBi (the reference database used to derive datasets for the ELCD), Ecoinvent, E3 and Gemis. The criteria for the database selection were based on the availability of EU-related data, the inclusion of comprehensive datasets on energy products and services, and the general approval of the LCA community. The proposed approach was based on the quality indicators developed within the International Reference Life Cycle Data System (ILCD) Handbook, further refined to facilitate their use in the analysis of energy systems. The overall Data Quality Rating (DQR) of the energy datasets can be calculated by summing up the quality rating (ranging from 1 to 5, where 1 represents very good, and 5 very poor quality) of each of the quality criteria indicators, divided by the total number of indicators considered. The quality of each dataset can be estimated for each indicator, and then compared with the different databases/sources. The results can be used to highlight the weaknesses of each dataset and can be used to guide further improvements to enhance the data quality with regard to the established criteria. This paper describes the application of the methodology to two exemplary datasets, in order to show the potential of the methodological approach. The analysis helps LCA practitioners to evaluate the usefulness of the ELCD datasets for their purposes, and dataset developers and reviewers to derive information that will help improve the overall DQR of databases.

This study tries to find out the hotspots of the Spanish cement sector in 2010 by the life cycle assessment (LCA) and evaluates some improvement scenarios where best available technologies and substitution measures are taken into consideration. The document presents an environmental LCA of the cement production using the 2011 International Reference Life Cycle Data System method recommended by the European Commission. Attending to the clinker production by stage, fossil fuel combustion is the most important source in terms of impacts. Besides, limestone’s calcination is crucial attending to the climate change. Electricity consumption is also relevant both in human toxicity with cancer effects and freshwater eutrophication (FE). Accordingly, solutions deployed lead to reductions in different impact categories. Fossil fuel substitution scenario achieves to reduce 33 and 37 % photochemical ozone formation and acidification (A), while material substitution scenario leads to reduce 10–13 % each impact category. On the other hand, fossil fuel substitution scenario entails an increase of 10 % in FE. Considering the ideal case of applying all these improvements together, reductions go from 15 % in FE to 49 % in A, respectively. To face the problems derived from fossil fuel combustion, a fuel shift is needed to reach less contaminant options such as biomass and bio-waste. Material substitution is another good solution for the industry, but it requires a change in the demand and further research to ensure the properties of cement. Authors recommend taking into consideration the collateral increase of the FE due to the phosphates increase coming from the alternative fuels combustion.

A Life Cycle Assessment (LCA) study of HidroBioDiesel (HBD) was carried out. This partly renewable diesel fuel is obtained from the co-processing of soybean vegetable oil with conventional fossil fuel in hydrotreating facilities of crude oil refineries. The environmental profile of HBD was assessed for the fossil energy use and climate change impact categories. The production systems of equivalent fuels -blends of Fatty Acid Methyl Ester (FAME, a biofuel obtained by means of transesterification of vegetable oil) and mineral diesel with sulphur content below 10 ppm were also assessed for comparison purposes. The environmental performance of HBD systems compares favourably to those of FAME and diesel blends for the selected impact categories. The estimated environmental benefits of HBD (assuming a 13% renewable blend) include reductions of up to 2% in fossil energy use and 9% in climate change impacts. (C) 2014 Elsevier Ltd. All rights reserved.