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Temporal fluctuations of the electricity grid generation composition, variability of electricity consumption in building operation over the year and of the on-site renewable energy systems are factors that should be properly considered, using high-resolution data in the building energy and environmental performance assessment. In this study a methodological framework is developed to model high-resolution electricity mixes in building operation and to assess the related energy and environmental impacts over the year, by means of a life cycle approach. For most impact categories, the imported electricity generation mixes, to meet the residual building demand, show impact variations not higher than +20 % and not lower than -38 % at seasonal and daily time compared with the annual average values. Temporal variations are even more relevant in building consumption electricity mixes, which are significantly characterized by self-consumption and show noticeable reductions compared to the annual electricity generation mix in both assessed scenarios. As an example, summer and spring energy generation mixes show the best results for climate change (0.09 kgCO 2eq /kWh) compared to the annual ones, while in winter and autumn mixes the contribution to climate change overcomes the respective annual results. Both summer day-mixes contribute to climate change for about 0.12 kgCO 2eq /kWh, with a reduction of nearly 30 % if compared the annual data. Conversely, in the winter day-mixes the contribution to climate change is about 0.20 kgCO 2eq /kWh and comes mostly from the grid. The results highlight that assessed temporal variations are significant through the year for the most assessed environmental indicators. Furthermore, the use of high-resolution electricity generation mixes allows to optimize efficiently the temporal use of electricity in buildings, in sight of energy and environmental impact reduction also thanks to the employment of life cycle oriented approaches. The results also highlight the relevance of the storage system in fulfilling periods of peak demand or low renewable generation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The development of solar technologies requires increased efficiency in converting solar radiation to energy, as well as innovative materials and structure to go beyond the conventional power conversion ratio. In line with these innovations, there are concerns about greenhouse gas emissions of the solar cells, materials for the solar technologies and other relevant environmental impacts of the manufacturing processes. This review is conducted on life cycle assessments of solar cells, considering the climate change and natural resource shortage context. It is identified that the majority of existing life cycle assessments on solar cells take into account four typical environmental impacts: energy consumption, greenhouse gas emissions, material depletion, and toxicity. Though the diverse methodological aspects make it difficult to directly compare these environmental impacts among various types of solar cells, the obtained results hinder that emerging solar cells such as perovskite solar cells or tandem solar cells are likely to have better environmental profiles than conventional silicon based and thin film solar cells, in terms of energy consumption, greenhouse gas emissions and material consumption. However, the emerging solar cells may utilize toxic materials in which their eco-toxicity and human toxicity should be further considered during the design of the technologies. Moreover, it is identified that the energy and environmental hotspot lies in the manufacturing process, regardless of impact indicators and types of solar cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

In response to the disruptive changes brought upon our society by the COVID-19 pandemic, most work activities and service providers had to resort to remote working. This is credited to reduce emissions for transportation, however the role of forced confinement within dwellings, especially if not designed for hosting working stations, deserves to be properly evaluated in terms of both user acceptance and long-term environmental impact. In this work, a dedicated survey campaign is used for investigating the potential pros and cons of remote working. In more detail, logistic regression and generalized linear models are used for capturing the effect of several independent variables on user acceptance of remote working. At a later stage, the main greenhouse gas emissions produced by each participant before and during remote working are assessed. According to the obtained results, the greater the distance between their home and workplace, the higher the acceptance score declared by the survey participants about remote working. Additionally, higher incomes and better-quality lifestyles with larger devotion to leisure activities also provide higher acceptance. Finally, the existence of a comfortable room to be used for work activities plays a crucial role on the declared acceptance. From an environmental point of view, remote working is always sustainable in case of long commuting distances (above 10 km) are avoided on a daily routine. In conclusion, a sensible use of remote working could reduce the environmental impact of any organization employing desk-workers as well as improve their work satisfaction and lifestyle., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.)

Biomasses and bio-waste have an important role in decarbonizing the European energy mix, the latter contributing to the transition towards a circular economy. In particular, Refuse Derived Fuel (RFD) - a biofuel obtained from dry residue of waste - appears a really interesting energy option. In this framework this study aims at assessing the environmental profile of electricity generation from RDF in Italy, comparing two different kinds of RDF production and combustion plants. The functional unit is 1 kWh of net electricity from RDF delivered to the grid. Two Italian plants are examined: one located in Ravenna (RDF is produced in a direct flow treatment plant) and the other one in Bergamo (RDF is produced in a unique flow treatment plant and electricity is generated in a cogenerator). Results show that, comparing the plants, it is not possible to identify an option for RDF production or electricity generation characterized by lowest impacts for all the examined impact categories. However, cogeneration process and the avoided burdens due to the valorisation of ferrous metals and dry fractions during RDF production can reduce most of the environmental impacts. A dominance analysis reveals that chimney direct emissions generated during RDF combustion significantly contribute to some impact categories, as well as electricity consumption during RDF production. Furthermore, disposal of incineration wastes is a relevant contributor to human toxicity and freshwater eutrophication. The eco-profile of electricity from RDF is compared with electricity from the Italian grid and from multi-Si PV. The comparison highlights that electricity from RDF performs worse for relevant environmental impact categories such as climate change, human toxicity and photochemical oxidant formation. On the other hand, electricity from RDF performs better than electricity from the grid and from photovoltaic for resource depletion, an impact category of growing importance in the framework of circular economy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Fuel cells are considered one of the key technologies to reach the ambitious European goal of a low carbon economy, by reducing CO 2 emissions and limiting the production of other pollutants. The manuscript presents an assessment of the life cycle energy and environmental performances of a solid oxide fuel cell system for household applications using primary data from the manufacturing phase and experimental data for the start-up and operation phases. The Life Cycle Assessment methodology is applied, based on a functional unit of 1 MJ of exergy and includes the life cycle steps from the raw materials extraction to the maintenance. The results show a particular relevance of the operation stage on the impacts (about 98% of cumulative energy demand and more than 63% of about half of the examined environmental impacts), mainly due to the fuel supply and, focusing on climate change, to the CO 2 emissions during the conversion of chemical energy into electricity. Manufacturing step is the main responsible of the remaining half of the impacts, with a contribution higher than 38%, mainly imputable to the stacks production. For almost half of the examined impact, a contribution of 20-30% is caused by the maintenance step, with a relevant contribution of the stacks and DC/DC booster substitutions. The analysis highlights that eco-design solutions of the assessed system can be traced in the improvement of the energy system efficiency and reduction of emissions during the operation, and in the increase of the durability of the system components, thus reducing the number of their substitutions. The results of a sensitivity analysis on the selection of the functional unit also clarified the importance of the recovery of the thermal energy generated by the fuel cells, in order to avoid concurrent energy generation from conventional sources., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Addressing climate change is one of the greatest environmental challenges. Due to the impact of cities to energy consumption, the involvement of the local authorities in environmental policies is rapidly increasing. The Covenant of Mayors (CoM), launched by the European Commission, is an urban initiative aimed at reducing CO 2 emissions. The signatories have to compile the greenhouse gas emissions (GHG) balance of their territory and, to do so, they can use the Intergovernmental Panel on Climate Change (IPCC) or the Life Cycle Assessment (LCA). Moreover, the signatories have to define strategies to reduce the GHG emissions. In this context, authors estimate the GHG balance of an Italian municipality using both methodologies in order to compare the results. In detail, the first application is the IPCC, the second one is the LCA approach for which two cases are analysed: i) LCA with fossil fuels and electricity GHG emission factors based on the European Reference Life Cycle Database, LCA (I); and ii) LCA with a site - specific GHG emissions for electricity generation, LCA (II). They propose energy strategies in order to quantify the achievable GHG emissions reduction by the exploitation of the renewable energy resources. The study shows that the GHG emissions results obtained with the LCA approach are higher by 20% than those calculated with the IPCC approach. This difference is relevant and it could be significant in identifying effective climate strategies. The LCA methodology ensures a systemic accounting of emissions, then, it can be more effective in order to achieve GHG emissions reduction at global level. The examined energy strategies allow for reducing the GHG emissions of about 7% of the total reduction required by the CoM. This confirms that a preliminary evaluation of the strategies is useful for the allocation of the financial resources to the environmental policies., (Copyright © 2018 Elsevier B.V. All rights reserved.)