• Energy Research

In this study, our aim was to explore the potential energy savings obtainable from the recycling of 1 tonne of Construction and Demolition Waste (C&DW) generated in the Metropolitan City of Naples. The main fraction composing the functional unit are mixed C&DW, soil and stones, concrete, iron, steel and aluminium. The results evidence that the recycling option for the C&DW is better than landfilling as well as that the production of recycled aggregates is environmentally sustainable since the induced energy and environmental impacts are lower than the avoided energy and environmental impacts in the life cycle of recycled aggregates. This LCA study shows that the transition to the Circular Economy offers many opportunities for improving the energy and environmental performances of the construction sector in the life cycle of construction materials by means of internal recycling strategies (recycling C&DW into recycled aggregates, recycled steel, iron and aluminum) as well as external recycling by using input of other sectors (agri-food by-products) for the manufacturing of construction materials. In this way, the C&D sector also contributes to realizing the energy and bioeconomy transition by disentangling itself from fossil fuel dependence.

Green hydrogen (GH2) is expected to play an important role in future energy systems in their fight against climate change. This study, after briefly recalling how GH2 is produced and the main steps throughout its life cycle, analyses its current development, environmental and social impacts, and a series of case studies from selected literature showing its main applications as fuel in transportation and electricity sectors, as a heat producer in high energy intensive industries and residential and commercial buildings, and as an industrial feedstock for the production of other chemical products. The results show that the use of GH2 in the three main areas of application has the potential of contributing to the decarbonization goals, although its generation of non-negligible impacts in other environmental categories requires attention. However, the integration of circular economy (CE) principles is important for the mitigation of these impacts. In social terms, the complexity of the value chain of GH2 generates social impacts well beyond countries where GH2 is produced and used. This aspect makes the GH2 value chain complex and difficult to trace, somewhat undermining its renewability claims as well as its expected localness that the CE model is centred around.

Abstract: Increasing pressure from population growth and climate change has placed various challenges to urban systems concerning the sustainable supply and use of food, energy and water. To achieve the synergistic and sustainable management of food, energy and water demand, the inter-linkages between the three subsystems should be explored. Taking Beijing as the case study reproducible in a like manner for other urban systems, this research aims to develop a household Food-Energy-Water (FEW) nexus dynamic model to explore the influence of various factors on the end-uses. Three main innovation points are included in this research. Firstly, long-term simulations from 2010 to 2050 can be provided in this model to quantitatively estimate climate change potential under possible management strategies. Secondly, three different levels of influencing factors of household resource consumption are included in this model at the same time, including individual level (behaviors), household level (appliances) and government level (resource prices). Thirdly, multiple scenarios combinations are analyzed in this research. The results demonstrate the complex interconnections among the household food-energy-water uses. What’ more, short-term effects, lag effects as well as lock-in effects can influence the policy effectiveness, so that policy combinations or complements are needed to enhance the effects.

The pursuit of sustainability in the construction and demolition (C&D) sector calls for effective decision-making strategies, both in terms of technical and environmental sustainability, capable of mitigating its huge demand for resources and emissions to the environment. The recycling of C&D waste is one of the potential solutions that could reduce the extraction of virgin materials as well as waste generation and landfilling. This study evaluates and compares, by means of the Life Cycle Assessment (LCA) approach, the production of concrete via five different mixtures made up of coarse natural aggregates (NA, primary, virgin materials), and coarse recycled concrete aggregates (RCA, recovered from previous uses). The present study assesses the environmental load of concrete production, by means of mixtures containing only coarse NA and mixtures with coarse RCA produced in fixed and mobile treatment plants, to be replaced with 30% and 100% of coarse NA by weight. The results point out that the use of coarse RCA in concrete mixtures provide greater energy savings and environmental advantages compared to the concrete with only coarse NA; the improvement increases up to a 100% replacement rate by weight of coarse NA with coarse RCA in the mixtures. In this case, the reduction of the impacts is significant for some impact categories such as freshwater ecotoxicity (−63.4%), marine ecotoxicity (−76.8%), human carcinogenic toxicity (−27.1%), human non-carcinogenic toxicity (−77.9%), land use (11.6%), and water consumption (−17.3%), while the total CED impacts decreases by about 10% and that of GWP by 0.4%. Results are discussed in light of the urgent need for advancing circular economy concepts and practices in the C&D sector and decrease the large use of primary resources (in particular sand and gravel). The replacement of NA with RA by weight could contribute to reducing the impacts of the C&DW management and disposal. For this to happen, further improvement of the quality of recycled aggregates is essential for their market development as well as dedicated policies and legislations.

This study proposes a framework of environmental and energy performance indicators identified and critically evaluated within the scientific literature and the Agricultural European Database for the monitoring and evaluation of the Common Agricultural Policy of the European Union. The identified set of performance indicators encompasses the whole life cycle of agri-food systems from primary production stage until end-of-life stage in agreement with the circular economy and EU “farm to fork strategy” frameworks. In particular, the practices/goals/targets suggested in the latter (e.g., organic farming goals, more relevance assigned to plant-based diets, support for the creation of short supply chains, and reduction in food losses and waste) have guided the search for the main topics of interest in our analysis and the associated environmental and energy indicators. The results of this study evidence a proposed set of performance indicators selected from the literature among LCA and non-LCA indicators (midpoint LCA impacts, cumulative energy use, emergy accounting, and material flow accounting, among others) that could be helpful in integrating the EU CAP indicators for monitoring and evaluating efforts and achieved results toward implementing and controlling the effectiveness of the adopted “farm to fork” policy and related legislative measures, as well as the application of the circular economy model.

AbstractThe study briefly recalls the evolution and crisis of the theory and thought of John Maynard Keynes with the rise and progressive dominance of the neoliberalism paradigm. The exercise has been made for evaluating the effects of such process for the sustainability of the global economy and society. In this view, we explored how Keynes’ contribution could be useful for the global economy in building a new paradigm of socio-economic development underpinning the transition to circular economy (CE). We also evaluated the adoption of the Global Green New Deal including a case study of Italy for the purpose of suggesting how that topical political programme can be key in the CE transition. Given the urgency of environmental problems, we underline the importance of the adoption of Keynesian expansionary “green mission oriented” fiscal policies with the purpose of allowing the triggering of a virtuous circle of sustainable welfare involving the Green New deal and the transition to CE. At the basis of such virtuous circle, we propose a new paradigm based on a revisited Keynesian paradigm and models of economy within the framework of Genovesi’s “civil economy” that entails an active role and responsibility of all the societal actors (consumers, companies and institutions). In this view, the “spirit” of Keynes in the economy, policy and society could be appreciated once more and be extremely useful along with other scholars’ contributions in accelerating the CE transition and a more sustainable development.

The current European context, affected by the dramatic conflict between Russia and Ukraine and the related energy and food shortages, is putting a strain on the natural gas availability of the European member states. The latter are forced to new negotiations with other potential energy suppliers, to urgent internal measures to reduce energy demand and, at the same time, to fulfil their commitments to internationally agreed climate targets, where the energy transition is a key strategy. A sustainable energy transition strategy is also essential in circular economy implementation (CE), requiring the replacement of fossil energies with renewable ones. In turn, the energy transition should meet the CE principles to reduce the consumption of natural resources and the contribution to climate change. In this context, this study assesses the environmental impacts of the Italian and EU electricity mixes under different governmental and research scenarios and perspectives, by means of the Life Cycle Assessment approach (Midpoint and Endpoint LCA). Results show that the shift from the BAU electricity mix (year 2021) to the emergency Government plan scenario (2021-2023) replacing 14% of Russian natural gas by means of 42% oil and coal and 58% renewables slightly reduces the contribution to Midpoint LCA impact indicators, including global warming and fossil resource scarcity, while still contributing to particulate matter formation, terrestrial acidification, eco-toxicity and water consumption. The contribution to global warming further decreases in the other modelled scenarios, where natural gas is assumed to decrease from 30% to a high 60% in favour of renewables (Governmental plan 2030 scenario). Other impacts, in particular terrestrial and human toxicity, are instead expected to worsen, calling for much needed improvement of renewable technologies. Further, the Endpoint LCA impact indicators, expressed as DALY (human health damage), lost species potential (biodiversity damage) and increased costs for the extraction of mineral and fossil resources, improve in the Governmental Plan 2030 scenario and other modelled options. LCA shows to be a key method for the energy transition, in order to identify hotspots of modelled electricity scenarios and suggest more environmentally, circular and socially just improvement solutions. The adoption of the concept of CE in energy transition entails the expansion of the boundaries of an LCA to include the end-of-life of renewable technologies (so-called "cradle to cradle" approach) and the assessment of the most successful options to mitigate the environmental and social impacts of energy transition.