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According to the European Commission, green infrastructure (GI) is conceived as a strategically planned network of natural and semi-natural areas. This definition highlights three important issues: environment protection, ecosystems multifunctionality and ecological connectivity. Building upon a methodology that identifies a Sardinian regional GI in relation to four values (conservation value, natural value, recreational value and landscape value), this study aims at assessing the suitability of areas situated within and outside protected areas’ boundaries to be included in the above-mentioned Sardinian regional GI. In relation to conservation value, outcomes reveal a higher suitability of patches situated within protected areas to be included in the regional GI, whereas in relation to the other three values, the behavioral patterns are less evident. These results suggest specific policy recommendations such as mitigation of land-taking processes, increase of Natura 2000 Network’s size, accurate identification of landscape goods, and improved accessibility to sites characterized by outstanding natural beauty.

Abstract Hydrothermal carbonization (HTC) of wet solid wastes has been pointed out as an eco-friendly, flexible and highly efficient technology for the sustainable valorization of multiple sourced wastes. In this review paper, most recent studies on hydrochars (solid residue of the HTC process) production, characterization and application for wastewaters treatment was summarized and deeply discussed. The role of initial feedstock source nature and characteristics as well as the HTC experimental conditions including the temperature, the residence time and the pH media was assessed. Physical and chemical activation methods including the use of oxygen, steam, microwave, acids, alkaline, organics and salty solutions for the improvement of the physicochemical properties of the produced hydrochars are compared. The efficiency of these raw/modified hydrochars along with the involved mechanisms during organic (dyes) and mineral pollutants (heavy metals and nutrients) removal from aqueous solutions is also reviewed. Finally, this paper addresses the main challenges and also demonstrates insights on new directions for hydrochars research and development in the future.

Sustainable consumption policies often rely on ecological modernisation rationality, where the focus is usually on making current consumption patterns more sustainable in such a way that status quo (ideas about the quality of life and growth) is not challenged. As a result, sustainable energy policies tend to black box the demand-side, often resulting in abstracting efficiency strategies from the social organisation within which the strategies and resulting solutions unfold. Rebound effects and other unintended consequences often happen as a result of this type of efficiency strategies. This chapter introduces alternative problem framings that may offer a way to mitigate rebound effects by addressing and challenging a wider set of socio-material, cultural and institutional aspects of energy demand.

The self-consumption without surplus to the grid is one of the aspects of the new Spanish law for prosumers. Increasing the share of renewable energy sources into the grid inherently leads to several constraints. The mismatch between the energy demand and the renewable energy production, which is intermittent in nature, is one of those challenges. Storage offers the possibility to decouple demand and supply, and therefore, it adds flexibility to the electric system. This research evaluates expanding electricity self-consumption without surplus to the grid by harnessing thermal mass storage in the residential sector. The methodology is investigated by using a variable refrigerant flow air conditioner system. Because there is no option to export the excess capacity to the grid, this research proposes an approach to profiting from this surplus energy by activating structural thermal mass, which is quantified from the information acquired using a building energy model. For this purpose, an EnergyPlus model of a flat in Pamplona (Spain) was used. The optimization analysis was based on a set-point modulation control strategy. Results show that under adequate climatological circumstances, the proposed methodology can reduce the total electric energy from the grid between by 60– 80 % .

Around 30% of the European building stock was built before 1950, when no regulations about energy efficiency were in force. Since only a small part of them has been renovated by now, the energy performance of this building stock is on average quite poor, resulting in a significant impact on the energy balance of European countries, as confirmed by data published by ISTAT (Italian National Statistical Institute). However, energy retrofit in historic edifices is a quite demanding issue as any intervention must take into account the need to preserve existing building materials and appearances while also allowing reversibility and low invasiveness. As an example, in these buildings it is not possible to apply an ETICS (External Thermal Insulation Composite System), since this would alter the historic and architectural value of the façade. On the other hand, internal insulation would have the drawback of reducing the net useful floor area, which also implies a loss of economic value. Moreover, internal insulation may induce overheating risks and mold formation. In this paper, all these issues are investigated with reference to an existing historic building located in southern Italy, showing that a retrofit strategy aimed at energy savings and cost-effectiveness is still possible if suitable materials and solutions are adopted.

100 Positive Energy Districts (PEDs) are to be created in Europe by 2025, with a stated goal of urban decarbonization. These are highly energy efficient residential urban areas, powered entirely through renewables. PED creation is to be guided by principles of quality of life, sustainability, and inclusiveness (specifically focusing on affordability and energy poverty prevention). Although there is research into the decarbonization aspects of PEDs, there has been little focus on the guiding principles, and their potential to reduce energy vulnerability. Using energy vulnerability factors and an energy justice framework, this article examines how the topic of energy vulnerability mitigation is perceived by professional PED stakeholders. Stakeholders from multiple countries were interviewed in order to determine how and to what extent they approached the topic of inclusivity and energy vulnerability. The contribution of this paper to academic research is in helping to frame energy vulnerability in European smart city urban areas, focusing on the perceptions of key stakeholders. This contributes to research on the identification and evaluation of innovations such as PEDs which offer a potential model for an inclusive transition. Furthermore, this article offers a contribution for policymakers, informing PED replication policies with a focus on the synergistic aims of decarbonization and energy vulnerability mitigation.

The concept of the Circular Economy (CE) is an increasingly attractive approach to tackling current sustainability challenges and facilitating a shift away from the linear “take-make-use-dispose” model of production and consumption. The public sector is a major contributor to the CE transition not only as a policy-maker but also as a significant purchaser, consumer, and user of goods and services. The circularization of the public sector itself, however, has received very little attention in CE research. In order to explore the current state of knowledge on the implementation of CE practices and strategies within Public Sector Organizations (PSOs), this research aims to develop an overview of the existing literature. The literature review was designed combining a systematic search with a complementary purposive sampling. Using organizational sustainability as a theoretical perspective, the main results showed a scattered landscape, indicating that the limited research on CE practices and strategies in PSOs has focused so far on the areas of public procurement, internal operations and processes, and public service delivery. As a result of this literature review, an organizational CE framework of a PSO is proposed providing a holistic view of a PSO as a system with organizational dimensions that are relevant for the examination and analysis of the integration process of CE practices and strategies. This innovative framework aims to help further CE research and practice to move beyond current sustainability efforts, highlighting that public procurement, strategy and management, internal processes and operations, assessment and communication, public service delivery, human resources dimensions, collaboration with other organizations, and various external contexts are important public sector areas where the implementation of CE has the potential to bring sustainability benefits.