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Abstract In recent years, distributed energy systems (DESs) have been recognized as a promising option for sustainable development of future energy systems, and their application has increased rapidly with supportive policies and financial incentives. With growing concerns on global warming and depletion of fossil fuels, design optimization of DESs through economic assessments for short-run benefits only is not sufficient, while application of exergy principles can improve the efficiency in energy resource use for long-run sustainability of energy supply. The innovation of this paper is to investigate exergy in DES design to attain rational use of energy resources including renewables by considering energy qualities of supply and demand. By using low-temperature sources for low-quality thermal demand, the waste of high-quality energy can be reduced, and the overall exergy efficiency can be increased. The goal of the design optimization problem is to determine types, numbers and sizes of energy devices in DESs to reduce the total annual cost and increase the overall exergy efficiency. Based on a pre-established DES superstructure with multiple energy devices such as combined heat and power and PV, a multi-objective linear problem is formulated. In modeling of energy devices, the novelty is that the entire available size ranges and the variation of their efficiencies, capital and operation and maintenance costs with sizes are considered. The operation of energy devices is modeled based on previous work on DES operation optimization. By minimizing a weighted sum of the total annual cost and primary exergy input, the problem is solved by branch-and-cut. Numerical results show that the Pareto frontier provides good balancing solutions for planners based on economic and sustainability priorities. The total annual cost and primary exergy input of DESs with optimized configurations are reduced by 21–36% as compared with conventional energy supply systems, where grid power is used for the electricity demand, and gas-fired boilers and electric chillers fed by grid power for thermal demand. A sensitivity analysis is also carried out to analyze the influence of energy prices and energy demand variation on the optimized DES configurations.

Polycyclic aromatic hydrocarbons (PAHs) are airborne pollutants that are deposited on soils. As climate change is already altering temperature and solar radiation, the global warming is suggested to impact the environmental fate of PAHs. This study was aimed at evaluating the effect of climate change on the PAH photodegradation in soils. Samples of Mediterranean soils were subjected to different temperature and light radiation conditions in a climate chamber. Two climate scenarios were considered according to IPCC projections: 1) a base (B) scenario, being temperature and light intensity 20°C and 9.6W/m(2), respectively, and 2) a climate change (CC) scenario, working at 24°C and 24W/m(2), respectively. As expected, low molecular weight PAHs were rapidly volatilized when increasing both temperature and light intensity. In contrast, medium and high molecular weight PAHs presented different photodegradation rates in soils with different texture, which was likely related to the amount of photocatalysts contained in both soils. In turn, the hydrogen isotopic composition of some of the PAHs under study was also investigated to verify any degradation process. Hydrogen isotopes confirmed that benzo(a)pyrene is degraded in both B and CC scenarios, not only under light but also in the darkness, revealing unknown degradation processes occurring when light is lacking. Potential generation pathways of PAH photodegradation by-products were also suggested, being a higher number of metabolites formed in the CC scenario. Consequently, in a more or less near future, although humans might be less exposed to PAHs, they could be exposed to new metabolites of these pollutants, which might be even more toxic.

Thermal energy storage systems (TES) based on shape-stabilized phase change materials (SSPCM) designed from recycled Tetra Pak (TP) waste, paraffin wax (PW), and expanded graphite (EG) were investigated in this study. This work represents the first study to explore TP waste composed of low-density polyethylene (LDPE)/aluminum (Al) components for energy storage applications. The LDPE part serves as a matrix conserving a material in a compact, solid shape after PW melting; PW acts as an active phase change component contributing to heat absorption/release through a phase change (from a solid to a liquid state, and vice versa) of its crystalline phase. EG serves as a filler that enhances the thermal conductivity and mechanical properties of materials. The focus was put on the optimization of the composition of SSPCM including PW, and EG, to check thermal, mechanical, and rheological properties which influence the future processability of such systems through extrusion, as well as to investigate the synergic effect of graphite and residual Al component on thermal conductivity and leakage of PW. There are two main demands on polymer/PW blends, namely well-separated melting peaks for both components at significantly different temperatures, and good compatibility between polymer and PW. The best performance of SSPCM investigated in this study was found for a mixture having the composition TP/PW/EG = 50/40/10 w/w/w. This mixture shows well-balanced properties, including appropriate heat storage and release parameters, thermal conductivity, thermal diffusivity, toughness and strength, and low leakage of PW from the material. This system can store 116.2 J/g of heat energy and release 93.8 J/g of heat energy. The determination of the heat energy storage and release was performed by the transient guarded hot plate technique. Tensile testing revealed that Young's modulus of the TP/PW/EG = 50/40/10 w/w/w composition was 924 ± 71 MPa and the stress at break was 8.2 ± 1.2 MPa, which are sufficient values from the applicability ...

While the member states of the Gulf Cooperation Council have economically and politically been dominated by the exploitation of fossil fuels, recent years have seen an increasing adoption of renewable energy technologies, the reasons of which are not yet sufficiently understood. This paper argues that the recent adoption of renewable energy technologies in the Gulf and its striking variation can be explained by theories of policy transfer. In addition, we find some support for the alternative hypothesis of endogenous policy development regarding political leadership. Yet there is no support for the alternative hypothesis of a strong direct influence of the international climate regime. Furthermore, the policy transfer hypothesis and political leadership stand as coexisting influences on renewable energy adoption, rather than competing ones. Based on an extensive study of primary and secondary sources, local reports and country analyses of international organizations, and personal interviews with key experts, this paper lays out in detail how transfers of renewable energy policies take place in the Gulf; their drivers; and their impacts. We also discuss the factors that lead countries to lag behind, which can be helpful for prospective research on a more extensive utilization of renewable energy in the region and beyond.

Growing scientific evidence for the indispensable role of environmental sustainability in sustainable development calls for appropriate frameworks and indicators for environmental sustainability assessment (ESA). In this paper, we operationalize and update the footprint-boundary ESA framework, with a particular focus on its methodological and application extensions to the national level. By using the latest datasets available, the planetary boundaries for carbon emissions, water use and land use are allocated to 28 selected countries in comparison to the corresponding environmental footprints. The environmental sustainability ratio (ESR)—an internationally comparable indicator representing the sustainability gap between contemporary anthropogenic interference and critical capacity thresholds—allows one to map the reserve or transgression of the nation-specific environmental boundaries. While the geographical distribution of the three ESRs varies across nations, in general, the worldwide unsustainability of carbon emissions is largely driven by economic development, while resource endowments play a more central role in explaining national performance on water and land use. The main value added of this paper is to provide concrete evidence of the usefulness of the proposed framework in allocating overall responsibility for environmental sustainability to sub-global scales and in informing policy makers about the need to prevent the planet’s environment from tipping into an undesirable state.

Background: Sodium oxybate (SMO) has been shown to be effective in the maintenance of abstinence (MoA) in alcohol-dependent patients in a series of small randomized controlled trials (RCTs). These results needed to be confirmed by a large trial investigating the treatment effect and its sustainability after medication discontinuation. Aims: To confirm the SMO effect on (sustained) MoA in detoxified alcohol-dependent patients. Methods: Large double-blind, randomized, placebo-controlled trial in detoxified adult alcohol-dependent outpatients (80% men) from 11 sites in four European countries. Patients were randomized to 6 months SMO (3.3–3.9 g/day) or placebo followed by a 6-month medication-free period. Primary outcome was the cumulative abstinence duration (CAD) during the 6-month treatment period defined as the number of days with no alcohol use. Secondary outcomes included CAD during the 12-month study period. Results: Of the 314 alcohol-dependent patients randomized, 154 received SMO and 160 received placebo. Based on the pre-specified fixed-effect two-way analysis of variance including the treatment-by-site interaction, SMO showed efficacy in CAD during the 6-month treatment period: mean difference +43.1 days, 95% confidence interval (17.6–68.5; p = 0.001). Since significant heterogeneity of effect across sites and unequal sample sizes among sites ( n = 3–66) were identified, a site-level random meta-analysis was performed with results supporting the pre-specified analysis: mean difference +32.4 days, p = 0.014. The SMO effect was sustained during the medication-free follow-up period. SMO was well-tolerated. Conclusions: Results of this large RCT in alcohol-dependent patients demonstrated a significant and clinically relevant sustained effect of SMO on CAD. Trial registration: ClinicalTrials.gov Identifier: NCT04648423

In recent years there has been increasing attention to the transition toward a bioeconomy. From comparable transitions toward sustainability, we know that transitions require integral, inclusive approaches toward developing a long-term strategy, focusing not only on technological innovation, but also on involving the public. This is not easy. Public engagement encompasses diverse forms of public and civil society participation, and it is crucial to understand the specificities of these interactions and their effects on potential transition pathways. We present a conceptual-analytical paper where the focus lies on understanding sense-making practices in the construction of publics in the bioeconomy. Using a case-study approach, this article describes five partialities of the constructed public in the bioeconomy and analyzes the orchestration, productive dimensions and effects of these constructions. Our analysis offers a new perspective on, and appreciation of, the partiality of different forms of public participation, and varying degrees in which possibilities of system change in the bioeconomy transition are inclusive or exclusive toward differentially constructed publics. This offers an alternative, constructive way of exploring actor dynamics and politics in system change. We aim to contribute to a more nuanced and integral interpretation of public engagement in sustainability transitions, which is relevant to actors from academia, policy, industry and other spheres relevant to the bioeconomy transition.