Sustainable waste-to-energy (WtE) planning requires coordinated decisions on feedstock valorization, conversion technology, plant siting, operating strategy, and the utilization of recovered energy and by-products. These decisions are complicated by conflicting economic, environmental, technical, and social criteria, together with uncertainty and hesitation in operational and stakeholder information. This study develops an intelligent decision-support framework for integrated WtE planning and smart-energy infrastructure under uncertain information. Six sine-based similarity measures are extended from intuitionistic fuzzy sets to $q$-rung orthopair and $T$-spherical fuzzy environments, allowing support, opposition, hesitation, and stakeholder abstention to be represented within a common decision structure. The framework integrates data acquisition from supervisory control and data acquisition systems, smart meters, municipal information, and expert assessments with fuzzification, entropy-based weighting, similarity-based ranking, the Aggregate Separation Index (ASI), and Monte Carlo rank-stability analysis. Its performance is examined through four illustrative energy-planning cases involving waste-valorization pathway selection, energy-facility siting, conversion-route selection, operating-strategy selection for a biogas combined heat and power (CHP) unit, and industrial-symbiosis partner selection. Anaerobic digestion is consistently identified as the preferred valorization pathway, while biogas CHP is the leading conversion route. Under entropy-derived weights, Baseload is the preferred CHP operating strategy, although Hybrid-adaptive operation becomes more attractive when revenue and grid-support priorities receive greater emphasis. Under the reference setting, Monte Carlo analysis gives rank-1 probabilities of 0.948 for pathway selection and 0.999 for operating-strategy selection. By contrast, the two leading industrial-symbiosis partners differ by only 0.008, and the nominal leader retains first place with a probability of 0.632, so the decision is classified as contested. A machine-learning benchmark further shows that the similarity-based matcher remains within 0.6–3.9 percentage points of the best crisp prototype benchmark while retaining explicit information on similarity, hesitation, and aggregate separation. The results demonstrate how uncertainty-aware decision support can connect waste valorization, energy recovery, conversion technology, grid-responsive operation, and industrial symbiosis within an integrated framework for sustainable urban energy planning.
The cavity geometry of a single-slope solar still directly influences the internal transport phenomena by altering natural convection, heat transfer, and vapor movement, as their alteration collectively determines the system’s freshwater productivity. Variations in the glass cover inclination modify the cavity geometry, thereby changing the natural convection flow pattern, evaporation, and condensation mechanisms, as well as the overall thermal behavior of the solar still. Despite its importance, the impact of cavity geometry on the internal transport phenomena has not yet been fully understood. Therefore, the present work conducted a systematic two-dimensional numerical investigation to assess the effects of five glass cover inclination angles (10°, 15°, 20°, 25°, and 30°) on the thermo-fluid behavior and freshwater productivity. To isolate the influence of cavity geometry, the basin length and front-wall height were kept constant, while the back-wall height was varied to produce the desired inclination angles without altering the remaining design parameters. The numerical results confirmed that modifying the glass cover inclination induced a substantial change in the natural convection flow regime within the still cavity, leading to significant nuances in heat and mass transfer characteristics. At steeper inclination angles, the airflow was dominated by a single large recirculating convection cell that confined convective heat transfer between the evaporating water surface and the glass cover, causing a uniform reduction in the effectiveness of condensation and freshwater production. In contrast, the shallowest inclination angle of 10° promoted the formation of multiple localized convection cells that enhanced fluid mixing, strengthened convective heat transfer, and improved vapor transport toward the condensing surface. Consequently, the 10° configuration exhibited the highest freshwater productivity among all investigated geometries.
The electricity grid is the physical backbone of the low-carbon transition, yet in most industrialised economies it was designed for a fossil-fuelled, unidirectional, and centralised system. This paper examines how the electricity grid of Great Britain has become the object of a comprehensive reform programme and asks what generalisable lessons its experience offers for other countries pursuing deep decarbonisation. A qualitative policy-document analysis, triangulated with publicly available quantitative indicators, is adopted: policy documents, regulatory determinations, and network operator business plans issued between 2020 and 2026 are analysed and triangulated with published quantitative indicators, including connection queue volumes, transmission constraint costs, and planned capital expenditure. The evidence shows that the pre-reform “first come, first served” model produced a connection queue of over 700 GW of generation and storage and more than 120 GW of demand by 2025, while transmission constraint costs reached approximately £1.9 billion in 2024/25. In response, three mutually reinforcing reform strands have been introduced: a redesigned connections process (Target Model Option 4+, TMO4+) that combines readiness with strategic alignment; a step change in transmission investment under the Accelerated Strategic Transmission Investment (ASTI) framework and the RIIO-T3 (Revenue = Incentives + Innovation + Outputs, transmission price control 2026–2031) price control; and a strengthened regulatory regime with enforceable delivery obligations. This policy synthesis concludes that reforming the grid is as much an institutional and regulatory task as a technical one, and that coordinated action across the system operator, the regulator, government and network companies is a necessary condition for delivering an affordable, secure and low-carbon electricity system.
Renewable energy communities (RECs) have emerged as one of the most promising instruments for advancing the social, economic, and environmental dimensions of the energy transition. Based on the principles of open participation, non-profit governance, and local value creation, RECs hold significant potential to alleviate energy poverty, revitalize inland areas, foster local employment, enhance the social acceptance of renewable energy infrastructure, and support sustainable mobility. Despite a well-defined regulatory framework, the deployment of RECs in Italy remains limited in both scale and scope. Current configurations are typically characterized by fewer than two generation units, a median installed capacity of approximately 12 kW, and around ten members. The paper aims to demonstrate that the gap between the theoretical potential of REC and their current implementation reflects a structural issue, which has led to the proliferation of models driven primarily by incentive schemes rather than by strategic, community-centered planning. Through a systematic review of the multidimensional benefits associated with RECs and an analysis of the structural barriers hindering their development, the study identifies the aggregator as a key missing organizational enabler. This actor can bridge citizens, institutions, industry, and the public sector, thereby translating regulatory intent into sustainable and scalable community energy initiatives.
Renewable energy communities (RECs) are central to the European energy transition because they can turn passive consumers into active prosumers and support more decentralized, community-based energy systems. This perspective paper examines the evolution of RECs in Italy, asking whether their current development trajectory can move beyond incentive-dependent deployment toward more resilient and market-integrated models. Italy offers a particularly relevant case because it combines advanced regulatory transposition and rapid diffusion with persistent structural weaknesses. The analysis draws on regulatory documents, diffusion data, economic and governance evidence, market and grid data, and recent audit evidence from the European Court of Auditors. We trace the development of RECs from the European Union (EU)’s Clean Energy Package through Italy’s Legislative Decree 199/2021 and Autorità di Regolazione per Energia Reti e Ambiente (ARERA)’s Testo Integrato Autoconsumo Diffuso (TIAD) framework, and the emerging Testo Integrato del Dispacciamento Elettrico (TIDE) pathway for market integration. The paper argues that REC diffusion in Italy is constrained by an “incentive trap”: although RECs are designed to promote local empowerment, they remain structurally dependent on national support schemes and are still weakly connected to wholesale markets, ancillary services, and grid flexibility mechanisms. We identify three strategic pillars for overcoming this limitation: governance innovation that combines economic viability, social equity, and digital solutions; regulatory pathways that enable aggregation, demand response, balancing-market participation, local flexibility, and storage; and diversified revenue streams based on local energy trading, demand response, multi-service provision, and grid-support services. The paper contributes to debates on energy democracy and decentralized energy systems by proposing an evolutionary framework through which Italian RECs can preserve their social value while becoming adaptive market actors.
Port cities and their hinterlands present particular challenges for sustainable development, including high energy demand, urban heat island (UHI) effects, energy poverty, and environmental impacts from port operations. This work aims at verifying two hypotheses: first, that increasing renewable energy community (REC)/self-consumption scheme (SCS) membership significantly improves self-consumption performance for a fixed photovoltaic (PV) installation; and second, that the spatial distribution of impervious surfaces in port hinterland areas is directly correlated with UHI intensity and therefore highlights priority zones for Nature-based Solution (NbS) intervention. An hourly photovoltaic simulation model is used to evaluate the effect of community size on the self-consumption factor, and a geographic information system analysis combining Copernicus reanalysis temperature data and high-resolution land cover layers is used to characterize UHI dynamics in Genoa. The implementation framework is provided by the EnerCmed project, which is co-funded by the European Union (EU)’s Interreg Euro-MED programme. The simulation results demonstrate that with an increase in REC/SCS membership from 1 to 30 apartments, the self-consumption factor increases from 5% to 50% for a 50 kWp installation. The results of the UHI analysis show nocturnal summer intensification of +3 to +4 °C in the Genoa port hinterland area, with strong correlation with impervious surface density. The results show how renewable energy governance coupled with nature-based climate adaptation strategies can simultaneously improve renewable energy self-consumption and mitigate urban heat stress in port cities’ hinterlands. These findings support the new hybrid approach as an effective replicability strategy for green harbors and sustainable Mediterranean port cities.
Liquefied natural gas (LNG) has been widely considered a transitional energy carrier owing to its lower combustion-related emissions relative to coal and oil and its compatibility with existing energy infrastructure. In this study, the role of LNG in facilitating the transition towards sustainable and low-carbon energy systems is critically examined from technological, environmental, and supply-chain perspectives. The thermodynamic principles governing phase conversion from natural gas to cryogenic liquid are analysed, and energy penalties associated with liquefaction, storage, regasification, and transportation are systematically evaluated, with particular attention given to boil-off gas (BOG) generation and mitigation strategies. The integration of LNG within evolving energy systems is further assessed, including its capacity to provide dispatchable backup for variable renewable energy sources and to enhance grid reliability during periods of intermittency. A lifecycle-oriented evaluation is conducted to quantify emissions, energy efficiency, and operational losses across production, liquefaction, maritime transport, storage, distribution, and end-use stages. In addition, supply chain management (SCM) considerations, price parity with conventional fuels, and infrastructure adaptability are examined to determine the feasibility of large-scale deployment. Particular emphasis is placed on the heavy-duty transportation sector in India, where LNG is increasingly considered a lower-emission alternative to diesel due to its higher energy density relative to compressed natural gas (CNG) and suitability for long-haul applications. The analysis highlights both opportunities and limitations, including methane slip, upstream fugitive emissions, and capital-intensive liquefaction infrastructure, which may influence the net climate benefit of LNG. The findings indicate that LNG can contribute to short- to medium-term emissions reduction and operational flexibility when deployed alongside renewable energy technologies; however, its long-term sustainability is constrained by its fossil origin and associated lifecycle greenhouse gas (GHG) emissions. Consequently, LNG is best interpreted as a bridging solution that may facilitate energy system decarbonisation while renewable generation, storage technologies, and hydrogen-based fuels continue to mature.
The transition towards low-carbon energy systems has been increasingly recognised as a critical global priority for mitigating climate change, reducing dependence on fossil resources, and promoting sustainable socioeconomic development. Although Brazil possesses one of the world’s most renewable energy matrices, supported primarily by hydropower, bioenergy, wind, and solar resources, significant challenges remain in the effective integration of waste-to-energy technologies and circular resource management strategies. In this review, the current status of renewable energy deployment in Brazil is critically assessed alongside the generation, management, and valorisation potential of major waste streams, including agricultural biomass, agro-industrial residues, food-processing wastes, municipal solid waste (MSW), wastewater sludge, construction and demolition waste (CDW), pulp and paper residues, and end-of-life tyres. Existing treatment practices and recovery technologies are systematically examined with emphasis on their capacity to convert waste into value-added products such as solid, liquid, and gaseous biofuels, secondary raw materials, and platform chemicals. Particular attention is given to technological limitations, regional disparities in infrastructure, and policy gaps that have constrained the broader implementation of decentralised renewable energy systems, especially in rural and residential sectors. It is observed that despite substantial progress in renewable electricity generation, waste recycling rates, energy recovery efficiency, and integrated waste management practices remain comparatively underdeveloped. The adoption of advanced thermochemical, biochemical, and material recovery technologies is shown to offer significant opportunities for emissions reduction, resource efficiency, and industrial symbiosis. Furthermore, the role of regulatory frameworks, economic incentives, and public investment in accelerating the transition towards a circular and low-carbon economy is highlighted. The findings demonstrate that the strategic integration of renewable energy expansion with waste valorisation could substantially enhance energy security, environmental performance, and economic resilience in Brazil. The technological pathways, policy mechanisms, and management strategies discussed are also considered transferable to other emerging economies facing similar energy and waste management challenges.
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