Search Results (113)

Façades play a decisive role in shaping the visual and symbolic character of historic urban environments. Recent European funding schemes promoting energy-efficient retrofitting have accelerated interventions on building envelopes. Although aligned with decarbonization objectives, these processes are generating significant chromatic and material transformations that risk eroding the visual coherence and cultural sustainability of consolidated urban areas. In the historic Ensanches of San Sebastián, the replacement of traditional envelope systems with new cladding solutions is leading to the loss of the architectural style of some facades and altering their materials, textures, and colors. A progressive “contagion effect” has been identified, whereby dissonant chromatic schemes—often associated with the proliferation of so-called “zebra blocks”, residential buildings with façades clad in alternating black and white stripes that have proliferated in recent urban developments—are replicated across adjacent buildings, gradually weakening spatial continuity and the genius loci of the neighborhood. In response to this phenomenon, this research develops a systematic methodology to analyze, quantify, and anticipate chromatic transformation in consolidated urban fabrics. The study combines historical morphological analysis, classification of architectural periods, and chromatic mapping of recent façade interventions. Based on this framework, a CARI, Chromatic Alteration Risk Index is proposed to evaluate the potential impact of façade alterations on urban chromatic coherence. Drawing on an epidemiological framework, the methodology enables the identification of critical transformation clusters, the assessment of contagion dynamics, and the definition of regulatory thresholds for color and material interventions. By integrating perceptual criteria, urban morphology, and spatial distribution patterns, the study moves beyond descriptive diagnosis and offers a transferable tool for municipal planning. The proposed approach supports the proactive regulation of façade rehabilitation processes, balancing energy efficiency objectives with the preservation of collective memory, material identity, and urban sensory quality. This study proposes a quantitative model of “urban chromatic contagion” to assess how façade color interventions propagate within a neighborhood. We define the Chromatic Integration Percentage (CIP) and the Chromatic Alteration Risk Index (CARI) of the analyzed area. Results indicate that poorly regulated façades show higher chromatic dissonance (low CIP) and act as contagion hotspots, while a clear risk gradient emerges: highly protected buildings present lower risk, whereas mixed typologies and recent rehabilitations concentrate higher CARI values. The model supports preventive urban color management by identifying areas at risk before visible alteration. Full article

This study evaluates the spatial and seasonal feasibility of residential PV integration across 52 Spanish municipalities representing the country’s main urban areas. The assessment is based on the normalized photovoltaic sizing indicator (A_PV,N), defined as the PV area required to offset electricity demand per square metre of conditioned floor area. Simulations were performed under current climate conditions and future projections for 2050 and 2100 using the RCP4.5 scenario. Results reveal strong climatic and seasonal contrasts. Under current conditions, annual PV generation offsets approximately 17–18% of residential electricity demand. Southern and Mediterranean municipalities show the highest feasibility, with annual A_PV,N values of approximately 2–2.5, whereas northern and inland regions present severe winter limitations, with A_PV,N values frequently exceeding 15–20. Summer is the most favourable season, with PV systems covering more than 50% of seasonal demand in several southern municipalities. Future climate projections indicate a progressive improvement in PV feasibility. Under RCP4.5, annual A_PV,N decreases by approximately 5–10% by 2100, while the production-to-consumption (P/C) ratio improves by about 15–20% relative to present conditions, mainly due to reduced heating demand. The results demonstrate that future climate conditions may improve the viability of residential PV systems in Spain, particularly in southern and coastal urban areas, while northern regions will remain constrained during winter. The study provides quantitative benchmarks for climate-sensitive PV planning and long-term urban energy strategies. Full article

China has established the world’s largest municipal wastewater treatment system through rapid infrastructure expansion over the past two decades. However, under the transition from infrastructure expansion toward urban renewal and low-carbon development, wastewater systems are increasingly challenged by regional imbalances and structural inefficiencies. Existing studies have primarily focused on individual facilities or specific operational issues, while multidimensional system-level assessments remain limited. To address this gap, this study proposed a multidimensional assessment framework for evaluating wastewater system development in China from three dimensions: infrastructure adequacy, operational performance, and adaptive capacity. Based on national and provincial statistical data, regional disparities and development patterns were systematically analyzed using correlation analysis and hierarchical cluster analysis. Results showed that treatment capacity expansion in several provinces outpaced sewer network development, resulting in low hydraulic loading rates and underutilized facilities. Extraneous water infiltration remained a widespread issue, increasing unnecessary wastewater handling, energy consumption, and treatment burden. Reclaimed water development was influenced more strongly by policy-oriented planning and water resource constraints than by economic level alone. In addition, eastern coastal provinces generally demonstrated stronger infrastructure adequacy and operational performance, whereas several western and northeastern provinces remained constrained by insufficient adaptive capacity and sewer coordination. Overall, China’s wastewater sector is transitioning from treatment-oriented expansion toward system-oriented renewal. Future strategies should prioritize sewer rehabilitation, hydraulic efficiency improvement, reclaimed water integration, and adaptive infrastructure planning. The proposed framework can support future infrastructure monitoring, regional policy evaluation, and low-carbon wastewater system transformation. Full article

Food markets represent a public good essential for urban supply and as intergenerational spaces supporting the small-scale economy, yet they face growing challenges in adapting to sustainability regulations and circular economy requirements. This study examines the current state of sustainability in Madrid’s municipal markets through interviews and questionnaires administered to market managers, analyzing building characteristics, renewable energy systems, passive savings strategies, and energy costs across different market typologies. Results reveal that in December 2025, only 9% of markets had solar thermal installations, while merely 11% were planning photovoltaic solar panel projects—figures insufficient to meet current EU energy efficiency mandates. The findings demonstrate a significant gap between existing infrastructure and the requirements of the Directive (EU) 2023/1791, which supersedes previous directives. These results indicate an urgent need for accelerated implementation of renewable energy systems in market buildings to achieve sustainability targets. The study contributes baseline data for developing intervention strategies that can reduce energy consumption and align Madrid’s market network with European decarbonization goals for 2030 and 2050. Full article

The energy transition of district heating systems in Poland requires the simultaneous consideration of energy efficiency, operating costs, technical feasibility, and local environmental constraints. This study addresses an identified gap in the literature by combining real operational time series from a municipal district heating system with time-resolved market signals and site-specific resource constraints in a single OPEX-based operational screening framework. A case study is conducted for the city of Ustka using a configuration-based comparison of hybrid supply systems that include a gas-fired combined heat and power (CHP) unit, air-source and ground-source heat pumps, thermal energy storage, and a peak-load boiler. The optimisation model was implemented in MS Excel using the GRG Nonlinear algorithm (Solver) and was driven by the district heating operational data for 2021–2022 together with electricity and natural gas prices from the Polish Power Exchange day-ahead market (TGE RDN), evaluated under both hourly and daily settlement assumptions. The results indicate an optimal capacity split of 1.2 MWel/1.3 MWth for the CHP unit and 1.5 MWel/3.0 MWth for the heat pump system, supported by a required peak boiler capacity of 8.23 MWth. Within the adopted OPEX-based assessment, the lowest value of the unit heat generation indicator was obtained for the CHP-led configuration with combined ground-source and air-source heat pumps (38.45–38.55 PLN/GJ). A distinctive element of the study is the explicit verification of whether an operationally favourable configuration remains practically feasible when local resource constraints are considered. The site assessment indicates limited practical feasibility of the borehole heat exchanger at the analysed location in Ustka, showing that the lowest OPEX result should not be interpreted as a final investment recommendation. The study provides a replicable approach for the Polish district heating operators to screen hybrid transition pathways under real market conditions and to avoid technology choices that are favourable in dispatch models but constrained in practice. From a sustainability perspective, the proposed framework supports more energy-efficient, resilient, and locally feasible district heating transition planning in municipal heat systems. Full article

Global climate change and rapid socio-economic development have increasingly exacerbated the imbalance between ecosystem service (ES) supply and demand. Taking the Pinglu Canal Economic Zone as a case study and employing a water–energy–food (WEF) nexus perspective, this study selected three key ESs—water yield, carbon sequestration, and food supply. The InVEST model, supply–demand index (SDI), Pearson correlation analysis, and four-quadrant model were integrated to systematically reveal the spatiotemporal patterns, correlation characteristics, and spatial matching of ES supply and demand from 2005 to 2020. Scale effects and appropriate management scales were clarified through municipal, county, and grid scale comparisons, and a comprehensive management zoning scheme was constructed using a “zoning–classification–grading” framework. The results show that water yield and food supply exhibited an overall increasing trend, while carbon sequestration supply remained stable. Demand for all three services showed continuous growth, with a spatial pattern of “high in the central area and low in the surrounding areas”, consistent with population and economic agglomerations. The county scale was the most effective at capturing local supply–demand characteristics. A “zoning–classification–grading” spatial governance system was constructed based on dominant functions, supply–demand status, and control priority. This study can provide a scientific basis for territorial spatial planning and integrated ecosystem management in the Pinglu Canal Economic Zone and similar regions. Full article

Rooftop photovoltaic (PV) deployment in historic European cities is often treated as an energy-maximization task, with limited attention to distributive equity and cultural heritage constraints. Linking rooftop PV deployment to sustainable development requires screening approaches that address not only renewable electricity generation, but also social inclusion, resource efficiency, and the protection of cultural heritage. This study presents an open-data, GIS-based screening framework to support Renewable Energy Community targeting in Bologna, Italy. Roof polygons from OpenStreetMap (51,950 roofs) were combined with a cultural-heritage Web Feature Service (892 assets) to classify roofs as protected and excluded (645 roofs), heritage-sensitive within a 25 m buffer (4352 roofs), or unconstrained. A conservative PV proxy estimated usable roof area and annual generation using fixed system parameters and a PVGIS-derived specific yield (1359.39 kWh kWp⁻¹ yr⁻¹). Social conditions were represented with the composite fragility index and 2024 population totals to compute normalized per capita PV potential. Three prioritization strategies were compared: S1 (technical opportunity), S2 (equal-weight energy–equity score), and S3 (S2 moderated by heritage concentration). After heritage conditioning, the citywide potential totals 7.38 million m² usable area (≈1.11 GWp; ≈1.51 TWh·yr⁻¹), and per capita potential ranges from 2.33 to 4.55 MWh·cap⁻¹·yr⁻¹. Equity weighting shifts priority toward more vulnerable areas, while heritage-dense areas remain lower-ranked. The workflow outputs transparent rules, priority maps, and reproducible layers for sustainability-oriented municipal decision-making by connecting urban decarbonization, energy justice, efficient use of existing rooftops, and heritage-compatible renewable energy planning. Full article

This study comparatively assesses the Municipal Emission Reduction Plans (MERPs) of Spetses, Platanias, and Souli, examining their role as analytical and strategic tools for local climate planning, with particular emphasis on water-related infrastructure. A descriptive comparative analysis was conducted using secondary data extracted from officially approved MERPs, covering sectoral and total greenhouse gas emissions for 2019 and 2023, as well as reported mitigation actions and 2030 targets. The results reveal significant inter-municipal variations in emission patterns, driven by geomorphological characteristics, infrastructure configuration, and energy consumption, but also by governance structures and system boundaries. Water supply and irrigation systems are identified as highly energy-intensive sectors, particularly in municipalities with extensive, pumping-dependent networks. At the same time, the analysis shows that the inclusion or exclusion of outsourced services—such as water supply and wastewater management—substantially affects the representation of emissions and the prioritization of mitigation actions. The study concludes that MERPs can support climate planning at the municipal level, but their effectiveness is conditioned by data completeness, system boundaries, and governance models. These findings highlight the need to move beyond purely accounting-based approaches toward integrated planning frameworks that capture the full operational scope of municipal systems, enabling more accurate emission assessment and more effective, context-specific mitigation strategies within the water–energy–nexus. Full article

AI data-center (DC) growth is increasingly constrained by limited deliverable electricity, interconnection capacity, and cooling demand. This study develops a boundary-consistent screening framework for waste-to-energy (WtE)-coupled AI DC cooling, treating cooling as an energy service that can be supplied through grade matching rather than solely through electricity-driven mechanical chilling. The framework translates plant-side exportable heat into corridor-level planning objects by explicitly accounting for thermal attenuation, absorption-based conversion, and parasitic electricity associated with delivery and auxiliaries. Three results structure the analysis. First, a reference-case energy-service ledger shows how a representative regulated WtE plant with municipal solid-waste throughput of 1500 t/day and lower heating value of 10 MJ/kg yields ~78.1 MWth of exportable driving heat and, at a 20 km corridor, ~53.0 MWcool of delivered cooling and ~8.0 MWe of net avoided cooling electricity after parasitic debiting. Second, the coupled system is governed by operating regimes, not a single efficiency score. Under the baseline package, full thermal coverage is maintained up to ~20.9 km, the stricter quality-adjusted criterion remains positive to ~22.9 km, and the electricity–relief criterion remains positive to ~44.7 km. Third, deployment-scale translation for a 1 GW IT campus ($u=0.70$, $L=5 \mathrm{k}$m) implies a net grid relief of ~116.9–264.4 MW across scenario packages, while the required WtE footprint ranges from roughly three to 148 equivalent representative plants, or about 0.6–40 full-load-equivalent plants at a 25% displacement target. The contribution is a siting-ready planning framework that identifies when WtE-coupled cooling remains corridor-feasible, when it becomes hybrid and marginal, and when infrastructure scale rather than thermodynamic benefit becomes the binding constraint. It is intended as a screening tool for planning and comparison, not as a project-specific hydraulic or plant-cycle design. Full article

Coastal socio-ecological systems are increasingly exposed to the combined pressures of climate change, land-use intensification, hydrological alterations and expanding infrastructure networks. These pressures interact across the land–catchment–lagoon–sea continuum, generating complex feedbacks that challenge traditional planning instruments, which remain sectoral and fragmented. The Mar Menor (SE Spain), a semi-enclosed Mediterranean lagoon affected by intensive agriculture, urbanisation, hydrological modifications and recurrent extreme climatic events, exemplifies this systemic vulnerability. Existing planning frameworks—local urban plans, regional territorial plans, river basin management plans, maritime spatial plans and lagoon-specific strategies—operate independently, each addressing only a fragment of the system and none integrating climate change as a structuring axis. This article introduces Integrated Spatial Planning (ISP) as a novel territorial–climatic framework designed to overcome these limitations. ISP integrates climate forcing, land uses, catchment processes, lagoon dynamics, marine conditions, critical infrastructures, intermodal and energy corridors and multilevel governance into a single analytical structure. A central component of the methodology is a four-zone multilevel zoning system that connects municipal, regional, basin, marine and EEZ planning domains within a unified territorial–climatic logic. The ISP matrix is applied to the Mar Menor to produce the first holistic diagnosis of the system. Results reveal strong land–sea–catchment interactions, high climatic exposure, vulnerable infrastructures and structural governance fragmentation. The matrix exposes systemic incompatibilities and vulnerabilities that remain invisible in sectoral planning instruments. The discussion demonstrates how ISP clarifies the roles and responsibilities of each governance level, supports multilevel coherence and integrates critical infrastructures and intermodal corridors into climate-resilient planning. ISP reframes climate change as the organising principle of territorial planning and provides a replicable, scalable methodology for coastal socio-ecological systems facing accelerating climate pressures. The Mar Menor case illustrates the urgent need for integrated territorial–climatic governance and positions ISP as a scientifically robust and operationally viable pathway for long-term adaptation and resilience. Full article

Urban rooftop photovoltaic systems represent a substantial yet still underutilized renewable energy resource, particularly in high-density residential environments. Accurate large-scale assessment of rooftop solar potential, however, remains challenging due to the complex geometry of urban morphology and the limited availability of high-resolution geospatial data. This study presents a large-scale methodological framework for estimating the theoretical photovoltaic potential of urban rooftop spaces using Unmanned Aerial System (UAS)-based digital photogrammetry and GIS-based spatial analysis. The approach integrates centimeter-resolution Digital Surface Models (DSMs) and orthophotos derived from fixed-wing UAS surveys with detailed rooftop vectorization and solar radiation modeling implemented in a GIS environment. The methodology accounts for rooftop geometry, surface orientation, slope, shading effects, and rooftop-mounted obstacles. The methodology consists of data collection of high-resolution RGB imagery suitable for detailed three-dimensional reconstruction. The images are captured with a UAS equipped with a S.O.D.A. 3D photogrammetric camera, creating a dense, georeferenced three-dimensional point cloud based on UAS imagery. Based on the point cloud, a high-resolution Digital Surface Model (DSM) was produced. Rooftop boundaries and rooftop-mounted structures were digitized on the basis of an orthophoto created from UAS imagery. The analysis workflow consists of solar modeling using ArcGIS Pro, including calculating the solar radiation. The next methodological step is to filter low radiation rooftops, steep slopes, and northern-oriented rooftops. Finally, we calculate the potential electricity production. The framework was applied to high-density residential districts in Sofia, Bulgaria, dominated by prefabricated panel buildings with predominantly flat rooftops. Drone applications in such studies are typically restricted to modeling individual roofs, which severely limits their scalability for district-wide evaluations. To overcome this, the study employs a specialized fixed-wing UAS uniquely certified for legal operations over densely populated urban environments. This platform rapidly maps large territories, ensuring consistent lighting and shading conditions that significantly enhance the accuracy of subsequent rooftop digitization. Furthermore, the resulting centimeter-level precision enables the exact vectorization of micro-rooftop obstacles. Capturing these intricate details is a critical innovation that effectively prevents the overestimation of solar energy potential commonly observed in conventional large-scale models. Solar radiation was modeled at the pixel level for a full annual cycle and filtered using photovoltaic suitability criteria, including minimum annual radiation thresholds, slope, and aspect constraints. Theoretical electricity production was subsequently estimated using zonal statistics and system performance parameters representative of contemporary photovoltaic installations. The results indicate a total theoretical annual electricity potential of approximately 76.7 GWh for the analyzed rooftop spaces, with an average production of about 34 MWh per rooftop and pronounced spatial variability driven by rooftop geometry and exposure conditions. The findings demonstrate the significant renewable energy potential embedded in existing urban rooftop infrastructure and highlight the applicability of UAS-based photogrammetry for high-resolution, large-area solar potential assessments. The proposed framework provides actionable information for urban energy planning, municipal solar cadaster development, and the strategic integration of photovoltaic systems into dense urban environments, particularly in regions lacking open-access high-resolution geospatial datasets. Full article

This article presents a systematic literature review on methane (CH₄) emissions from municipal solid waste (MSW) disposal sites and their implications for footprint outcomes. This review followed a PRISMA 2020 screening logic using Scopus and ScienceDirect (2019–2024); English and Spanish; subject areas: engineering and environmental, earth sciences), yielding a final sample of 30 studies for qualitative synthesis. This review focuses on how landfill CH₄ is quantified and how system boundaries and functional units shape reported CO₂ results. Evidence indicates that reported CH₄ estimates are sensitive to methodological choices and key assumptions and site-context drivers (degradable organic carbon (DOC)/model first-order decay (FOD) and constant k, the methane correction factor (MCF), gas collection, oxidation, waste composition, landfill age/type, and climate), limiting direct comparability between studies. Mitigation and waste-to-energy pathways (capture/utilization, anaerobic digestion, and incineration) are summarized in terms of the reported climate benefits. Finally, reporting gaps are identified, and the minimum information set is outlined to improve the reproducibility of landfill-related carbon footprint estimates for planning and future research. Full article

Latin America faces growing challenges in the management of municipal solid waste (MSW). This is particularly evident in medium-sized and metropolitan cities where rapid urbanization, limited infrastructure, and high proportions of organic waste (40–70%) converge. This review synthesizes the most recent advances in organic waste management, valorization strategies, environmental performance, and policy frameworks in Mexico and Latin America. To provide a comprehensive overview, evidence from studies on informal recycling systems, route optimization, sustainable landfill siting, food waste valorization, life cycle assessments (LCAs), and biogas production is integrated. Techno-economic analyses of energy recovery from organic fractions are specifically reviewed. This review highlights that valorization of organic waste through composting, anaerobic digestion, food supplementation, and bioproduct generation can reduce greenhouse gas emissions by 40–70% compared to landfilling, with AD–composting hybrids achieving the highest reductions of 60–70%. Community composting achieved moderate reductions, 30–50%, but at significantly lower cost and with greater social co-benefits. These alternatives for valorizing the organic fraction extend the lifespan of both confined and open landfills. It also contributes to mitigating the public health impacts related to open dumping, disease vectors, and contaminated leachate. In short, this review also highlights shortcomings in policy coherence, financial mechanisms, source separation, and technology adoption. A strategic framework is proposed that prioritizes decentralized treatment systems, the integration of informal recyclers, tax incentives, community-based waste separation, and planning based on Life Cycle Assessment (LCA). The findings point to a viable strategy for transitioning from landfill dependency to circular waste management systems that improve the quality of life for the population of Latin America and the Caribbean. Full article

The increasing cost of energy and the need for low-carbon solutions have strengthened interest in wastewater as a stable and underutilized source of recoverable heat. This study assesses the technical feasibility, economic viability, and environmental benefits of a wastewater heat recovery system based on a case study of the Gorzyce municipal wastewater treatment plant in Poland. Water-to-water heat pump configurations and application scenarios are analyzed together with data-driven forecasting of wastewater outflow using artificial neural networks (MLP and RBF). Operational data from 2025 were used to estimate thermal potential and support system sizing. RBF networks provided more accurate flow forecasts than MLP models, improving reliability of energy recovery planning. Results show that even with a 1 K cooling depth, the annual heat recovery potential reaches about 1.16 GWh. The proposed heat pump system achieved the COP values of 3.0–3.4 and seasonal COP around 3.2, confirming high technical performance supported by stable wastewater temperatures. The recovered heat can fully cover the facility’s heating demand, demonstrating clear technical feasibility. The economic analysis indicates annual savings of about EUR 2310 compared to gas heating, with a simple payback period of roughly 13 years, reduced to 7–8 years when combined with on-site photovoltaics. Environmental benefits include CO₂ emission reductions of about 5.5 tones per year. Overall, wastewater heat recovery supported by predictive modeling and renewable electricity is a practical, cost-effective, and environmentally friendly solution for municipal infrastructure. Full article

Methane emissions from abandoned coal mining operations represent a persistent environmental and safety challenge in post-mining regions undergoing urban redevelopment. As urban infrastructure expands over former underground workings, the uncontrolled migration of mine gas can compromise public safety, exacerbate greenhouse gas emissions, and undermine sustainable development goals. This study investigates the origin of methane emissions detected in an urban area of the municipality of Lupeni, Romania, following the commissioning of a new natural gas distribution pipeline installed within a historically mined perimeter. The emissions had not been previously reported and were unexpectedly discovered during technical inspections conducted after the gas network installation, highlighting the absence of historical data on gas presence in this area. This is the first documented case of an accidental discovery of methane emissions in an urban perimeter overlying historical coal mine workings in Romania, granting this study a pioneering status, both scientifically and in terms of urban risk management. The findings emphasize that administrative mine closure does not equate to risk closure, as latent methane emissions may reactivate during urban transformations (e.g., excavations, utility upgrades, drainage changes). To ensure a scientifically sound and sustainable risk assessment, an integrated diagnostic framework was applied, combining chronological field monitoring with chromatographic gas composition analysis. This methodology enabled precise attribution of the methane source to abandoned underground mine workings, excluding the public gas network as a contributor. Based on this diagnosis, a controlled drainage and methane recovery system was implemented, resulting in the elimination of detectable concentrations at all monitoring points by February 2025. The captured methane was redirected for local energy use, transforming an environmental liability into a usable resource. This intervention supports circular economy principles and aligns with EU climate and energy transition goals. The proposed methodological framework provides a replicable model for identifying and managing residual mine gas in post-industrial urban environments. Although emission fluxes were not quantified, concentration-based screening enabled risk diagnosis, prioritization, and targeted intervention. These findings are relevant to EU Regulation (2024/1785) on methane emission reduction, emphasizing the need to include post-mining methane (AMM) in urban planning and environmental monitoring strategies. Limitations of the study include the absence of baseline data and the inability to calculate total methane flux. However, the results support immediate and practical risk mitigation and highlight the need for future work focused on long-term monitoring and emission quantification. This case provides critical insights for other post-mining cities in Central and Eastern Europe facing similar challenges at the intersection of legacy coal infrastructure and modern urban development. This study is designed as a concentration-based diagnostic and risk-oriented case study and does not aim to quantify methane emission fluxes. Full article