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Jeddah is the most important port city in the Kingdom of Saudi Arabia. The climate of Jeddah is mostly dry; however, events of intensive rainfall followed by urban flooding have been reported in recent history. These floods interrupt the logistics and lifelines of the city. In this study runoff analysis and Flash Flood management by the green roof low impact development (LID) control system, was performed using United States Environmental Protection Agency (EPA)'s Stormwater Management Model (SWMM). Six middle districts of Jeddah city had been selected and modeled in five sub-catchment areas. The local soil and geographic conditions were incorporated into the model. The effect of the soil-based, rooftop, LID system has been emphasized in the analysis. In flood simulations, 30–70% of the impervious area of each sub-catchment has been treated with LID. It has been observed that the LID application can significantly reduce the overall flood flow. Thus, simple but well-planned LID control systems can be effectively utilized for the flood management of heavily urbanized regions. [ABSTRACT FROM AUTHOR]

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Extreme meteorological and hydrological phenomena, including high air temperatures and rainstorms, are becoming increasingly dangerous, causing floods and inundations, as well as long periods without precipitation, which lead to droughts. Green roofs may be one of the possible measures providing solutions to these problems. Rainfall, runoff and water quality data from three different intensive green roof models covered with wildflower meadows (WFs) over 20 months have been analysed to establish the extent to which the type of drainage layer affects hydrological performance. The field experiment was conducted at the Warsaw University of Life Sciences Water Centre park from November 2019 to November 2021. The monitoring of the quality and quantity of runoff was carried out on three models of green roofs incorporating wildflower meadows with drainage layers of 2 cm (WF 1) and 4 cm (WF 2) of polypropylene mat, as well as 6 cm of chalcedony (WF 3), in an urbanized area under moderate climate conditions. The model with the 4 cm polypropylene mat drainage layer retained approx. 6 % more rainwater compared to the model with the one made of chalcedony, and 4 % more than the one with the 2 cm polypropylene mat. Phosphates were detected in most of the leachates from all the wildflower-covered green roof models at 0 ÷ 0.459 mg PO4-P/L, 0 ÷ 0.402 mg PO4-P/L, and 0÷0.360 mg PO4-P/L for WF 1, WF 2 and WF 3. This may suggest that the type of drainage layer was not an important source of phosphates in the leachates. [ABSTRACT FROM AUTHOR]

This study simplifies the recession process, includes the hourly evapotranspiration, and modifies the surface layer of the green-roof hydrological model based on the Green-Ampt (G-A) method and Curve Number (CN) method. The existing G-A and CN methods are usually applied for event-total runoff. The results show that the proposed model improves the predicting accuracy of the outflow, and the model performs well for rainfall events with different intensities, duration, and hyetograph. the CN method performs as prominent as the G-A method but is more efficient. Based on observation, the retained volume and peak reduction are close to 50 % on average with a 1-to-2-hour peak delay. The results of the three-year simulation show that the retained volume and peak reduction reach 50 % for 75 % of the events when the antecedent water content is 30 %. Almost all rainfall is retained for events with rainfall amounts smaller than 20 mm when the antecedent water content is smaller than 30 %. On the other hand, 50 % (60 %) rainfall (peak) is retained (reduced) for events larger than 20 mm when the antecedent water content is smaller than 20 %. With the model verified using various rainfall events, the study generalizes an equation to estimate the rainwater retained by green roofs. Moreover, the stormwater-detention performance of a green roof in general is concluded quantitatively under different antecedent water content to assist the decision-making of irrigation concerning the goal of stormwater detention. [ABSTRACT FROM AUTHOR]

Urban villages are unique residential neighborhoods in urban areas in China. Roof tanks are their main form of water supply, and water quality deterioration might occur in this system because of poor hygienic conditions and maintenance. In this study, water samples were seasonally collected from an urban village to investigate the influence of roof tanks as an additional water storage device on the variation in the microbial community structure and pathogenic gene markers. Water stagnation in the roof tank induced significant decreases in chlorine (p < 0.05), residual chlorine was as low as 0.02 mg/L in spring. Propidium monoazide (PMA)-qPCR revealed a one-magnitude higher level of total viable bacterial concentration in roof tank water samples (2.14 ± 1.81 × 105 gene copies/mL) than that in input water samples (3.57 ± 2.90 × 104 gene copies/mL, p < 0.05), especially in spring and summer. In addition, pathogenic fungi, Mycobacterium spp., and Legionella spp. were frequently detected in the roof tanks. Terminal users might be exposed to higher microbial risk induced by high abundance of Legionella gene marker. Spearman's rank correlation and redundancy analysis showed that residual chlorine was the driving force that promoted bacterial colonization and shaped the microbial community. It is worth noted that the sediment in the pipe will be agitated when the water supply is restored after the water outages, which can trigger an increase in turbidity and bacterial biomass. Overall, the findings provide practical suggestions for controlling microbiological health risks in roof tanks in urban villages. [Display omitted] [ABSTRACT FROM AUTHOR]

• We develop a simple mathematical model to estimate the energy stored in a green roof and provide analytical solutions. • The effect of different key parameters on both energy and surface temperature is discussed. • A typical green roof is significantly cooler and stores less energy than a concrete even with a high albedo coating. • Evaporation of even a few millimeters per day leads to threefold reduction of stored energy compared to concrete roofs. A simple mathematical model to estimate the energy stored in a green roof is developed. Analytical solutions are derived corresponding to extensive (shallow) and intensive (deep) substrates. Results are presented for the surface temperature and energy stored in both green roofs and concrete during a typical day. Within the restrictions of the model assumptions the analytical solution demonstrates that both energy and surface temperature vary linearly with fractional leaf coverage, albedo and irradiance, while the effect of evaporation rate and convective heat transfer is non-linear. It is shown that a typical green roof is significantly cooler and stores less energy than a concrete one even when the concrete has a high albedo coating. Evaporation of even a few millimetres per day from the soil layer can reduce the stored energy by a factor of more than three when compared to an equivalent thickness concrete roof. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen evolution from water is one of the top issues to achieve green hydrogen energy and utilize solar energy. Construction of cocatalyst is a major part for efficient photocatalysts. Lamellar flower-like CoP@C cocatalyst is synthesized via the phosphating of cobalt precursor derived from metal-organic framework ZIF-67. Different from usual phosphating of ZIF-67 directly, a typical solvothermal treatment of ZIF-67 contributes to tuning the formation of C nanodots on the lamellar CoP. CoP@C as cocatalyst exhibits a remarkable role of improving photocatalytic activity for hydrogen evolution. CoP@C/CdS composite shows a photocatalytic hydrogen evolution rate of 164.4 mmol g−1 h−1, which is much higher than those of pure CdS and other CoP/CdS photocatalysts. The heterojunction and interaction are verified between CoP@C and CdS. Light absorption and photoelectric properties of CoP@C/CdS are enhanced accompanying with strong reduction ability. A type-Ⅱ transfer path of photoelectrons is underway in CoP@C/CdS photocatalyst, accelerating the separation of electron-hole pairs and the transfer of carriers, and further resulting in the promoted photocatalytic performance. This work provides a suitable way to achieve carbon nanodots involved metal compound cocatalysts for efficient hydrogen production. [Display omitted] • A lamellar flower-like CoP@C cocatalyst is constructed from ZIF-67-derived Co(OH) 2 precursor. • A typical solvothermal treatment of ZIF-67 contributes to tuning the formation of C nanodots on CoP. • The present CoP@C/CdS exhibits much higher photocatalytic activity for H 2 evolution than other CoP/CdS. • The CoP@C/CdS heterostructure brings strong reduction ability and superior light adsorption. [ABSTRACT FROM AUTHOR]

• Effective strategies for UHI mitigation and building energy saving were evaluated. • Pavement, rooftop replacement and tree planting were effective in UHI mitigation. • Insulation thickness and AC temperature were important for building energy savings. • Planting large deciduous trees was recommended as optimal single strategy. • Recommendations of strategy combinations were finally determined. The urban heat island (UHI) phenomenon and high building energy consumption are increasingly being associated with urbanization. Various strategies have been proposed for UHI mitigation and energy conservation in buildings. Nonetheless, the combined effects of the multiple strategies must be studied. This study clarifies the individual and combined effects of commonly used building-scale strategies (i.e., replacing ground materials, adding greenery, adjusting window-to-wall ratios, using high-performance glazing, increasing insulation thickness in the building envelope, changing roof surfaces, and adjusting air-conditioning operating temperatures) on UHI mitigation and building energy consumption reduction in both summer and winter. The selected strategies were implemented in a city block in Yokohama, Japan using a surface energy balance (SEB) simulation model. The simulation results demonstrated that planting tall deciduous trees was the most effective individual strategy for mitigating UHI and reducing energy consumption. While the highest UHI mitigation and energy savings were achieved by implementing all tested strategies simultaneously, a combination of water-retaining pavement, adjusting the air-conditioning operating temperature (28 °C in summer and 20 °C in winter), and a 100 mm insulation layer in the building envelope along with a green roof, demonstrated substantial effectiveness with fewer strategies. The interactions among these strategies provided either additive or offset effects. Therefore, selecting strategies with distinct action targets is crucial to maximize the combined effectiveness. [ABSTRACT FROM AUTHOR]

The transportation sector is a major source of greenhouse gas emissions. Reducing emissions of the Highway Service Area (HSA) can help decrease the sector's carbon footprint and serve as a model for green transformation. Consequently, this study firstly employs the Life Cycle Assessment (LCA) to calculate the carbon emissions during the operational phase of a certain HSA in 2022, and then analyses the emission structure. Subsequently, four emission reduction pathways are identified, including Photovoltaic (PV) power generation, electrification retrofitting, forestry carbon sinks, and green roofs, in terms of both Three 100 Initiatives and carbon neutrality measures. On this basis, the planning of carbon peak and carbon neutral strategies for this service area under different scenarios are carried out, taking into account the dual carbon targets and relevant policies. The findings indicate that: (1) the HSA emitted approximately 766.84 tons of carbon emissions in 2022, with 96.53 % from purchased electricity. (2) PV power generation offers the optimal emission reduction benefits among four emission reduction pathways. (3) In carbon peaking scenarios, initiating PV construction is the optimal emission reduction strategy. (4) In most carbon neutrality scenarios, the simultaneous implementation of PV construction and bamboo planting can meet the neutrality requirements by 2060. However, if the HSA continues to develop economically after 2030, the economy could grow until 2035 to meet neutrality requirements. These findings can guide emission reduction strategies for other HSAs, accelerating the sector's transition to low-carbon emissions while supporting the development of policies for zero-carbon HSAs. • The emission scope of the highway service area (HSA) is clearly defined, enabling the calculation and analysis of its emission structure. • Four emission reduction pathways are identified from both the Three 100 Initiatives and carbon neutrality measures. • In carbon peaking scenarios, initiating photovoltalic (PV) construction is the optimal emission reduction strategy. • In most carbon neutrality scenarios, the simultaneous implementation of PV construction and bamboo planting can meet the neutrality requirements by 2060. [ABSTRACT FROM AUTHOR]

• 3-year monitoring of 30 green roofs with vegetation based on Grime's CSR theory. • Green roofs retained >50 % of the 409 mm cumulative precipitation. • A stress tolerant non-succulent plant mixture had the best overall performance. • Hydrological performance of a Sedum monoculture was similar to the bare substrate. • The highest species richness did not have the best hydrological function. Green roofs have emerged as effective stormwater management systems, but understanding the contribution of their various components to hydrological performance is crucial for optimizing their design and implementation. More empirically measured data on the hydrological function of green roof vegetation is needed, especially under realistic low-maintenance, non-irrigated scenarios. Further, targeted, evidence-based plant selection based on ecological theories may improve green roof hydrological performance. Previous research has suggested that, in contrast to monocultures, mixtures of species with complementary traits could optimize provisioning of various ecosystem services. Thus, species mixtures based on their adaptive life strategy using the CSR theory (Competitor, Stress tolerator, and Ruderal) were hypothesized to have better hydrological performance than a Sedum monoculture or bare substrate under natural conditions over multiple seasons. To test this hypothesis, the runoff from thirty 2 m2 green roof modules was measured. The retention and detention performance of different green roof treatments were evaluated for 84 precipitation events of varying rain depth and intensity during snow-free periods. Differences in retention as well as detention between the vegetation treatments varied, but generally increased with increasing rain event volume and the Stress-tolerant treatment generally performed better than bare substrate. On a mean event basis, the mixture of stress-tolerator species demonstrated a 74 % retention rate, while the Bare substrate retained 72 % of the rainfalls. Overall, the green roofs, including bare substrate and vegetated treatments, effectively retained >50 % of the cumulative precipitation depth. In line with previous studies, the Sedum monoculture generally showed worse hydrological performance than other non-succulent vegetation mixtures, despite its relatively high cover and survival. The vegetated treatment with the highest species richness and diversity in life strategies (Mix) did not provide the best vegetation cover, or hydrological performance. Instead, the Stress-tolerant treatment, characterized by the high survival rate of a single graminoid species, consistently demonstrated superior event-based stormwater retention and peak attenuation capabilities. [ABSTRACT FROM AUTHOR]

The European Union has emphasized policies promoting photovoltaic (PV) energy generation to achieve the United Nations' Sustainable Development Goals 7 and 13. Notably, building roofs suitable for PV panels also present opportunities for passive energy-saving methods, such as green roofs. Both approaches impact beyond buildings to the urban level; PV panels intensify the urban heat island (UHI) effect, while well-irrigated green roofs mitigate it. In the Mediterranean region, where cities face challenges from extreme weather events and droughts leading to water restrictions, a comprehensive analysis of the influence of these approaches at both the building and urban levels becomes crucial. This work addresses this gap by employing dynamic simulations of a typical Mediterranean roof, an extensive green roof and a summer-irrigated green roof, all with and without PV panels, under Mediterranean climate. While both green roofs and PV systems prove beneficial at the building level, only irrigated green roofs effectively reduce the UHI impact. Unirrigated green roofs show no benefit on the UHI, whereas PV panels consistently amplify it. Combining an unirrigated green roof with PV panels has the highest UHI impact among all analyzed roof types. Summer irrigation of the extensive green roof can compensate the additional convective heat flux by PV panels, and moreover enhancing heat loss through the roof—a beneficial aspect at the building level during summer. The findings underscore the complexity of defining strategies that meet goals for renewable energy and UHI mitigation, highlighting the need for further research in this area. [Display omitted] • Green roofs reduce conductivity, this is increased by irrigation. • PV panels increase the impact on the UHI on all roof types. • Combination of unirrigated green roof and PV result in highest impact on the UHI. • Summer irrigation can compensate the additional convective heat flux by PV panels. [ABSTRACT FROM AUTHOR]

• A deep learning-GIS integrated model was developed to identify utilizable rooftops. • Occupied rooftops were excluded to accurately identify utilizable rooftops. • Rooftop agriculture could help Singapore achieve its 30 by 30 food security target. • Vertical farming and converting green roofs can boost food self-sufficiency levels. Food security is a key sustainable development goal globally, and rooftop agriculture offers a promising solution for high-density cities. However, many rooftops are occupied by uses such as photovoltaic panels or green roofs. Therefore, identifying utilizable rooftops for agriculture must exclude occupied rooftops, defined as those that are not vacant or already have other installations, a consideration often overlooked in previous studies. In this study, a deep learning and GIS integrated model was developed to more precisely identify and exclude these areas, including unusable rooftops and occupied roofs. This model was applied to four high-density cities across diverse climate regions: Singapore, Hong Kong (China), Toronto (Canada), and Amsterdam (Netherlands). The findings revealed utilizable rooftop areas of 619 hectares in Singapore, 607 hectares in Hong Kong, 1,870 hectares in Toronto, and 297 hectares in Amsterdam. Different development scenarios revealed varying food self-sufficiency levels. By accounting for vertical farming and technological advancements, the four cities could achieve food self-sufficiency levels of 34.71 %, 22.35 %, 112 %, and 74 %, respectively, by 2030. Singapore, in particular, could meet its "30 by 30″ food security target. Additionally, converting existing green roofs into agricultural use could further increase self-sufficiency by 33.29 %, 9.89 %, 25.25 %, and 37.8 %, respectively. This study provides an accurate assessment of utilizable rooftop areas and their agricultural production potential in four high-density cities worldwide. The findings offer critical data and policy insights to support urban spatial planning and the implementation of rooftop agriculture, contributing to enhanced urban sustainability. [ABSTRACT FROM AUTHOR]

The integration of vertical greening systems and green roofs with buildings is currently a popular urban development approach aimed at mitigating the urban heat island effect and promoting sustainable development. However, most existing studies on vertical greening systems and green roofs are based on short-term experimental results, which might not reflect their overall performance. Thus, this paper aims at evaluating the energy performance of vertical greening systems and green roofs in a hot summer and cold winter region in China over a three-year period. Although energy-saving was found in summer, occasionally increases in energy demand occurred in winter. It confirms the need for long-term experiments to avoid contingency. The energy saving rate of vertical greening systems and green roofs was approximately 27.49 %-42.48 % (monthly) or 28.89 %-34.02 % (quarterly) during the cooling period (33.84 % on average), and approximately −7.42 %-13.79 % (monthly) or −1.19 %-6.58 % (quarterly) during the heating period (3.6 % on average). The impact of climatic conditions on energy saving rate was evaluated. It was found that solar radiation intensity is the most important factor, followed by the outdoor air temperature and relative humidity. This paper provides an insight on the long-term energy-saving benefits of vertical greening systems and green roofs in hot summer and cold winter regions and the correlation between climatic conditions and energy saving rate. • Long-term energy performance of Vertical Greening System was evaluated. • Impact of climatic conditions on energy savings was analyzed. • Averaged energy savings of approximately 33.84 % during cooling period. • Approximately 3.60 % saving during heating period with intermittent negative saving. • Results from short-term energy-saving data might be bias. [ABSTRACT FROM AUTHOR]

Rooftop Mitigation Strategies (RMSs) have garnered global recognition as effective measures for mitigating urban thermal environments. However, the cooling effectiveness of Green Roof (GR) and Cool Roof (CR) remains a subject of ongoing debate, especially when considered within diverse climatic contexts. This study conducted RMSs observation experiments within the subtropical urban landscape of Guangzhou, China, to assess the cooling potential of these strategies during both normal weather conditions and heatwaves. Our experiments identified a critical temperature threshold that influences the cooling potential of GR, a phenomenon rooted in vegetation transpiration. Below 33 °C, transpiration gradually intensifies, resulting in a noticeable cooling effect. However, as temperatures exceed this threshold, transpiration diminishes. Coupled with the aerodynamic drag imposed by vegetation leaves on wind flow, this complex dynamic leads to a temperature increase at heights ranging from 0.3 m to 0.6 m above the roof. Given the subtropical climate's characteristics of high temperatures and humidity, prudent consideration is warranted when selecting appropriate mitigation strategies. In this context, our observations suggest that CR may be a more cost-effective and potentially more efficacious choice due to their lower costs and substantial cooling potential. Our research provides a significant contribution to the reevaluation of RMSs' cooling potential and its role in reducing urban energy consumption and lowering building carbon emissions. • Green roofs with mixed plants have a more significant cooling effect. • Heatwave weather leads to the failure of green roof cooling. • Plant transpiration and wind resistance cause near-surface warming during heatwaves. • Cool roof is an effective cooling strategy in subtropical climates. [ABSTRACT FROM AUTHOR]

The excessive warming in the built environment, due to urbanization and anthropogenic heat emissions, has adverse effects on building energy consumption. Diverse technology using, e.g., vegetated roofs or innovative roof materials, have been proposed and implemented to ameliorate both indoor and outdoor thermal environments and reduce energy consumption. In this study, we apply a state-of-the-art urban canopy model to simulate the thermal performance of multiple roof technology, viz. the white, green, and hybrid roofs, in the contrasting urban environments of Princeton, NJ and Phoenix, AZ, USA. In addition, we estimate the combined energy-water saving potential for green roofs with five different irrigation schemes. It is found that green roofs can achieve a combined energy-water saving of $9.68 m−2 roof area in Phoenix with moisture-controlled irrigation, and $5.23 m−2 in Princeton without irrigation. These results can help to promote building energy efficiency by adapting to flexible and sustainable roof technology for heat mitigation. • Evaluating diverse roof systems for cooling and building energy performance. • Green roofs with flexible irrigation maximize combined energy-water savings. • The use of hybrid roofs can avoid the heating penalty in cold seasons. • Optimal building energy efficiency depends on background climate conditions. [ABSTRACT FROM AUTHOR]

• Progressive convergence of nature and artifice in envelope design. • Use of performant Greenery as a cultural expression in contemporary architecture. • Definition of "Technological Greenery" • Cutting-edge solutions for integrating Greenery into building envelopes can arise from cross-disciplinary applications. • An abacus of technological solutions with measurable performances for practitioners. In recent years, there has been a growing integration between nature and technology, which has led to the emergence of Greenery as a bio-based building technology that can provide not only aesthetics but also ecosystem services. Similar to photovoltaic in its early days, Greenery is undergoing extensive design experimentation to make it an expression of contemporary culture rather than a mere 'greenwashing' practice. In urban areas, competition for space is driving the development of innovative envelope designs, often stemming from the combination of different disciplines and, therefore, not easy to be systematized. This study aims to explore potential technological systems from both practice and academic research to maximise the integration of Greenery into building envelopes. The systems are categorised as Technological Greenery and are classified according to their primary function, such as thermal insulation, air purification, electricity generation, and food production. This classification makes it easier to identify the most pressing and innovative technological research topics related to building envelopes and greenery integration. The resulting abacus of solutions accompanied by performance data might be helpful for building designers and architects. [ABSTRACT FROM AUTHOR]

Cities are accountable for more than 70% of global CO2 emissions and consume around 65% of the world's energy. In the pathway towards urban decarbonisation, nature-based solutions rise as a promising opportunity. They improve a city's resilience, stabilise temperatures and capture CO2, both mitigating climate change effects and adapting to them. This paper presents a novel methodology to assess the potential effects of green roof retrofit in urban areas, selecting suitable buildings for greening and estimating their decarbonising capacity. The proposed method combines the use of Geographic Information Systems (GIS) and artificial vision algorithms to select the roofs. Once selected, direct carbon sequestration and energetic savings are estimated based on empirical results. This methodology is successfully applied to the L'Illa Perduda neighbourhood of Valencia (Spain) as a case study. The GIS analysis shows that about 50% of the roofs' surface could be greened, directly absorbing around 350 tCO 2 yr−1 and reducing the energetic emissions of the neighbourhood in about 100 tCO 2 yr−1 by improving the insulating envelope of the buildings. The artificial vision computation selected 38% of the surface of the neighbourhood residential buildings. • Novel method to assess the decarbonisation potential of urban green roof installation. • The methodology combines GIS and artificial vision to select suitable roofs. • The potential area to be greened and the energy savings are estimated. • The direct and indirect atmospheric carbon reduction by green roofs is estimated. • Half of the studied rooftops in one of Valencia's neighbourhoods could be greened. [ABSTRACT FROM AUTHOR]

Extensive green roofs (EGRs) play a crucial role in urban environments, offering numerous environmental, economic, and social benefits. However, their performance largely depends on plant selection and adaptation to local climatic conditions. This study investigates the suitability of six perennial Euro-Mediterranean species for EGRs in Mediterranean and semi-arid regions, under different water regimes. A two-year experimental analysis was conducted in Rome (Italy) assessing flowering and mortality rates. Results revealed species-specific responses to irrigation levels, with notable performances observed in Thymus serpyllum , Saponaria ocymoides , and Teucrium chamaedrys , showcasing resilience to water stress. Conversely, Lavandula stoechas and Cerastium tomentosum exhibited sensitivity to water availability, emphasizing the importance of species selection for EGRs. No species completely adhered to the expected flowering period, but showed a general tendency of anticipation, and sometimes an extended flowering period, with some differences between the species. The study underscores the complexity of plant-environment interactions and highlights the need for diversified species composition to enhance EGR functionality and resilience. • Performance of species potentially suitable for Mediterranean EGRs, are evaluated through their resilience against water stress conditions. • In the water retention capacity of green roofs in Mediterranean climates, an important role should also be given to the vitality of plants. • Synergies between of different species optimizes green roof functionality. [ABSTRACT FROM AUTHOR]

Green roofs are among the ideas of sustainable growth. However, there is a lack of knowledge of the substrate layer, especially its composition. Thus, this paper aims to review the substrate compositions of green roofs used in literature in the last ten years. The main green roof substrate components include inorganic matter (perlite, vermiculite, crushed bricks), organic matter (compost and peat), and alternative materials such as recycled ones, biochar, and mushrooms. Compost was the most used material for plant growth, with 10 %. Peat was the most mentioned component for runoff quality, with 30 %. For thermal performance, sand was the major material utilized with 10 %. Moreover, compost is the major substance used in making substrate, with 38 out of 62 papers reviewed. Out of 38 papers, including compost, only 16 mentioned the type of material used. In fact, the compositions used till now mainly focus on the plants. Therefore, more studies must be conducted to establish new substrate compositions for not only the vegetation but also for the ecosystem services provided by green roofs, such as thermal and acoustic insulation. [Display omitted] • There is no definite composition for green roof substrates. • Generally, a mixture of organic and inorganic matter is used. • Compost and peat were among the organic content. • Sand and crushed brick were frequently used as mineral part. [ABSTRACT FROM AUTHOR]

As the European Union transitions towards cleaner energy production, significant emphasis is placed on the use of photovoltaic (PV) panels on roofs. Although PV panels offer the advantage of renewable energy generation, they alter the energy balance of roofs and increase heat emissions into the atmosphere. This raises concerns about their potential to intensify the urban heat island (UHI). Hence, this study evaluates the effects of eight different roof models, including four roof types, analyzed both with and without PV panels, on the UHI in the Mediterranean, a region experiencing increasingly urban overheating. Convective heat fluxes are used as a clear indicator. The models were conducted using EnergyPlus simulations throughout the year. Roof types include a typical Mediterranean roof, a cool roof, a soil roof and an extensive green roof. The main results indicate an intensification of the UHI for all roof types when PV panels are installed, both in summer and winter. However, among the PV-panelled roof types, the cool roof is effective in reducing the UHI impact compared to the other roofs during both seasons. Contrary, in winter, the extensive green roof with PV panels increases the impact on the UHI among all roof types the strongest. • PV panels increase UHI impact across all roof types. • Non-irrigated green roofs with PV panels do not reduce UHI impact. • Unirrigated green roofs have the highest UHI impact in winter. • Cool roofs, with or without PV panels, mitigate UHI impact. [ABSTRACT FROM AUTHOR]

Climate change leads to more frequent and intense heat waves, exposing urban populations to extreme heat conditions and significant health risks. Many cities are adopting Nature-based Solutions (NbS) to mitigate urban heat, with green roofs emerging as a widely recognized NbS. Although numerous green roof projects are implemented on a small scale, research on the effectiveness of small-scale green roofs on an urban scale is limited, making it challenging to identify the critical factors for both maladaptation and success. Therefore, we assessed the cooling potential of 18 small-scale green roofs in Seoul, Republic of Korea. This comparative study that adopted a multi-site approach examined the cooling capacity of green roofs to reduce surface temperature and identified characteristics of effective and ineffective green roofs. We utilized a developed difference-in-differences method to improve causal inference, effectively isolating the effects of individual green roofs from background climate change. The multi-site comparative approach and more robust causal inference methods improved our understanding of the effects of small-scale green roofs. The findings of this study indicate that three out of 18 green roofs were statistically significant maladaptation cases with an increase in LST. This evidence can help an urban planner reduce ineffectiveness and enhance effective adaptation practices. Our proposed method is expected to support government projects, especially those with limited budgets, in efficiently managing urban heat and reducing trial and error. [Display omitted] • DiD-MBACIP designs could identify the cooling effects of small-scale green roofs. • There were three maladaptive cases that have an increase in LST, contrary to expectations. • Small-scale green roofs could increase LST statistically, ranging from 0.173 to 0.481 °C. • Six small-scale green roofs could reduce LST statistically, ranging from −1.057 to −0.078 °C. • Green roofs should be considered for greening intensity and the artificial factors on the roof. [ABSTRACT FROM AUTHOR]

• Utilized Lidar data and ANN to model the cooling effects of green roofs in urban environments. • Showcasing the use of combined 2D/3D urban matrics to improve the accuracy of urban heat predictions. • Revealed the significant impact of building heights, sky view factors, and solar radiation on urban cooling. • Documented a notable decrease of 2.8°F in urban temperatures by greening 4.2% of building rooftops. • Illustrated the potential of integrating technology with natural solutions for urban sustainability. Urban areas frequently exhibit higher elevated temperatures than their rural counterparts due to the prevalence of structures over natural resources, a phenomenon known as daytime surface urban heat island (DSUHI). This study simulates the cooling effects of green roofs (GR) for mitigating DSUHI by utilizing 2D and 3D urban morphological parameters over downtown Austin, Texas, USA. We estimated spectral indices using Landsat 8, Sentinel-2A, and Lidar data to include built-up, vegetation, waterbodies, daytime land surface temperature (DLST), buildings (height volume and density), sky view factor (SVF), and solar radiation (SR). Finally, we integrated eleven different neural network algorithms for GR simulation, validation, and correlation between DLST and the above urban features- the strongest model generated an R2 of 0.783 and an RMSE of 0.925°F. We found converting 4.2% of the total rooftop area to GR resulted in an average DLST decrease of 2.80°F. The most significant cooling effects occurred with buildings heights between 13 and 28 m, high SVFs, SR, and closer proximity to water bodies. Our findings amplify the strategic importance of GRs in urban morphology and planning, guiding green infrastructure development to mitigate and foster urban environment sustainability. [Display omitted] [ABSTRACT FROM AUTHOR]

Green roofs, also known as vegetated roofs or living roofs, have gained increasing attention in recent years due to their potential to address various environmental challenges in urban areas. These innovative roofing systems offer a promising solution to mitigate urban heat island effects, manage stormwater runoff, reduce energy consumption, improve air quality, enhance biodiversity, and contribute to cities' sustainability and liveability. This paper presents a comprehensive analysis of the feasibility and sustainability of green roofs in the Mediterranean zone, with an Italian location as a case study. The analysis considers intensive or extensive green roofs, applicable tax incentives, and different cost/benefit considerations. A probabilistic study of the financial model was performed using a Monte-Carlo based method. The results show that green roofs provide private and social benefits and are financially feasible. Critical factors for increasing sustainability and financial feasibility are increment of energy saving potential, long lifetime, and reduction of maintenance. The payback period is sensitive to scenarios where all the benefits become applicable, with regulatory incentives and tax reductions. Policymakers should encourage the application of green roof technology in new buildings and retrofitting old ones. • Comprehensive analysis of green roofs in the Mediterranean region. • Evaluated financial feasibility using Monte Carlo simulations. • Considered both extensive and intensive green roofs. • Identified critical factors for sustainability and economic benefits. [ABSTRACT FROM AUTHOR]

• We propose a framework choosing locations for green roofs (GRs). • Coupled benefit simulation models with NSGA-III for the optimal GR layouts. • The optimization for minimizing cost and for maximizing benefit was simulated. • A GR spatial layout is given based on different objectives in Xiamen. Rapid urbanization and increasing environmental challenges driven by climate change have diminished the efficacy and efficiency of traditional green infrastructure, particularly in high-density urban areas with a prominent contradiction between ecological construction and land scarcity. Green roofs (GRs) can provide multiple ecological benefits, and have proven to be an effective measure for addressing complex environmental issues in high-density urban areas. However, whether GR layout can deliver significant ecological benefits at a low investment cost requires further exploration. A multi-objective optimization framework for GR layout in high-density urban areas was proposed, balancing both costs and benefits. The framework intelligently extracted potential GRs, established a multi-objective evaluation system, integrated benefit simulation models with a multi-objective optimization algorithm (NSGA-III) to determine the optimal GR layout, and recommended the best layout scheme using the entropy weight-TOPSIS method. A case study in Xiamen, China, demonstrated the applicability and implications of this framework. The results indicated that the genetic algorithm effectively optimized the scheme to meet the objectives of runoff reduction, cooling effect, and investment cost in Xiamen Island. Specifically, the GRs contributed major runoff reduction (2.115–2.556 %), cooling effect (0.395–0.485 %), and investment cost (12.65 × 109–15.32 × 109RMB) across all optimal scenarios. This approach enables the visualization of GR layouts and quantification of associated benefits and costs, assisting decision-makers in scientifically balancing the costs and ecological benefits of GR layout options. The proposed framework provides a new and feasible path for high-density urban areas to achieve optimized GR spatial planning. [ABSTRACT FROM AUTHOR]

Green roofs serve as an innovative strategy for urban architecture, playing a pivotal role in mitigating urban heat island effects and enhancing building energy efficiency. This study proposes a hybrid model based on the Sparrow Search Algorithm (SSA) optimized Convolutional Neural Network − Long Short-Term Memory Network (CNN-LSTM) for rapid and accurate prediction of the thermal performance of green roofs. The model integrates the spatial feature extraction of CNN with the temporal analysis capability of LSTM, enhancing the predictive accuracy of multi-feature time series through global optimization by SSA. Taking the green roof in Guangzhou China as a case study and utilizing hourly meteorological and thermal property data, this model has demonstrated superior predictive performance: the Mean Absolute Error (MAE), Root Mean Square Error (RMSE), R-squared (R2), and Mean Absolute Percentage Error (MAPE) for the prediction of inner surface temperature are 0.718, 0.908 %, 0.922, and 0.025 %, respectively; for the outer surface temperature prediction, the corresponding values are 0.618, 0.886 %, 0.983, and 0.028 %. Comparative analysis with existing AI models and ablation experiments further confirm the superiority of this model. Additionally, through Spearman correlation analysis, this study reveals the correlation between key input parameters and surface temperatures, providing data support for the effective design and management of green roofs. The model presented in this study not only provides an efficient tool for predicting the thermal performance of green roofs but also holds significant importance for promoting green building and sustainable urban development. [ABSTRACT FROM AUTHOR]

Low-maintenance extensive green roofs hold the potential for adapting to climate change, but there is a limited understanding of their effective design in humid subtropical regions. In this study, we aimed to investigate low-maintenance green roof ecosystems capable of thriving under heat stress. Plant growth performance was evaluated in the second year of an experimental green roof in southwest China. This green roof was unirrigated and involved two plant communities (forbs and grasses) cultivated in four substrate types. Metrics of growth performance, including plant survival, green coverage, visual appearance, leaf stomatal conductance, and substrate volumetric water content were used to analyze the impact of substrate on plant growth. ESP substrate, comprising 30 %v (percent of volume) expanded shale, 25 %v perlite, 25 %v vermiculite, and 20 %v compost, featured the highest porosity and optimal growth of forbs, achieving an average green coverage of 66.76 % and average visual appearance value of 3.56 throughout the monitoring period. The high total porosity of this substrate could be critical in facilitating root development and drainage. Moreover, during the summer's heat and drought, while substrate water content is not a limiting factor for the survival of some established forbs, it remains crucial for the growth of grasses. Additionally, the same substrate impacts different plant communities variably. Four particularly well-performing forb species, namely Lycoris chinensis , Tradescantia pallida , Liriope muscari , and Salvia farinacea , demonstrated survival rates closed to 100 % and an average visual appearance value exceeding 3 was noted, and thus, they are recommended as plant candidates for unirrigated green roofs. The distinguished performance of these species is attributable to their adaptation to heat and drought through specific physiological traits. Our findings provide insights into vegetation selection and substrate optimization for the successful establishment of extensive green roofs that could be feasibly developed without irrigation in the humid subtropical regions. [Display omitted] [ABSTRACT FROM AUTHOR]

Green roofs (GR) are nature-based solutions for climate change adaptation and mitigation in buildings and cities. However, few GR maintenance, installation, and challenge-solving guidelines are available for semiarid climates. We present how three case-study types of GR (urban gardens (UGR), native gardens (NGR), and wetland roofs (WR)) varied in installation costs, irrigation volumes, maintenance times, vegetation cover, survival, biomass and yield, in Ensenada, México, from 2022 to 2023. In UGR, nine edible species were cultivated to yield produce; in NGR, six native plants were planted, and four were grown in WR. UGR installation costs were 31 % and 21 % lower, but maintenance costs were four and 1.5 times higher than NGR and WR, respectively. UGR consumed 17 % more water annually than NGR and 42 % less than WR. Likewise, UGR demanded 94 and 92 % more annual maintenance time than NGR and WR. WR presented the highest survival, height, cover, and biomass values, followed by NGR (except for biomass) and UGR. Our results point to different GR solutions for distinct types of applications and users, demonstrating their versatility in design. All GR categories are suitable to reduce the ecological footprint of buildings; however, we emphasize that each GR design involves different economic, time, and challenge-solving commitments that should be considered before installation and operation. • We studied the economic, labor, and irrigation costs of three extensive green roofs. • We provide maintenance guidelines from a Mediterranean climate case study. • Urban Garden roofs demand more maintenance but can be very productive. • Wetlands and Native Gardens have high installation costs and low maintenance. • Green roofs are highly adaptable for distinct types of applications and users. [ABSTRACT FROM AUTHOR]

Green roofs (GRs) are vital for shaping the material cycles of urban ecosystems as a form of distributed green infrastructure. However, current studies have predominantly focused on the material exchange between GRs and the urban environment, neglecting the internal distribution and equilibrium of constituent elements. By monitoring carbon (C), nitrogen (N), and phosphorus (P) in Sedum lineare Thunb and four substrates throughout the seasons, this study analyzes the ecological stoichiometric characteristics of an extensive GR in Nanjing, China. Intra-annual ratios of C:N (46.02, 13.38, 15.40), C:P (252.41, 57.85, 47.22), and N:P (5.75, 4.23, 3.84) were identified in the plant, substrate, and substrate microbial biomass, respectively. The intra-annual ratios of plant to substrate C, N, and P were roughly 9:1, 7:3, and 6:4, respectively. The use of different substrates resulted in significant variations in plant C, N, and P levels and their quantitative ratios, leading to distribution differences of these elements. Furthermore, substrate C, N, and P levels exhibit a generalized threshold effect on microbial biomass and plant C, N, and P concentrations. Notably, the substrate demonstrates an organic C sink potential of 7.11 g/kg/season, surpassing that of plants in unit mass. These findings contribute to understanding the distribution and dynamics of C, N, and P elements within extensive GRs. [ABSTRACT FROM AUTHOR]

The development of green roofs to mitigate urban heat island effect is critical for conserving energy and reducing carbon footprint. This study evaluated the thermal performance of an extensive green roof design compared with a conventional roof and assessed the suitability of thirty-two plants for low-maintenance green roofs in a tropical area. Experiments were carried out in four phases, covering the tropical climatic conditions from June 2016 to December 2017. The results indicate that a green roof temperature was significantly lower than that of a conventional roof by 12 °C. This led to an 84 % reduction in heat transfer through the building, potentially leading to a decrease in electricity consumption by 0.20 kWh/m2/8 h and saving electricity costs by 0.019 USD/m2/8 h, achieved through a reduction in the cooling load on air conditioners. The highest carbon dioxide removal achieved in this study was 3.01 kgCO 2 /m2, with an effective mitigation of greenhouse gases by 28.46 kgCO 2 eq/m2/year. The top three plant species recommended for a low-maintenance green roof are Dracaena cochinchinensis, Santisukia kerrii, and Dracaena kaweesakii. The plant characteristics for low-maintenance green roofs in tropical climates include drought and extreme weather tolerance, disease and insect resistance, short and spreading roots, succulent leaves with ability to store water, low water requirements, slow growth rate, easy availability locally and affordability, thriving in low-nutrient conditions, and a high evapotranspiration rate. In applicable contexts, green roofs designed with suitable tropical plants could potentially enhance urban environments and contribute to achieving low-carbon and environmental sustainability. • Thermal performance of green roofs varies depending on the specific climatic conditions of the region. • Green roofs mitigate greenhouse gas emissions by reducing energy consumption. • Carbon dioxide removal by plants varies with solar radiation intensity. • Selection criteria for tropical plants are based on drought tolerance, sunlight, and watering requirements. [ABSTRACT FROM AUTHOR]

Given the importance of the energy system transition towards more sustainable models consistent with Sustainable Development Goal 7, this article is a narrative literature review regarding the production technologies and handling methods of blue and green hydrogen to meet the European Union decarbonisation objectives set by 2030. The European hydrogen use roadmap seems difficult to implement because, although technologies have matured, their large-scale application has been hindered by technical and infrastructure barriers. Green hydrogen is still hardly competitive with fossil fuels-based hydrogen production both for performance factors and for the availability of renewable energy, already needed for other uses in a decarbonised electricity market. Blue hydrogen production may pave the way to green hydrogen, but short-term implementation of these technologies is borderline. Adaptating and upgrading hydrogen storage and deployment, together with regulations for international trade, must be a priority. Finally, objectives and targeted strategies that are more realistic should be executed, with attention focused primarily on sectors that cannot take advantage of electrification, such as heavy industry and heavy-duty transport. [Display omitted] • The feasibility of blue and green hydrogen exploitation within 2030 is discussed. • Current RES availability does not allow green hydrogen production reaching EU goals. • Doubts arise on short-term blue hydrogen implementation for market penetration. • Existing technologies, infrastructure and regulation inhibit the spread of hydrogen. • Research and technological innovation on hard-to-abate sectors is needed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multi-objective model to evaluate solar systems' air pollution reduction capacity • MIVES-based approach to assess the sustainability impacts of suitable solar systems • Annual CO 2 & PM avoiding by using PV & PVT to 211 & 488 kg/m2 and 1.2 & 1.9 g/m2 • BAPV obtains higher sustainability value as the best socio-economic alternative. • BAPV/T is the eco-friendly alternative having the potential to reduce air pollution. Renewable energy applications are lucrative alternatives to minimize urban environmental impacts. Solar energy, the most abundant, inexhaustible, and cleanest of all renewable sources, provides an opportunity to transform buildings from energy consumers into active energy producers. Nevertheless, photovoltaic (PV) and hybrid photovoltaic/thermal (PV/T) are considered the most viable alternatives for urban settlements. This study, as part of a broader research project, develops a new model to evaluate solar systems' air pollution mitigation capacity and assist decision-makers in adopting the most suitable solution. The approach is based on the integrated value model for sustainability assessment (MIVES), combined with the analytic hierarchy process (AHP) and sensitivity analysis. This multi-objective tool is applied to residential buildings in Tehran, a megacity example with unused rooftops, solar energy harvest potential, and air pollution reduction needs. Results reveal one square meter of PV and PV/T enables avoiding 211 and 488 kg CO 2 emissions annually, as well as 1.2 and 1.9 g PM pollutants, respectively. Although PV achieves higher sustainability indexes as a better socio-economic alternative, PV/T can be a robust solution when stakeholders are more sensitive to environmental requirements and air pollution decrement potential. The critical obstacle to PV/T deployment is the lack of financial incentives. However, allocating 38 % of solar electricity feed-in tariffs to solar thermal energy could solve this issue. Compared to green roofs, solar systems stand out with CO 2 saving and energy production potential. Researchers expect future solar collectors' improvements, such as lower resource consumption, thus, becoming more environmentally friendly and cost-effective solutions. [ABSTRACT FROM AUTHOR]

The objective of this paper is to analyse the relationship between income inequality and environmental innovation. To this end, we use the Economic Fitness and Complexity algorithm to compute an index of green inventive capacity in a panel of 57 countries over the period 1970–2010. The empirical analysis reveals that, on average, inequality is detrimental to countries' capacity to develop complex green technologies. Using non-parametric methods we further articulate this general finding and uncover interesting non-linearities in the relationship between innovation and inequality. • Innovation can contribute to mitigate climate-induced hazards. • Countries most exposed to environmental degradation are often poor and more unequal. • Economic complexity links countries' development path and green inventive capacity. • Rich countries develop complex green technologies irrespective of income inequality. • Middle-income countries with low inequality develop complex green technologies. [ABSTRACT FROM AUTHOR]

The roots of Pyrenacantha volubilis contain camptothecin (CPT), a high-value bioactive compound possessing anticancer and anti-HIV properties. Isolated root cultures of P. volubilis established in half MS media fortified with 0.3 mgL-1 indole-3-acetic acid and 0.2 mgL-1 indole-3-butyric acid and transferred to light conditions resulted in induction of green roots which obtained a maximum biomass content of 1.09 ± 0.03 g fresh weight with a growth index of 2.07 ± 0.02 in 60 days. The chlorophyll and camptothecin content of the roots was found to increase throughout the culture period attaining a maximum total chlorophyll content of 2.97 ± 0.004 mgg-1 fresh weight in 60 days and CPT content of 2.59 ± 0.02 mgg-1dry weight in 50 days. In the elicitation studies, the green roots treated with 200 mgL-1 yeast extract yielded a maximum camptothecin content of 5.3 ± 0.40 mgg-1 dry weight in 7 days of incubation, which was a 1.94 fold increase in camptothecin content than the control cultures. The thin layer chromatography, high performance liquid chromatography, and liquid chromatography-mass spectroscopy analysis further confirmed the presence of camptothecin (2.17 ± 0.04 mgg-1DW) in the 30 day old in vitro root samples. The overall results suggest the feasibility of green root cultures of P. volubilis as an efficient system for sustainable in vitro production of camptothecin provided further scaling up experiments in bio reactors are imperative. • In vitro green root culture system of Pyrenacantha volubilis was established for camptothecin production. • Root cultures subjected to elicitation yielded a maximum camptothecin content of 5.3 ± 0.40 mgg-1 DW. • Root cultures can be used as an alternative source for camptothecin production instead of conventional sources. [ABSTRACT FROM AUTHOR]

[Display omitted] Recently, the scientific community has become more interested in solar-driven steam materials and systems for desalination and disinfection. Solar thermal energy for membrane distillation desalination provides a green and sustainable option for building settings where there is a strong connection between water constraint and high solar irradiation. Artificial intelligence (AI) is rapidly being used to optimize water treatments and saltwater desalination because of its high precision and accuracy. Explainable AI (XAI) enables people to better understand and trust a model's predictions and to detect and rectify inaccurate AI predictions. This study analyses recent advances in solar-driven steam materials engineering and the significant technological constraints that impede its wide-scale deployment. Using local interpretable model-agnostic explanations (LIME), our study provides an interpretable solution (in addition to the binary classification result of the developed black-box deep learning (DL) model) so that experts can understand why the machine thinks this way, providing critical insights for the decision-making process. The proposed XAI-DL model is based on a DL network consisting of three cascaded convolutional blocks for processing tabular data. Therefore, the XAI-DL classification model achieves a cooling quality accuracy of 82.64% during the validation stage, supporting the explaining capability. During the testing, the [inlet-cooling-water-temperature] pushes the model lower, whereas the [ambient-temperature], [feed-water-flow-rate], and the [inlet-feed-water-temperature] pushes the model higher. The LIME explanation result is consistent with the statistical analysis of the data. Consequently, the proposed explainer assists non-experts in comparing and improving the untrustworthy model through and clarifies the importance of each feature and its relationship to other features and its relationship to the class. Finally, the XAI-DL fits and supports the different manufacturers of membrane desalination system(s) to inspect cooling quality in their designed system and consistency of interpretability and trust. [ABSTRACT FROM AUTHOR]

Reversing the consequences of climate change and achieving more resilient societies involves reducing CO 2 emissions and energy consumption, especially in sectors as important as construction. Green roofs, due to their particularities, imply a series of benefits, among which energy saving stands out. This implies a reduction in the consumption of resources and in CO 2 emissions, more evident in the case of the refurbishment of buildings. A comparison is proposed between the energy savings obtained by renovating only the roof and renovating the entire thermal envelope. This is done with three roof construction systems (including two green roofs) and in 6 Spanish cities that represent different climatic zones. The novelties provided by this research are based on the comparison of both renovation cases to obtain the influence of the roof with respect to the thermal improvement of the envelope. The energy savings obtained by renovating the roof are very similar in all cities, but after renovating the entire envelope, the savings increase as the climate gets colder. Determining the most influential variables in these savings, as well as the influence of the roof, allows choosing the most appropriate construction techniques to optimize the energy renovation of existing buildings. • The roof's influence decreases at lower outdoor temperature and solar radiation. • Roof-only renovation is a viable option in warm climates, not in cold climates. • Extensive green roof is the best option in building renovations. [ABSTRACT FROM AUTHOR]

In the post-COVID-19 era, the importance of green finance in green recovery is underlined. As a financial instrument serving green development, green bonds promise to raise funds to support climate- and environment-friendly projects. However, whether green bonds can improve corporate performance is of great concern to companies, affecting the long-term intrinsic driving force of green bond issuance. This study applies the dynamic difference-in-differences (DID) model to explore the impact of green bonds on corporate performance and its potential pathway by using the panel data of Chinese listed companies from 2010 to 2020. The main findings are as follows: (1) Green bonds can significantly increase corporate performance by an overall effect of 1.65%. (2) The positive effect of green bonds could be transferred and enhanced by possible mechanisms, including internal green patents and external social reputations. (3) The overall effect of green bonds varies among companies due to different ownership and eco-geographical locations. (4) Green bonds would motivate better corporate performance if the company is related to renewable energy or located in provinces with high renewable energy consumption. Therefore, it is necessary to promote green bonds, ultimately helping to achieve green recovery. • The effects and mechanisms of green bonds on corporate performance are explored. • Green bonds can increase corporate performance by an overall effect of 1.65%. • Potential mechanisms include internal green patents and external social reputations. • The overall effect varies among different ownership and eco-geographical locations. • Green bonds motivate a better performance of renewable-energy-related companies. [ABSTRACT FROM AUTHOR]

The world is fronting water quality crisis and industrialization has augmented the illegal discharge of wastewater to the environment. Textile is one of such industry, generates large amount of colored wastewater and discharges untreated wastewater into nearby environment, poses major threats to the environment worldwide. The textile wastewater consists of the spent water from pretreatment, dyeing and post treatment process of the textiles. However the dyebath wastewater is highly concentrated and consists of mixture of unfixed dyes. The effective and eco-friendly treatment of textile wastewater is challenging. It is essential to remediate the dyebath wastewater in order to maintain environmental sustainability. In this paper, the feasibility of green iron particles on real textile and dyebath wastewater decolorization was investigated. Green iron particles were synthesized using green tea leaves extracts and grape leaves extracts. The synthesized particles were characterized for size, morphology, crystal structure, elemental analysis, functional groups attached and specific surface area. 2-6 g/L of green iron was utilized to decolorize 63%-89% of highly concentrated dyebath wastewater and 80%-92% of textile wastewater. The pH 10.1-10.8 of wastewater was reduced to 8.1-8.9. Green iron removed nearly 50%-54% of chemical oxygen demand from the wastewater and concluded that partial mineralization was possible. The reusability of green iron particles was achieved for 3 cycles. Thus the present investigation confirmed the feasibility of green iron particles in textile and dyebath wastewater decolorization. [ABSTRACT FROM AUTHOR]

Clean and renewable energy plays important role in achieving carbon neutrality and nature sustainability, especially the application of green hydrogen in new energy system. Hydrogen (H 2) produced from visible light has attracted attention owing to its high conversion efficiency and cleaner process. In this review, different photocatalyst preparation methods which can directly design the same structure were clarified. Also, different mechanism design which can realize different electron transfers were also proposed. Thus, various morphologies and different mechanisms of electron transfer have been summarized and evaluated. Also, the methods of photocatalysts' construction were mentioned, all H 2 production reactions depend on the amount of reaction sites and photo-generate electrons. It was evident that the concentration of reaction sites and photo-generate electrons play important roles in efficient H 2 production. This review provides fundamental knowledge to design and construct variable morphologies with different electron transfer processes to enhance efficiency of H 2 production. [Display omitted] • Structure-mechanism relationship was applied to analysis H 2 production process. • Heterojunction structures was applied to analyze mechanism of electron transfer. • Different combination and preparation of morphology were reviewed to evaluate system. • Different preparation method and electron transfer mechanism of photocatalysts were summarized. [ABSTRACT FROM AUTHOR]

• Hybrid cooling techniques enhanced PV module performance with low energy consumption. • Low thermal conductivity of TPT layer inhibited natural convection cooling. • Thermoelectric cooler with fans as a unit was designed to cool the module from backside. • Water-thin film cooling system (WFCS) was applied to improve the efficiency of PV. • FEM simulation was effective in understanding the heat transfer within the module layers. Photovoltaic (PV) module efficiency is often impeded by concomitant temperature elevations, which may lead to cell degeneration and decreased electrical efficiency. Cooling techniques are commonly used to avoid this problem; however, current techniques, such as water-sprayer and active cooling systems, still have limitations, including the scattering and reflection of photons. In this study, we present a new active dual-cooling system design using two thermoelectric cooling (TEC) units fixed to the back of a PV module to provide rear-end cooling, which were experimentally and numerically studied. A water-thin film cooling system (WFCS) was maintained at the top surface of the module using a small affixed 72-W DC pump, for improving efficiency. For testing, the system was installed on the roof of an agricultural building in South Korea, and its performance efficiency was compared with that of a reference cooling-free PV module. The results showed that the innovation led to a decrease in the module temperature to 21 °C, which led to an efficiency improvement of 11.23 % with an increase in the daily output energy of 8.3 %. Additionally, a numerical simulation model based on the Finite Element Method (FEM) was used to evaluate the temperature profile of the PV module owing to the cooling technique and temperature distribution on the module's top surface. The maximum temperature reductions were 17.27 and 12 °C in the experimental and simulation results, respectively. [ABSTRACT FROM AUTHOR]

The USA is confronted with three epic-size problems: (1) the need for production of energy on a scale that meets the current and future needs of the nation, (2) the need to confront the climate crisis head-on by only producing renewable, green energy, that is 100% emission-free, and (3) the need to forever forestall the eruption of the Yellowstone Supervolcano. This paper offers both a provable practical, novel solution, and a thought experiment, to simultaneously solve all of the above stated problems. Through a new copper-based engineering approach on an unprecedented scale, this paper proposes a safe means to draw up the mighty energy reserve of the Yellowstone Supervolcano from within the Earth, to superheat steam for spinning turbines at sufficient speed and on a sufficient scale, in order to power the entire USA. The proposed, single, multi-redundant facility utilizes the star topology in a grid array pattern to accomplish this. Over time, bleed-off of sufficient energy could potentially forestall this Supervolcano from ever erupting again. With obvious importance to our planet and the research community alike, COMSOL simulation demonstrates and proves the solution proposed herein, to bring vast amounts of green, emission-free energy to the planet's surface for utilization. Well over 11 Quadrillion Watt hours of electrical energy generated over the course of one full year, to meet the current and future needs of the USA is shown to be practical. Going beyond other current and past research efforts, this methodology offers tremendous benefits, potentially on a planetary scale. • New and revolutionary engineering approach to clean energy production is proposed. • Scalable energy is produced using copper cylinders and computer science techniques. • Energy production from the Yellowstone Supervolcano prevents its future eruption. [ABSTRACT FROM AUTHOR]

Environmental sustainability is the most crucial concern of the world. The existing literature has documented various factors that can play a remedial role in fixing the gregarious carbon emissions issue; however, little is known regarding consumption-based emissions. Trade diversification is one of the potential remedies for carbon emission reduction, enhancing economic growth and reducing trade risk and volatility by structural changes in critical production and development. Similarly, green innovation accelerates energy efficiency and improves environmental quality. However, in previous studies, trade diversification and green innovation have not received sufficient attention regarding emerging economies. Therefore, this study evaluates the impact of trade diversification, green innovation, and renewable energy on carbon emissions in BRICST countries (Brazil, Russian Federation, India, China, South Africa, and Turkey) from 1995 to 2020. The advanced panel data estimates empirically proved the existence of cointegration among the study variables. The long-run and short-run outcomes of the cross-sectionally augmented autoregressive distributed lag (CS-ARDL) model revealed that trade diversification, green innovation, and renewable energy are negatively associated with carbon emissions. Thus it has been proven that the trade baskets of these countries have a high number of eco-friendly products, and their manufacturing technologies are transforming toward green technologies, promoting renewable energy consumption to abate consumption-based carbon emissions. In contrast, the economic growth in this specific economic bloc amplifies environmental degradation by increasing the consumption-based carbon emission. In terms of policy implementation, this study suggests adopting harmonic trade policies, trade synchronization, and expansion of green innovations investment to reduce the current carbon emission level. • CS-ARDL applied using BRICST Data. • Trade diversification and renewable energy reduce consumption-based carbon emissions. • Green innovation shows the most substantial emissions mitigation effects. • Economic growth contributes to higher trade-adjusted emissions. [ABSTRACT FROM AUTHOR]

The retrofit of building envelopes in rural areas is a necessary measure to reduce building energy consumption. However, the traditional retrofit strategy is mostly a subjective decision, therefore, a scientific and objective evaluation method is proposed, which is a multi-factor and multi-objective preferred method based on orthogonal tests and entropy weights. The construction strategy for an additional sunspace of a typical rural residence in severe cold areas is studied. The results show that the glass type and the window-to-wall ratio have a remarkable influence on the optimization of the sunspace, accounting for 64.03 % and 17.42 %, respectively. Compared with the original rural building, the heating energy consumption of building with retrofit sunspace reduces by 12.82 %. Considering comprehensive energy saving, incremental cost, cost-benefit ratio and carbon emission reduction, the optimal construction strategy is the scheme 13, which has three layers of insulating glass with a window-to-wall ratio of 0.9, a depth of 0.9 m, 60 mm foamed concrete insulation board on the roof, 20 mm extruded polystyrene thermal insulation board on the ground and 120 mm foamed concrete insulation board on the adjacent south wall. The weights of the aforementioned parameters are 0.2967, 0.1916, 0.2021, and 0.3095, respectively, which are calculated by the entropy weight method. • Using orthogonal test and entropy weight method to evaluate building retrofits • Optimized 18 groups of retrofit schemes for the sunshine space • The weights of the four evaluation objectives were determined. • The best choice for retrofitting was obtained. [ABSTRACT FROM AUTHOR]

Green hydrogen reduces carbon dioxide emission, advances the dependency on fossil fuels and improves the economy of the energy sector, especially in developing countries. Hydrogen is required for the green transportation sector and many other industrial applications. However, the high cost of green hydrogen production reduces the fast development of renewable energy projects based on hydrogen production. So, sizing by optimization is required to determine the optimum solutions for green hydrogen production. In this context, this paper aims to analyze three methods that can be developed and implemented for the production of green hydrogen for refueling stations using photovoltaic (PV) systems. Techno-economic models are adopted to calculate the Levelized Hydrogen Cost (LHC) for the PV grid-connected system, stand-alone PV system with batteries, and stand-alone PV system with fuel cells. The photovoltaic systems based green hydrogen refueling stations are optimized using Homer software. The optimization results of the Net Profit Cost (NPC), and the LHC permit the comparison of the three cases and the selection of the optimal solution. The analysis has shown that a 3 MWp grid-connected PV system represents a promising green hydrogen production at an LHC of 5.5 €/kg. The system produces 58 615 kg of green hydrogen per year reducing carbon dioxide emission by 8209 kg per year. The LHC in the stand-alone PV system with batteries, and stand-alone PV system with fuel cells are 5.74 €/kg and 7.38 €/kg, respectively. • Levelized costs of hydrogen produced in photovoltaic refueling stations are analyzed. • Grid-connected photovoltaic system is an optimal solution providing green hydrogen. • Surplus of electricity produced in hydrogen stations is sold back to the power grid. • A 3 MWp photovoltaic system produces 58 615 kg of hydrogen at a levelized cost of 5.5 €/kg. [ABSTRACT FROM AUTHOR]

This paper presents a new fault-tolerant operation method of multiphase stacked interleaved Buck converter for green hydrogen production. An improved topology and new fault-tolerant control strategy is proposed. Multi-mode fault-tolerant operation of multiphase stacked interleaved Buck converter for different performance requirements of electrolyzer in hydrogen production system is realized. The multiphase stacked interleaved Buck converter can not only achieve elimination of output current ripple in normal operation mode, but also adopt different fault-tolerant modes according to different demands of electrolyzers in case of failure of any phase of converter. The proposed method is able to improve the availability of multiphase stacked interleaved Buck converter, reduce the times of equipment shutdown, and ensure the continuous operation of hydrogen production system from renewable energy sources. The effectiveness of the proposed method has been verified by experimental results. • An new topology and fault-tolerant control strategy is proposed for green hydrogen production. • The proposal not only achieves the current ripple elimination, but fault-tolerant operation in case of failure. • The proposed solution improves the system operation performance and reliability. • Experimental investigation of the proposed solution is provided. [ABSTRACT FROM AUTHOR]

Niger offers the possibility of producing green hydrogen due to its high solar energy potential. Due to the still growing domestic oil and coal industry, the use of green hydrogen in the country currently seems unlikely at the higher costs of hydrogen as an energy vector. However, the export of green hydrogen to industrialized countries could be an option. In 2020, a hydrogen partnership has been established between Germany and Niger. The potential import of green hydrogen represents an option for Germany and other European countries to decarbonize domestic energy supply. Currently there are no known projects for the electrolytic production of hydrogen in Niger. In this work, potential hydrogen demand across electricity and transport sectors is forecasted until 2040. The electricity demand in 2040 is expected at 2934 GWh and the gasoline and diesel demand at 964 m3 and 2181 m3 respectively. Accordingly, the total hydrogen needed to supply electricity and the transport sector (e.g. to replace 1% gasoline and diesel demand in 2040) is calculated at 0.0117 Mt. Only a small fraction of 5% of the land area in Niger would be sufficient to generate the required electricity from solar PV to produce hydrogen. • Hydrogen demand across electricity and transport sectors is forecasted until 2040. • Moving average technique is used for the forecasting due to its maximum R2 value. • Results show the electricity demand at 2934 GWh and hydrogen demand at 0.117 Mt. • Hydrogen potential with different electrolyzes and water requirement is assessed. • 17.8 Mt hydrogen can be produced at 5% of land available for solar PV. [ABSTRACT FROM AUTHOR]

This study was conducted to estimate the potential for green H 2 in Paraguay. A total production potential of 22.5 × 106 tons/year was obtained with a main contribution (93.34%) from solar photovoltaic. The greatest potential for producing H 2 from solar and wind resources is in the Western region, and from hydro resources is in the Eastern region of the country. Two end-uses of green H 2 were assessed: (1) automotive transportation, replacing gasoline and diesel; and (2) residential energy, replacing firewood and LPG for cooking in households across the country. In 16 of the 17 departments, green H 2 is able to replace the overall consumption of gasoline and diesel, as well as firewood and LPG. Finally, energy service cost (mobility), environmental aspects and CO 2 emissions were considered for three urban mobility technologies for the Metropolitan Area of Asunción. Results show that the mobility cost of fuel cell hybrid electric buses is still very high in comparison to diesel buses and battery electric buses. However, when a longer driving range is required, fuel cell hybrid electric buses could become a viable alternative in the long term. From an environmental point of view, green H 2 used in fuel cell hybrid electric buses has the potential to save about 96% of CO 2 emissions in comparison to diesel buses. It is concluded that the estimated green H 2 production potential favors the incorporation of the Hydrogen Economy in Paraguay. • The estimated green H 2 production potential in Paraguay is 22.5 × 106 tons/year. • The H 2 produced exceeds the demand of fuels in the selected sectors. • In urban mobility, FCHEB buses have environmental advantages and economic disadvantages. • An important reduction in GHG emissions could be achieved throughout green H 2 use. • The development of the Hydrogen Economy in Paraguay fosters its energy transition. [ABSTRACT FROM AUTHOR]

This research examines the effect of environmental policy stringency on green innovation in renewable energy technology and whether the green innovation response differs with varying degrees of environmental policy. Based on panel data of 33 countries over the period 1990–2015, we show that a stringent environmental policy does encourage green innovation in renewable energy technology, and this impact is more pronounced in OECD countries and high-income countries. More specifically, a stringent non-market-based environmental policy induces more patents in renewable energy generation. The findings also show that a stringent environmental policy yields green innovation for geothermal energy, hydro energy, and marine energy, but not for wind energy and solar energy. Heterogeneity analysis suggests that innovation capacity and environmental pressure enhance the impact of environmental policy stringency on green innovation in the renewable energy field. Finally, the paper presents that clean energy investment plays the role of a mechanism through which environmental policy stringency spurs green innovation in the renewable energy field, offering insights into the influence of environmental policy stringency on green innovation. [ABSTRACT FROM AUTHOR]