Benefits Of Green Roofs Research Articles

Hydrological Benefits of Green Roof Retrofitting Policies: A Case Study of an Urban Watershed in Brazil

Green roofs (GRs) are emerging as effective tools for mitigating urban runoff, particularly in cities facing challenges related to increased impervious surfaces and flooding risks. This study evaluates the potential hydrological performance of GR retrofitting in São José dos Campos, Brazil, based on municipal legislation, focusing on the effects of reducing the Effective Impervious Area (EIA) in urban watersheds. Using a range of projected EIA reduction scenarios (Mandatory, Incentivized, and Ideal), this study compares key hydrological indicators such as peak flow attenuation, runoff volume reduction, and hydrograph delay during rainfall events with different return periods. The results show that retrofitting with GRs significantly attenuates peak flows and delays runoff, with the ‘Ideal’ scenario (EIA = 16%) achieving peak flow reductions of up to 41% and runoff volume reductions of 35%. However, the effectiveness of GRs diminishes for high-intensity rainfall events, suggesting that GRs are most effective for frequent, low-intensity storms. These findings demonstrate the potential of GRs in reducing flooding risks in urban environments, highlighting the importance of integrating GRs into broader sustainable drainage systems. This study further emphasizes that while financial support is crucial for promoting GR adoption, it alone is not sufficient. Policies should be complemented by educational efforts and urban regulatory measures to ensure widespread adoption and long-term impact. This research provides urban planners and stakeholders with evidence to enhance urban resilience, sustainability, and effective flood risk management.

Assessing the Spatial Benefits of Green Roofs to Mitigate Urban Heat Island Effects in a Semi-Arid City: A Case Study in Granada, Spain

Studies show that Nature-Based Solutions can mitigate Urban Heat Island (UHI) effects by implementing green spaces. Green roofs (GRs) may minimize land surface temperature (LST) by modifying albedo. This research predicts, assesses, and measures the impact of reducing the LST by applying green roofs in buildings by using a Random Forest algorithm and different remote sensing methods. To this aim, the city of Granada, Spain, was used as a case study. The city is classified into different Local Climate Zones (LCZs) to determine the area available for retrofitting GRs in built-up areas. A total of 14 Surface Temperature Collection 2 Level-2 images were acquired through Landsat 8–9, while 14 images for spectral indices such as the Normalized Difference Vegetation Index (NDVI), the Normalized Difference Building Index (NDBI), and Proportion Vegetation (PV) were calculated from Sentinel-2 in dates coinciding or close to LST images. Additional factors were considered including the sky view factor (SVF) and water distance (WD). The results suggest that Granada has limited suitable areas for retrofitting GRs, and available areas can reduce LST with a moderate impact, at an average of 1.45 °C; however, vegetation plays an important role in decreasing LST. This study provides a methodological example to identify the benefits of implementing GRs in reducing LST in semi-arid cities and recommends a combination of strategies for LST mitigation.

The Benefits of Green Roofs and Possibilities for Their Application in Antalya, Turkey

Rapid population growth, urbanization, and industrialization have many negative environmental effects. These adverse effects are felt more in urban areas than in rural areas. Considering the high rate of urban development, the idea that green roof structures can be used on rooftops is important in reducing the current negative effects. In addition, water retention on these roof areas can be helpful in the face of drought periods. In this study, the amount of water that can be retained on a 100 m2 roof area in Antalya Province, Turkey was calculated. As a result, it was determined that August is the month when the least water can be retained due to rainfall. It was calculated that between 0.168 m3 and 0.363 m3 of water can be retained in August. Furthermore, the month in which the most water can be retained due to rainfall is December, and the amounts of water that can be retained are between 5.762 m3 and 21.640 m3. These calculated values are anticipated to be important in understanding how much water can be retained in the planned green roofs. In addition, it has been determined that the energy savings that can be made for heating purposes in a 100 m2 green roof area can be between 3900 kWh and 11,250 kWh.

How to overcome local policy conflicts that hinder climate actions? A green roof planning dispute between politicization and de-politicization

The integration of green infrastructure, such as green roofs (GR), in urban centres is considered crucial for climate change adaptation, and improving environmental quality. Previous research highlights the benefits of GR, including urban heat island mitigation, energy efficiency, biodiversity enhancement, and stormwater management. However, it also addresses the challenges, particularly in cold climates, where seasonal variations affect GR performance. Furthermore, barriers such as policy constraints, financial limitations, and cognitive challenges can hinder the mainstreaming of vegetated roofs. This study examines the political and policy dynamics surrounding GR implementation through a case study of a planning conflict in Turku, Finland. It employs a mixed-method approach, analyzing planning documents, municipal decision-making data, media reports, and stakeholder interviews. Findings reveal that the politicization of GR in Turku was driven by conflicting interests among stakeholders, including a local affordable housing developer. The introduction of the Blue-Green Factor (BGF) planning tool in 2021 facilitated the depoliticization of GR by providing a flexible framework for enhancing urban greenness and stormwater management. This case underscores the importance of adaptive policy frameworks in overcoming local conflicts and advancing urban sustainability goals. The study also contributes to the broader discourse on urban political ecology and critical planning studies, emphasizing the need for context-sensitive approaches to green infrastructure implementation.

Investigation of the Interaction of Water and Energy in Multipurpose Bio-Solar Green Roofs in Mediterranean Climatic Conditions

The advantages of green roofs and solar panels are numerous, but in dry periods, green roofs can place urban water resources under pressure, and the efficiency of solar panels can be affected negatively by high temperatures. In this context, our analysis investigated the advantages of bio-solar green roofs and evaluated the impact of green roofs on solar panel electricity production and solar panels on green roof water consumption. The assessment was conducted through simulation in a selected case study located in Cosenza, a city with a Mediterranean climate, with solar panels covering 10% to 60% of the green roof. Analyses were performed on the power outputs of four kinds of photovoltaic panels: polycrystalline, monocrystalline, bifacial, and Passivated Emitter and Rear Contact (PERC). The energy production and shade frequencies were simulated using PVGIS 5.3 and PVSOL 2024 R3. The impact of photovoltaic (PV) shade on the water consumption of green roofs was evaluated by image processing of a developed code in MATLAB R2024b. Moreover, water–energy interconnections in bio-solar green roof systems were assessed using the developed dynamic model in Vensim PLE 10.2.1. The results revealed that the water consumption by the green roof was reduced by 30.8% with a bio-solar coverage area of 60%. However, the electricity production by the PV panel was enhanced by about 4% with bio-solar green roofs and was at its maximum at a coverage rate of 50%. This investigation demonstrates the benefits of bio-solar green roofs, which can generate more electricity and require less irrigation.

Optimization of heat transfer coefficient in green roof modules based on life cycle carbon emissions

ABSTRACT As cities face increasing challenges related to climate change and energy consumption, green roofs offer an innovative solution by improving building insulation, reducing energy demands, and mitigating urban heat island effects. However, the environmental benefits of green roofs, particularly regarding carbon emissions and heat transfer, are not well understood. This study aims to address this gap by investigating the influence of life cycle carbon emissions on the heat transfer coefficient in green roof modules. The study quantifies the roof heat transfer coefficient of green roof modules and their carbon emission benefits across their life cycle, with a focus on identifying optimization pathways for maximizing both energy efficiency and carbon reduction. Using IPCC guidelines, assimilation methods, and life cycle assessment (LCA) techniques, models for calculating heat transfer and carbon emissions at each stage of the life cycle are developed, and to explore the relationship between these two factors. The results show that for different soil thicknesses, heat transfer coefficients are 0.1 m (0.76 W/m2·K), 0.2 m (0.624 W/m2·K), 0.3 m (0.53 W/m2·K), and 0.4 m (0.46 W/m2·K). The carbon emissions across the life cycle are as follows: construction phase (57.07 kg·m−2) > maintenance phase (36.08 kg·m−2) > material production phase (19.65 kg·m−2) > material transportation phase (14.15 kg·m−2) > daily usage phase (7.02 kg·m−2). Daily carbon emissions positively affect the heat transfer coefficient, while soil thickness has a significant negative effect. A green roof module with a combination of three plant types and a 0.3 m soil substrate presents the optimal parameters for reducing heat transfer. These findings have important implications for the design of green roofs in urban environments, suggesting pathways for optimizing energy efficiency and minimizing carbon footprints, thereby contributing to more sustainable urban planning.

Environmental, Economic and Psychophysical benefits of volcanic soil green roofs

Environmental, Economic and Psychophysical benefits of volcanic soil green roofs

Application of the TONIC model to assess the effectiveness of green roofs for a combined sewer network in Thu Duc City

Urban flooding in cities in Vietnam presents a complex challenge from natural occurrences and human activities. This research investigates the effectiveness of nature-based solutions (NbS) in fostering sustainable urban water management. The study utilized the TONIC model (Tools fOr greeN resilient Cities) to evaluate spill events within the combined sewer system of a drainage catchment in Thu Duc City, Ho Chi Minh City, Vietnam. The occurrence and magnitude of spills will likely escalate with the expansion of non-absorbent surfaces, indicating a pattern of unsustainable urban growth. The implementation of Green Roofs (GR) as an NbS measure was examined. In 2020, there were 16 days with stormwater spills totaling 3,035 m³. However, introducing GRs significantly decreased total discharge, from 2.78 million m³ to 2.17 million m³, and eliminated spill days in the study area. GRs effectively reduced impermeable areas and runoff coefficients (RC), achieving a 22% reduction in discharge volume and preventing spills during heavy rainfall. Although the real-world accuracy of these findings may vary, the study underscores the potential of NbS to improve urban water management practices. Thus, the TONIC simulation highlighted the benefits of GRs in lessening the hydraulic pressure on the sewer system and reducing pollution in urban canals due to overflow.

Energy Performance Assessment on Vertical Greening Systems with Green Roof in Hot Summer and Cold Winter Regions Based on Long-term Experimental Data

Energy Performance Assessment on Vertical Greening Systems with Green Roof in Hot Summer and Cold Winter Regions Based on Long-term Experimental Data

Thermal modelling of Green Roofs

Urban changes highlight the need for expand vegetated spaces in built environments. In this sense, green roofs represent a valuable opportunity due to their potential to provide ecosystem services. Among the components of green roofs, substrates are essential and can be optimized to enhance their thermal properties, thus influencing heat transfer into buildings. Using additives in substrates for thermal optimization is a promising approach, especially when these additives include environmental by-products that make the substrates lighter and more cost-effective. The thermal performance of green roofs is also influenced by meteorological conditions that regulate substrate temperatures. This study conducted thermal modeling of the internal temperature of five green roof substrates by using generalized additive models and linear models based. Data collected during the summer months of 2021 and 2022 from five identical green roofs, except for their substrate composition - local soil (SOIL), commercial substrate (SCOM), and three mixtures incorporating carbonized rice husk, construction waste, vermiculite, and vermicompost into the local soil (SC2, SC4 and SC5) - were assessed. The correlation between monitored temperatures and meteorological variables was also assessed. The results showed correlations ranging from moderate to strong between the internal temperature of the substrates and climatic variables, especially temperature and humidity. It was proposed a predictive model for the internal temperatures of green roofs, achieving a Nash-Sutcliffe coefficient of up to 0.86, effectively evaluating the thermal benefits of green roofs under different meteorological conditions.

The Evapotranspiration Characteristics and Evaporative Cooling Effects of Different Vegetation Types on an Intensive Green Roof: Dynamic Performance Under Different Weather Conditions

Previous research has demonstrated that the multiple environmental benefits of green roofs are primarily associated with their evaporative cooling effect. However, current studies on green roof evapotranspiration (ET) mainly focus on extensive green roofs, and the evaporative cooling effect of intensive green roofs is still unclear. Using the intensive green roof of AQUA City in Nanjing as a case study, this research employs the three-temperature (3T) model combined with high-resolution thermal infrared imagery obtained via an unmanned aerial vehicle (UAV) to estimate the ET of different vegetation types. The study aims to explore the spatiotemporal variations in surface temperature, evapotranspiration (ET) rate, and evaporative cooling rate for various vegetation types under typical seasonal (summer and winter) and weather conditions (sunny, cloudy, and rainy before and after rainy days). The results showed that: (1) the ET rates and evaporative cooling effects of different types of vegetation differed significantly, with shrubs having the fastest ET rates, followed by arbors, and grasslands having relatively low ET rates. (2) Solar radiation and air temperature are the most crucial meteorological parameters for inducing ET on green roofs. In this study, the evaporative cooling performance showed the patterns of summer > winter and sunny > cloudy > rainy days. (3) In the spatial distribution of tree and irrigation plant groups, some low-temperature diffusion phenomena to the adjacent small microenvironments were evident, while the diffusion effect in winter is smaller and mainly shows the opposite warming characteristics. This study offers a valuable reference for quantifying the ET and evaporative cooling effects of various vegetation types on intensive green roofs, facilitating the optimization of vegetation configuration and supporting sustainable urban development.

The Contribution of Green Roofs in the Achievement of Sustainable Development Goals

Green roofs are eco-friendly systems designed to deliver environmental, economic and social benefits while they enhance the aesthetic appeal of buildings. Their construction on rooftop of buildings in urban communities is important for the local residents and the environment. The Sustainable Development Goals are a set of 17 global objectives established by the United Nations in 2015 serving as a blueprint for developing a more sustainable, equitable and prosperous world by 2030, focusing on environmental, economic and social progress. The multiple benefits of green roofs are related with the achievement of the sustainable development goals. Creation of green roofs in urban areas facilitates the achievement of the SDG3 related with good health and well-being as well as SDG11 related with sustainable cities and communities, SDG13 related with climate action and SDG15 related with life on land. Therefore, the development of green roofs in urban areas is very useful and beneficial for the buildings’ residents, the environment and the local community. Due to multiple external benefits of green roofs their construction should be promoted with financial and non-financial incentives by municipal and regional authorities combined with removal of several barriers hindering their adoption and development.

The Role of Solar Photovoltaic Roofs in Energy-Saving Buildings: Research Progress and Future Development Trends

The depletion of global resources has intensified efforts to address energy scarcity. One promising area is the use of solar photovoltaic (PV) roofs for energy savings. This study conducts a comprehensive bibliometric analysis of 333 articles published between 1993 and 2023 in the Web of Science (WOS) core database to provide a global overview of research on solar photovoltaic (PV) roofs, with a particular emphasis on their energy-saving benefits. The analysis identifies current trends and future development trajectories in this field. Over the past three decades, research on solar PV roofs has shown steady growth, progressing from initial exploration to stable development. Key research themes include integrating renewable energy with building efficiency, the synergistic benefits of green roofs and PV systems, the design and practical application of PV-integrated roofs, and optimization techniques for parametric models. Future research will likely prioritize the efficient integration of PV components with roof maintenance structures, shifting from solely assessing PV component performance to evaluating the holistic performance of roofs and their broader impact on the built environment. This shift underscores the importance of improving the overall sustainability of the building. By aligning research efforts with these emerging trends, stakeholders can contribute to developing more effective and sustainable energy solutions for the future.

Review of the Benefits of Green Roofs

Green roofs installed on rooftop of buildings in urban communities have multiple environmental, economic, energy and social benefits. They promote the urban sustainability and the well-being of the local residents. The impact of green roofs in buildings, in the environment and in local communities have been studied. Green roofs remove atmospheric pollutants including carbon dioxide, release oxygen, mitigate the urban heat island effect, reduce the energy consumption in buildings, improve the rainwater management, promote urban agriculture, enhance urban green spaces and bring nature closer to local residents. The development of green roofs results in many benefits in the buildings that have been constructed as well as in the broader community. Their construction is financially subsidized in several countries due to their multiple external benefits. In the era of climate change and of sustainable development construction of green roofs in urban environments has multiple positive impacts. Therefore, local and municipal authorities should promote their construction in public and private buildings. The current work emphasizes the benefits of green roofs and it could be useful to policy makers, to public and municipal authorities as well as to architects, construction companies and buildings’ owners who should promote their development in urban communities.

Carbon Removal from Green Roofs in Urban Communities: A Case Study in the City of Chania, Crete, Greece

Construction of green roofs on rooftop of buildings in urban areas has multiple environmental, economic and social benefits including the atmospheric carbon removal. Rooftops of buildings can be also used for the installation of solar photovoltaic and solar thermal systems generating green energy. The use of green roofs in buildings in Crete, Greece is very limited. The impact of green roofs and of solar-PV systems installed on rooftop of buildings located in the municipal unit of Chania, Crete, Greece has been examined. It has been estimated that green roofs remove atmospheric carbon through plants’ photosynthesis and contribute in carbon emission savings due to lower energy consumption in buildings. Additionally, installation of solar-PV panels on rooftop of buildings contributes to green energy generation and to climate change mitigation. Apart from climate change mitigation green roofs have multiple external environmental, economic and social benefits. It has been indicated that the impacts of green roofs to climate change mitigation are lower than the impacts of solar photovoltaics’ installation on rooftop of buildings. The multiple external benefits of green roofs indicate that their construction should be financially subsidized in Greece like in other EU countries. The findings could be useful to municipal authorities who should promote the construction of green roofs in urban buildings in their municipalities.

Biochar Amendment in Green Roof Substrate: A Comprehensive Review of the Benefits, Performance, and Challenges

Green roofs (GRs) are a well-established green infrastructure (GI) strategy that have been extensively studied for decades to address a growing array of social and environmental challenges. Research efforts have been continuously made to contribute to the awareness of benefits of GRs and towards their widespread application. The substrate, which is one of the crucial layers of a GR system, plays a major role in the serviceability of GRs. Thus, several studies have been undertaken to alter the substrate characteristics by applying innovative substrate additives. Biochar, a carbon-rich material with a highly porous structure and large specific surface area, has been found advantageous in several areas such as agriculture, water filtration, environmental remediation, construction, and so on. However, the application of biochar in GRs has been insufficiently studied, partially because biochar amendment in GRs is a relatively recent innovation. Furthermore, a comprehensive review of the performance of biochar-amended GR substrates is lacking. This review paper aims to summarize the past performance of GRs enhanced with biochar by considering the various benefits that biochar offers. The results indicate that most of the reviewed studies observed increased retention of runoff and nutrients when utilizing biochar. Additionally, the capabilities of biochar in improving thermal insulation, plant performance, and microbial diversity, as well as its effectiveness in sequestrating carbon and controlling soil erosion, were mostly agreed upon. Notwithstanding, a definitive conclusion cannot yet be confidently made due to the limited research information from biochar–GR systems and the uneven research focus observed in the studies reviewed. The influence of biochar-related variables (including amendment rates, application methods, processed forms, and particle size) on the effectiveness of biochar was also discussed. Opportunities for future research were suggested to fill the research gaps and address challenges restricting the application of biochar in GRs. Detailed information from past research findings could serve as a foundation for further investigations into the large-scale implementation of biochar in GRs.

Public Benefits Valuation of Dynamic Green Roof Stormwater Retention

This study evaluates the public benefits associated with different green roof systems to manage stormwater runoff in Milwaukee, Wisconsin. An internet-based stated-preference conjoint choice experiment was administered to residents of Milwaukee to ascertain the public benefits value of different potential green roof infrastructure programs. This study contributes to the literature on the public benefits of green roofs in two ways. First, this study examined the perceived value of dynamic stormwater retention facilitated using “smart” green roofs with access to real-time weather data versus traditional extensive green roofs. Second, a wider range of public benefits associated with green roofs, including improved water quality, air quality, biodiversity, and urban heat island effects, were estimated. Estimation of these public benefits allows for determination of the optimal public policy for supporting green roofs as a component of decentralized stormwater management in municipalities.

Unlocking energy and economic benefits of integrated green envelopes in office building retrofits

Unlocking energy and economic benefits of integrated green envelopes in office building retrofits

A daily time-step hydrological-energy-biomass model to estimate green roof performances across Europe to support planning and policies

Nature-based solutions (NBSs) and urban greening are well-established strategies used in various planning and policy instruments to promote the sustainability of cities and mitigate the effects of climate changes. Within this context, green roofs are emerging as an effective NBS in urban areas where space is often limited. The estimation of green roofs' benefits is essential for their effective implementation and engineering design. In this contribution, we present a daily time-step model to estimate the surface temperature, the growth of vegetation cover and the hydrological behaviour of a green roof. The model is tested using twenty time series of real and independent European green roofs. Results show that, in the absence of calibration, the model can reproduce the daily surface temperature with high accuracy. The vegetation growing period is also reproduced. The hydrological variables can be estimated with moderate accuracy, and higher accuracy can be achieved when the model is calibrated. Therefore, the model proves a useful tool to support the appraisal of green roofs and the planning of green infrastructures in European cities.

Land Cover Classification and Change in Porto, Portugal: Spatial Analysis for Urban Vegetation and Green Roof Adoption

There are increasing pressures to create multifunctional urban areas, which provide space for people as well as ecosystem services. We analyzed landcover classification and change for Porto, Portugal, using geographic information systems and remote sensing data. Landcover was classified into seven categories for five counties of Porto District Portugal using PlanetLabs PlanetScope satellite imagery. Images were selected for low cloud cover and similar time of year and obtained for 4 July 2017 and 1 July 2022. Political boundaries were obtained from the National Institute of Statistics. Of the four classification methods tested, K-Nearest Neighbor was the most accurate supervised classification method with 2017 Kappa = 0.87 and 2022 Kappa = 0.98. Classified landcovers show Shadow, Other Roofing Material, and Bare Ground increased, and Water, Tiled Roof, Pavement, and Vegetation decreased from 2017 to 2022. NDVI showed a decrease in vegetation overall, mean difference -0.043. Classification showed 142.5 million square meters classified as impervious surface in 2022, of which 32.68 million square meters were “other roofs”, commercial or industrial white surfaced roofs, which may be the most likely targets for vegetative interventions. Zonal statistics show neighborhoods that gained or lost vegetation over the study period, and these neighborhoods are not randomly distributed, Moran’s I = 0.0249 or 0.402. Additional socioeconomic data could help understand this distribution and make decisions addressing climate justice. LiDAR data would increase the accuracy further and allow for clearer selection of roofs and quantification of green roof benefits.