Search

Collection, as the first stage of the recycling process, and pre-processing to increase waste stream purity constitute key operations for achieving high recycling rates and a closed loop in the circular economy. For wastepaper recycling in Hong Kong, it is the semi-formal-informal recycling (SFIR) sector that plays a central role in both stages. This study analyses the so far little explored SFIR stakeholder network in Hong Kong and sheds light on value chains, recovered waste paper quantities and the impact of policies on the sector. The findings show that SFIR stakeholders reclaim 55.6 t/recycling station/month of wastepaper and thereby achieve about a 5.7 times higher reclaim rate than the formal-private recycling system. Critical to this achievement is the SFIR transaction network, which enables its stakeholders to develop a value chain and thereby generate an added value of around 1900 HKD (243.9 USD/t) for wastepaper. Given limited circular structures in Hong Kong, financial subsidies are critical to sustain the SFIR's operations over the short-term. However, over the long-term legalization and integration of its stakeholders are necessary to ensure an economically and socially sustainable wastepaper recovery system in Hong Kong. [Display omitted] • Qualitative & quantitative analysis of the semi-formal-informal recycling (SFIR) sector. • The SFIR's wastepaper value chain achieves a cumulative added value of 1900 HKD/t. • The SFIR recovered 5.7 times higher capacities than the formal system in 2021. • Financial support can enhance the SFIR sector's recovery capacities. [ABSTRACT FROM AUTHOR]

In recent years, promoting regional synergistic development has become the shared objective in city-regions during the new stages of development. This paper aims to uncover the dynamics of synergistic development in urban agglomerations by constructing an index measurement system based on four dimensions: industrial synergy, innovation synergy, infrastructure synergy, and institutional synergy. By comprehensively employing theories and methods such as "space of flow" big data analysis, network analysis, and interlocking network models, this study examines patterns and capacities of synergistic development in the Guangdong-Hong Kong-Macao Greater Bay Area. The main instances of industrial cooperation between cities are observed in Hong Kong-Shenzhen and Guangzhou-Shenzhen; capital flows primarily concentrate in Guangzhou-Shenzhen and Hong Kong-Shenzhen. Research paper and patent collaborations between cities are predominantly concentrated in Hong Kong-Shenzhen; joint laboratories are mainly established in Hong Kong-Macao and Hong Kong-Guangzhou; inter-city co-construction of higher education institutions is mainly focused on Guangzhou-Foshan and Shenzhen-Hong Kong. Infrastructure synergistic development performs best in Guangzhou-Shenzhen, Guangzhou-Foshan, and Shenzhen-Dongguan. Cross-border collaboration benefits from institutional advantages held by Hong Kong and Macao. Urban interactions with outstanding performance include Guangzhou-Shenzhen, Hong Kong-Shenzhen, Guangzhou-Foshan, Shenzhen-Dongguan. Additionally, increasing interaction trends can be observed between Guangzhou-Dongguan as well as Shenzhen-Zhuhai/Shenzen-Foshan partnerships. Understanding the typical characteristics and potential trends of synergetic development within the GBA holds significant practical value for establishing a first-class bay area along with a world-class urban agglomeration. • Concept and connotation of synergistic development in urban agglomeration area was examined. • Indicators and methods for evaluation of synergistic development in the GBA were conducted. • Patterns and capacities of synergistic development at urban scale in the GBA were explained. • Urban interaction with highest synergistic development level is Guangzhou-Shenzhen. [ABSTRACT FROM AUTHOR]

In this paper, we estimate the energy efficiency of educational buildings with the case study of buildings in City University of Hong Kong by constructing an energy demand stochastic frontier model. The model is estimated by using the university statistical data from 2011 to 2015. For the consistent frequency of data among the variables, we have adopted the quadratic-match sum method to convert annual university report data into a monthly dataset. Our result shows the average energy efficiency is 0.87, implying that 13% of total energy consumption can be saved. We then calculate how much of the energy saving potential has been achieved by constructing the performance score, which increases from 0.08 to 0.17. It implies that the campus performs more efficiently in saving energy over time. We further develop econometric decomposition analysis based on the energy demand frontier model to identify the factors affecting energy consumption. It suggests that research activities account for a large share of overall energy consumption. Analysis on energy end-use shows university should improve efficiency in lab instrument as it is least efficient among the four usages. We expect this paper can provide the fundamental and methodological guideline for university-scale energy efficiency estimation. • Estimating energy efficiency of educational buildings needs to consider the composition of research related factors. • Energy efficiency of campus building presents increasing tendency with seasonal cycle over time. • Research related variables affect significantly on energy efficiency of educational buildings. • Energy use in lab instrument needs to be effectively managed to save energy. [ABSTRACT FROM AUTHOR]

Radiative cooling coating technology is gaining increasing attention in the context of mitigating urban heat island and tackling global climate change. This paper is concerned with the development of an inorganic geopolymer-based radiative cooling coating using red mud, incorporating varying sizes of TiO 2 and hollow glass beads. The developed colored coating demonstrates its radiative cooling capability in reducing the surface temperature by harnessing the potential of red mud. The physico-chemical properties, surface morphology, and element distribution of the coating were characterized by XRD, FTIR, TG-DAT, SEM and EDS. The coating exhibited lower UV (0.0844) and visible reflectance (0.5275) but high NIR reflectance (0.7536), as well as high infrared emissivity of 0.9455, enabling a red color with a CIE value of L* = 74.56, a* = 9.55, and b* = 11.98, and a maximum temperature reduction of 7.3 °C under the climate of Hong Kong. Additionally, the skid resistance, abrasive resistance and adhesion strength of the proposed coating could meet the requirements of standards, indicating a great potential for footway applications. [ABSTRACT FROM AUTHOR]

Electricity consumption in cities is steadily increasing. Using a life cycle approach and fuel mix data from power companies’ sustainability reports, this paper analyzes greenhouse gas (GHG) emissions from electricity consumption in Hong Kong. The results show that coal contributed on an average 74.3 percent, liquefied natural gas 25.1 percent, and oil 0.6 percent of the thermal energy consumed for generating electricity in Hong Kong between 2002 and 2015. Besides, Hong Kong imported an average of 7.96 billion kWh per year net electricity from a nuclear power plant in Shenzhen. During this period, GHG emissions from annual electricity consumption ranged between 27.0 and 34.1 million tons (MT) and the emission factor ranged between 702 and 792 g CO 2 -eq/kWh. Hong Kong’s gross domestic product (GDP) increased steadily from USD 176 billion in 2002 to USD 297 billion by 2015. As a result, Hong Kong’s electricity productivity increased from 4.62 to 6.75 USD/kWh while GHG emission from electricity consumption per GDP decreased from 0.153 to 0.104 MT CO 2 -eq/USD billion. Hong Kong’s annual electricity consumption was predicted over the short-term period (2016–2020) and medium term (up to year 2030). Electricity consumption is likely to increase to 44.63 billion kWh by 2030 while GHG emissions from electricity consumption would increase to 33.92 MT of CO 2 -eq. The implications are discussed at the end of the paper. [ABSTRACT FROM AUTHOR]

The environmental performance of organizations is an increasing focus in cleaner production. This paper explores how the importance and performance of environmental practices were perceived among professional-level employees in Hong Kong, China. Based on a literature review on sustainable development and environmental management, we developed a structured questionnaire to measure respondents' perceptions towards environmental practices. Using responses from 348 professional-level employees in Hong Kong organizations, we employed importance-performance analysis for identifying some improvement opportunities. In addition, we applied exploratory factor analysis to identify the underlying environmental factors based on the importance ratings. Results of the study demonstrated that the performance of environmental practices was strongly associated with perceived importance of environmental practices. As environmental practices, it was found that Hong Kong organizations and employees primarily focused on saving paper and energy resources. However, they are not embracing the concept of green value chain and have yet to engage their suppliers to go green. This paper contributes to identify the key internal and external factors of environmental practices. [ABSTRACT FROM AUTHOR]

Modular integrated construction (MiC) has received remarkable attention for enhancing the productivity performance of delivering housing projects in densely populated cities such as Hong Kong. MiC projects suffer from unique risk factors compared with traditional construction methods. Previous studies have mainly focused on the direct linear impacts of risk factors and how they may affect project success. However, the MiC supply chain involves many stakeholders with high interdependency. How the risks are interconnected and interact with different stakeholders is a crucial issue to be analyzed and addressed. This paper deploys a social network analysis (SNA) method to identify and decipher stakeholder-associated productivity performance risks (PPRs) and their interrelations in an MiC project in Hong Kong. Fifteen critical PPRs and twelve essential interactions were demonstrated by simulating the complex network of the target project. Research findings show that inadequate project planning and scheduling has the greatest influence on collaborative decision-making support; Delayed assembly schedule and delayed delivery of modules also exert considerable influence on project planning and scheduling; The main contractor plays a leading role as a coordinator in the whole MiC process. The research further identifies several primary challenges, including the inefficient data capture approach, insufficient supply chain planning and progress monitoring, poor communication and information interchange among project stakeholders, and lack of collaborative decision-making support. This is the first study that dynamically examines and demystifies stakeholder-associated PPRs embedded in MiC projects in Hong Kong on a network basis, which could assist researchers and construction professionals in perceiving, investigating, addressing, and mitigating these risks in an effective and efficient approach. [ABSTRACT FROM AUTHOR]

Carbon emission trading mechanism is an important market-based instrument to address global climate change. The auction ratio and price of carbon emission allowances (CEA) are cores of the carbon emission trading mechanism. What combination of CEA auction ratio and auction price is most conducive to carbon emission reduction for emission control enterprises? There are still relatively few studies conducted on this issue, and there is no clear answer from the views of theory and practice. In this paper, the AIM/Enduse model was used to analyze the changes and differences of installed power capacity, power supply, energy consumption and carbon emissions in the Guangdong-Hong Kong-Macao Great Bay Area (GBA) with different combinations of CEA auction ratios and prices. Moreover, the best pathway of energy transition was explored in the power industry of the GBA, and the best combination of CEA auction ratios and prices was identified in the GBA. The results show that: (1)The carbon emission constraint starts to work only when the auction ratio of CEA is increased to 50% and the auction price is increased to 60 CNY/ton (Scenario p 3). When the auction ratio of CEA is 100% and the auction price reaches 120 CNY/ton (Scenario p 5), a low-carbon transition of the power sector in the GBA can be achieved. (2) Under scenario p 5 , the total cost of power transition rises and then falls. And the cost of carbon in the power sector increases exponentially as the auction ratio of CEA and the auction price rise. However, the growth in the cost of power supply is relatively flat, which shows that appropriate carbon trading mechanism can improve the economic benefits of power sectors. With the increase of installed capacity of clean low-carbon energy generation and power supply, as well as the decrease of local power cost in the GBA, the proportion of outsourcing power can be appropriately reduced in the future, with an aim to reduce the external dependence of electricity to ensure the security of energy supply. In the end, it suggests that cities in the GBA should give full play to their regional advantages and establish a unified carbon emission trading market in the GBA as soon as possible. This study provides a theoretical basis for the supplementation and improvement of China's carbon emission trading mechanism. • What is the best combinations of CEA auction ratios and auction prices in the GBA? This paper gives a clear answer. • The best transition pathway of the power industry under technological progress and carbon trading policy was suggested. • With the decrease of local power cost, the proportion of outsourcing power can be appropriately reduced in the future. • Provides a theoretical basis for the supplementation and improvement of China's carbon emission trading mechanism. [ABSTRACT FROM AUTHOR]

The use of structural steelwork (SS) for buildings continues to grow worldwide owing to its sustainability benefits. However, the market share of SS in the building sector of Hong Kong greatly lags behind other markets. This paper focuses on providing a comprehensive understanding of the issues that greatly drive or inhibit SS adoption in Hong Kong from a project lifecycle perspective. The methodology encompasses both qualitative and quantitative approaches. Semi-structured interviews were conducted with 28 professionals from developer, structural engineering consultant, main contractor, steel specialist contractor, and steel stockholder companies. The results identified 12 driving factors and 25 barriers affecting SS adoption in Hong Kong. A questionnaire survey with 118 practitioners was carried out to identify the most important driving factors and barriers. The results revealed that "increased speed of construction" and "must-have requirements" were the two most important driving factors; while "shortage of skilled labor", "shortage of supervisors working directly under main contractors", "high construction costs", "shortage of experienced designers and draughtsmen", and "lack of education, training, and design experience on structural steelwork" were the five most critical barriers. This may imply that education and training are needed to improve knowledge and skills of professionals and workers, and thus to ensure an adequate supply of manpower. The findings of this study not only contribute to the existing body of knowledge on SS practices but also provide valuable references for helping practitioners and policymakers to promote sustainable construction methods within the building sector. • Increased speed of construction and must-have requirements are important drivers. • Manpower shortages in the design and construction phases are critical barriers. • High construction cost also inhibits the use of structural steelwork. [ABSTRACT FROM AUTHOR]

The construction industry in Hong Kong has been exposed to serious housing production issues such as insufficient manpower, safety, environmental concerns and inefficient housing supply. Prefabrication housing production has shown as efficient construction model which enables to overcome these issues and it is applied in construction industry in Hong Kong. In this paper, hybrid modeling techniques that combine system dynamics and discrete event simulation are used to analyze the interrelationships of schedule risks within the six-day cycle assembly of prefabrication housing production. Moreover, a hybrid dynamic model is developed to simulate and evaluate the impact of schedule risks on the schedule performance of the six-day cycle assembly of PHP via the Anylogic software package. The resulting model is validated by data which is collected from a PHP project in Hong Kong. Based on the simulation results, the first most influential level contains five schedule risks, namely, inefficient verification of precast components because of ambiguous labels, misplacement on the storage site because of carelessness, owner crane breakdown and maintenance, slow quality inspection procedures, and inefficient design data transition that cause average schedule delays of more than 300 min. The second most influential level includes delay of the delivery of precast element to site, design information gap between designer and manufacturer, installation error of precast elements, and logistics information inconsistency because of human errors, with average schedule delays less than 300 min and greater than 200 min. Design change, low information interoperability between different enterprise resource planning systems, and inefficiency of design approval belong to the third level that imposes the least influence on the schedule delay of the assembly. This research contributes to the current knowledge of the management of prefabrication construction by developing an effective model that offers an in-depth understanding of how schedule performance of PHP is dynamically influenced by interrelationships of various risk variables. Also, it provides an experimental platform for simulating and analyzing schedule risks that significantly affect the schedule performance of the six-day cycle assembly of prefabrication housing production. Such critical schedule risks could be identified and managed prior to the implement of prefabrication housing production projects. Compared with traditional techniques, the hybrid dynamic model simultaneously considers macro and micro levels, thereby enabling project managers to gain a deeper insight into schedule management and acquire a multidimensional understanding of schedule delay. [ABSTRACT FROM AUTHOR]

Given the urgent need to enhance industry practices in a green, safe, and economical manner, facilitating the wider adoption of green procurement in building developments has been a major concern of the construction industry. This paper aims to provide insight into the factors that are important in enhancing green procurement in the construction process and to suggest recommendations for the effective adoption of green procurement through a questionnaire survey and expert interviews. The top three most significant factors identified are mandatory environmental regulations by the government, client requirements in tendering, and government and non-governmental organization requirements. The results of a factor analysis of 35 variables identify 10 underlying grouped factors for facilitating effective green procurement in Hong Kong's construction industry. The factor group “Regulations and standards of green procurement by the government” is the most significant, followed by “Life-cycle considerations and green construction technology” and “Executive management's commitments and requirements.” Efforts or initiatives undertaken by the community and the government on green procurement, such as competitions/awards, incentive schemes, and executives' green procurement commitments and requirements, are considered important in the green procurement process. The experts interviewed indicated that the government should take a proactive role in pushing green procurement adoption. Advanced construction IT (e.g., BIM) should be employed to stimulate the construction process to incorporate a green design approach and reduce waste. In addition, the establishment of a fully functioning green material market would help to promote the concept of green procurement and gradually lower material costs. Active engagement of suppliers to provide the performance details of construction materials is also necessary. [ABSTRACT FROM AUTHOR]

Conventional cast in-situ, precast and prefabricated construction are construction methodologies with increasing construction modularity. Construction methodologies and modularity, in turn, are determinants of sustainability onsite. This paper analyses 38 construction projects in Hong Kong, spanning a substantial period of twenty years for a systematic comparison on their construction methodology and sustainability performance. Specific indicators are developed to evaluate projects' sustainability performance with various levels of prefabrication. Environmental sustainability indices capture the carbon emissions and waste generation of projects. Social sustainability indices represent the human resource usage and overall accident rate of projects. Economic sustainability indices denote the project cost and time used for completion. Finally, a composite sustainability index is compiled. The study finds significant positive correlations between the percentage of prefabrication applied onsite and the sustainability attributes. Detailed project analysis further suggests that the highest sustainability performance was found in projects that adopted modular integrated construction methodology (MiC) as the primary construction methodology. • Construction methodologies, level of modularity and sustainability are interrelated. • Hong Kong's building construction has been increasingly modularised since the 1990s. • Construction-specific Composite Sustainability Index (CSI) used to evaluate sustainability onsite. • Level of prefabrication and construction sustainability are positively correlated. • Project adopted highest level of prefabrication (88%) achieved the highest CSI (84.4). [ABSTRACT FROM AUTHOR]

Building information modeling (BIM) has been leveraged to reduce manual efforts in the life cycle assessment (LCA) of buildings. However, data interoperability between BIM and LCA tools remains a significant challenge because of disparate data structures, leading to a deficiency in automatic data mapping methods. Few studies have adopted professional BIM and LCA tools to evaluate the embodied carbon of prefabricated buildings at multiple spatial levels. Thus, this paper developed a BIM-integrated LCA solution to automate the embodied carbon assessment of prefabricated buildings based on a five-level framework: material, component, assembly, flat, and building. The solution framework involved three modules: (1) BIM data preparation, (2) data extraction and integration, and (3) embodied carbon assessment. An Industry Foundation Classes (IFC)-enabled data transfer tool was developed to adapt BIM data to the LCA data structure automatically. A real-life prefabricated building in Hong Kong was used to validate the feasibility of the developed solution by comparing it with the traditional LCA method. Embodied carbon was reported in five levels. The cradle-to-end-of-construction embodied carbon of the case building was calculated as 561 kg CO 2 /m2, showing an acceptable 1% discrepancy with traditional LCA results owing to inevitable quantity differences between design and construction. The results also indicate a dramatical time reduction in the LCA modeling process from 729 min to 62 min, achieving a 91.5% efficiency improvement. It can thus practically increase practitioners' willingness to conduct LCA at an early design stage with quick feedback. The developed solution also extends the knowledge on automatic BIM-integrated LCA methodologically by addressing data interoperability using the IFC standard. Further, it provides systematic insights into the embodied carbon emissions of prefabricated buildings based on the five-level theoretical framework, guiding low-carbon designs for prefabricated buildings. • Embodied carbon assessment is automated by integrating BIM into LCA. • A tool named BIMToSimaPro is developed to automate data transfer from BIM to LCA. • Data interoperability between BIM and LCA is enhanced using the IFC standard. • A five-level framework is proposed for standardized embodied carbon evaluations. • The solution achieves consistent carbon results with a 91.5% efficiency improvement. [ABSTRACT FROM AUTHOR]

Aggregate is one of the most widely used construction materials in the world. Due to its global extensive use, extracting and transporting the huge amounts of aggregate result in significant environmental impacts and economic burdens. Therefore, selecting aggregate supply sources with low environmental impacts and material cost has become important, particularly for the regions with limited local resources. This study presents an integrated model based on life cycle assessment and multi-objective optimization to plan the optimal aggregate supplies from different sources. The results can help stakeholders formulate sustainable material supply strategies that minimize the associated environmental impacts and material cost while meeting the demand and emission targets. As over 70% of the aggregates used in Hong Kong are imported across the border, the aggregate industry of Hong Kong is used to elaborate the model development and optimization in this paper. The results show that the use of locally-recycled aggregate should be encouraged as it is beneficial from both environmental and economic perspectives. However, due to the lacks of public perception and engineering experience, the annual supply and consumption of recycled aggregate are still very low (i.e., 0.3% market share). The local industry should overcome the application barriers and increase the supply capacity of recycled aggregate in order to maximize the environmental and economic benefits. Furthermore, use of locally-quarried aggregates can help achieve emission reduction targets, but at the expense of increased material cost. The acceptable emission targets in Hong Kong can be achieved under current aggregate production capacities, but medium and ambitious emission caps are too stringent and require substantial improvements in local aggregate supplies. It is suggested that material availability from various sources should be considered when formulating the reduction targets. [ABSTRACT FROM AUTHOR]

Under the Kyoto Protocol's Clean Development Mechanism (CDM), countries worldwide co-operate on encountering climate change by emissions trading, which enables a win–win situation by effectively “regenerating” a cleaner environment in developing countries, whilst efforts in developed countries may still not meet their committed targets of carbon reduction. According to the CDM rules, energy efficiency improvement projects in the building sector are valid for emissions trading. Although the potential saving of energy is significant, there is only a limited number of building projects being registered as CDM projects. This paper explores the applicability of CDM in the building sector by reviewing the implementation of CDM and its advantages and disadvantages. Hong Kong was selected for an in-depth study due to its eligibility for CDM and yet non-starter status. According to a questionnaire survey supplemented by interviews with the stakeholders in this study, major hindrances such as the lack of financial incentive, inadequate knowledge about emissions trading and insufficient governmental support were found in potential CDM projects in the building sector. It is recommended that an inter-city emissions trading market covering mainland China and Hong Kong, and suitable emission reduction targets should be established and led by the government at the initial stage. By setting up an emission exchange centre, local emissions trading activities could be facilitated and job opportunities could be created. In addition to conducting emissions trading, Hong Kong may also contribute to emissions trading in the region by making use of its highly skilled professional services and efficient business environment. This study paves the way for a densely built city such as Hong Kong to benefit environmentally and economically from a cleaner region in its vicinity. [ABSTRACT FROM AUTHOR]

Hong Kong's construction industry is currently facing problems involving a rapidly aging workforce and labor shortage. With Hong Kong as the case study, this paper illustrates how existing residential buildings can be repaired and maintained using alternative materials, in order to minimize life-cycle labor inputs, costs, or carbon emissions. With different combinations of repair and maintenance materials, two of the three objectives can be achieved at any one time, when labor inputs, costs, and carbon emissions are set as separate constraints. With our methodology, we are able to identify materials that would cost the least, emit minimum carbon levels, and require the right levels of labor resources in relation to residential building maintenance. These can support the adoption of green technologies that suit the socio-economic and physical environment of Hong Kong. [ABSTRACT FROM AUTHOR]

Abstract: Tolo Harbour is an almost land-locked semi-enclosed sea inlet with a narrow outlet in the South China Sea. With the rapid growth in economic development and urbanization, evidence of increasing eutrophication is seen by the drastic increase in the severity and frequency of algae blooms, which are closely correlated to the excessive nutrient loading. The bottom waters in Tolo Harbour exhibit serious dissolved oxygen depletion. A co-ordinated sequence of pollution control activities are being undertaken by the Hong Kong Government. Technological advances can be utilized in effective water quality management in the coastal zone. This paper presents the application of a robust three-dimensional numerical eutrophication model, integrating hydrodynamics with water quality, for simulation of the algal growth dynamics and water quality processes. After calibration and verification, the tool is used to predict different eutrophication scenarios as well as the effectiveness of alternative management solution strategies. [Copyright &y& Elsevier]

Radiative sky cooling has attracted worldwide attention due to its passive cooling potential with zero energy input. Daytime cooling materials with outstanding spectral properties are developing rapidly. Using these new cooling materials as roof coatings can become one of the most prominent radiative cooling methods integrated with buildings. Current existing models and numerical tools are not able to incorporate the spectral selectivity of radiative cooling materials and local precipitable water vapor, thus failing to accurately predict roof thermal performance. To this end, the paper newly develops a spectral selectivity-based passive radiative roof cooling model to integrate full spectral properties of emerging cooling materials and consider precipitable water vapor-induced atmospheric radiation for precise evaluation of roof cooling performance. A field experiment was carried out to validate the developed model. The mean bias errors (MBEs) of the model in the prediction of rooftop temperatures were found less than 4.6%, verifying the sufficient accuracy of the new model in characterizing roof temperature variations. After validation, the developed model was used to investigate the potential benefits of radiative cooling as a rooftop strategy in the hot and humid region of Hong Kong. The whole year on-site weather data were collected as the model input. Compared to the baseline coating, the reductions in monthly cumulative roof thermal transfer values by applying a porous polymer cooling coating are 18.5–22.3, 33.7–40.5 and 2.9–3.5 kWh/m2 for residential concrete-based, industrial galvanized steel-based, and standard-compliant commercial multilayered roofs, respectively. For the above three roofs, the radiative cooling coating is able to save the annual roof-induced cooling electricity of 54.7–76.6, 97.4–136.4, and 8.8–12.2 kWh/m2, corresponding to the cooling cost saving of 71.8–100.5, 127.8–179.0, 11.5–16.0 HK$/(m2·yr), respectively. The new spectral selectivity-based radiative roof cooling model can be widely employed to accurately evaluate the utilization of daytime radiative coolers as a rooftop strategy in improving building thermal and energy performance. • Radiative roof cooling model incorporating spectral selectivity was newly developed. • The new model was validated by a field experiment with the MBEs within 4.6%. • Monthly RTTVs are reduced by 33.7-40.5 kWh/m2 for industrial metal roofs. • Annual roof-induced cooling electricity is reduced by 97.4-136.4 kWh/m2. [ABSTRACT FROM AUTHOR]

With continuous growth of economy and population in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), pressure of resources and environment is increasing. Therefore, sustainable green development of the GBA has attracted more and more attention from society. What is relationship among economy, resource and environment in the GBA? How to balance and analyze relationship between Green Economy and carrying capacity of resource and environment in the GBA? It is an important scientific question facing sustainable development of the GBA. This paper constructs a comprehensive ECC index system for economy - resources – environment with data from statistics yearbooks, calculates weights of indicators by entropy weight method and Ecological Carrying Capacity by TOPSIS model later using C++ programming language. It also carries out exponential smoothing for ECC prediction by SPSS software and coupling coordination of economy - resources - environment system in this area. The results show that the comprehensive ECC of the GBA has an upward trend from 2000 to 2017. In the next five years, Comprehensive Ecological Carrying Capacity of GBA will continue to increase linearly. In the process of GE development in the GBA, the environmental carrying capacity has steadily increased. There is a negative correlation between resource carrying capacity and GE but a positive correlation between environmental carrying capacity and GE. The coordination of economy - resource - environment system in the GBA has been continuously strengthened, and development of economy is advancing towards direction of high resource carrying capacity and high environmental carrying capacity. From perspective of comprehensive ecological carrying capacity to explore the world's two kinds of different political and economic system under comparative analysis of the urban Green Economy development. We found that the Macao and nine cities of the GBA are basically stable but Hong Kong is experiencing tortuous growth with dramatic changes. This research would provide theoretical reference for subsequent development direction of GBA and other bay areas. The future research can carry out deep simulation on the economy - resource - environment dynamics system model and formulate specific development plans. Government departments concerned with development of China's GBA should be committed to reducing pressure on resources, developing new energy and clean energy, while continuing to maintain even increase investment in environmental protection • An Eco-Carrying Capacity evaluation index system of the GBA was constructed to economy-resources-environment. • The comprehensive Eco-Carrying Capacity of the GBA were analyzed. • Coupling analysis of green economy and carrying capacity of resource and environment in the GBA was explored. • Provide comparative analysis under two different political and economic systems of the urban green economic development. [ABSTRACT FROM AUTHOR]

Noncooperative policies for transboundary pollution abatement are inefficient and ineffective, but cooperative policies for pollution abatement are seldom successful in regions that have different development goals and conflicting interests. In this paper, by extracting the key components that lead to the success of pollution reduction policies between Hong Kong (HK) and Guangdong, we aim to construct a general framework for cooperative environmental management. The incentive for and the dynamic trajectory, core measures, and outcomes of cooperative pollution abatement policies to address transboundary air pollution were studied using incrementalism analysis. The context that drives the abnormal increment of cooperative policies between HK and Guangdong was analyzed to determine the factors that affect the full cooperation process. The political union between HK and China is the main driving force for fostering cooperative policies in these two regions that have highly asymmetric economic development levels and pollution emission intensities. The factors for successfully designing cooperative pollution reduction policies are revealed from trust building, political support, efficient governance, precise policies, a rational cost-sharing mechanism, and detailed management and implementation plans. Innovative multi-level and cross-department governance, and an unequal but rational cost-sharing scheme sustain long-term cooperation. A general framework is derived from these empirical key components and constructed as a systematic approach to provide a guide for designing cooperation in transboundary pollution reduction for the sustainable management of cross-border natural resources in different regions with conflicts of interest. • An empirical framework of cooperative air pollution abatement model is constructed. • Factors contributing to foster cooperative polices is analyzed via incrementalism model. • Political support produces adequate institutional arrangements and precise policies. • A matching cost-sharing mechanism can catalyze and stabilize the cooperation model. • Multi-level and cross-department policies sustain long-term cooperation. [ABSTRACT FROM AUTHOR]

The 'zero carbon building (ZCB)' approach has been hailed as an innovative strategy for addressing climate change and achieving a low carbon society. There has been burgeoning research on the technical aspects of ZCBs. However, the aspect of stakeholder engagement, albeit imperative for zero carbon development, has been largely overlooked in the literature. This paper examines stakeholder knowledge, attitude and practice (KAP) with regard to ZCBs in a systems manner, employing a new KAP model that integrates ontology, axiology and epistemology as the theoretical lens. The research was carried out through a questionnaire survey and focus group discussions with multiple stakeholders in the building industry in Hong Kong, which is a typical example of a high-density city. The results indicate the generally ambiguous and inconsistent knowledge, relatively negative attitude, and poor practice of stakeholders towards ZCBs. The statistical analysis findings reveal that differentiation exists between different stakeholder groups as to their knowledge, and this highlights the significant role that explicit ZCB knowledge plays in creating a knowledge-induced attitude that favours changes in practice leading to zero carbon developments. The applicability of the developed KAP model is verified using the case of Hong Kong, enabling the dialectics and complexities of stakeholder KAP towards ZCBs to be further clarified. Practical implications are provided to enhance the knowledge, shape the attitudes, and encourage the practices of building towards zero carbon in future cities. • Knowledge, attitude and practice (KAP) with regard to ZCB are systematically examined. • A KAP model that integrates ontology, axiology and epistemology of ZCB is developed. • There are gaps between practitioners and researchers regarding knowledge of ZCB. • Stakeholders in HK have relatively negative attitude and poor practice towards ZCB. • Well-structured knowledge is key to induce attitude and practice favoring ZCB. [ABSTRACT FROM AUTHOR]

The introduction of green building certifications, on the one hand, can provide useful information for different stakeholders, such as developers and buyers, to evaluate "green" buildings' environmental performance. On the other hand, it gives rise to an issue resembling the "lemons" problem in New Institutional Economics, as sellers such as developers and owners of properties with poorer ratings do not disclose, or only partially disclose this information to the public. Given that a likely result of this "lemons" problem is lower average market prices that drive good products out of the market, this paper, thus, investigates this latent issue by assessing how the knowledge of these "lemons", referring to BEAM Plus-assessed buildings with an "Unclassified" rating, influences the price effect of BEAM Plus certification for other certified properties. Utilizing Bayesian Modeling, the findings indicate that should the "green lemons", or BEAM Plus-assessed properties with an Unclassified rating, be known, the price premium for other BEAM Plus-certified properties on Hong Kong Island and in the New Territories is higher than the scenario under which "green lemons" are not known as thus mistaken as non-assessed properties. This finding is akin to the traditional "lemons" issue which can result in the saturation of "lemons" in the market due to lower average prices that drive the good quality products out of it. This situation, we believe, is further exacerbated by the HKSAR government's GFA Concession Policy that grants GFA concessions to projects assessed under BEAM Plus regardless of rating, which is reflected by the high percentage of assessed projects with an "unclassified" rating. A higher degree of disclosure for these "lemons" compared to what is required now, according to the findings, could benefit potential investors and the BEAM Society alike. [ABSTRACT FROM AUTHOR]

Reducing building energy demand plays a vital role in addressing the depletion of energy resources and energy-related environmental issues. Previous research identified the statistical correlations between embodied energy and costs of buildings. However, little research has explored the relationship between operational energy and life cycle cost performance of buildings. This paper aims to investigate the energy efficiency and cost effectiveness of energy saving measures (ESMs) and thereby identify the relationship between operational energy and life cycle cost performance of high-rise office buildings. Five types of ESMs with 32 scenarios were examined using a real-life 35-storey office building in Hong Kong as a typical high-rise high-density city. The five types of ESMs are (1) increase temperature setpoint, (2) adopt daylighting sensors and light-emitting diode lamps (3) replace with low-e glass, (4) upgrade heating, ventilation and air conditioning system, and (5) implement on-site renewable energy. The results discover a U-curve relationship between operational energy saving and initial investment cost of the five ESMs. Moreover, the results show a significant linear correlation between operational energy saving and net present value of the ESMs. Such relationship reveals trade-off and synergy effects largely existing between opertional energy and cost performance in improving energy efficiency of high-rise offic buildings. This research suggests that increasing indoor temperature setpoint should be prioritised in lowering operational energy. The results are also discussed drawing on the findings of previous studies in other city contexts. This research contributes a novel life cycle perspective to future systematic research into building energy and economics. The findings are important to building designers in their decision-making of reducing buildings' operational energy consumption in a cost-effective way. • Cost effectiveness of different energy saving measures (ESMs) varies significantly. • U-curve relation is found between energy saving and initial investment of buildings. • Linear correlation is found between energy saving and net present value of building. • Variations in cost effectiveness of ESMs lead to the found energy-cost relations. • Cost effectiveness of renewable technology relies much on financial incentives. [ABSTRACT FROM AUTHOR]

The rapid growth of energy consumption in buildings has become an alarming threat to the climate. Various building-level energy saving measures have been studied and adopted to achieve energy efficiency. However, high-rise public residential buildings in subtropical climate as an important contributor to building-level energy consumption have received insufficient attention of research. The aim of this paper is to analyse the energy use of high-rise residential buildings in subtropical climate and examine the impacts of different energy saving measures for developing strategies for achieving very low-energy high-rise buildings. A typical high-rise (40-storey) public residential building in Hong Kong was selected as the case building, which has the energy use intensity of 106.6 kWh/m2 for the total building area and of 153.8 kWh/m2 for the area inside the residential units. The energy model of the case building developed using EnergyPlus software was carefully calibrated using metered energy use data and expert consultations adopting a systematic approach. Sensitivity analyses were then conducted using the parametric analysis tool jEPlus to quantify the impacts of different energy saving measures on energy use intensity reduction. It was found the measures in relation to human behaviours have the largest impact, followed by building service system efficiency and renewable energy. Building form and building envelope have the modest impact. The findings enhance the knowledge of subtropical high-rise public residential buildings' energy performance, and the developed and calibrated energy model could be used to explore more strategic energy saving measures in the long term. The quantified impacts of the measures should inform design decisions of low-energy housing production in high-rise sectors. • A 40-storey building is examined with energy use 153.8 kWh/m2 for residential area. • Energy model uses EnergyPlus software with sensitivity analyses tool jEPlus. • Behaviours have largest impact on energy use, then building services and renewables. • Building form and envelope have the modest impact on energy use reduction. • Systemic strategies are suggested for very low-energy high-rise residential buildings. [ABSTRACT FROM AUTHOR]

Urban rail system is a critical component of a smart and sustainable city. This paper applies the triple bottom line framework to assess Hong Kong's mass transit railway (MTR) performance. We collected data from MTR's annual reports and sustainability reports over the period 2008–2017. The data showed that MTR's urban rail system consumed 1,573 GW-hour (GWh) in 2017, up from 1,290 GWh in 2008. In terms of service capacity, MTR's urban rail system made 1.767 billion passenger-trips in 2017, up from 1.309 billon passenger-trips in 2008. The average passenger-km (pkm) travelled ranged from 10.4 to 11 km for city lines and from 28.4 to 29.5 km for airport express. The total pkm travelled by rail was 19.38 billion in 2017, up from 13.82 billion in 2008. Sustainability analysis showed that MTR's urban rail system had an efficiency of 0.076–0.093 kWh per pkm and produced 0.055–0.071 kg CO 2 -eq per pkm. Tobin's q value ranged from 0.638 to 1.043, suggesting that MTR's stock was undervalued in the capital market over the past decade. In terms of social performance, MTR's rail operations provided over 15 thousand jobs and handled 38.2 percent of public transport in 2017. • HK's urban rail handled 1.767 billion passenger-trips and consumed 1,573 GWh in 2017. • The total passenger-km travelled was 19.38 billion in 2017. • HK's urban rail system had an energy efficiency of 0.076–0.093 kWh per passenger-km. • HK's urban rail system emitted 0.055–0.071 kg CO 2 -eq per passenger-km. • The system's environmental and social performance has improved in the past decade. [ABSTRACT FROM AUTHOR]

Buildings contribute significantly to carbon emissions worldwide. Prefabrication is regarded as a cleaner production and sustainable construction approach, which has been utilized for public residential building construction in Hong Kong to achieve more productive, safer and higher-quality construction process with less negative impacts on the environment. Previous studies explored the life cycle carbon assessment of prefabricated buildings, but no unified embodied carbon assessment model or reporting format has been established in Hong Kong. This paper aims to contribute a better systematic understanding of the embodied carbon of prefabricated high-rise public residential buildings at different levels of unit of analysis and to identify appropriate measures for effective embodied carbon reduction. The research was carried out through a case study using a typical 30-storey public residential building in Hong Kong. The embodied carbon was calculated and reported at five levels of unit of analysis, i.e. material, component, assembly, flat and building. The cradle-to-end of construction embodied carbon of the case building was found to be 561 kg CO 2 /m2. Off-site activities accounted for 27.3% of the total embodied carbon, most of which were contributed by the production of façades (6.9%), bathrooms (6%), kitchens (4.5%) and slabs (4.2%). Embodied carbon from the manufacturing of materials was mainly attributed to concrete (59.2%) and steel (20.1%). The results reveal that the embodied carbon could be reduced significantly by adopting low carbon concrete such as replacing the ordinary Portland cement with blast furnace slag cement (with 22.8% reduction potential) and utilizing cement substitutes (25% pulverized fly ash (PFA)) (with 9.8% reduction potential). However, other measures were revealed to only impose marginal effect, such as decreasing the thickness of walls (with 1.9% reduction potential) and optimizing prefabrication rate (with 1.5% reduction potential), which was believed to be hindered by the high transportation carbon to and in Hong Kong. The developed five-level analytical framework paves the foundation for future standardization and benchmarking of prefabricated buildings' embodied carbon and the findings provide strategies for the most effective carbon reduction of prefabricated buildings in cities. • Embodied carbon of typical precast concrete housing blocks in HK is 561kgCO 2 /m2. • A five-level analytical framework is developed for benchmarking and standardization. • Embodied carbon can be reduced significantly by adopting low carbon materials. • The use of prefabrication helps to reduce embodied carbon of HK high-rise buildings. • To establish precast database at the five levels helps to achieve efficient comparisons. [ABSTRACT FROM AUTHOR]