Search Results (22)

Identifying factors that influence the choice of Leadership in Energy and Environmental Design (LEED) certification strategies for existing office building projects in the United States is a pressing issue requiring attention as it will help LEED professionals select the optimal certification strategy for each project. In this context, a quantitative research methodology with purposive sampling was used in this study to evaluate the impacts of project/building characteristics in LEED for Existing Buildings version 4 (LEED-EB v4) gold-certified projects in the U.S. LEED-EB v4 project/building characteristics include the project size and the number of buildings built before and after the 1973 energy crisis. LEED-EB-certified projects include a score for Location and Transportation credit (LTc1, “alternative transportation”) and scores for Energy and Atmosphere credits (EAcs) (EAc6, “renewable energy and carbon offsets”, and EAc8, “optimize energy performance”). From 112 LEED-EB v4 projects, the two following groups of projects with specific achievements were selected: Group 1 (n₁ = 13), which included high achievements in LTc1 and low achievements in EAc6 and EAc8, and Group 2 (n₂ = 13), which included high achievements in LTc1, EAc6, and EAc8. Exact Wilcoxon–Mann–Whitney and Fisher’s exact 2 × 2 tests were used to estimate significant differences between the two groups. The results of the selection of LEED-EB-certified projects in Groups 1 and 2 were that Group 2 outperformed Group 1 in EAc6 and EAc8 (p < 0.0001), while there was no significant difference between Groups 1 and 2 in LTc1 (p = 0.199). As a result, Group 1 outperformed Group 2 in LEED-EB v4 project size (p = 0.017). Group 2 outperformed Group 1 in the number of LEED-EB v4 gold-certified projects in buildings constructed after the 1973 US energy crisis (p = 0.005). It is concluded that, when choosing a LEED certification strategy for existing office buildings in the United States, LEED professionals should consider the 1973 energy crisis and the size of the LEED project. Full article

The integration of sustainability standards and value engineering methods in public education projects is a significant concern, as it ensures the well-being and sustainability goals of students, lecturers, and employees. This study aims to enhance sustainability within public education campuses by utilizing value engineering processes that establish a balanced correlation between the available budget costs and the sustainability costs that affect educational objectives, strategies, and the overall sustainability of the environment. In order to evaluate the integration of value engineering and the sustainability rating system “LEED protocols” for schools, the study utilized HAP (Hourly Analysis Program) software to perform numerical analysis, with the objective of improving environmental efficiency and cost-effectiveness in school buildings from the perspective of both male and female students. By applying this approach to all engineering disciplines, systems, and materials involved in the project, the study achieved impressive results, including a reduction in energy usage by 53.67%, a cost reduction of 27.48% from the total project budget, and 13 points earned in credit C1 and credit C2 in the Energy and Atmosphere EA category in LEED 2009. These findings are of great importance for the planning and execution of construction projects, specifically in the context of educational infrastructure, and provide valuable insights into the construction and renovation of school buildings, which can be used to enhance the safety, functionality, and aesthetic appeal of these facilities. Full article

Over the past five years, Leadership in Energy and Environmental Design Commercial Interior version 4 (LEED-CI v4)-certified office projects have been intensively studied in the USA and China, but they have not yet been studied in the Mediterranean region. The purpose of this study was to explore office building certification strategies for LEED-CI v4-certified projects in the Mediterranean region. The study design included pairwise comparative analyses between Spain (number of projects (n) n₁ = 14), Türkiye (n₂ = 13), and Israel (n₃ = 11). Cliff’s δ and exact Wilcoxon–Mann–Whitney tests were used to process ordinal and discrete data, while the natural logarithm of the odds ratio and 2 × 2 Fisher’s exact tests were used to handle dichotomous data. It was found that Spain and Türkiye outperformed Israel in the Location and Transportation (LT) category due to their desire to reduce the use of private transport. Spain and Türkiye were ahead of Israel in the LTc5 “reduced parking footprint” credit (p = 0.008 and 0.0005, respectively). Israel outperformed Spain and Türkiye in the Energy and Atmosphere (EA) category due to the sum of all six EA credits (p = 0.086 and 0.010). Spain overtook Türkiye and Israel in the Materials and Resources (MRs) category due to Spain’s increased use of environmental product declarations. Spain and Türkiye were ahead of Israel in the following four MRs credits: MRc1 “long-term commitment” (p = 0.030), MRc2 “interiors life cycle impact reduction” (p = 0.037), MRc3 “building product disclosure and optimization—environmental product declarations” (p = 0.029), and MRc5 “building product disclosure and optimization—material ingredients” (p = 0.034). Spain, Türkiye, and Israel showed similarly low levels of achievement in the Indoor Environmental Quality (EQ) category (p ≥ 0.405). However, Spain and Türkiye outperformed Israel in the following two credits: EQc1 “enhanced indoor air quality strategies” and EQc2 “low-emitting materials” (p = 0.001 and 0.060, respectively). In parallel, Israel outperformed Türkiye in the EQc3 “construction indoor air quality management plan” (p = 0.026), and Israel outperformed Spain in the EQc8 “quality views” credit (p = 0.066). As a result, a pairwise comparison of the three Mediterranean countries showed that each country has a unique LEED certification strategy. Knowledge of the above green building strategies will be helpful for LEED professionals. Full article

The Leadership in Energy and Environmental Design for Existing Buildings (LEED-EB) version 3 (v3) and version 4 (v4) gold-certified office space certification strategies in Spain have not yet been studied. The two purposes of this study were to evaluate (1) the impact of high or low achievements in the energy and atmosphere (EA) “optimize energy performance” credit (EAc1 for v3 and EAc8 for v4) on the compensation strategy for LEED “compensation group” credits and (2) the impact of EAc1-v3 or EAc8-v4 on the monotonic change in LEED “compensation group” credits. Data on a total of 77 LEED-EB v3 and 43 LEED-EB v4 gold-certified office space projects were collected. In the v3 group, 26 LEED-certified projects had the highest EAc1 achievements (v3 group 1), and 26 LEED-certified projects had the lowest EAc1 achievements (v3 group 2). In the v4 group, 15 LEED-certified projects had the highest EAc8 achievements (v4 group 1), and 15 LEED-certified projects had the lowest EAc8 achievements (v4 group 2). The exact Wilcoxon–Mann–Whitney test and Fisher’s exact 2 × 2 with Lancaster’s correction test were used to estimate the difference between groups 1 and 2. Spearman’s rank-order correlation was used to assess monotonic change in LEED credits. The results show that v3 and v4 group 1 outperformed v3 and v4 group 2 in EAc1 and EAc8 (p < 0.0001, respectively). However, v3 and v4 group 2 outperformed v3 and v4 group 1 in “renewable energy” (EAc4 for v3 and EAc6 for v4, p = 0.0039 and 0.0088, respectively) and “building commissioning” (EAc2.2 for v3, p = 0.0015; EAc3 for v4, p = 0.0560, respectively). EAc1-v3 and LEED v3 “compensation group” credits showed a moderate negative correlation (r_s = −0.53 and p < 0.0001). EAc8-v4 and LEED v4 “compensation group” credits showed a strong negative correlation (r_s = −0.74 and p < 0.0001). As a result, increasing the share of renewable energy and performing building commissioning in LEED-EB v3- and v4-certified projects occurred only as a compensation strategy in response to the low achievement in the “optimize energy performance” credit. Full article

The aim of this study was to investigate strategies for the certification of environmentally friendly office buildings in Germany. A total of 39 LEED-NC gold-certified office space projects were ranked according to their “optimize energy performance” credit (EAc1) achievements from the energy and atmosphere (EA) category and divided into two groups: 13 projects (group 1) with the highest and 13 projects (group 2) with the lowest EAc1 achievements. Nonparametric statistics were used to evaluate the differences between groups 1 and 2. A two-stage nested analysis of variance test was used to evaluate the differences between the two groups in terms of their life cycle assessment (LCA). A comparison of the two groups showed that group 1 outperformed group 2 in the EA category (p < 0.0001). However, in the other LEED categories, the differences between the two groups were not significant (p ≥ 0.0761). As a result, group 1 outperformed group 2 in terms of overall LEED points (p = 0.0048). The LCA of EAc1 showed that group 1 enacted the lowest environmental damage when compared to group 2 (p = 0.0040). The environmental assessment of LEED-certified projects can help green building managers choose the most sustainable certification strategy. Full article

This research focuses on the fabrication and characterization of TAZ532-xNb composites, employing high-purity, micron-sized powders of Mg, Sn, Al, Zn, Mn, and Nb as the raw materials. These powders were subjected to a paraffin coating process aimed at mitigating oxidation. The formation of composites was achieved via hot pressing and was followed by surface preparation and analysis using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). An X-ray diffraction (XRD) study was conducted to identify the microstructural phases. Quantitative assessments including the theoretical density, actual density, and relative density were computed, and their fluctuations in relation to the increasing Nb reinforcement ratio were scrutinized. Furthermore, the mechanical attributes of the composites, such as hardness and tensile strength, were assessed via experimental procedures. The absence of oxygen-related peaks in the XRD patterns endorsed the successful execution of the paraffin coating technique and protective gas atmosphere during sintering. The detection of α-Mg, Mg₂Sn, MgZn, Mg₁₇Al₁₂, and Nb phases within the Nb-reinforced composite patterns authenticated the formation of the intended phases. Notably, the relative density values of the composites surpassed 95%, indicating efficient sintering. SEM results disclosed a densely packed microstructure, with Nb reinforcement particles evenly distributed along the grain boundaries, devoid of particle clustering or significant grain growth. These composites manifested exceptional wetting characteristics, which can be attributed to the employment of Mg alloy as the matrix material. EDS data confirmed the proportions of Nb within the composites, aligning with the quantities incorporated during fabrication. The composites showcased an increase in microhardness values with the escalating Nb reinforcement ratio, credited to the harder constitution of Nb particles in comparison to the matrix alloy. Concurrently, tensile strength showed a significant improvement with the increment in Nb reinforcement, while elongation values peaked at a specific Nb reinforcement level. The positive evolution of tensile strength properties was ascribed to the escalated Nb reinforcement ratio, grain size, and consequent higher sample densities. Full article

The purpose of this study was to explore green office building certification strategies in Shanghai. The 45 LEED-CI v4 gold-certified office space projects were sorted by energy and atmosphere credit (EAc6, optimize energy performance) into two groups: 15 projects with the lowest EAc6 achievement (Group 1) and 15 projects with the highest EAc6 achievement (Group 2). To reach the gold certification level in Group 1, high achievement in EAc6 is associated with low achievement in two indoor environmental quality credits (EQc2, low-emitting materials, and EQc8, quality views), while in Group 2, low achievement in EAc6 is associated with high achievement in EQc2 and EQ8. For the life-cycle assessment (LCA), the functional unit was designated as follows: production (P) stage: production of building materials needed to ensure the requirements of EQc2 and EQc8 for 1 m² of the building area; and operational energy (OE) stage: OE of 1 m² of the building area over 50 years of the building’s lifetime. For the OE stage, two fuel source scenarios were used: 71.07% coal + 28.08% natural gas + 0.81% wind power (WP) + 0.04% photovoltaic (PV) (Scenario 1) and 50% WP + 50% PV (Scenario 2). The results of the LCA (P + OE) showed that under Scenario 1, the LEED certification strategy in Group 1 was greener than that in Group 2. When using Scenario 2, no differences were found between the two groups. Full article

Over the last decade, it has been clearly shown that the same achievements in Leadership in Energy and Environmental Design (LEED) projects can lead to different life cycle assessments (LCAs). However, the problem of contradictory achievements in LEED and LCA has not yet been resolved. This study aimed to identify and evaluate different strategies for LEED projects using LCAs. Thirty-nine LEED projects with the same characteristics—location and transportation, rating system, rating version, certification level, and space type—were collected and sorted by their energy and atmosphere (EA) category, “optimize energy performance” credit (EAc6) achievement into three equal groups (EA_Low, EA_Medium, and EA_High, where each group includes 13 LEED projects) to minimize the influence of uncontrolled factors on the LEED project strategy. The author focused on two extreme groups with very different EAc6 credit scores: EA_Low (13 projects) and EA_High (13 projects). The groups were compared across LEED categories and credits. Wilcoxon–Mann–Whitney and Cliff’s $\delta$ test results showed that the EA_Low and EA_High groups are associated with high/low achievements in materials-related credits such as “interiors life cycle impact reduction”, “building product disclosure and optimization—material ingredients”, and “low-emitting materials”. As a result, the EA_Low and EA_High groups were reclassified into Energy_Low–Materials_High and Energy_high–Materials_Low certification strategy groups. In this context, LCAs were used to assess the differences between the two strategies. The results showed that if natural gas was used for operational energy (OE), the Energy_High–Materials_Low strategy showed lower environmental damage compared to the Energy_Low–Materials_High strategy ($p$ = 0.0635); meanwhile, if photovoltaic energy was used for OE, the Energy_Low–Materials_High strategy showed lower environmental damage compared to the Energy_High–Materials_Low strategy ($p$ = 0.0036). The author recommends using the LEED protocol and the LCA method in parallel to better reflect the environmental impact of different certification strategies. Full article

The threat of global climate change has encouraged the international community to pay close attention to the levels of greenhouse gases, such as carbon dioxide, in the atmosphere. China has the world’s largest metal smelting industry, which is a major energy-consuming and carbon-emitting industry. Thus, this industry’s low-carbon transition is of great significance. Carbon emission efficiency (CEE) is a key indicator for the metal smelting industry to prioritize sustainable development. This paper applies a three-stage data envelopment analysis model with undesirable outputs to estimate CEE for 30 provinces from 2005 to 2020 in China, and analyzes the influencing factors using a spatial Durbin model. The results show that the CEE level generally improved in all Chinese provinces during the sample period, but the average CEE in the eastern region was 1.05 compared to 1.07 in the western and central regions, with the latter two regions progressing faster in terms of low carbon production capacity. The national average Malmquist–Luenberger (ML) index demonstrates a significant increase in technical efficiency across regions in 2010 and 2017, peaking in 2017. The study also suggests that current green credit and environmental regulations are not effective in promoting CEE improvements in the metal smelting industry, and that existing policies should be modified. Moreover, the spatial regression results indicate that the cross-regional transfer of low-carbon production technologies in China is largely complete. This study provides a more objective evaluation of the CEE levels of metal smelting across China, providing the government with a new perspective to guide the green transformation of energy-intensive industries. Full article

This study aimed to identify different certification strategies for Leadership in Energy and Environmental Design Commercial Interior version 4 (LEED-CI v4) gold-certified office projects in California’s cities and to explore these certification strategies using life-cycle assessments (LCAs). The LEED-CI v4 data were divided into two groups: high- and low-achievement groups in the Location and Transportation (LT) category. The author identified two strategies for achieving the same level of certification across LEED-CI v4 projects: (1) high achievements in LT (LT_High) and low achievements in the Energy and Atmosphere (EA) category (EA_Low), and (2) low achievements in the LT category (LT_Low) and high achievements in EA (EA_High). The author adopted LT_High–EA_Low and LT_Low–EA_High achievements as functional units for LCA. Three alternatives were LT_High: typical bus, EA_Low: gas; LT_Low: typical car, EA_High: gas; and LT_Low: eco-friendly car, EA_High: gas, where a typical bus used diesel, a typical car used natural gas, an eco-friendly car used EURO5diesel, and natural gas was used as a building’s operational energy. The ReCiPe2016 results showed that the LT_High: typical bus, EA_Low: gas strategy was preferable from a short-term perspective, and the LT_Low: eco-friendly car, EA_High: gas strategy was preferable in a long-term and an infinite time perspective, while the LT_Low: typical car, EA_High: gas strategy continued to be the most environmentally damaging certification strategy for all the time horizons of the existing pollutants. Thus, it can be concluded that if there are alternative strategies for LEED certification, an analysis of their LCAs can be useful to refine the best sustainable strategy. Full article

A previous study (Pushkar 2021) showed a significant non-parametric correlation between the Optimize Energy Performance credit from the energy and atmosphere category (EAc7) and project size in Leadership in Energy and Environmental Design for New Construction and Major Renovations version 4 (LEED-NC v4) office space projects. However, in such an empirical analysis, there are at least two problems: the choice between parametric and non-parametric statistics, and the choice between the Wilcoxon–Mann–Whitney (WMW) and analysis of covariance (ANCOVA) non-parametric tests. This study aims to evaluate EAc7 credit achievement for different types of spaces in LEED-NC v4 projects. We show that, in order to evaluate the differences between two LEED data groups, (1) a non-parametric procedure is preferable to a parametric one, and (2) if there is Spearman’s correlation between EAc7 credit achievement and project size for the same LEED-NC v4 project, then Quade’s ANCOVA is preferable to WMW. The results of these tests show that, in two out of three cases, office space projects had better EAc7 credit achievement than higher-education spaces at the gold certification level and public assembly spaces at the silver certification level. Full article

Refined bio-crude production from hydrothermal liquefaction of algae holds the potential to replace fossil-based conventional liquid fuels. The microalgae act as natural carbon sequestrators by consuming CO₂. However, this absorbed CO₂ is released to the atmosphere during the combustion of the bio-crude. Thus, the life-cycle greenhouse gas (GHG) emissions of refined bio-crude are linked to the production and supply of the materials involved and the process energy demands. One prominent raw material is CO₂, which is the main source of carbon for algae and the subsequent products. The emissions associated with the supply of CO₂ can have a considerable impact on the sustainability of the algae-based refined bio-crude production process. Furthermore, the diurnal algae growth cycle complicates the CO₂ supply scenarios. Traditionally, studies have relied on CO₂ supplied from existing power plants. However, there is potential for building natural gas or biomass-based power plants with the primary aim of supplying CO₂ to the biorefinery. Alternately, a direct air capture (DAC) process can extract CO₂ directly from the air. The life-cycle GHG emissions associated with the production of refined bio-crude through hydrothermal liquefaction of algae are presented in this study. Different CO₂ supply scenarios, including existing fossil fuel power plants and purpose-built CO₂ sources, are compared. The integration of the CO₂ sources with the algal biorefinery is also presented. The CO₂ supply from biomass-based power plants has the highest potential for GHG reduction, with a GHG footprint of −57 g CO₂ eq./MJ refined bio-crude. The CO₂ supply from the DAC process has a GHG footprint of 49 CO₂ eq./MJ refined bio-crude, which is very similar to the scenario that considers the supply of CO₂ from an existing conventional natural gas-based plant and takes credit for the carbon utilization. Full article

Greenhouse gases from industrial activities have become a global problem. Emissions management is being developed to raise awareness of the importance of controlling pollution in general and atmospheric emissions in particular. In 2017, the deficit of the rights of issuance in the industrial sectors increased up to 8.3% (verified emissions in 2017 versus allocation in 2017). This trend will increase more at the end of Phase III due to a progressive reduction in allocation. Phase IV will be much more restrictive in allocating emission rights than Phase III. The extra cost of this deficit reinforces the need for industry in general to reduce CO₂ and for the paper industry to reduce GHG emissions and generate credits. Old factories are typically identified as sources of pollution in addition to being inefficient compared to new factories. This article discusses the possibilities offered by maintenance actions, whose integration into a process can successfully reduce the environmental impact of industrial plants, particularly by reducing the CO₂ equivalent emissions (CO₂-eq units henceforth CO₂) they produce. This case study analyzes the integration of maintenance rules that enable significant thermal energy savings and consequently CO₂ emissions reduction associated with papermaking. Managing Key Performance Indicators (KPIs), such as the amount of cold water added to the boiler circuit and the conditions of the air blown into the dryer section hood, can be used as indicators of CO₂ emissions generated. The control of the water and temperature reduces these emissions. A defined measure—in this case, t CO₂/t Paper—indicates an achievement of a 21% reduction in emissions over the past 8 years. Full article

This study aims to explore the influence of project size on the Energy and Atmosphere (EA) credits in the Leadership in Energy and Environmental Design for New Construction and Major Renovations (LEED-NC) version 3 (v3) in California and version 4 (v4) in the United States (US) in office-type projects. If the relationship between the ordinal data of EA credits and project size changed monotonically, then Spearman’s correlation coefficient was used. If the relationship between the EA credits ordinal data and project size did not change monotonically, then the EA credit data were divided into below and above the median project size groups, and, as a consequence, the Cliff′s δ effect size and exact Wilcoxon–Mann–Whitney tests were used. If the EA credits were binary or dichotomous data, then the natural logarithm of the odds ratio and Fisher’s exact 2 × 2 test with Lancaster’s mid-p-value were used. The results showed that the performance of operational energy, enhanced the refrigerant management and that the renewable energy credits in LEED-NC v3/v4 Certified, Silver, and Gold projects depended on the project size. We concluded that the LEED project size is an important variable for developing LEED-NC strategies for office-type projects. Full article

Reducing deforestation and forest degradation presents a climate-change mitigation opportunity that is critical to meeting the Paris Agreement goals, and to achieving reductions in the atmospheric concentrations of greenhouse gases (GHGs). Reducing Emissions from Deforestation and Forest Degradation (REDD) provides developing countries with results-based financial incentives for reducing deforestation and forest degradation through either non-market payments (payments without generation of carbon credits), or market-based mechanisms (carbon credits). REDD credits have been recently accepted to be used in offsetting programs (e.g., CORSIA) and are being considered under Article 6. However, various publications have questioned whether carbon credits from REDD should be accepted under market-based mechanisms, and have identified issues regarding their environmental integrity and their ability to offset emissions from other sectors. In recent years, REDD implementation has moved from the project level to the national or subnational (jurisdictional) level, and is addressing some of the concerns that have been raised for project-level interventions regarding the robustness of baselines and leakage, for example. In this paper we compare the environmental integrity of credits from REDD programs with that from on-grid renewable energy projects by examining aspects related to permanence, additionality, baselines, uncertainty, and leakage. We show that the environmental integrity of emission reductions sourced from REDD programs has unique strengths, and that those sourced from renewable energy projects have weaknesses of their own. Probably due to a lack of understanding of the respective weaknesses and strengths of these two sources of credits, the emission reductions from REDD programs have been historically questioned and subjected to a level of scrutiny that has not been made with emission reductions from other sectors, such as renewable energy projects. Recognizing the strengths and weaknesses of emission reductions from both types should help decision makers and carbon standards recognize the high quality of emission reductions from REDD programs, and rationalize the current requirements or restrictions imposed. Full article