Life Cycle Assessment of Plywood Manufacturing Process in China

Emerging Engineered Wood for Building Applications

The building sector, including building operations and materials, was responsible for the emission of ∼11.9 gigatons of global energy-related CO₂ in 2020, accounting for 37% of the total CO₂ emissions, the largest share among different sectors. Lowering the carbon footprint of buildings requires the development of carbon-storage materials as well as novel designs that could enable multifunctional components to achieve widespread applications. Wood is one of the most abundant biomaterials on Earth and has been used for construction historically. Recent research breakthroughs on advanced engineered wood products epitomize this material's tremendous yet largely untapped potential for addressing global sustainability challenges. In this review, we explore recent developments in chemically modified wood that will produce a new generation of engineered wood products for building applications. Traditionally, engineered wood products have primarily had a structural purpose, but this review broadens the classification to encompass more aspects of building performance. We begin by providing multiscale design principles of wood products from a computational point of view, followed by discussion of the chemical modifications and structural engineering methods used to modify wood in terms of its mechanical, thermal, optical, and energy-related performance. Additionally, we explore life cycle assessment and techno-economic analysis tools for guiding future research toward environmentally friendly and economically feasible directions for engineered wood products. Finally, this review highlights the current challenges and perspectives on future directions in this research field. By leveraging these new wood-based technologies and analysis tools for the fabrication of carbon-storage materials, it is possible to design sustainable and carbon-negative buildings, which could have a significant impact on mitigating climate change.

Environmental impact comparison of wheat straw fast pyrolysis systems with different hydrogen production processes based on life cycle assessment

This study aimed to evaluate the environmental impact of 1000 kg h^-1 wheat straw to produce biofuel via fast pyrolysis with three different hydrogen production processes by the life cycle assessment (LCA) based on Chinese Life Cycle Database (CLCD). The primary energy depletion (PED), global warming potential (GWP), abiotic depletion potential (ADP) and respiratory inorganics (RI) impact categories of 1 MJ biofuel produced were employed for comparison. In case 1, the hydrogen was derived from natural gas steam reforming, and all the bio-oil was hydrotreated to produce the biofuel. In case 2, a part of the aqueous phase was reformed to produce hydrogen, whereas the remaining bio-oil was hydrotreated to produce biofuel. In case 3, all the aqueous phase of bio-oil was reformed to produce hydrogen, a part of hydrogen generated by reforming was used to oil phase hydrotreated and the excess hydrogen was considered as a co-product. Our results show that the PED, GWP, ADP and RI of case 3 are 0.1355 MJ, -17.96 g CO_2eq., 0.0338 g antimony_eq and 0.0461 g PM2.5_eq.. Compared with conventional diesel, the PED, GWP, ADP and RI of case 3 were reduced by 89.81, 117.44, 1.74 and 85.03%, respectively. The results of sub-process contribution analysis and sensitivity analysis suggested that the electricity consumption for the bio-oil production has the maximal effect on the total PED, GWP and RI of case 3, whereas the amount of fertilizers in the biomass production sub-process has the maximal effect on the total ADP.

Sustainability Assessment Methodologies: Implications and Challenges for SIDS

Over the past years, an increasing number of initiatives was considered to address emerging global sustainability issues. Sustainability assessment tools were the most commonly applied methodologies towards measuring sustainability performance. There are a number of assessment tools and techniques for sustainable development. This article aims at identifying the various sustainability assessment tools at country level taking into consideration the integration of environmental, economic, and social dimensions. The target of this paper is to compare the various sustainability measurement techniques and their characteristics using evaluation criteria. The outcome of this analysis is used to direct and clarify researchers and practitioners on sustainability assessment at country level, more specifically in developing countries. The focus of the paper rests on the Brundtland Report definition of sustainable development. The work was carried out using a bibliometric analysis approach based on Web of Science platform from the period 2000 to 2020. There was tremendous works which were conducted on sustainability assessment during the last two decades. The comparative analyses show the research gap among the various tools with respect to the criteria they satisfied. The research discussion suggests that a sustainability assessment framework for Small Island Developing States (SIDS) is identified as a future research direction.

Environmental benefits of soy-based bio-adhesives as an alternative to formaldehyde-based options

The restrictions imposed on the use of formaldehyde in wood panel adhesives have been the driving force behind the development of formaldehyde-free resins for the manufacture of wood products. Considering as a boundary condition the idea that the use of fossil-based raw materials should be replaced by biological options, there is growing interest in the environmental assessment of different alternatives for soy-based adhesives, as possible options to replace commonly used synthetic resins. This report includes the environmental profiles of soy-based adhesives taking into account the life cycle assessment (LCA) methodology. In addition, in order to increase their potential to replace synthetic resins, a sensitivity analysis of the main contributors to environmental damage was performed, thus giving an open guide for further research and improvement. This study aims to provide innovative alternatives and new trends in the field of environmentally friendly bio-adhesives for the wood panel industry.

Life Cycle Assessment of Complex Forestry Enterprise: A Case Study of a Forest–Fiberboard Integrated Enterprise

The complex forestry enterprises incorporate the production activities of different links in the value chain of forest products and should be the mainstay for the sustainable forestry production of China in the foreseeable future. This case study was carried out and main data were collected in a forest–board integrated enterprise of South China. A life cycle model using the impact 2002+ method was applied to identify the resource consumption and environmental impacts of different production stages along the industrial chain. This study incorporates the calculation of carbon sequestration per unit output into the standard LCA to evaluate the effect of the forest cultivation stage. The objective of this study is two-fold. The first objective is to gain a better understanding of the environmental impacts of the complex forestry enterprises. The second objective is to put forward environmental management suggestions for the identified hotspots along the forest value chain. Factors affecting the environment include carbon sequestration and seedlings, electric power, and the use of wood fuel. Improvement suggestions are put forward from three perspectives: Changing the type and application method of fertilizer, reducing electric power consumption, and reducing wood fuel consumption.

Environmental Impacts of Building Construction Using Cross-laminated Timber Panel Construction Method: A Case of the Research Building in Kyushu, Japan

In Japan, there has been an increase in the number of buildings built using cross-laminated timber (CLT) in order to utilize the abundant forest resources in the country. However, no studies have evaluated the environmental impact of the construction of CLT buildings in Japan. This study evaluates the environmental impacts from the start of construction to the completion of a real CLT building in Kumamoto city, Kyushu region, southern Japan. We investigated the input of the materials and energy used in the construction of the building. The environmental impact categories evaluated include climate change, ozone layer depletion, eutrophication, acidification, and photochemical oxidation. We found that the concrete used for the foundations, and the cement-based soil stabilizer used for ground reinforcement accounted for 42% of the greenhouse gas (GHG) emissions. The construction site was previously used as a seedbed field, necessitating ground reinforcement. Furthermore, the large foundations were designed in order to raise the low height of the wooden structure from the ground level. Developing and applying methods with lower environmental impacts for ground reinforcement and building foundations is recommended. In addition, we found that by using biomass-derived electricity in CLT manufacturing, the environmental impacts of CLT manufacturing could be reduced, thus reducing the environmental impacts of the entire building. The biogenic carbon fixed in the wooden parts during the building usage accounted for 32% of the total GHG emissions of the building construction. Since this biogenic carbon will be released to the atmosphere at the end-of-life stage of the building, a long-term usage of the CLT buildings and/or reuse of the CLT is recommended.

Environmental Footprints of High-Speed Railway Construction in China: A Case Study of the Beijing-Tianjin Line

The environmental footprints of China’s high-speed railway (HSR) have attracted much attention nationally and internationally. Although there is some research focusing on CO₂ emissions, a comprehensive environmental impacts assessment of HSR construction is still lacking. In this study, the emissions of the Beijing–Tianjin intercity HSR line was calculated using a hybrid input–output life cycle assessment method to quantify the environmental impacts of HSR throughout its construction. The environmental footprints during the construction stage were analyzed in terms of different subsystems and sectors. The results showed that bridges contribute the largest environmental footprints at approximately 60%, followed by rail and electric multiple unit (EMU) systems. The top three sectors that contribute to pollutant emissions are the metal smelting and rolling industry, transport equipment manufacturing, and non-metallic mineral production. CO₂ and NO_x are the major pollutants directly emitted by site equipment operation. More chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), and petroleum are emitted in EMU production than in rail construction, while NH₃-N is emitted more in rails instead. Cd, Pb, As, and Hg are the significant pollutants in the metal smelting and rolling industry, whereas Cr, Cu, and Zn are the main heavy metal emissions in the transport equipment manufacturing sector. Heavy metals are the main types of environmental footprints in bridges, stations, and electric systems. Water pollutants are the main environmental impacts for rail and EMU systems, and the emissions of air pollutants are significant in subgrades. The production efficiency of upstream materials, desulfurization and denitration in fossil combustion, and the length of the bridge construction should be considered for an HSR under construction, in order to become environmentally friendly and sustainable.

Life Cycle Assessment of Forest-Based Products: A Review

Climate change, environmental degradation, and limited resources are motivations for sustainable forest management. Forests, the most abundant renewable resource on earth, used to make a wide variety of forest-based products for human consumption. To provide a scientific measure of a product’s sustainability and environmental performance, the life cycle assessment (LCA) method is used. This article provides a comprehensive review of environmental performances of forest-based products including traditional building products, emerging (mass-timber) building products and nanomaterials using attributional LCA. Across the supply chain, the product manufacturing life-cycle stage tends to have the largest environmental impacts. However, forest management activities and logistics tend to have the greatest economic impact. In addition, environmental trade-offs exist when regulating emissions as indicated by the latest traditional wood building product LCAs. Interpretation of these LCA results can guide new product development using biomaterials, future (mass) building systems and policy-making on mitigating climate change. Key challenges include handling of uncertainties in the supply chain and complex interactions of environment, material conversion, resource use for product production and quantifying the emissions released.