Carbon footprint in building distributed energy system: An optimization-based feasibility analysis for potential emission reduction

The design of building energy systems is derived by load prediction data. Though many kinds of load forecasting methods have been developed over the decades, accurate load data cannot be acquired before heating/cooling demand happens in the energy system. Therefore, the ability of a building energy system to maintain good performance even when the heating/cooling demand curves diverge from the forecasted load curve is very important. In this discussion, such ability is defined as building energy system’s tolerance. The tolerances of three typical building cooling systems have been calculated and discussed combined with case studies. Eight cooling load curves are proposed from stochastic disturbances to simulate uncertainty and fluctuating cooling demand. The fluctuation ratio of each energy system’s annual return on investment is used as an evaluation indicator. The variation of the yearly economic efficiency of three cooling energy systems is compared, and the main influencing factors that affect the system’s tolerance are analyzed when the load curve changed. Combined with the tolerance evaluation of three typical building cooling energy systems, a simplified equation for tolerance evaluation of building energy systems is proposed and verified.

Cooking is one of the most important final household uses of energy. In Ecuador, the main energy carrier for this use is liquefied petroleum gas (LPG), which normally is supplied in bottles. LPG is imported and heavily subsidized for household consumption. The Government has promoted the use of electric induction stoves provided the hydropower generation capacity in Ecuador is projected to grow. Sustainability issues should be considered when changes in energy systems are analyzed. Life cycle assessment (LCA) is a methodological framework that can be used to quantify the environmental performance of any product or service, including energy systems. LCA can be used to quantify a range of environmental impact categories including Climate Change. The life cycle greenhouse gas emissions of a product or service are also known as carbon footprint. The objective of this study is to quantify the change in the carbon footprint of the household cooking system from the current based on LPG to the proposed based on electricity, and the cumulative energy demand (CED) for cooking with both technologies, using the LCA methodology, in order to provide a basis for the development of policies to reach the maximum mitigation of greenhouse gases (GHG). Several scenarios that consider different electricity generation mixes, cooking efficiency and emissions profile are studied. The functional unit for comparison was defined as “1 effective MJ”, which is 1 MJ transferred to the food during cooking. System boundaries for the assessment included resources extraction, processing, energy carrier supply, cooking and manufacturing of the stove. The results depend highly on the carbon footprint of the electricity system and, in a lesser extent, on the stove efficiency. Main results indicate that a carbon footprint mitigation occurs when changing the conventional LPG to a highly hydropower based cooking system, and that a higher life cycle energy efficiency is obtained when a high stove efficiency is considered. However, a greater carbon footprint may occur when cooking is performed using fossil derived power, which is a possible case when cooking is performed during peak demand of electricity.

The nitrogen and carbon footprints of ammonia synthesis in China based on life cycle assessment

Due to the high energy consumption of buildings, there is a demand for both economically and environmentally effective designs for building energy system retrofits. While multi-objective optimization can be used to solve complicated problems, its use is not yet widespread in the industry. This study first aims to develop an efficient and applicable multi-objective building energy system optimization method, used to dimension energy production and storage retrofit components in a case campus building in Lahti, Finland. Energy consumption data of the building are obtained with a dynamic energy model. The optimization model includes economic and environmental objectives, and the approach is found to function satisfactorily. Second, this study aims to assess the feasibility and issues of multi-objective single-building energy system optimization via the analysis of the case optimization results. The results suggest that economically beneficial local energy production and storage retrofits could not always lead to life cycle CO2-eq emission reductions. The recognized causes are high life cycle emissions from the retrofit components and low Nordic grid energy emissions. The performed sensitivity and feasibility analyses show that correctness and methodological comparability of the used emission factors and future assumptions are crucial for reliable optimization results.

Under the background of carbon peaking and carbon neutrality goals, the Ministry of Ecology and Environment, together with 15 national ministries and commissions, has formulated the Implementation Plan on Establishing a Carbon Footprint Management System, and it is urgent for traditional Chinese medicine(TCM) pharmaceutical enterprises to carry out research on carbon footprint accounting methods of related products. Based on the life cycle assessment(LCA) theory, taking mulberry leaf extract produced by a certain enterprise as an example, this study analyzed the carbon footprint of TCM extracts during the life cycle. The results show that for every 1 kg of product produced, the carbon emissions from the stages of raw material acquisition, transportation, and extract production are-20.569, 1.205, and 173.577 kgCO_2eq(CO_2 equivalent), respectively. The carbon footprint of the product is 154.213 kgCO_2eq·kg~(-1). In addition, the carbon emission is the highest in the production stage, in which the consumption of ethanol solvents makes the greatest contribution to the carbon footprint, accounting for 25.71%, more than one-fourth of the total carbon footprint. The second contribution was from the treatment process of TCM residues, accounting for 19.67%, closely followed by wastewater treatment(17.71%), the consumption of hot steam(17.43%), and drinking water(16.90%). The consumption of electric power and packaging materials has a smaller carbon emission of 2.58%. In particular, the carbon emission caused by the consumption of packaging materials is only 0.04%, which is negligible. The results of the study are expected to provide a reference for TCM enterprises to carry out research on the carbon footprint of products, offer ideas for collaborative innovation in reducing pollution and carbon emissions throughout the entire industry chain of TCM, and develop new quality productivity of modern TCM industry based on green and low-carbon manufacturing.

SUMMARY A regional energy system consists of diverse forms of energy. Energy-related issues such as utilization of renewable energy and reduction of greenhouse gas (GHG) emission are confronting decision makers. Meanwhile, various uncertainties and dynamics of the energy system are posing difficulties for the energy system planning, especially for those under multiple stages. In this study, an interval multi-stage stochastic programming regional energy systems planning model (IMSP-REM) was developed to support regional energy systems management and GHG control under uncertainty. The IMSP-REM is a hybrid methodology of inexact optimization and multi-stage stochastic programming. Not only can it handle uncertainties presented as intervals and probability density functions but also reflect dynamics of system conditions over multiple planning stages. The developed IMSP-REM was applied to a hypothetical regional energy system. The results indicate that the IMSP-REM can effectively reflect issues of GHG reduction and renewable energy utilization within an energy system planning framework. In addition, the model has advantages in incorporating multiple uncertainties and dynamics within energy management systems. Copyright © 2011 John Wiley & Sons, Ltd.

<div class="section abstract"><div class="htmlview paragraph">Considered one of the greenest forms of transport, the rail industry is at an exciting point pursuing several key initiatives to decarbonise its operations, assets, and supply chains. Therefore, having a brake shoe with a lower carbon footprint is essential for achieving the goals related to decarbonizing the operation, as it is a wear item. For this purpose, a carbon footprint measurement methodology was applied to the development of a friction material for railway brake shoes in order to reduce the carbon footprint generated in the production of the material, combining a sustainable material with greater durability in operation, thus reducing the total cost of ownership. In order to assess the advantages of the new product, a comparative analysis was carried out of the carbon footprint of the conventional shoe and the new railway shoe proposal, both used in the same application, considering the performance and environmental impact of each raw material and stage of the production process. This assessment was carried out by compiling and analyzing greenhouse gas emissions throughout the entire life cycle, from the extraction of raw materials, through all the links in its production chain to the gate, in accordance with ABNT ISO/TS 14067:2018. Performance was also assessed based on the AAR M-926 standard using a 1:1 scale inertial dynamometer capable of simulating the various operating conditions following the specifications of the Brazilian market. The comparative analysis showed that the new railway shoe is a more sustainable option, as it emits 43% less greenhouse gases than the conventional shoe (avoiding 4.7 kg of CO<sub>2</sub>e in the environment). The performance results also indicated a durability gain of 20% compared to conventional brake shoes.</div></div>

Mycoplasma hyopneumoniae is the primary causative agent of enzootic pneumonia, one of the most common bacterial pathogens affecting pigs and the main contributor to respiratory comorbidities. Infection with M. hyopneumoniae, commonly observed in growing pigs, results in decreased feed intake and an increase in the number of days to reach market weight. Based on extended days to market, pigs infected with M. hyopneumoniae will have a greater life cycle carbon emissions and water usage than that of non-infected pigs. However, the magnitude of additional carbon footprint and water use in pigs infected with M. hyopneumoniae has never been calculated. Therefore, the objective of this study was to estimate the potential variation in carbon emissions and water footprint generated by M. hyopneumoniae infected pigs. This study was conducted using data from previous publications on M. hyopneumoniae infected pigs in experimental and commercial conditions. The carbon footprint and water usage of pork production was obtained from the literature and was used as a baseline (3,470 kg of CO2 eq and 1,678 m3 water eq; both per 1,000 kg of pork carcass weight). The change in average daily gain was estimated and additional days on feed to reach market weight were used to calculate potential carbon and water impact for pigs infected with M. hyopneumoniae. The estimated carbon emissions and water usage of M. hyopneumoniae infected pigs increased in a range of 84.69 to 142.93 kg of CO2 eq/1,000 kg of pork carcass weight and 40.95 to 69.12 m3 eq/1,000 kg of pork carcass weight respectively, compared with the carbon emissions of non-infected pigs (Table 1). Results of this study showed an increased carbon footprint for M. hyopneumoniae infected pigs by 2 to 4% and water usage increased by 2.5 to 4.1% suggesting that the sustainability of pork production was negatively affected by this bacterial infection. Previous literature on the impact of controlling vaccine-preventable diseases has shown similar results for other swine respiratory pathogens. In addition, these data only included M. hyopneumoniae infected pigs, thus the effect of respiratory co-infections was not estimated and the impact on sustainability metrics may be greater than currently calculated. The application of sustainable practices in animal production, including disease prevention, is key to ensuring a secure food supply for future generations. The carbon and water footprints of swine production are measurements of sustainability, with average daily gain being an important factor.

Carbon emission energy management analysis of LCA-Based fabricated building construction

Environmental sustainability is a vital issue in the clothing industry due to a large percentage of greenhouse gas (GHG) emissions from clothing manufacturing to consumption. The main GHGs are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydro fluorocarbons (HFCs), per fluorocarbons (PFCs) and sulphur hexafluoride (SF6). Carbon dioxide is considered as the most significant greenhouse gas. The carbon footprint (CFP) of clothing supply chain reflects the GHG emissions throughout the life cycle of a product or activity, and CFP assessment is an important approach to assess GHG emissions. Polyester is one of the most widely used synthetic fibres in the world, but it is produced from non-renewable resources. In this study, a life cycle assessment (LCA) of a polyester T-shirt imported to Australia from China has been undertaken to examine the processes which cause GHG emissions across the life cycle. The results of the baseline model showed that consumer use phase contributes the highest CFP 30.35%, and second highest contributor is polyester fibre production process. Within the production phase, spinning is the highest contributor of CFP due to high electric energy demand. Within the consumer use phase, CFP is dominated by the washing process. The results of the model can be considered reliable comparing with other related studies.

Land, carbon and water footprints in Taiwan

Digital twin (DT) or so-called ‘building information model (BIM)’ has brought great revolution to the current building industry. Its applications to life cycle management of buildings and infrastructures can further increase the social and economic benefits. As a complete information model, a digital twin integrates the information of a project from different stages of the life cycle into a model, in order to facilitate better asset management and communicate through data visualizations with participants. This paper unprecedently introduces a digital-twin aided life cycle assessment to evaluate a subway station. Dadongmen subway station in Hefei was used as a case study. This new study benchmarks the cost estimation and carbon emission at each life cycle stage of the project. The cost in the construction stage of the project is the highest, accounting for 78% of the total cost. However, the amount of carbon emissions in the operation and maintenance is higher than the amount during the production of building materials, accounting for 67%. Among them, concrete only accounts for 43.66% of the carbon emissions of building materials, even though concrete was mainly used for constructing the metro station. Steel bar and aluminum alloy have carbon emissions of 29.73% and 17.64%, respectively. In addition, emerging risks of the subway stations can be identified. The digital twin has been used to illustrate vulnerability and potential solutions to emerging risks, and to assess the suitability through life cycle cost and carbon footprint. This initiative is relatively new to the industry. The new insight into life cycle assessment or LCA (especially carbon footprint over the life cycle) integrated with digital twin applications will enable sustainable development that will enhance resilience of metro railway systems globally.

Design Optimization of Hybrid Renewable Energy Systems for Sustainable Building Development based on Energy-Hub

As the demand for automotive materials grows more stringent in environmental considerations, it becomes imperative to conduct thorough environmental impact assessments of dual-phase automotive strip steel (DP steel). However, the absence of detailed and comparable studies has left the carbon footprint of DP steel and its sources largely unknown. This study addresses this gap by establishing a cradle-to-gate life cycle model for DP steel, encompassing on-site production, energy systems, and upstream processes. The analysis identifies and scrutinizes key factors influencing the carbon footprint, with a focus on upstream mining, transportation, and on-site production processes. The results indicate that the carbon footprint of DP steel is 2.721 kgCO2-eq/kgDP, with on-site processes contributing significantly at 88.1%. Sensitivity analysis is employed to assess the impact of changes in resource structure, on-site energy, CO2 emission factors, and byproduct recovery on the carbon footprint. Proposals for mitigating carbon emissions in DP steel production include enhancing process gas recovery, transitioning to cleaner energy sources, and reducing the hot metal-to-steel ratio. These findings offer valuable insights for steering steel production towards environmentally sustainable practices.

Governments, environmental groups and industry associations are reducing greenhouse gas emissions to insure environmental sustainability. Manufacturing plays an important role in economic development but is a main cause of global warming since production requires energy consumption. The supply chain leadership coalition has requested all members to publish their carbon emission data and to reduce emissions. In addition, the International Standard Organization (ISO) has legislated and published ISO14064 as an industrial guideline to control global greenhouse gas emissions. The British Standards Institution developed PAS2050 as the world's first government regulation to control a product's carbon footprint. Providing carbon labelling on products increases product appeals and sales revenues, but also increases manufacturing costs. This research aims to minimise a product's carbon footprint, while controlling its manufacturing cost during collaborative green product design and production planning. An economic input–output life cycle assessment approach is used to evaluate the carbon emissions of new products. The life cycle assessment identifies problematic carbon emissions within the supply chain. Based on the input and output data, the research applies system dynamics modelling to simulate and identify green product redesigns with cost-effective carbon footprints during manufacturing. The purpose of this research is to derive optimal means to reduce the carbon footprint for green product development and production. Finally, the paper uses the case of an electronic image projector to demonstrate the application of the methodology.