Life Cycle Carbon Research Articles

Optimization on hybrid energy vessel routing and energy management for floating marine debris cleanup

Marine debris pollution is increasingly threatening the marine environment and human health. The most effective way to remove macro-debris floating offshore is to send vessels to collect it. We employ advanced remote sensing technology to locate debris and vessels equipped with a hybrid energy system composed of photovoltaic, battery packs and diesel to collect debris. In order to establish an effective collection mechanism in an economical and eco-friendly manner, we propose a two-stage optimization approach of vessel routing and energy management strategy. In the first stage, a mixed integer linear programming is to minimize the vessel travel time for removing debris, which is reduced to the vessel routing problem with time window considering discrete speed. Advanced remote sensing technology and trajectory prediction software are used to locate debris at sea. An adaptive large neighborhood search algorithm with pheromone heuristic rule is tailored to solve the problem. A mixed integer linear programming model is proposed to optimize the power flow for the hybrid energy system in the second stage. The objective is to minimize the total cost, taking into account of the constraints of power load balance, battery charge and discharge state and output limit of each energy source. The proposed models and algorithm are validated by a group of numerical examples with different sizes. Compared with VRP Spreadsheet Solver and CPLEX solver, our proposed algorithm not only has obvious advantages in both time and results, but also has cubic function fitting property in time complexity within 100 data. We also compare the optimal power flow and total cost under three illumination intensity scenarios and analyze the optimal power flow for each energy. We find that in optimal power flow, diesel can charge the battery only if it supplies power to vessel load. The results show that compared with the pure diesel system, the hybrid energy system has an overwhelming advantage in terms of total cost and carbon emissions, which can be reduced by 65.78% and 82.69%, respectively. We also find no change in the cost savings of hybrid vessels when considering battery and diesel life-cycle carbon emissions.

Life cycle dynamic sustainability maintenance strategy optimization of fly ash RC beam based on Monte Carlo simulation

Small and medium span bridges account for 86% of the bridges in China, and maintenance is necessary to ensure their safety and serviceability. The infrastructure sector causes substantial CO2 emissions, and it is one of the most polluting sectors. Fly ash (FA) is often used in bridges to reduce CO2 emissions. Moreover, the lack of temporal information is an important limitation of the life cycle CO2 assessment of bridges. Taking the upper structure of small and medium span bridges as the research object, this paper proposes a Monte Carlo simulation-based life cycle multi-objective dynamic maintenance strategy optimization model to analyze the life-cycle carbon emissions, costs, and life cycle reliability of different preventive maintenance (PM) and essential maintenance (EM) methods of FA reinforced concrete (RC) beams. Considering the continuous effect of carbon emissions and the net present value of the cost, the time effect of carbon emissions and costs of maintenance and reinforcement at different times is analyzed. Through 50,000 simulations of the case beam, the parameter characteristics of different optimal reinforcement schemes and the relationship between the reliability, life cycle CO2 emissions, and costs are studied. When introducing the discount rate, the essential maintenance with higher carbon emissions and costs has a marginal effect, i.e., the longer that future carbon emissions and costs occur, the smaller the net present value. The proposed method is demonstrated to be effective at supporting decision making for bridge managers. It would be helpful for identifying the effectiveness of PM and EM, selecting optimal maintenance time interval, and providing a rational estimate of the CO2 emissions and costs of bridges.

Life-Cycle CO2-Equivalent Emissions of Cars Driven by Conventional and Electric Propulsion Systems

As an important trend in the automotive industry, electrification of propulsion systems has potential to significantly reduce greenhouse-gas emissions of the transportation sector. Whereas electric vehicles do not produce exhaust emissions during driving, the impact of electricity provision for charging batteries, as well as the impact of vehicle production play an essential role in a holistic consideration of the carbon footprint. The paper introduces a comprehensive evaluation of greenhouse gas-emission-related factors of cars driven by different propulsion technologies, considering the entire product life cycle. This comprises vehicle production, including battery system, electric powertrain and other relevant components, the car’s use phase under consideration of different electricity mixes and the end-of-life phase. The results of the study give insights of influencing factors on life-cycle-related carbon-dioxide-equivalent emissions of cars driven by combustion engines, hybrid powertrains and battery-electric propulsion systems. In addition, a comparison of actual mass-production cars is made and the total life-cycle carbon footprints are discussed under different boundary conditions of electric power supply. In this way, the article comprehensively introduces an automotive life-cycle assessment and provides fundamental information, contributing to an objective discussion of different propulsion technologies.

Consumer understanding and evaluation of carbon-neutral electric vehicle charging services

Electricity from renewable and/or nuclear sources (“carbon–neutral electricity”) can be used for charging plug-in electric vehicles in order to significantly reduce their lifecycle carbon emissions. However, little is known about how carbon–neutral charging services (CNCS) for electric vehicles must be designed to attract consumers’ interest. Therefore, we conducted a survey including an Adaptive Choice-based Conjoint Analysis to investigate private consumers’ awareness and preferences for different service attributes of CNCS, specifically the energy source, regionality of generation, additionality, balancing period, charging flexibility, and price. The online survey in Germany of 510 private consumers who were interested in electric vehicles shows that awareness is highest for the energy source and regionality. Behind price, these are also the second and third most important attributes when choosing a CNCS. Even though, on average, there seems to be a link between the awareness for an attribute, its importance and consumers’ willingness to pay, this link proves to be non-significant for individual respondents. In conclusion, providers of CNCS could prominently advertise the attributes consumers are most aware of (i.e., the energy source and regionality of generation). Explaining the less-known, and therefore deemed unimportant, attributes (i.e., additionality, balancing period, and charging flexibility) to consumers could be difficult and costly for providers. From a system perspective, however, more convincing explanation efforts could lead to an increased use of renewables and enhanced system reliability. This raises the challenge for policymakers to create a framework which is both advantageous for the energy system and attractive to consumers. Government-set standards for charging tariffs may be a viable option.

Refurbish or replace? The Life Cycle Carbon Footprint and Life Cycle Cost of Refurbished and New Residential Archetype Buildings in London

The environmental performance of existing buildings can have a major role in achieving significant reductions in CO2 emissions: In the UK, around 75% 2050's housing stock has already been built. While building performance improvement efforts mostly focus on operational performance, buildings environmental impact is the result of processes that occur throughout their life cycle.To achieve significant emission reductions in an economically viable way, this study uses Life Cycle Performance approaches to carry a cross-comparison between the refurbishment and replacement of two housing archetypes in London: mid-terrace-house and a bungalow. Specifically, the study integrates Life Cycle Carbon Footprint (LCCF) and Life Cycle Cost (LCC) protocols (EN 15978:2011 and BS ISO 15686–5), thermal simulations (EnergyPlus), building generative design framework (PLOOTO - Parametric Lay-Out Organisation generator) and mathematical optimisation algorithms (NSGA-II).Results show that the optimal refurbishment archetypes generally performed better than replacements (Refurbishments LCCF ranges between 1,100 and 1,500 kgCO2e/m2 and LCC 440-680 £/m2, compared to that of the replacements scenarios, ranging 1,220-1,850 kgCO2e/m2 and 550-890 £/m2). The study also highlights benefit of incentivising re-use to achieve quicker emissions reductions. The study lastly discusses a range of embodied and operational performance issues.

Towards low-carbon cities through building-stock-level carbon emission analysis: a calculating and mapping method

• A bottom-up method is proposed to calculate and map carbon emissions from urban building stock. • Building types and geometry are extracted to derive life cycle carbon emission inventories. • The calculation result is verified with a modified top-down method. • The method improves calculation accuracy and facilitates low-carbon urban planning. Building stock represents the primary source of urban carbon emissions. However, the amount and spatial distribution of building-stock-level carbon emissions remain unclear when formulating detailed carbon emission reduction goals for cities. In present study, a bottom-up method was established for calculating and mapping carbon emissions from urban building stock, which involves: (1) using inventory data to derive an aggregated reference model for calculating urban building carbon emissions and sinks with a building life cycle assessment model and a building archetype method; and (2) mapping and assessing carbon emissions from building stock to support low-carbon urban planning. The method was applied in Xi'an, China. The embodied carbon emissions from building stock in Xi'an were calculated as 4.13 million tCO 2 e·a –1 , the operational emissions as 20.45 million tCO 2 e·a –1 , building and natural carbon sinks as 0.067 million tCO 2 e·a –1 and 0.014 million tCO 2 e·a –1 , respectively. The method was validated with municipal statistical data for Xi'an. In addition, carbon emissions from urban building stock were mapped to identify carbon reduction hot spots. The proposed method allows municipalities to assess the environmental performance of urban building stock and urban planning schemes, thereby supports the sustainable development of cities.

A framework for specifying low-carbon construction materials in government procurement: A case study for concrete in a new building investment

There are numerous strategies that can be used to reduce the embodied carbon footprint of real property investments, many of which can be accomplished for no additional cost and with minimal performance impacts. This study aims to propose the incorporation of the life cycle carbon quantification into the government procurement of real property process in order to reach out to low-carbon durable and sustainable structures as a theoretical contribution. As a practical contribution, an integrated embodied carbon measurement application is developed in a building information model (BIM) environment to act as a decision making tool in a government office building as a case study. It supports updating procurement policies and procedures to request construction materials with lower embodied carbon in construction. Analysis of concrete assembly groups in the case study along with determination of volume of concrete in each assembly is conducted to devise a reasonable list of elements to be considered for low-carbon concrete compliancy based on an industry average benchmarking approach. Considering the numerous concrete vendors that supply concrete products to a given region, a novel concrete embodied carbon measurement approach is proposed where cradle-to-construction impacts were accounted for. The outcome of the proposed integrated tool showed the procurement of concrete mix design from one specific nearby facility resulted in more efficient GHG reductions and the results showed especially the significance of considering transportation impacts of delivering ready-mixed concrete elements to the project site.

The Renewable Hydrogen–Methane (RHYME) Transportation Fuel: A Practical First Step in the Realization of the Hydrogen Economy

The permanent introduction of green hydrogen into the energy economy would require that a discriminating selection be made of its use in the sectors where its value is optimal in terms of relative cost and life cycle reduction in carbon dioxide emissions. Consequently, hydrogen can be used as an energy storage medium when intermittent wind and solar power exceed certain penetration in the grid, likely above 40%, and in road transportation right away, to begin displacing gasoline and diesel fuels. To this end, the proposed approach is to utilize current technologies represented by PHEV in light-duty and HEV in heavy-duty vehicles, where a high-performance internal combustion engine is used with a fuel comprised of 15–20% green hydrogen and 85–89% green methane depending on vehicle type. This fuel, designated as RHYME, takes advantage of the best attributes of hydrogen and methane, results in lower life cycle carbon dioxide emissions than BEVs or FCEVs and offers a cost-effective and pragmatic approach, both locally as well as globally, in establishing hydrogen as part of the energy economy over the next ten to thirty years.

Research on carbon emissions of urban residents’ three types of dining based on the whole life cycle

Abstract Following the promulgation and implementation of China’s ‘carbon peak’ and ‘carbon neutrality’ policies, the evaluation of the carbon footprint of the domestic catering industry is particularly important. Currently, comparative studies on the life-cycle carbon footprint of different common dining styles, such as home cooking, restaurant dining and takeaway, are scarce. Focused on three dining methods, this paper involved in-depth research on carbon footprint of the whole life cycle from the perspectives of whole industry and specific dish. The carbon footprint contribution of each stage of three different dining ways is obtained from the four stages, namely, the stage of upstream raw materials and manufactures, the stage of platform empowerment, the stage of consumer dining and the stage of waste treatment. The study found that the carbon emissions of the three dining ways in the overall industry analysis were canteen (2.9564 kgCO2e/per person) > takeaway (2.4821 kgCO2e/per person) > home cooking (2.2778 kgCO2e/per person); and the carbon emissions of honey sauce fork-fired were canteen (6.5843 kgCO2e/per person) > home cooking (6.4721 kgCO2e/per person) > takeaway (5.6718 kgCO2e/per person). The production of raw materials and products is the largest stage of carbon emissions among the three dining ways. Besides the carbon emissions of raw materials, the storage and cooking of food products are the unit processes with large carbon emissions. According to the results of sensitivity analysis, traffic travel mode is an important factor affecting the carbon footprint of canteen food. The above research can provide effective basis and data support for policy formulation.

Life Cycle Assessment of Battery Electric and Internal Combustion Engine Vehicles Considering the Impact of Electricity Generation Mix: A Case Study in China

Battery Electric Vehicles (BEVs) are considered to have higher energy efficiency and advantages to better control CO2 emissions compared to Internal Combustion Engine Vehicles (ICEVs). However, in the context that a large amount of thermal power is still used in developing countries, the CO2 emission reduction effectiveness of BEVs can be weakened or even counterproductive. To reveal the impact of the electricity generation mix on carbon emissions from vehicles, this paper compares the life cycle carbon emissions of BEVs with ICEVs considering the regional disparity of electricity generation mix in China. According to Life Cycle Assessment (LCA) analysis and regional electricity carbon intensity, this study demonstrates that BEVs in the region with high penetration of thermal power produce more CO2 emissions, while BEVs in the region with higher penetration of renewable energy have better environmental performance in carbon emission reduction. For instance, in the region with over 50% penetration of renewable energy, a BEV can reduce more CO2 (18.32 t) compared to an ICEV. Therefore, the regions with high carbon emissions from vehicles need to increase the proportion of renewable generation as a priority rather than promoting BEVs.

Carbon emission analysis of two crystalline silicon components throughout the life cycle

Take PERC P-type monocrystalline silicon and PERC P-type polycrystalline black silicon modules as examples to establish a life cycle carbon emission inventory of crystalline silicon modules. Study the contribution of five recycling technologies to the life cycle carbon emission reduction of two crystalline silicon modules, and the impact of the life cycle of 1MWP PERC P-type monocrystalline silicon and PERC P-type polycrystalline black silicon module systems on the environment. The results show that the carbon emissions of the two photovoltaic systems are concentrated in the production stage, and the carbon emissions of the crystalline silicon purification process are the highest, accounting for more than 41%. Through green low-carbon recycling technology to process waste photovoltaic modules to obtain glass, aluminum, silicon and other materials to achieve resource recycling, it can reduce the energy consumption of the module production process and life cycle carbon emissions. According to calculations, 1 MWp PERC P-type monocrystalline silicon system has 10% higher life cycle carbon emissions than PERC P-type polycrystalline black silicon system.

A STUDY ON THE POSSIBILITY OF ACHIEVING LIFE CYCLE CARBON MINUS IN APARTMENT HOUSES

This study aimed to examine the feasibility of two-story life-cycle carbon minus (LCCM) rental apartments. To assess feasibility, we analyzed the ability of LCCMs for improving heat insulation, improving photovoltaic power generation system performance, using biomass in lumber and oriented strand board manufacturing, and improving the air conditioner efficiency. Our results identified cases where the LCCM can be achieved by combining all of these measures. Further, we conducted a case study on housing life and the amount of power generated for future dissemination, clarifying the issues related to achievability.

Quantitative Study on the Life-Cycle Carbon Emissions of a Nearly Zero Energy Building in the Severe Cold Zones of China

This work aimed to quantitatively study the carbon emissions and carbon reduction potential of a nearly Zero Energy Building in a severe cold zone of China from the perspective of its life cycle. The methods were based on China’s “Standard for building carbon emission calculation” (GB/T51366-2019), which include the production, transportation, operation, and demolition stages. For the nearly Zero Energy Building, the total carbon emissions over its whole life were 789.43 kg CO2/m2, an 86.20% reduction compared to the 5719.68 kg CO2/m2 for a 65% energy-saving building. The carbon emission percentages of the production stage and operation stage for the building materials are 75.62% and 20.40%, respectively. To enhance the carbon reduction potential, a sensitivity analysis was conducted to explore the impact of the use of a wood structural system, recycled concrete replacement, and photovoltaic power generation. The use of a wood structure system can achieve zero or negative carbon emissions in the production stage. The sensitivity of the carbon emissions of the nearly zero energy building (nZEB) to the increment of photovoltaic power generation is much higher than that of the recycled concrete replacement rate, providing a basis for further exploration of the development of nZEBs into zero carbon buildings.

Importance of corrosion protection on steel materials in reducing carbon emissions: Carbon emission measurement throughout the life cycle of steel pipeline as an example

<p indent="0mm">This paper studies the calculation method of carbon emissions throughout the life cycle of steel materials covering all stages of manufacturing, transportation, installation, service, and recycling. Taking steel pipelines as an example, this paper explores the impact of corrosion protection on the life cycle carbon emissions and annual average carbon emissions of steel materials. A carbon emission calculation method for all links in the life cycle of engineering steel materials in corrosive environments has been established. In addition to “carbon emissions per unit GDP (carbon emission intensity),” another intensity index is proposed as “life cycle average annual carbon emissions (carbon emissions per unit time).” This intensity index can constrain the life cycle carbon footprint in the time dimension. It is the first to quantify the important role of corrosion protection in controlling carbon emissions from steel materials at home and abroad. Through. Using appropriate anticorrosion technology, steel pipelines can reduce emissions by more than 60% in typical chemical production environments, more than 83% in oil and gas field environments, more than 50% in long-distance pipelines, and more than 28% in urban gas pipeline networks. This study is important in developing low-carbon corrosion control methods and improving corrosion protection, which controls the life cycle carbon emissions and annual average carbon emissions of steel materials, thereby providing a new perspective for the corrosion protection design and engineering implementation of steel structures. Consequently, it provides a new methodology for reducing carbon emissions of steel materials.

Low-GHG culturally acceptable diets to reduce individual carbon footprint by 20%

For mitigating climate change and respect targets, humanity must decrease emissions as soon as possible: the later is the action, the harsher will be the trajectory of the mitigating pathway. Structural actions need time to become operational. Therefore, individual actions shall also enter into play, focusing on what has a high impact and whose change is at hand: food-related emissions build up 30% of total anthropogenic impacts and eating is an everyday activity. In this study, regional culturally acceptable low-carbon diets are proposed for China, Europe and US. They are developed considering the requirements of energy and nutrients supply, they respect regionality of food consumption – e.g., they include only foods that are diffused in the area – and they are aimed to limit the individual effort to be adopted – e.g., they include all the food categories, meat included. They are low-carbon since food items are selected on the basis of their lifecycle carbon footprint (CF). Eventually, the regionality constraints are relaxed to develop a World's low-carbon diet. For every area, we found a diet that halves the food-related CF. Instead, our World's low-carbon diet reduces the average food-related CF by 75%. Therefore, the overall individual CF would be reduced by a fifth in case of its adoption.

Is sufficient carbon footprint information available to make sustainability focused computer procurement strategies meaningful?

End user computing generates 1% of global greenhouse gas emissions therefore contributing to environmental pollution, global warming and ultimately climate change. Research indicates the carbon footprint is predominantly produced by production and use-phase electricity consumption. As such, new international legislation exists to ensure businesses include sustainability criteria when assessing and purchasing computers. Such criteria must include valid science based evidence that the selected devices, contribute to greenhouse gas abatement and net-zero emissions strategies based upon exhibiting a low life cycle carbon footprint. As such, it is reasonable to suggest that sufficient carbon footprint information must be publicly available to enable the selection process to be meaningful. The rationale being that if information is limited or misleading, then accurate identification and comparison between computers cannot be assured. Consequently, the research objective is to quantify availability of end user computing carbon footprint information, examine data uniformity and validity and propose a solution to overcome identified issues. To enable this, asset profiling of 71,990 end user computing devices located at six organisations is undertaken to generate an unbiased data pool representing popular devices used by organisations subject to the new procurement rules. Carbon footprint reports are sought for each unique model identified to examine both scope 2 use-phase emissions and scope 3 supply chain manufacturing emissions data. The findings substantiate that 22% of the 707 unique end user computer models identified have associated published information. The predominant limitation being that only six of the forty-two computer brands identified participate in product carbon footprint reporting. Additionally, methods used to form and present the carbon footprint data are incongruent for both emissions sources. Scope 3 is affected by a feasible range of emissions methodology being adopted by 50% of manufacturers compared to exact values published by the remainder. Scope 2 emissions are affected by a lack of uniformity applied to use location and device retention periods. To overcome the parity issue, a dynamic carbon footprint application is developed to harmonise available data. Consequently, it is concluded that sufficient carbon footprint information is not currently available to make sustainability focused computer procurement strategies meaningful. However, the diffusion of the proposed application and illustrated increased participation from manufacturers to publish data in the near future will enable such strategies to achieve legislative compliance and most importantly, reduce greenhouse gas emissions associated with end user computer procurement and use.

Challenges to quantify the life cycle carbon footprint of buildings in Chile

This study identifies key challenges to measure the carbon footprint (CF) over the whole life cycle of buildings in Chile, although its findings are also applicable to other countries. This paper presents four of the said challenges that emerge from the analysis of certification programs, design guides, databases, CF/LCA calculators, standards, and Measurement, Reporting and Verification (MRV) programs worldwide. The four challenges are: (i) a sustainable governance for the carbon footprint system which ensures CF quality, enables regular updates of the data, and has guaranteed funding, (ii) adoption of the system by industry, (iii) standardization of reporting, and (iv) standardization of measurements over the full life cycle. An MRV appears as the best option to coordinate multiple actors and data needs; however, it requires a sustainable governance model as well as widespread adoption. Such an MRV would need a common reporting system. However, comparability may be compromised due to a lack of consensus on which standard to follow in the industry and on definitions for basic building measurements, such as area. The reporting system must be based on a standardized tool, i.e., a CF calculator for buildings. Many of these exist; however, they differ in a fundamental aspect: whether they are used to guide low carbon design or to certify carbon emissions by buildings. Finally, the calculator will need an agreed upon methodology. Although several standards exist, one must be chosen, updated and deployed. Some countries may be more advanced than others on these challenges, but none have solved them completely. A concerted effort would be best to reduce the CF of the construction sector globally.

Quantification of Building Carbon Emissions in China a Using Hybrid LCA Model

During their life cycle, buildings not only consume a lot of resources and energy, but also produce a large amount of carbon emissions, which have a serious impact on the environment. In the context of global emissions reduction, the trend has been to low carbon buildings. As a major carbon emitting country, it is urgent to promote emission reduction in the construction industry and to establish a model for carbon emissions and calculation in buildings. To this end, this paper collates life cycle carbon emission calculation methods based on life cycle theory and establishes a mixed life cycle carbon emission calculation model for buildings to provide ideas for low carbon buildings in China. A case study of a hospital in Guangming City, Anhui Province is also conducted to verify the feasibility of the model. The results show that the total carbon emission of the hospital is 43283.66 tCO2eq, with the production phase, construction phase, use and maintenance phase and end-of-life phase accounting for 9.13%, 0.35%, 90.06% and 0.46% of the total carbon emission respectively. An analysis of the factors influencing carbon emissions at each stage is presented, and recommendations are given for corresponding emission reduction measures. The carbon emission calculation model based on the hybrid LCA proposed in this study enables a more comprehensive consideration of carbon emissions in the life cycle of a building, and has implications for the study of building carbon emission calculation.

Study on Life-Cycle Carbon Emission Optimization Method of High-Rise Residential Buildings Under Double Carbon Background: A Case Study in Nanjing

Study on Life-Cycle Carbon Emission Optimization Method of High-Rise Residential Buildings Under Double Carbon Background: A Case Study in Nanjing

Valorisation of lignocellulosic biomass to value-added products: Paving the pathway towards low-carbon footprint

Biofuel is the presently needed potential energy reservoir as an alternative to wearying fossil fuel-based technology. Second generation lignocellulose is considered to be the most abundant source of renewable feedstock among the biomaterials. Lignocellulose biomass (LCB) is the effective feed stock for bio-based chemicals for carbon neutrality, which paves critical prospect for significant sustainable and renewable development. This review discusses the types of biomass, characterization, and value-added products developed. Integrating the biological funnelling pathway in the bio-refinery concept and explaining the genetic modification of lignocellulosic biomass for enhanced yield is also discussed. The outlook on lowering the carbon footprint by discussing in detail the life cycle carbon balance, process development tools, supply chain description, and circular economy.