Global Warming Potential Indicator Research Articles

Precision of a Streamlined Life Cycle Assessment Approach Used in Eco-Rating of Mobile Phones

There is a lack of prescribed databases and approaches in place for performing comparable Life Cycle Assessments (LCAs) of smartphones and other electronic devices in a coherent manner. Hence there is a need within certain eco-rating initiatives for simplified, yet still precise enough, approaches that are expert independent. Here, five independently published Full LCAs (FLCA) of smartphones—and a metal content declaration of a tablet—are analyzed and compared with the simplified LCA method (Open Eco Rating LCA, OLCA) used by the open eco rating (OER) sustainability assessment. OLCA is described in detail. The comparisons use the same characterization factors that are used for climate change and abiotic resource depletion (ARD) midpoint impact categories. The tablet is only analyzed for the ARD indicator (ARDI). The results show that the difference between the FLCAs and the OLCA is up to 20% for the Global Warming Potential indicator (GWPI). The difference is explained by significantly different emission intensities used in FLCAs and OLCA, especially for integrated circuit and screen production. The life cycle use of metals relevant for ARDI is identified in one of the FLCAs of mobile phones, and used in OLCA and compared with the corresponding FLCA ARDI score. The total FLCA ARDI score is 67% (2.0 vs. 1.2 grams Sb—eq.) and 32% (4.98 vs. 3.76 grams Sb—eq.) higher than OLCA ARDI for the mobile phone and the tablet, respectively. The reason is that OLCA only captures a few of the most relevant metals (gold, silver, tin, indium, and tantalum) for the ARDI. However, cobalt—and to some degree copper and lithium—are significant gaps in the OLCA. The conclusion is that OLCA is an efficient and fair approach for LCAs that are focused on the GWPI of smartphones as the divergence to FLCA can easily be explained. However, the circular footprint formulae, renewable electricity options, and ARD characterization indices for cobalt, copper and lithium should be added to OLCA for further precision. The next step is to compare the Product Environmental Footprint (PEF) FLCA method with OLCA for GWPI and ARDI evaluations of new smartphones. Moreover, the effect of adding more midpoint or single score indicators could be tested in OLCA.

On the necessity of improving the environmental impacts of furniture and appliances in net-zero energy buildings

There is now clear evidence regarding the extensive use of furniture and appliances in daily human life, but there is less evidence of their impact on the environment. Responding to this gap in knowledge, this study focuses on an assessment of the environmental impacts of furniture and appliances as used in highly energy efficient buildings. Their primary energy, non-renewable energy and global warming potential indicators have been assessed by extending the boundaries of the Life Cycle Assessment (LCA) study beyond the building itself. In conclusion, we found that furniture and appliances were responsible for around 30% of greenhouse gas emissions and non-renewable energy consumption and 15% of primary energy consumption comparing to the overall impacts of the building. Since embodied impacts represent the largest values, the process for labelling the appliances' energy efficiency should encompass a life-cycle point of view, not just a usage point of view as the case currently. Among office appliances, computer equipment was ranked as the highest impacting element, especially laptops and monitors. As for domestic appliances, refrigerators and electric ovens had the biggest impacts. Concerning furniture, the greatest impacts were from office and kitchen cabinets.

Energy flows and greenhouses gases of EU (European Union) national breads using an LCA (Life Cycle Assessment) approach

Bread represents a staple food in many parts of the world including Europe. Depending on the region of origin and the respective cultural heritage bread is made with different ingredients and is consumed in various forms. This work consists of an environmental sustainability assessment of 21 different types of bread, representing a wide spectrum of typologies of such food consumed across the European Union, via a Life Cycle Assessment approach. The embedded energy and equivalent greenhouse gas emissions of each type of bread were estimated, from cradle to bakery gate, by considering a mass, a nutritional value and a price based functional unit. Overall, the results have highlighted the variability of the embedded energy and the equivalent GHG (greenhouse gas) emissions associated to the consumption of the 21 kinds of bread rooted in the cultural environment of 21 EU countries. When considering a functional unit of 1 kg of bread, the Cumulative Energy Demand results range from 9 MJ/kg to 32.9 MJ/kg. The Global Warming Potential indicator has a minimum value of 0.5 kgCO2eq/kg and a maximum of 6.6 kgCO2eq/kg. For a functional unit amounting to a 100 kcal provided by the consumption of bread, the Cumulative Energy Demand results vary from 0.33 MJ/100 kcal to 0.93 MJ/100 kcal whilst the Global Warming Potential indicator varies from 0.019 kgCO2eq/100 kcal to 0.135 kgCO2eq/100 kcal. For a functional unit amounting to the quantity of bread purchased with 1€ (weighted according to the purchasing price of each nation in the European Union), the Cumulative Energy Demand results vary from 1.197 MJ/€ to 3.708 MJ/€ whilst the Global Warming Potential indicator varies from 0.15 kgCO2eq/€ to 0.376 kgCO2eq/€.The study has pinpointed the importance of evaluating food, in terms of environmental sustainability, with more than one type of functional unit in order to account not only for the bread's nutritional purposes but also the need to satisfy social, cultural, hedonistic and other qualitative functions. Specifically, when using a mass based functional unit, the less impactful results involve bread types with simple recipes, based essentially on flour, yeast and water. By assessing the breads with an energy based functional unit, bread types which also contain vegetable oils and small amounts of animal based ingredients result as more carbon and energy friendly. The use of a price based functional unit indicates that the higher priced bread types, manufactured with more expensive ingredients that are produced in an environmentally efficient manner, are the more sustainable ones. Overall, for many types of bread, the energy consumption during the production phase, in particular the baking process, represents a hot spot and is dependent on the size and shape of the bread. Furthermore, the efficiency of ingredient production (in terms of material and energy use and in terms of the respective yields of each nation in the European Union), such as that of milk and flour, also influences the sustainability of the bread types.

Influence of simplification of life cycle inventories on the accuracy of impact assessment: application to construction products

The simplification of life cycle inventories (LCIs) by reducing the number of elementary flows is a major issue regarding their use in sector-specific applications. It can ease the understanding of complete LCIs and focus on the most relevant elementary flows. Current LCIs that have been created for Environmental Product Declarations (EPDs) differ from databases provided by academics, in which more than a thousand flows are considered, as they contain a reduced list of substances. In this paper, we examine the consequences of these simplified LCIs on the accuracy of the life cycle impact assessment (LCIA) step. We consider the specific case of an LCI database for building products that was developed in France. Three environmental midpoint and endpoint indicators are analysed: the global warming potential (GWP), the photochemical ozone formation potential (POCP), and the disability-adjusted life years (DALY). The results for 110 building materials indicate that a simplification is not always relevant, as large uncertainties were detected in the final results, especially for the environmental indicators describing the photochemical ozone creation and the damage to human health that require a larger number of LCI flows. In the case of the GWP indicator, the simplification is relevant for approximately 95% of the building materials. The analysis of the key elementary flows for each indicator enables the identification of missing elementary flows in the simplified LCI. Perspectives and recommendations are provided to improve the level of details of simplified LCIs according to the impact assessment methods.

On the study of energy use and GHG (greenhouse gas) emissions in greenhouse cucumber production in Yazd province

In recent years, besides the energy issues, the GHG (greenhouse gas) emission, which is the most important cause of global warming, has received high attention. In order to have sustainable development, it is necessary to manage energy usage and GHG emissions in all production processes. This study aimed to evaluate the energy consumption and GHG emissions of cucumber production in selected greenhouses in Yazd province of Iran. The total energy input was found to be 1284 GJ ha−1 where the output energy was 125 GJ ha−1. Energy use efficiency and productivity were 0.10 and 0.12 kg MJ−1, respectively. Diesel fuel and electricity had the biggest contributions in the total energy input. Regression results showed that labor, diesel fuel, manure, electricity and chemicals had significant impact on yield. The amount of GHG emissions was calculated as 82,724 kg CO2eq ha−1 where diesel fuel had the highest emission (61%), followed by electricity (19%) and manure (14%). GWP (Global warming potential) was 0.53 kg CO2eq ha−1(kg Output)−1. The average GWP per MJ output was 0.66 kg CO2eq ha−1(MJ Output)−1, where the highest value belonged to smaller greenhouses. The results of energy analysis, GHG and GWP indicators based on different greenhouse sizes implied better performance of larger greenhouses.

Life Cycle Assessment of Representative Swiss Road Pavements for National Roads with an Accompanying Life Cycle Cost Analysis

The subject of this paper is an environmental life cycle assessment (LCA) and life cycle cost analysis (LCCA) of processes needed to construct and maintain representative Swiss asphalt, concrete, and composite pavements (including subbase layers) applicable for the Swiss national road network over a period of 75 years. The environmental indicators analyzed are the global warming potential indicator, the nonrenewable cumulative energy demand, and the Swiss ecological scarcity indicator. Processes of the use phase of the road (fuel consumption, noise, etc.) have been evaluated qualitatively based on intensive research. The study shows that the global warming potential of concrete and asphalt pavements equilibrates over the analysis period and that concrete pavements compared to asphalt and composite pavements offer advantages in regards to the nonrenewable cumulative energy demand, the ecological scarcity indicator, and life cycle costs. The qualitative evaluation of the processes of the use phase shows for example the positive qualities of concrete pavements regarding fuel consumption and permanent noise properties.

Environmental analysis of new construction and maintenance processes of road pavements in Switzerland

The subject of this paper is an environmental analysis of processes needed to construct (material production, pavement construction, transport) and maintain (pavement deconstruction, recycling, material production, pavement construction, transport) representative Swiss asphalt, concrete and composite pavements (including subbase layers). The analysed environmental indicators are the IPCC Global Warming Potential indicator, the Ecological Scarcity Indicator and the Non-renewable Cumulative Energy Demand indicator. It is shown that material production processes have the largest impact on the values of the analysed indicators, and that pavement construction and deconstruction processes have a marginal impact on the analysed indicators in comparison to material production, transport and recycling processes. It is also demonstrated that the values of the IPCC Global Warming Potential indicator and the Ecological Scarcity indicator for the processes needed to construct and maintain concrete and composite pavements are higher than those for all processes required to construct and maintain asphalt pavements, due to the greater thickness of concrete and composite pavements. The values of the Non-Renewable Cumulative Energy Demand indicator are higher for processes applied to construct and maintain asphalt pavements than for concrete pavements, due to the use of bitumen within asphalt pavements, which causes a depletion of fossil energy resources.

Towards the Evaluation of Environment and Business Trade-offs in Supply Chains

Supply chains (SCs) are one of the most environment impacting systems. Analysis of such systems should thus take into account not only performance but also environment indicators. The amount of energy consumed for producing goods and the total emissions of greenhouse gases (GHG) of an activity are examples of such indicators. This paper presents a framework for assessing performance as well as Global Warming Potential (GWP) and exergy indicators in SCs. In order, exergy accounting helps on finding reliable GWP indicators for different energy sources adopted in the supply chain. This framework supports the evaluation of supply chainsʼ business and environment indicators trade-offs using a unified model. A real case study is conducted to demonstrate the application of the proposed modeling technique.