Life cycle assessment of emerging technologies at the lab scale: The case of nanowire‐based solar cells

Nanomaterials are expected to play an important role in the development of sustainable products. The use of nanomaterials in solar cells has the potential to increase their conversion efficiency. In this study, we performed a life cycle assessment (LCA) for an emerging nanowire‐based solar technology. Two lab‐scale manufacturing routes for the production of nanowire‐based solar cells have been compared—the direct growth of GaInP nanowires on silicon substrate and the growth of InP nanowires on native substrate, peel off, and transfer to silicon substrate. The analysis revealed critical raw materials and processes of the current lab‐scale manufacturing routes such as the use of trifluoromethane (CHF₃), gold, and an InP wafer and a stamp, which are used and discarded. The environmental performance of the two production routes under different scenarios has been assessed. The scenarios include the use of an alternative process to reduce the gold requirements—electroplating instead of metallization, recovery of gold, and reuse of the InP wafer and the stamp. A number of suggestions, based on the LCA results—including minimization of the use of gold and further exploration for upscaling of the electroplating process, the increase in the lifetimes of the wafer and the stamp, and the use of fluorine‐free etching materials—have been communicated to the researchers in order to improve the environmental performance of the technology. Finally, the usefulness and limitations of lab‐scale LCA as a tool to guide the sustainable development of emerging technologies are discussed.     

Lifting the veil on the correction of double counting incidents in hybrid life cycle assessment

Life cycle assessment (LCA) and environmentally extended input–output analyses (EEIOA) are two techniques commonly used to assess environmental impacts of an activity/product. Their strengths and weaknesses are complementary, and they are thus regularly combined to obtain hybrid LCAs. A number of approaches in hybrid LCA exist, which leads to different results. One of the differences is the method used to ensure that mixed LCA and EEIOA data do not overlap, which is referred to as correction for double counting. This aspect of hybrid LCA is often ignored in reports of hybrid assessments and no comprehensive study has been carried out on it. This article strives to list, compare, and analyze the different existing methods for the correction of double counting. We first harmonize the definitions of the existing correction methods and express them in a common notation, before introducing a streamlined variant. We then compare their respective assumptions and limitations. We discuss the loss of specific information regarding the studied activity/product and the loss of coherent financial representation caused by some of the correction methods. This analysis clarifies which techniques are most applicable to different tasks, from hybridizing individual LCA processes to integrating complete databases. We finally conclude by giving recommendations for future hybrid analyses.     

LCI1, a Chlamydomonas reinhardtii plasma membrane protein,functions in active CO2 uptake under low CO2

In response to high CO₂ environmental variability, green algae, such as Chlamydomonas reinhardtii, have evolved multiple physiological states dictated by external CO₂ concentration. Genetic and physiological studies demonstrated that at least three CO₂ physiological states, a high CO₂ (0.5–5% CO₂), a low CO₂ (0.03–0.4% CO₂) and a very low CO₂ (< 0.02% CO₂) state, exist in Chlamydomonas. To acclimate in the low and very low CO₂ states, Chlamydomonas induces a sophisticated strategy known as a CO₂‐concentrating mechanism (CCM) that enables proliferation and survival in these unfavorable CO₂ environments. Active uptake of C_i from the environment is a fundamental aspect in the Chlamydomonas CCM, and consists of CO₂ and HCO₃^– uptake systems that play distinct roles in low and very low CO₂ acclimation states. LCI1, a putative plasma membrane C_i transporter, has been linked through conditional overexpression to active C_i uptake. However, both the role of LCI1 in various CO₂ acclimation states and the species of C_i, HCO₃^– or CO₂, that LCI1 transports remain obscure. Here we report the impact of an LCI1 loss‐of‐function mutant on growth and photosynthesis in different genetic backgrounds at multiple pH values. These studies show that LCI1 appears to be associated with active CO₂ uptake in low CO₂, especially above air‐level CO₂, and that any LCI1 role in very low CO₂ is minimal.     

Angular range,sampling and noise considerations for inverse light scattering analysis of nuclear morphology

In recent years, significant work has been devoted to the use of angle‐resolved elastic scattering for the extraction of nuclear morphology in tissue. By treating the nucleus as a Mie scattering object, techniques such as angle‐resolved low‐coherence interferometry (a/LCI) have demonstrated substantial success in identifying nuclear alterations associated with dysplasia. Because optical biopsies are inherently noninvasive, only a small, discretized portion of the 4π scattering field can be collected from tissue, limiting the amount of information available for diagnostic purposes. In this work, we comprehensively characterize the diagnostic impact of variations in angular sampling, range and noise for inverse light scattering analysis of nuclear morphology, using a previously reported dataset from 40 patients undergoing a/LCI optical biopsy for cervical dysplasia. The results from this analysis are applied to a benchtop scanning a/LCI system which compromises angular range for wide‐area scanning capability. This work will inform the design of next‐generation optical biopsy probes by directing optical design towards parameters which offer the most diagnostic utility.      

Comparative LCA of industrial objects

Goal, Scope and Background  This paper is the second part of the publication which is devoted to comparative LCA analysis of the industrial pumps. The previous paper deals with the methodological aspects concerning quality assessment and forms an independent work. This paper uses practically only the methodological suggestions made there. The main aim of the presented study is to make a comparison between the industrial pumps which are based on two different technologies. The Life Cycle Assessment method is used to check whether the differences of the manufacturing processes influence the level of the potential environmental impact during the whole life cycle of the analysed products. Methods  The Life Cycle Assessment is carried out using the Ecoindicator99 method. Additionally, an extensive quality analysis of the LCA study is made (Part I). To make the process of an identification of the data easier and faster, they are assigned to a special data documentation form. To ensure the credibility of the LCA results different methods of interpretation are used. Results and Discussion  The LCA analysis shows clear superiority of the pumps manufactured using modern technology. It seems that this superiority results not only from the differences in the emissions, but also from different characteristics of effectiveness in the usage stage. Thanks to the uncertainty analysis, each LCA result is provided with the range of uncertainty. Conclusions  The LCA results are supported by different techniques of interpretation: the sensitivity-, the contribution-, the comparative-, the discernability- and the uncertainty analysis. There is strong evidence of the superiority of the pumps based on the modern technology. Recommendations and Outlook  The main source of the environmental impact in the case of pumps is the usage stage and the consumption of energy. That is why it should be the main area to improve. The LCA results show that actions taken in the usage stage and energy consumption can lead to a considerable reduction of the environmental impacts.     

Current LCA database development in Japan -results of the LCA project

In 1998, the Japan’s Ministry of Economy, Trade, and Industry (METI) launched a five-year national project entitled ‘Development of Life Cycle Impact Assessment for Products’ (commonly known as ‘the LCA Project’). The purpose of the project is to develop common LCA methodology as well as a highly reliable database that can be shared in Japan. Activities over these five years have resulted in the supply of LCI data on some 250 products. Industrial associations voluntarily provided data. The results of these activities are currently being made available on the Internet on a trial basis in the form of an LCA database. In addition, a method entitled ‘Life-cycle Impact assessment Method based on Endpoint modeling (LIME)’ was developed. It is expected that these results will be widely used in Japan in the future. This paper presents an outline of the results of the research and development that has been conducted in the LCA Project in Japan.     

Guidelines for consistent reporting of exchanges/to nature within life cycle inventories (LCI)

Data availability and data quality are still critical factors for successful LCA work. The SETAC-Europe LCA Working Group ‘Data Availability and Data Quality’ has therefore focused on ongoing developments toward a common data exchange format, public databases and accepted quality measures to find science-based solutions than can be widely accepted. A necessary prerequisite for the free flow and exchange of life cycle inventory (LCI) data and the comparability of LCIs is the consistent definition, nomenclature, and use of inventory parameters. This is the main subject of the subgroup ‘Recommended List of Exchanges’ that presents its results and findings here:

拟南芥核酸外切体亚基RRP41L与RRP42及RRP45B的互作关系

在真核生物中,核酸外切体(exosome)是一个由9个核心蛋白亚基组成的在进化上十分保守的大分子复合物,具有加工和降解RNA的重要功能。为了了解影响拟南芥生长发育的核酸外切体亚基RRP41-LIKE (RRP41L)与其他外切体亚基之间的互作关系,本文利用酵母双杂交和荧光素酶互补技术从体外和体内两个方面验证了RRP41L与另外两个核酸外切体亚基RRP42及RRP45B的互作关系。结果显示RRP41L不能与RRP42互作,而能与RRP45B互作。     

Life Cycle Inventories of Metals and Methodological Aspects of Inventorying Material Resources in ecoinvent (7 pp)

Goal, Scope and Background The ecoinvent database provides harmonised generic life cycle inventories for metal production and processing. They can be used as background data for different LCA applications. The goal of this paper is to provide an overview of the metals inventoried in ecoinvent. Beside, some methodological background information is given. The focus lies on a new methodology developed to inventorying joint resources. The implementation is shown in a case study of the production of primary copper on a global average. The respective process is assessed with Eco-indicator 99 (H,A) to identify dominant impacts within the production chain.Methods In ecoinvent, a coupled production is inventoried in multi output unit processes. For database calculation, an allocation by economic revenue is applied. Elementary flows for resources, especially joint resources, include information on type and quality of the resources.Results and Conclusion With the presented method, the extraction of resources can be valuated based on the cost of restoration or the change in the future impact due to the extraction of a specific resource. The case study indicates, for copper / molybdenum production, that the mineral extraction is of minor importance compared to the metallurgical step according to the LCIA results. Air emissions of heavy metals are identified as main impacts. Also, the resource depletion shows a notable impact. The environmental impacts of metals from sulphidic ores, however, are underestimated by neglecting emissions from tailings for lack of reliable data.Recommendation and Perspective Impact assessment methods will have to be updated to account for different grades of ore. The ecoinvent database should be enlarged by more inventories of technically important metals and alloys, e.g. by gold, silver, solders, etc. for the electronics industry and by specific steel and aluminium alloys. Reliable composition data of sulphidic tailings and transfer coefficients for their disposal considering Acidic Rock Drainage (ARD) are to be developed as well.     

Scenario Modelling in Prospective LCA of Transport Systems. Application of Formative Scenario Analysis (11 pp)

Background Tools and methods able to cope with uncertainties are essential for improving the credibility of Life Cycle Assessment (LCA) as a decision support tool. Previous approaches have focussed predominately upon data quality. Objective and Scope. An epistemological approach is presented conceptualising uncertainties in a comparative, prospective, attributional LCA. This is achieved by considering a set of cornerstone scenarios representing future developments of an entire Life Cycle Inventory (LCI) product system. We illustrate the method using a comparison of future transport systems. Method Scenario modelling is organized by means of Formative Scenario Analysis (FSA), which provides a set of possible and consistent scenarios of those unit processes of an LCI product system which are time dependent and of environmental importance. Scenarios are combinations of levels of socio-economic or technological impact variables. Two core elements of FSA are applied in LCI scenario modelling. So-called impact matrix analysis is applied to determine the relationship between unit process specific socio-economic variables and technology variables. Consistency Analysis is employed to integrate unit process scenarios, based on pair-wise ratings of the consistency of the levels of socio-economic impact variables of all unit processes. Two software applications are employed which are available from the authors. Results and Discussion The study reveals that each possible level or development of a technology variable is best conceived of as the impact of a specific socio-economic (sub-) scenario. This allows for linking possible future technology options within the socio-economic context of the future development of various background processes. In an illustrative case study, the climate change scores and nitrogen dioxide scores per seat kilometre for six technology options of regional rail transport are compared. Similar scores are calculated for a future bus alternative and an average Swiss car. The scenarios are deliberately chosen to maximise diversity. That is, they represent the entire range of future possible developments. Reference data and the unit process structure are taken from the Swiss LCA database 'ecoinvent 2000'. The results reveal that rail transport remains the best option for future regional transport in Switzerland. In all four assessed scenarios, four technology options of future rail transport perform considerably better than regional bus transport and car transport. Conclusions and Recommendations. The case study demonstrates the general feasibility of the developed approach for attributional prospective LCA. It allows for a focussed and in-depth analysis of the future development of each single unit process, while still accounting for the requirements of the final scenario integration. Due to its high transparency, the procedure supports the validation of LCI results. Furthermore, it is well-suited for incorporation into participatory methods so as to increase their credibility. Outlook and Future Work. Thus far, the proposed approach is only applied on a vehicle level not taking into account alterations in demand and use of different transport modes. Future projects will enhance the approach by tackling uncertainties in technology assessment of future transport systems. For instance, environmental interventions involving future maglev technology will be assessed so as to account for induced traffic generated by the introduction of a new transport system.