Highly efficient 3rd generation multi-junction solar cells using silicon heterojunction and perovskite tandem : prospective life cycle environmental impacts

In this study, the environmental impacts of monolithic silicon heterojunction organometallic perovskite tandem cells (SHJ-PSC) and single junction organometallic perovskite solar cells (PSC) are compared with the impacts of crystalline silicon based solar cells using a prospective life cycle assessment with a time horizon of 2025. This approach provides a result range depending on key parameters like efficiency, wafer thickness, kerf loss, lifetime, and degradation, which are appropriate for the comparison of these different solar cell types with different maturity levels. The life cycle environmental impacts of SHJ-PSC and PSC solar cells are similar or lower compared to conventional crystalline silicon solar cells, given comparable lifetimes, with the exception of mineral and fossil resource depletion. A PSC single-junction cell with 20% efficiency has to exceed a lifetime of 24 years with less than 3% degradation per year in order to be competitive with the crystalline silicon single-junction cells. If the installed PV capacity has to be maximised with only limited surface area available, the SHJ-PSC tandem is preferable to the PSC single-junction because their environmental impacts are similar, but the surface area requirement of SHJ-PSC tandems is only 70% or lower compared to PSC single-junction cells. The SHJ-PSC and PSC cells have to be embedded in proper encapsulation to maximise the stability of the PSC layer as well as handled and disposed of correctly to minimise the potential toxicity impacts of the heavy metals used in the PSC layer

Greening agri-food value chains in emerging economies

This book provides insight into the implementation of Life Cycle approaches along the entire business value chain, supporting environmental, social and economic sustainability related to the development of industrial technologies, products, services and policies; and the development and management of smart agricultural systems, smart mobility systems, urban infrastructures and energy for the built environment. The book is based on papers presented at the 8th International Life Cycle Management Conference that took place from September 3-6, 2017 in Luxembourg, and which was organized by the Luxembourg Institute of Science and Technology (LIST) and the University of Luxembourg in the framework of the LCM Conference Series

Energieverbrauch der Schweizer Kantone : Endenergieverbrauch und Mittelabfluss durch den Energie-Import

Mit der Energiestrategie 2050 hat sich der Bundesrat zum Ziel gesetzt, den Energieverbrauch der Schweiz bis 2050 zu reduzieren und die Nutzung erneuerbarer Energien zu erhöhen. Damit die Umsetzung der Energiestrategie 2050 vorangetrieben werden kann, braucht es eine fundierte Datengrundlage zum heutigen Energieverbrauch. Solche Daten sind mit der Gesamtenergiestatistik auf nationaler Ebene verfügbar. Die Mehrzahl der Kantone, welche eine grosse Verantwortung bei der Umsetzung der Energiestrategie 2050 tragen, verfügt bis heute allerdings nicht über verlässliche Energieverbrauchsdaten. Ziel der vorliegenden Studie ist es daher, die kantonalen Energieverbräuche aus den nationalen Daten abzuleiten und darauf basierend zu bestimmen, welche finanziellen Beträge durch den Import von Energie jährlich ins Ausland fliessen. Die Aufteilung des gesamtschweizerischen Energieverbrauchs auf die Kantone erfolgte nach Möglichkeiten nach dem Territorialprinzip. Die Energieverbräuche werden damit denjenigen Kantonen angerechnet, in denen die Energie bezogen wird. Der Mittelabfluss wurde anhand des Produkts von Importpreis und Importmenge bestimmt. Der berechnete Pro‐Kopf‐Energiebedarf pro Jahr liegt bei den Kantonen zwischen 24.8 MWh (Kanton Waadt) und 53.5 MWh (Kanton Basel‐Stadt), wobei sich der Pro‐Kopf‐Energiebedarf des Kantons Basel‐Stadt auf 43.2 MWh/Einwohner reduziert, wenn der Tanktourismus und der Flugverkehr ausgeklammert werden. Dass der Energiebedarf des Kantons Basel‐Stadt auch in diesem Fall noch überdurchschnittlich hoch ist, liegt hauptsächlich am hohen Energiebedarf der Branchengruppe "Chemie/ Pharma". Ein Grossteil des Energiebedarfs der Kantone wird durch importierte Energieträger gedeckt (Heizöl, Benzin, Diesel, Erdgas etc.). Dadurch fliessen gesamtschweizerisch jährlich knapp 13 Milliarden Franken ins Ausland. Absolut betrachtet ist der Mittelabfluss in den Kantonen Zürich und Bern am grössten, während der Mittelabfluss pro Einwohner in den Kantonen Basel‐Stadt und Genf überdurchschnittlich hoch ist. Werden die Flugtreibstoffe und der Tanktourismus vernachlässigt, so liegt der jährliche Mittelabfluss pro Einwohner in allen Kantonen bei 1‘405 ± 232 Franken. Rund 30% bis 50% des Mittelabflusses der Kantone sind auf den Import von Benzin und Diesel zurückzuführen, während Heizöl zwischen 15% und 40% des Mittelabflusses der Kantone ausmacht. Bei einer Weiterführung der heutigen Energiepolitik wird der Mittelabfluss auch zukünftig hoch bleiben. Zwar wird für die Zukunft ein sinkender Energieverbrauch prognostiziert, wegen der steigenden Importpreise nimmt aber der Mittelabfluss je nach Preisszenario nur leicht ab oder sogar stark zu. Dies bedeutet, dass die heutigen Massnahmen nicht ausreichen, um den Mittelabfluss längerfristig substanziell zu reduzieren. Damit die Energiebereitstellung zukünftig vermehrt zur lokalen Wertschöpfung beitragen kann, sind zusätzliche Investitionen in die Energieeffizienz und eine stärkere Förderung lokaler, erneuerbarer Energien nötig. In diesem Zusammenhang spielen die Kantone insbesondere in den beiden Bereichen Gebäude und Raumplanung eine Schlüsselrolle. Durch die Umsetzung von kantonalen Energiestrategien können sie massgeblich zur Energiewende beitragen

Environmental benefits of a circular economy : connecting waste type and geographic proximity

Introduction: The aim of a circular economy is to transform waste into resources. There is a plethora of waste and by-products that remain unused in the traditional linear industrial system. However, transformation from a linear to a circular system is challenging, limited by several constraints such as the availability of information on the specific composition of the waste, the availability in time and space, the quantity of waste, as well as limited knowledge of the usability of such waste products. These challenges are exacerbated by the initial effort needed for implementation before an economy benefits from economic, ecological or societal improvements. Nevertheless, a circular economy generates less waste and consumes fewer resources, which in return makes it more profitable due to cost savings enabled by efficient resource use. The goal of the SHAREBOX project is the development of a platform for the facilitation of synergies within the industry to enable a more circular flow of resources within the European process industries. The project consortium has 15 partners including research organisations, SMEs and industrial partners as well as market actors and is part of the EU framework program Horizon 2020. Materials and Methods: The SHAREBOX platform is a database of available waste and resources required by companies, enabling the transformation of waste to resources by matching of two demands. The platform also serves as the first point of contact between different partners in a circular system. Furthermore, the platform enables the identification of new synergies overarching the different subsectors of the industries as well as optimal matching from the perspective of a circular economy. The key objectives are the facilitation of circular synergies through information and communications technology, the provision of information required to realise circular synergies within European industries and the identification of new circular synergies. Results and Discussion: The results of circular industry systems facilitated by the National Industrial Symbiosis Program (NISP) in the United Kingdom show a substantial reduction in the consumption of resources and generation of emissions compared to linear systems. Nevertheless, if there is a plethora of different types of waste, there is also a plethora of different synergies. This leads to different results for each type of waste that is transformed to a resource. Furthermore, the life cycle stage of transformation also has to be included. A transformation such as the reuse of polyethylene terephthalate (PET) can lead to emissions or require additional auxiliary materials as well as transportation. Therefore, the potential benefit will never be equal to the total impact of the primary input because of the transformation stage and the associated environmental impacts of collection and beneficiation. We analysed the implications of the transformation of different waste types to resources when industries are located in different geographic locations under consideration of the life cycle stage of transformation. Figure 2 shows the most significant results of the net benefit within the set of analysed waste types: the transformation of PET and concrete waste. Waste PET can be transported up to 10 000 km by lorry and still provide a net benefit regarding greenhouse gas emissions due to circular use. However, in case of concrete, the results are very different. A net benefit only occurs if the additional transport distance compared to primary concrete is less than 5 km. As a reference, the median of the transported distance of completed transformations within the NISP in the United Kingdom according to Jensen et al. is indicated with a black cross. About half of the 979 transformations within NISP were realised within a radius of 33 km and only one quarter of the synergies involved distances greater than 64 km. Conclusions: Transformation from linear to circular systems can substantially reduce total resource consumption as well as emissions of the whole value chain and therefore contribute to a greener economy. However, matching industries for transformations leading to the substitution of primary materials is still a major challenge. In addition, the environmental benefits of the reuse of resources is limited by the life cycle stage of the transformation as well as by additional transportation that may be required. The analysed set of types of waste shows a broad range of potential benefits. For some types of waste, the net benefits are still considerable after the subtraction of the additional impacts due to the life cycle stage of transformation as well as additional transport requirements. However, for selected types of waste, the net benefit tends to be negligible. The completeness of the scope will be crucial for the assessment and generalisations overarching different types of waste remain challenging

Clean technologies in agriculture : how to prioritise measures?

As agriculture continues to be under pressure due to its negative environmental impacts, resource-efficiency and the use of clean technologies gain importance. Meanwhile, there is an abundance of technological solutions that help “clean” agriculture’s hotspots, either by reducing inputs, by producing renewable energy or by protecting ecosystems. Decisions about clean technologies remain difficult due to the variety of options, difficulties in cost-benefit calculations, and potential trade-offs in sustainability. We therefore addressed the issue of decision-making regarding clean technologies in agriculture. A multi-criteria decision analysis (MCDA) was used to rank the most sustainable technologies. Evaluation of 17 selected clean technologies was based on literature information and expert opinion. Wireless sensor irrigation networks, frequency converters for vacuum pumps and stable air conditioning, PV electricity and drip irrigation were the five technologies with the highest sustainability scores, outperforming the 12 other clean technologies. When all sustainability dimensions and criteria were equally weighted, PV electricity was superseded by variable speed drive technology for irrigation in the top five. This paper shows that MCDAs are a useful method for choosing between sustainable clean technology options. By applying different weighting, the MCDA can reflect the priorities of the decision maker and provide customised results

LCA of energetic biomass utilization: actual projects and new developments—April 23, 2012, Berne, Switzerland

Introduction: In the last years, the use of biomass for energy purposes has been seen as a promising option to reduce the use of nonrenewable energy sources and the emissions of fossil carbon. However, LCA studies have shown that the energetic use of biomass also causes impacts on climate change and, furthermore, that different environmental issues arise, such as land use and agricultural emissions. While biomass is renewable, it is not an unlimited resource. Its use, to whatever purpose, must therefore be well studied to promote the most efficient option with the least environmental impacts. The 47th LCA Discussion Forum gathered several national and international speakers who provided a broad and qualified view on the topic. Summary of the topics presented in DF 47: Several aspects of energetic biomass use from a range of projects financed by the Swiss Federal Office of Energy (SFOE) were presented in this Discussion Forum. The first session focused on important aspects of the agricultural biogas production like the use of high energy crops or catch crops as well as the influence of plant size on the environmental performance of biogas. In the second session, other possibilities of biomass treatment like direct combustion, composting, and incineration with municipal waste were presented. Topic of the first afternoon session was the update and harmonization of biomass inventories and the resulting new assessment of biofuels. The short presentations investigated some further aspects of the LCA of bioenergy like the assessment of spatial variation of greenhouse gas (GHG) emissions from bioenergy production in a country, the importance of indirect land use change emissions on the overall results, the assessment of alternative technologies to direct spreading of digestate or the updates of the car operation datasets in ecoinvent. Conclusions: One main outcome of this Discussion Forum is that bioenergy is not environmentally friendly per se. In many cases, energetic use of biomass allows a reduction of GHG and fossil energy use. However, there is often a tradeoff with other environmental impacts linked to agricultural production like eutrophication or ecotoxicity. Methodological challenges still exist, like the assessment of direct and indirect land use change emissions and their attribution to the bioenergy production, or the influence of heavy metal flows on the bioenergy assessment. Another challenge is the implementation of a life cycle approach in certification or legislation schemes, as shown by the example of the Renewable Energy Directive of the European Unio

The environmental mitigation potential of photovoltaic-powered irrigation in the production of South African maize

Agriculture is under pressure to reduce its environmental impact. The use of renewable energy sources has potential to decrease these impacts. Maize is one of the most significant crops in South Africa and approximately 241,000 hectares are irrigated. This irrigation is most commonly powered by grid electricity generated using coal. However, South Africa has high solar irradiation, which could be used to generate photovoltaic electricity. The aim of this study was to determine the environmental mitigation potential of replacing grid-powered irrigation in South African maize production with photovoltaic irrigation systems using Life Cycle Assessment. The study included the value chain of maize production from cultivation to storage. Replacing grid electricity with photovoltaic-generated electricity leads to a 34% reduction in the global warming potential of maize produced under irrigation, and – applied at a national level – could potentially reduce South Africa’s greenhouse gas emissions by 536,000 t CO2-eq. per year. Non-renewable energy demand, freshwater eutrophication, acidification, and particulate matter emissions are also significantly lowered. Replacing grid electricity with renewable energy in irrigation has been shown to be an effective means of reducing the environmental impacts associated with South African maize production