Life cycle assessment of a novel electrocatalytic process for the production of bulk chemical ethylene oxide from biogenic CO2

Carbon capture and utilization (CCU) technologies support future energy and climate transition goals by recycling carbon dioxide (CO2) emissions. The use of biogenic CO2 from renewable sources, is an avenue for the production of fully renewable products. Fossil-based materials can potentially be replaced in the long term while allowing for the use of so called “waste” streams. To foster the development of a circular economy more insights need to be gained on the life cycle impact of CCU technologies. This study analyzed a CCU process chain, with focus on the utilization of volatile renewable electricity and biogenic CO2. We performed a cradle-to-gate life cycle assessment, evaluating various environmental impact categories (CML 2001 methodology) and primary energy demand (PED) with GaBi LCA software by sphera®. The targeted olefin is ethylene oxide (C2H4O), which is a crucial intermediate chemical for the production of various synthetic materials, such as polyethylene terephthalate (PET). As functional unit, 1 kg ethylene oxide was chosen. In the novel process at first ethylene (C2H4) and hydrogen peroxide (H2O2) are produced from water and CO2via an electrocatalytic process (Power-to-X process). In a second step, the two intermediates are synthesized to ethylene oxide. The theoretical implementation of a medium-scale process under average European conditions was considered in 12 scenarios that differed in energy supply and CO2 source. Sensitivity analyses were conducted to evaluate the influence of the energy and resource efficiencies of the production steps. The process was compared to its fossil benchmark, an existing conventional EO production chain. Concerning the global warming potential (GWP), negative emissions of up to −0.5 kg CO2 eq./kg product were calculated under optimized process conditions regarding energy and conversion efficiency and using biogenic CO2. In contrast, the GWP exceeded the fossil benchmark when the European grid mix was applied. The PED of 87 MJ/kg product under optimized conditions is comparable to that of other Power-to-X processes, but is high compared to fossil-based ethylene oxide. Based on the results we conclude that the energy efficiency of the electrocatalytic cell and renewable energy as input are the main levers to achieve a low environmental impact

Effects of Alpine hydropower dams on particle transport and lacustrine sedimentation

Abstract.: The effects of high-alpine hydropower damming on lacustrine sedimentation and transport of solid particles were investigated in the glaciated Grimsel area and in downstream Lake Brienz, providing quantitative denudation rates and sediment yield on a source-sink basis. A total of 271 kt/yr of solid particles entered the Grimsel reservoirs on average in the last 71 years, mostly by turbiditic underflows that focused sedimentation in depocenters upstream of obstacles such as bedrock ridges, submerged moraines, or dams. This is equivalent to a sediment yield of 2430 t/(km2yr) in the catchment (111.5 km2) or a denudation rate of 0.94 mm/yr. A total of 39 kt/yr of the fine fraction (<~4 μm) leave the reservoirs and are transported to downstream Lake Brienz, while 232 kt/yr of mostly coarse particles are retained, reducing total sediment input of the River Aare into Lake Brienz by two thirds. Modeling the particle budgets in the Aare with and without dams indicates that the fine fraction budgets are only slightly affected by damming, but that the reservoirs cause a shift in seasonal runoff timing resulting in increasing and decreasing particle transport in winter and summer, respectively. Thus, hydrodamming alters mostly deltaic sedimentation in Lake Brienz, where the coarse fraction is deposited, whereas fine grained distal sedimentation and varve formation on lateral slopes are less affected. All varved records of the reservoirs and Lake Brienz that provide sediment rates and grain size records on an annual basis indicate that climate is the main control on these proxies, while, for instance, the onset of pump storage activity in the reservoirs did not impose any significant change in lacustrine sedimentation patter

Element Content in Volcano Ash, Soil and River Sediments of the Watershed in the Volcanic Area of South Iceland and Assessment of Their Mobility Potential

In this work, we present the results of element content in river sediments and soil of the Rangárvellir river in southern Iceland as well as in the volcano ash from the Eyjafjallajökull eruption in 2010. Severe natural catastrophes have devastating impact on the environment. We selected the Rangárvellir area located in the vicinity of Mt Hekla, Iceland’s most active volcano, for our study. This study site is ideal to investigate wind and water erosion and sediment transport processes of two main glaciers rivers: the Eystri-Rangá and the Ytri-Rangá and the Hroarslækur River. Sediments of these rivers consist of volcano materials, ash and lava. In order to assess the sediment dynamics, we collected sediment, soil and volcanic ash. The fractioning of the elements was carried out using sequential extractions. The distribution of Si indicates that the sediments originate from the same geochemical basis. Li and partly B exist in the first phase of volcanic ash and river sediments but not in the mobile phases of soils. In the mobile phase of volcanic ash, P was found but it did not exist in the first phase of soil and sediments. These results suggest the different chemical fingerprints in the water sediments and surrounding soil

Characterisation of the chemical composition in geothermal hot springs in Iceland and Serbia

Geothermal hot springs are located in various tectonic environment proving environmentally friendly energy source to fulfil energy demand. The geothermal energy sources are often associated with divergent tectonic plate boundaries as in the Icelandic case or in orogeny geological settings as in the Serbian case. The chemical composition of a hot spring is a signature of the sub-surface geology and its chemical composition. Hence, the comparison of the chemical composition of geothermal sources can help us provide more detailed information prior to sub-surface exploration. In order to assess the suitability of geothermal sources we analysed the chemical composition in Icelandic and Serbian geothermal sources. For this purpose we collected samples from various hot springs in Iceland and in Serbia and analysed them using ion chromatography (IC) to determine anion concentrations and using inductively coupled plasma-optical emission spectrometry (ICP – OES) to determine cation and other element concentrations. The preliminary results reveal that chemical composition reflects differences between locations of sampling as well as the depths from which the fluid was extracted. Preliminary data obtained from the chemical analysis from sources located near to the Ocean in Iceland indicate a high concentration of Na+, K+ and Cl- ions, revealing an inflow of sea water. The data from the chemical analysis of the samples obtained from sources in Serbia, however, shows a high concentration of Na+, Ca2+ and Mg2+. These results reveal that Serbian geothermal sources are characterized by very hard water and accordingly have to be used with precaution. Further analysis of the temporal evolution of the chemical composition is advisable before sub-surface exploration.European Geosciences Union (EGU) General Assembly 2019, Vienna, Austria, April 7-12, 201

A review of nature-based solutions for urban water management in European circular cities: a critical assessment based on case studies and literature

Abstract Nature-based solutions (NBS) can protect, manage and restore natural or modified ecosystems. They are a multidisciplinary, integrated approach to address societal challenges and some natural hazards effectively and adaptively, simultaneously providing human well-being and biodiversity benefits. NBS applications can be easily noticed in circular cities, establishing an urban system that is regenerative and accessible. This paper aims to offer a review on NBS for urban water management from the literature and some relevant projects running within the COST Action 'Implementing nature-based solutions for creating a resourceful circular city'. The method used in the study is based on a detailed tracking of specific keywords in the literature using Google Scholar, ResearchGate, Academia.edu, ScienceDirect and Scopus. Based on this review, three main applications were identified: (i) flood and drought protection; (ii) the water-food-energy nexus; and (iii) water purification. The paper shows that NBS provide additional benefits, such as improving water quality, increasing biodiversity, obtaining social co-benefits, improving urban microclimate, and the reduction of energy consumption by improving indoor climate. The paper concludes that a systemic change to NBS should be given a higher priority and be preferred over conventional water infrastructure

Scenarios for European agricultural policymaking in the era of digitalisation

CONTEXT Digitalisation affects the agri-food sector and its governance. However, what digitalisation of the sector will imply for future agricultural policymaking remains unclear. OBJECTIVE The objective of the study is to develop and evaluate explorative scenarios of digitalisation in the agri-food sector of Europe that are explicitly relevant to agricultural policy. The study aims to provide guidance for strategic development of agricultural policy to address the potentials, uncertainties and unknowns arising with digitalisation of the sector. METHODS We combine a Delphi study and a participatory scenario workshop to develop and evaluate plausible explorative scenarios of digitalisation of Europe's agri-food sector. For all scenarios we identify gaps in achieving a range of important European agricultural policy goals, drawing on the Delphi study and desk-based analysis. Subsequently we deduce strategies to address these agricultural policy gaps. RESULTS AND CONCLUSIONS Four scenarios of digitalisation of the agri-food sector were developed for Europe in 2030. They comprise of 1) digitalisation of the sector following current directions at current rates as a baseline scenario, 2) strong digitalisation of a regulatory government, 3) use of autonomous farming technology and 4) digitalised food business. These explorative scenarios entail various gaps in achieving European agricultural policy goals. Our findings suggest that the baseline scenario needs strategies to ramp up technological and institutional infrastructure for digitalisation. The other scenarios need strategies to prevent risks, e.g., of technological failures or undesired social impacts. They also need strategies to cater for special cases and diversity, e.g., of ecosystems and farming practices. Across the scenarios, it seems useful to increase digital competencies of the stakeholders. SIGNIFICANCE The study is the first that derives implications for policy strategies from explorative scenarios of future digitalisation of agricultural systems that target gaps in achieving agricultural policy goals. The combination of developing and analysing scenarios generated findings that are of significance to policymaking stakeholders and researchers alike, who all need to address the uncertainties arising with future digitalisation of the agri-food sector

Scenarios for European agricultural policymaking in the era of digitalisation

peer-reviewedCONTEXTDigitalisation affects the agri-food sector and its governance. However, what digitalisation of the sector will imply for future agricultural policymaking remains unclear. OBJECTIVEThe objective of the study is to develop and evaluate explorative scenarios of digitalisation in the agri-food sector of Europe that are explicitly relevant to agricultural policy. The study aims to provide guidance for strategic development of agricultural policy to address the potentials, uncertainties and unknowns arising with digitalisation of the sector. METHODSWe combine a Delphi study and a participatory scenario workshop to develop and evaluate plausible explorative scenarios of digitalisation of Europe's agri-food sector. For all scenarios we identify gaps in achieving a range of important European agricultural policy goals, drawing on the Delphi study and desk-based analysis. Subsequently we deduce strategies to address these agricultural policy gaps. RESULTS AND CONCLUSIONSFour scenarios of digitalisation of the agri-food sector were developed for Europe in 2030. They comprise of 1) digitalisation of the sector following current directions at current rates as a baseline scenario, 2) strong digitalisation of a regulatory government, 3) use of autonomous farming technology and 4) digitalised food business. These explorative scenarios entail various gaps in achieving European agricultural policy goals. Our findings suggest that the baseline scenario needs strategies to ramp up technological and institutional infrastructure for digitalisation. The other scenarios need strategies to prevent risks, e.g., of technological failures or undesired social impacts. They also need strategies to cater for special cases and diversity, e.g., of ecosystems and farming practices. Across the scenarios, it seems useful to increase digital competencies of the stakeholders. SIGNIFICANCEThe study is the first that derives implications for policy strategies from explorative scenarios of future digitalisation of agricultural systems that target gaps in achieving agricultural policy goals. The combination of developing and analysing scenarios generated findings that are of significance to policymaking stakeholders and researchers alike, who all need to address the uncertainties arising with future digitalisation of the agri-food sector

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns