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The EU has set out to reduce negative impacts from electricity generation on the environment, human health and towards our dependence on fossil fuels. As the fastest growing renewable source of electricity, photovoltaics plays an important role in the energy transition. The manufacturing of photovoltaic modules requires materials classified as critical, making them prone to supply disruptions. Although these materials are essential to the EU economy, they are not sufficiently recovered at the end of a photovoltaic module’s life. An alternative intermediate solution could be to extend the lifespan of existing modules, to slow down demand for these materials in the future. The aim of this study was to analyse the theoretical options and practical examples of product life extension strategies for photovoltaics. The R-Ladder was used as a guiding framework, which provided examples of life extension strategies. These include Reuse, Repair, Refurbishment, Remanufacture and Repurpose. Aspects for each of these strategies were analysed to find potential benefits and challenges related to four aspects: economics, environment, energy, and materials. The approach of this study includes a literature review to identify the life extension strategies discussed specifically for photovoltaics in the context of the circular economy. This was followed by a multi-case study on practical applications of Reuse, Repair and Repurposing of photovoltaic modules. Findings from literature and the case study were further supplemented with the insights from six experts. These experts had diverse backgrounds in research, manufacturing, and procurement to offer a variety of insights and perspectives on life extension strategies for photovoltaics. Finally, two scenarios were created for possible life extension pathways for used photovoltaic modules to illustrate the potential impacts compared to a commonplace premature replacement scenario. Economics and module performance are key factors in decision-making and acquisition of a photovoltaic ...

The level of advancement in the understanding of the mechanical properties of volcanic rocks is comparatively lower than that of sedimentary rocks. As part of the SUCCEED Project (Synergetic Utilisation of CO2 Storage Coupled with Geothermal Energy Deployment), which aims to investigate the feasibility of injecting captured and produced CO2 into the reservoirs to enhance geothermal production and achieve permanent CO2 storage at the Hellisheiði Geothermal Field in Iceland, this experimental research provides significant insights into the petrophysical and mechanical properties of the volcanic rocks collected from surface outcrops. The subsurface in Hellisheiði is mainly built up of hyaloclastite formations and interglacial basaltic lavas. During a field campaign samples were collected in different outcrops, ensuring that the samples were of high quality and sufficiently diverse to enable comprehensive analysis. Four samples per block and rock type have been prepared from the collected blocks, and they have been subjected to different laboratory tests to evaluate their petrophysical properties, such as porosity, density, and permeability, and their geomechanical behavior, using Unconfined Compression Test (UCS), Active-Source Acoustic Test, and Splitting Tensile Strength Test. Additionally, laboratory experiments have been conducted to investigate the impact of rapid cooling on rock damage due to thermal fracturing. The results show that there are interdependent relationships between porosity, bulk density, ultimate strength, Young's modulus, and wave velocities that can be observed when considering average values per rock. The rocks studied showed a negative correlation between porosity and other parameters and a direct correlation between ultimate strength and Young's Modulus. When examining individual rock samples, no significant correlations were observed between porosity and other parameters, however, those correlations where evident when comparing between different rock types, emphasizing the importance of ...

Global endeavors to reduce emissions in the shipping industry are accelerating the interest in fuel cell systems. This paper explores the application of different fuel cell types (LT-PEMFC, HT-PEMFC and SOFC) in combination with different fuels (LH2, LNG,MeOH and NH3) in expedition cruise ships. An impact model is developed for the first design phase. The goal of this paper is to evaluate the impact of the combination of fuel cell system implementation and operational profile on expedition cruise vessels. Impact is expressed in ship size, capital cost, operational cost and emissions. The model takes into account: fuel storage, on-board fuel processing, fuel cell system characteristics, balance of plant components, fuel cost over operational lifetime and all onboard emissions. In the research, seven different fuel cell systems and three different hybridization strategies are considered. For the six best performing combinations of fuel cell system and hybridization strategy, the range, endurance and capacity requirements are systematically varied to determine whether the best performing option depends on these requirements. Finally, hybrid option 2 (using diesel generators to support during long transits) combined with a methanol fueled LT-PEMFC system results in the lowest newbuild price. This option does comply with emission regulations and CO2 goals for 2030. Hybrid option 2 combined with an LNG fueled LT-PEMFC system results in the lowest total cost (newbuild price and fuel cost). This option does comply with emission regulations, but does not meet CO2 goals for 2030. When it is desired to reach this CO2 target, hybrid option 2 with methanol fueled LT-PEMFC is also recommended from a total cost perspective. ; Marine Technology

River systems play an important role in the filling of sedimentary basins and record the history of external forcing processes, such as climate, tectonics and sea-level change, acting on them. They are potential reservoirs for oil, gas and water, and can host coal and placer mineral deposits. Because of the complex interplay between the external forcing processes, however, understanding of the genesis of the stratigraphy of river systems and interpreting the stratigraphy correctly is far from straightforward. Current conceptual models are oversimplified, and more insight into the impact of external forcing processes must be gained to improve these models. The aim of this study was to assess the impact of climate (i.e., discharge and sediment influx) on the development of the large-scale stratigraphic architecture of river systems, in isolation and in conjunction with sea-level fluctuations, through an analogue modelling approach. Analogue physical models reproduce the long-term average effects and products of the transport processes in a river system, rather than the transport processes themselves. An advantage of analogue modelling over numerical modelling is that it is hard to make the model fit preconceived notions about the results, making it possible to test and develop conceptual models. The impact of climate (i.e., discharge and sediment influx) on the large-scale stratigraphic architecture of river-delta-shelf-basin systems appears not to be as dominant as the impact of sea-level change, but it does significantly affect the smaller scale stratigraphic architecture, such as the relative size of systems tracts and the rate and extent of erosion. Furthermore, we found a fundamental difference between the impact of changes in discharge and the impact of changes in sediment influx on the yield and mass accumulation at the mouth of a river system. River systems can act as buffers for rapid changes in sediment influx, while they react very rapidly to changes in discharge. Thus, the small-scale stratigraphy at the river mouth is controlled mainly by changes in discharge, and the large-scale stratigraphy is controlled by changes in sediment influx (and sea-level fluctuations). Also, because the response of the river gradient to an increase in discharge is the opposite to its response to an increase in sediment influx (and vice versa), the mass accumulation at the river mouth, combined with the overall stratigraphic architecture of the system, can be used to constrain paleo-discharge and paleo-sediment influx scenarios. Finally, our experiments show that a complex stratigraphic architecture is not necessarily the result of complex forcing, but can result from very simple changes in discharge. To assess the development of the stratigraphy in physical models, a new method for processing the data obtained in the experiments was developed. Series of subsequent digital elevation models of the surface of the model are converted, using custom-made software, into synthetic three-dimensional stratigraphy, containing true isochronous surfaces. This data set contains the development of the system through time in three dimensions, and can be presented in various formats, such as geological maps, geological sections and Wheeler diagrams.

The integration of Variable Renewable Energy Sources (VRES) creates challenges for meeting load demand. The lack of on-demand power generation of these VRES effectively threatens energy security. Therefore, storage facilities, especially hydrogen, have been broadly researched for potential implementation in our energy system, enabling on-demand power "generation". This thesis adds to this research by providing a framework on how VRES and long-term storage technologies can be most optimally utilized to ensure weekly or monthly energy security. This framework is explicitly applied to the Netherlands and reviews the opportunities of a VRES dominated future energy system. The framework consists of a VRES generation model and load model and identifies the optimal load coverage using single- and multi-objective genetic algorithms. The VRES generation model is designed for a weekly and monthly timeframe by using 31 years of available weather data (1988-2018), specifically average wind speeds and solar irradiance, for a number of locations in the Netherlands. Using the available weather data, power generation per MW of onshore wind, offshore wind, and solar PV are calculated. Subsequently, this calculated VRES power generation is compared to available real-world VRES power generation data and a correction factor is determined. Applying the correction factor to the more extensive weather data set allows to effectively create a VRES power generation model, based on the weather circumstances as in these 31 years. Additionally, a weekly and monthly 31-year load profile is determined, using available data for load demand in the Netherlands. Thereafter, both a single and multi-objective algorithm is tasked to provide load coverage in two main scenarios at minimum cost. First, load coverage is achieved exclusively utilizing VRES capacity. Secondly, a variety of long-term storage facilities are introduced in combination with VRES capacity to acquire energy security. Furthermore, these two methods for achieving energy security ...

Rising carbon dioxide concentrations in the air increase the global temperature since the industrial revolution. Today, there exists a great need to limit global warming, and an energy transition is vital to do so. With the upcoming changes in our energy system, bioenergy is widely discussed, resulting in a heated debate on including or excluding bioenergy in the energy transition. This study aims to identify the least controversial feedstocks out of 40 different ones and if they will help to resolve the controversies around bioenergy. Before a feedstock is deemed controversial, a background of bioenergy was established to see what role bioenergy has in today's energy system and in the future. A literature analysis identifies the role of bioenergy today. Using the 'IAMC 1.5C Scenario Explorer' hosted by IIASA the role in the future is identified. To determine the least controversial feedstocks, a multi-criteria decision analysis (MCDA) is performed. The PROMETHEE II method is used to perform the MCDA and the entropy weight method for weighting the criteria. The ranking and weighting make use of MATLAB. Since the aim is to classify feedstocks as the least controversial, the criteria are deduced from a literature analysis and represent the controversies of bioenergy. The first part of the report indicates a significant role in today's renewable energy system and a shift towards more modern bioenergy implementations like biofuels and bio-electricity. According to the scenario analysis, for the five different shared socio-economic pathways, bioenergy will be used. Besides the identification of a clear use of bioenergy in the future energy system, the scenario analysis of TFE of bioenergy indicated a shift towards modern bioenergy use. It was observed that the solid biomass use reduced and a strong increase in liquid biofuels in the transport sector will happen. These findings are in line with the predictions made by the IPCC. Also, this is in accordance with the observed growth rates and development trends found for ...

Numerous LNG (Liquefied Natural Gas) import terminals are under construction to fulfil the growing demand for energy carriers. After storage in tanks, the LNG needs to be heated and evaporated, also called ‘regasified’, to the natural gas needed in households and industry. Several options exist for providing the required heat. In the interest of sustainable development it is important to decide carefully upon which technology to apply for LNG evaporation. In this research, three options for LNG evaporation have been investigated: using the waste heat from a power plant, integrating the LNG terminal with an air separation unit and an oxy-fuel power plant, and combining the evaporation process with an Organic Rankine Cycle to produce electricity. The research consisted of an environmental life cycle assessment, calculation the life cycle costs, conducting a social life cycle assessment and determining the cumulative exergy extracted from the natural environment (CEENE). The option in which the LNG terminal is integrated with an air separation unit and an oxy-fuel coal power plant appeared to be preferable. This research is part of a study after the effects of involving exergy analysis in decisions regarding future energy supply on the environmental, economic and social aspects of its sustainability. Infrastructure Systems & Services Technology, Policy and Management

The escalating demand for green hydrogen as a sustainable energy carrier has sparked significant interest in offshore wind-to-hydrogen systems, which hold the promise of expediting the transition towards renewable energy sources. The objective of this research is to provide insight in the techno-economic feasibility of semi-centralised electrolysis in an offshore wind farm. The semi-centralised offshore wind-to-hydrogen configuration will be compared with centralised and decentralised offshore wind-to-hydrogen to potentially reduce the levelised cost of hydrogen (LCOH) in future wind-to-hydrogen production designs. This research was conducted in collaboration with Vattenfall, a leading player in offshore wind energy within Europe, who recognizes the potential of green hydrogen as a key driver in the ongoing energy transition. Vattenfall provided access to an in-house wind farm layout optimisation model to create optimised wind farm layouts as well as site specific data for the case study. This model and data allowed a narrowed focus on the hydrogen aspects of the wind-to-hydrogen configurations. The technical examination explores crucial elements such as the conversion of wind energy into hydrogen through electrolysis, hydrogen transmission and variances in offshore substations and hydrogen wind turbines, to understand the technical differences between the different offshore wind-to-hydrogen configurations. Additionally, by analysing the hydrogen production process and comparing the scale of hydrogen production in offshore substations or hydrogen wind turbines, the study exhibits the technical feasibility of a wind-to-hydrogen farm with numerous semi-centralised monopile hydrogen substations in comparison with wind-to-hydrogen farms consisting of a single centralised jacket hydrogen substation or decentralised hydrogen wind turbines. To enable a quantitative comparison of the different offshore wind-to-hydrogen setups in the economic analysis, the LCOH for each configuration was modelled. This process involved ...

The EU Project AquaTerra generates knowledge about the river-soil-sediment-groundwater system and delivers scientific information of value for river basin management. In this article, the use and ignorance of scientific knowledge in decision making is explored by a theoretical review. We elaborate on the 'two-communities theory', which explains the problems of the policy-science interface by relating and comparing the different cultures, contexts, and languages of researchers and policy makers. Within AquaTerra, the EUPOL subproject examines the policy-science interface with the aim of achieving a good connection between the scientific output of the project and EU policies. We have found two major barriers, namely language and resources, as well as two types of relevant relationships: those between different research communities and those between researchers and policy makers. © 2007 Elsevier Ltd. All rights reserved.