Scopus

Chemical recycling (CR) could support a circular approach for municipal solid waste (MSW) treatment. In promoting the recirculation of recyclable carbon-containing waste as secondary feedstock for chemical production, it could contribute to resource conservation, emissions reduction, and supply security. To evaluate CR's contribution to the transition from a linear to a circular carbon economy - and correspondingly to the achievement of environmental, economic, and social sustainability as indicated in the UN Sustainable Development Goals (UN-SDGs) - this study builds on extant literature of life cycle sustainability assessment (LCSA) to investigate consequential environmental, economic, and social CR impacts. Specifically, an integrated approach whereby process-based life cycle assessment, techno-economic analysis, and social indicators are linked in the framework of an agent-based model is developed to investigate sustainability consequences of CR via gasification of residual MSW in Germany. Results suggest that CR contributes to reducing climate change and to addressing terrestrial acidification and fossil resource scarcity. However, its deployment will be associated with significant system costs. Hence, to promote CR implementation, measures such as obliging direct waste incineration to trade CO2 certificates - provided that certificate prices increase sharply in the future - as well as implementing a recycling rate are found to be necessary to gap economic disadvantages. This study not only contributes to extending life cycle approaches for LCSA methodologically, it furthermore provides valuable insights into temporal and spatial interactions in waste management systems to inform science, industry, and politics about the sustainability impacts of CR on the achievement of the UN-SDGs.

In this work the influence of the LECO treatment on the typical PERC degradation mechanisms was investigated. It was found that the treatment has no significant impact on the Boron-Oxygen related Light Induced Degradation and Light and elevated Temperature Induced Degradation behavior. Furthermore, it is shown that stabilized cells remain stable after the LECO treatment. Also, we did not find any indication of LECO influencing the Potential Induced Degradation susceptibility. Finally, the variation of the process order of the LECO treatment and the B-O Stabilization Process was analysed and showed no restrictions or differences in the outcome of the solar cell quality or stability. Based on these results it is proposed to implement LECO as an approach to decrease the LeTID-sensitivity by combining LECO with modified firing processes. We claim that a combination of reduced peak firing temperatures with the LECO process leads to a decrease in LeTID sensitivity without any drawbacks in the cells' efficiencies.

In order to harmonize the supply and demand of green energy, new future-proof technologies are needed. Here, hydrogen plays a key role. Within the current framework conditions, the production of green hydrogen is not yet economically viable. The use of the oxygen produced and the possible increase in efficiency associated with it mostly remain unconsidered. The aim is to demonstrate that the economic efficiency of a power-to-gas (PtG) project can be increased by using the byproduct oxygen. In this research project, a water electrolyzer connected to grid is powered to supply hydrogen to a hydrogen refueling station. By utilizing the byproduct oxygen from water electrolysis for a wastewater treatment plant (WWTP), it is shown that the net present value (NPV) of the project can be improved by up to 13% compared to the initial scenario. If a photovoltaic (PV) system is used in addition to grid electricity for higher green hydrogen production, the NPV can be further improved by up to 58%. The levelized cost of hydrogen (LCOH) is calculated for different scenarios with and without oxygen configuration. A sensitivity analysis is then performed to find important parameters.

State-of-the-art solar cell technologies, such as hetero-junction cells or PERC cells, exhibit a time-dependent deformation of their current-voltage characteristics in fast solar simulator measurements. This hysteresis effect is due to an increased internal capacitance. It manifests itself as a pronounced difference between I–V-curves depending on the measurement direction, i.e. Isc→Voc or Voc→Isc. Thus, it leads to an imprecise determination of the cell performance parameters in particular at the maximum power point. In this study, an algorithm-based correction procedure for these capacitance-induced effects is presented. Using evolutionary optimization algorithms, our correction approach allows the determination of a steady-state curve together with the extraction of all cell parameters featured in a time-dependent equivalent circuit model. It can be implemented without any hardware upgrades and applied to measurement times as low as a few milliseconds. As our basic approach is entirely independent of the underlying model, it is applicable to any solar cell technology by adapting the model under consideration.