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Addressing the environmental risks related to contamination of groundwater with the phenolics, benzene, toluene, ethyl benzene, xylene (BTEX) and polycyclic aromatic hydrocarbons (PAHs), which might be potentially released from the underground coal gasification (UCG) under adverse hydrogeological and/or operational conditions, is crucial in terms of wider implementation of the process. The aim of this study was to determine the main organic pollutants present in the process condensate generated during the UCG trial performed on hard coal seam in the Experimental Mine ‘Barbara’, Poland; 8,933 L of condensate was produced in 813 h of experiment duration (including 456 h of the post-process stage) with average phenolics, BTEX and PAH concentrations of 576,000, 42.3 and 1,400.5 μg/L, respectively. The Hierarchical Clustering Analysis was used to explore the differences and similarities between the samples. The sample collected during the first 48 h of the process duration was characterized by the lowest phenanthrene, anthracene, fluoranthene and pyrene contents, high xylene content and the highest concentrations of phenolics, benzene, toluene and ethyl benzene. The samples collected during the stable operation of the UCG process were characterized by higher concentrations of naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, while in the samples acquired in the post-process stage the lowest concentrations of benzene, toluene, naphthalene, acenaphthene and fluorene were observed.

This review organizes the current state of knowledge on the role of financial markets in energy transition. The originality of the study lies in the delimitation of its scope and diagnosis of research trends concerning the role of financing, innovation, and financial development sources. The study sets out to identify the role of the financial market in the energy transition process and present the state-of-the-art and main research focuses. For this purpose, a literature review was carried out based on the search results from the Web of Science database and using VOSViewer software, version 1.6.20. The analysis of 54 papers in the final sample allowed us to pinpoint the key links between financial markets and energy transition. Capital markets support green initiatives, with green bonds as a primary funding source. Blockchain and fintech technologies also significantly contribute to transition by offering innovative solutions. Additionally, a range of papers examine the costs associated with energy transition and the role of financial instruments in managing these. Regulatory challenges are another significant focus. This comprehensive analysis underscores the multifaceted relationship between financial markets and energy transition, providing insights into the current trends and the critical role of finance in fostering a sustainable future.

The utilization of autonomous unmanned aerial vehicles (UAVs) has increased rapidly due to their ability to perform a variety of tasks, including industrial inspection. Conducting testing with actual flights within industrial facilities proves to be both expensive and hazardous, posing risks to the system, the facilities, and their personnel. This paper presents an innovative and reliable methodology for developing such applications, ensuring safety and efficiency throughout the process. It involves a staged transition from simulation to reality, wherein various components are validated at each stage. This iterative approach facilitates error identification and resolution, enabling subsequent real flights to be conducted with enhanced safety after validating the remainder of the system. Furthermore, this article showcases two use cases: wind turbine inspection and photovoltaic plant inspection. By implementing the suggested methodology, these applications were successfully developed in an efficient and secure manner.

This work addresses the problem of energy consumption time series forecasting. In our approach, a set of time series containing energy consumption data is used to train a single, parameterised prediction model that can be used to predict future values for all the input time series. As a result, the proposed method is able to learn the common behaviour of all time series in the set (i.e., a fingerprint) and use this knowledge to perform the prediction task, and to explain this common behaviour as an algebraic formula. To that end, we use symbolic regression methods trained with both single- and multi-objective algorithms. Experimental results validate this approach to learn and model shared properties of different time series, which can then be used to obtain a generalised regression model encapsulating the global behaviour of different energy consumption time series.

AbstractSolar fuels offer a promising approach to provide sustainable fuels by harnessing sunlight1,2. Following a decade of advancement, Cu2O photocathodes are capable of delivering a performance comparable to that of photoelectrodes with established photovoltaic materials3–5. However, considerable bulk charge carrier recombination that is poorly understood still limits further advances in performance6. Here we demonstrate performance of Cu2O photocathodes beyond the state-of-the-art by exploiting a new conceptual understanding of carrier recombination and transport in single-crystal Cu2O thin films. Using ambient liquid-phase epitaxy, we present a new method to grow single-crystal Cu2O samples with three crystal orientations. Broadband femtosecond transient reflection spectroscopy measurements were used to quantify anisotropic optoelectronic properties, through which the carrier mobility along the [111] direction was found to be an order of magnitude higher than those along other orientations. Driven by these findings, we developed a polycrystalline Cu2O photocathode with an extraordinarily pure (111) orientation and (111) terminating facets using a simple and low-cost method, which delivers 7 mA cm−2 current density (more than 70% improvement compared to that of state-of-the-art electrodeposited devices) at 0.5 V versus a reversible hydrogen electrode under air mass 1.5 G illumination, and stable operation over at least 120 h.

Pyroelectric energy harvesting has the ability to transform wasted heat into useful energy and as such has a potential to create “green” energy from freely available sources such as ambient temperature changes, and contribute to the fight against climate change. Current pyroelectrics applications are limited to low-power electronics, portable systems or tasks needing only very low range of power (μW–mW). Developing further this highly promising technology should ultimately lead to the creation of more powerful, autonomous and self-powered electronic devices that could one day use to recycle currently “lost” thermal energy to power electronic devices in both domestic and industrial settings. To the best of our knowledge, hexagonal phase ZnS (wurtzite ZnS) has not been studied as a possible energy harvesting pyroelectric material despite w-ZnS being isostructural to the well-exploited and widely praised hexagonal ZnO [1]. In addition, the Tc temperature (1020 ˚C for bulk material) is high enough for ZnS that it has the ability to operate at higher temperature that are good match with the working temperature of power plants and automobiles, and hence w-ZnS ceramics should have a potential to be used in pyroelectric harvesters of waste heat coming from those activities [2]. Here we report on the pyroelectric output registered for a wurtzite phase ZnS ceramic fabricated as part of our project. To probe the pyroelectric output for a w-ZnS ceramic a simple device (a “pyro-cell”) was created by evaporating gold electrods on both sides of a ceramic sample, which was mounted on a Cu-metalized rectangular insulating base (vetronite) using silver paint. This device is stable from room temperature up to approximately 180°C. Two different heating and cooling testing set-ups were established: Set-up n°1 used an industrial scale laser, providing a source with fast temperature change, and Set-up n°2 had a standard lab hot plate heating element, providing a much slower temperature change. The characterization required an accurate measurement of the currents of the order of 10-9 A. In addition, using the Pyroelectric Test System (PK‐SPIV17T, State College, PA, USA) with a Keithley 6517 B Picoammeter, we were able to measure the pyroelectric coefficient and monitor its change at different frequencies as a function of temperature from 20 °C up to 150° C, with a heating rate of between 2 and 10 °C/min. Figure 1: Pyroelectric current measurements on an ZnS ceramic sample, using testing set-up n°1. The horizontal axis shows the time (seconds). References [1] Y. Yang, W. Guo, K.C. Pradel, G. Zhu, Y. Zhou, Y. Zhang, Y. Hu, L. Lin, Z. Lin Wang, “Pyroelectric Nanogenerators for Harvesting Thermoelectric Energy”, Nano Lett, 12 (6), 2012, 2833–2838 [2] L.A. Chavez, F.O. Zayas Jimenez, B.R. Wilburn, L.C. Delfin, H. Kim, N. Love, Y. Lin, “Characterization of Thermal Energy Harvesting Using Pyroelectric Ceramics at Elevated Temperatures”, Energy Harvesting and Systems, 5(1-2), 2018, 3–10 This project was also partially supported by the Piano triennale di realizzazione 2019-2021 della ricerca di sistema elettrico nazionale – Progetto 1.3 Materiali di frontiera per usi energetici (C.U.P. code: I34I19005780001).

The paper describes formation and spreading of dense shelf waters in the Adriatic Sea (North Adriatic Dense Water, NAdDW) during the winter of 2012 as a consequence of an intense and long cold air outbreak of northeasterly Bora winds. As a result, during February 2012 northern Adriatic Sea water temperature dropped to about 6 degrees C and density exceeded 1030 kg/m(3), most likely the maximum value since 1929. NAdDW dynamics has been investigated by means of a 3-D ocean-wave coupled model running on a high resolution and eddy-permitting grid. The numerical experiments have relied on the Coupled-Ocean-Atmosphere-Wave-Sediment-Transport (COAWST) system forced one-way with atmospheric forcings provided by the model COSMO-17. A suite of observational data has been used to characterize the Bora event and evaluate numerical model performance. At sub-basin scales, the newly formed waters flowing southerly have produced a water renewal of the northern Adriatic, as more than 50% of water volumes have left the basin. Dense waters volume transports, evaluated through different Adriatic cross-sections, have been modulated by tides (damped for the densest water masses) and reached about 1 Sv. The contribution of wave-induced forcings has been quantified and examined, indicating that these represent a major driving mechanism during NAdDW production and spreading phases. This work provides evidence that NAdDW is spread accordingly with two different mechanisms: at early stages of its formation, the wind-driven ocean circulation pushes newly formed waters to leave the northern basin with relatively high speeds (about 0.30 m/s). Later on, remaining NAdDW leaks slowly out (0.09 m/s as average) from the production site. Residence times of dense waters in the north, middle, and south Adriatic Sea are also documented. (C) 2014 Elsevier Ltd. All rights reserved.