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<p>Commonly used host rock reservoirs for Enhanced Geothermal Systems (EGS) are composed of granite, as they display highly conductive and sustainable fracture networks after stimulation. However, considering the large amount of metamorphic rocks in Europe’s underground, these rock types may also show a large potential to extract geothermal energy from the subsurface. Within the framework of the European Union’s Horizon 2020 initiative ‘MEET (Multi-Sites EGS Demonstration)’, we are conducting fracture permeability experiments at elevated confining pressures, p<sub>c</sub>, temperatures, T, and differential stresses, </p>

Abstract The objective of this study was to investigate the effects of particle size reduction and solubilization on biogas production from food waste (FW). To clarify the effects of volatile fatty acids (VFAs) in the digestion process, the relationship between particle size and VFA accumulation was investigated in detail. For this purpose, substrates of various particle sizes were prepared by bead milling to support hydrolysis. Batch anaerobic digestion experiments were carried out using these pretreated substrates at mesophilic temperature for a period of 16 days. The results of pretreatment showed that the mean particle size (MPS) of substrates ground with a bead mill decreased from 0.843 to 0.391 mm, and solubilization accounted for approximately 40% of the total chemical oxygen demand (total COD) for grinding pretreatment by bead milling. Anaerobic digestion batch experiments revealed that MPS reduced by bead milling at 1000 rpm improved methane yield by 28% compared with disposer treatment. Moreover, this may have increased microbial degradation during the VFA production process with increasing total number of revolutions (operation time × revolutions per minute). However, excessive reduction of the particle size of the substrate resulted in VFA accumulation, decreased methane production, and decreased solubilization in the anaerobic digestion process. These results suggest that optimized reduction of the particle size of the substrate in conjunction with optimized microbial growth could improve the methane yield in anaerobic digestion processes.

The most significant thermal water resource in the Carpathian Basin can be found under the territory of the Hungarian-Serbian border, in the Szeged-Morahalom-Subotica triangle. The abstraction for extensive and complex utilization is currently being started on both sides of the border. For the safe and sustainable abstraction, and its international monitoring, it is necessary to determine the hydrogeological-hydrodynamic features of the common thermal water base, and to elaborate a two-phase 4D model of the water base for the mapping of the water resource and its gas content. FP7

Wave power is a potential technology for generating sustainable renewable energy. Several types of wave energy converters (WECs) have been proposed for this purpose. WECs operate in a harsh maritime environment that sets strict limitations on how and when the device can be economically and safely reached for maintenance. Thus, to ensure profitable energy generation over the system life cycle, system reliability is a key aspect to be considered in WEC development. In this article, we describe a reliability analysis approach for WEC development, based on the use of reliability block diagram (RBD) modelling. We apply the approach in a case study involving a submerged oscillating wave surge converter device concept that utilizes hydraulics in its power take-off system. In addition to describing the modelling approach, we discuss the data sources that were used for gathering reliability data for the components used in a novel system concept with very limited historical or experimental data available. This includes considerations of the data quality from various sources. As a result, we present examples of applying the RBD modelling approach in the context of WEC development and discuss the applicability of the approach in supporting the development of new technologies.

Unequivocal change in the climate system has put coastal regions around the world at increasing risk from climate-related hazards. Monitoring the coast is often difficult and expensive, resulting in sparse monitoring equipment lacking in sufficient temporal and spatial coverage. Thus, low-cost methods to monitor the coast at finer temporal and spatial resolution are imperative for climate resilience along the world’s coasts. Exploiting such low-cost methods for the development of early warning support could be invaluable to coastal settlements. This paper aims to provide the most up-to-date low-cost techniques developed and used in the last decade for monitoring coastal hazards and their forcing agents via systematic review of the peer-reviewed literature in three scientific databases: Scopus, Web of Science and ScienceDirect. A total of 60 papers retrieved from these databases through the preferred reporting items for systematic reviews and meta-analyses (PRISMA) protocol were analysed in detail to yield different categories of low-cost sensors. These sensors span the entire domain for monitoring coastal hazards, as they focus on monitoring coastal zone characteristics (e.g., topography), forcing agents (e.g., water levels), and the hazards themselves (e.g., coastal flooding). It was found from the meta-analysis of the retrieved papers that terrestrial photogrammetry, followed by aerial photogrammetry, was the most widely used technique for monitoring different coastal hazards, mainly coastal erosion and shoreline change. Different monitoring techniques are available to monitor the same hazard/forcing agent, for instance, unmanned aerial vehicles (UAVs), time-lapse cameras, and wireless sensor networks (WSNs) for monitoring coastal morphological changes such as beach erosion, creating opportunities to not only select but also combine different techniques to meet specific monitoring objectives. The sensors considered in this paper are useful for monitoring the most pressing challenges in coastal zones due to the changing climate. Such a review could be extended to encompass more sensors and variables in the future due to the systematic approach of this review. This study is the first to systematically review a wide range of low-cost sensors available for the monitoring of coastal zones in the context of changing climate and is expected to benefit coastal researchers and managers to choose suitable low-cost sensors to meet their desired objectives for the regular monitoring of the coast to increase climate resilience.

The EU has set clear targets regarding energy conservation of buildings and heavily supports activities towards achieving these targets on a European scale. The Green Deal, renovation wave, Energy Performance of Buildings Directive (EPBD) and Energy Efficiency Directive (EED) are some examples of EU's actions. For more than a decade, Energy Performance Certificates provide detailed data about the current energy needs of a building/building unit as well as information about the building construction and systems. A Building Renovation Passport (BRP) has, on a European level lately, been conceived as a tool that can stimulate cost-effective renovation in the form of a long-term basis, step-by-step deep renovation roadmap following defined quality criteria, and outline energy renovation measures that will improve the energy performance of the building. A Digital Building Logbook (DBL) is another tool that can serve as an archive where all building information can be stored and continuously updated. In this way, a full record of the building history will be electronically available with data regarding construction plans and permits, maintenance and system replacement activities, energy and heat consumption and production, etc. Building Renovation Passports and the Digital Building Logbook are tools that can help in achieving energy efficiency in existing buildings and contribute to reaching the EU renovation wave goals. The objective of this report is to investigate how the current EPC schemes best make the link towards the BRP and the DBL to further incentivise and stimulate cost-effective deep energy renovations of buildings across Europe. Three surveys were carried out to collect relevant information about the current status of the EPC data records and to identify stakeholders' potential needs, perceptions, thoughts and expectations, regarding a future connection between the EPC and the BRP or DBL. These surveys were prepared in two forms: using an excel file format circulated via email, and through an online questionnaire. Their completion was carried out by 16 countries. Regarding the EPCs, the state or regional energy agencies are the owner of the EPC data records and make full use of them. Their current main usage is for statistical reasons in the majority of the countries and their access is publicly available in half of the responding countries. Many common data is stored in the EPC database which can be linked with other tools (half of the EPC databases are already linked with another source). Regarding the BRP, a review of existing European schemes showed that successful BRPs have combined the renovation advice with financial support, legal requirements and/or communication campaigns. An important factor of the BRP is that it should be issued by a qualified expert and should provide customised measures for the specific building together with the investment costs per renovation measure(s). The DBL analysis showed that it should provide access to building information and contribute to better decision-making for future interventions as well as operation, use and maintenance records. The building owner/user is proposed to have full access to the logbook and provide/input about energy bills and building plans/construction materials info. An important aspect is that every time the building undergoes intervention works, the DBL should be updated accordingly. The most important barrier is the lack of motivation to update the DBL contents followed by the absence of synergies and consistency with other tools. Another interesting finding is that both BRP and DBL should be fed automatically by EPC data without any user interference. There is a clear possible interconnection between EPC data and BRP and DBL future contents. In addition, BRP can be an instrument to increase the renovation rates and DBLs are necessary for the management of buildings' information. The linkage of EPC data and BRP and DBL can be strengthened by introducing BRP and DBL as voluntary schemes under national incentives and should be fully implemented once they have demonstrated acceptance by the stakeholders.

Applications of Solar Heat for Industrial Processes (SHIP) frequently require the coupling of the solar energy source with a thermal energy storage (TES) system, in order to accommodate the solar irradiance dynamics and its fluctuations with the eventually variable heat demand of the process. The complexity of the physical mechanisms that take place during the phase change process is still a challenge to an accurate modelling while keeping the calculation time low enough to provide fast calculations. This communication presents a simplified 1D model of a real latent thermal energy storage system with extended surfaces. The model has been validated against a 3D CFD model, providing good results and low calculation times. Preliminary results for a future real application are presented to show the applicability of the model.