Keynote: The role of bioenergy on the increased penetration of RES – the green transition of Lesvos island by prof. Stergios Vakalis, University of the Aegean (link)
Abstract: The green transformation of the energy sector on islands has perpetually presented a formidable challenge. Establishing a reliable connection between these islands and the mainland grid on the mainland can prove problematic, particularly when substantial distances are involved. In such scenarios, independent electrical grids have been developed on islands, with utilized fuel sources being primarily diesel or fuel oil. A transition towards sustainable energy is currently in progress, with renewable energy systems progressively augmenting their share in the overall energy mix. Notably, wind and solar power, characterized as variable renewable energy (VRE) systems, are witnessing the most substantial capacity expansions. It is important to acknowledge that integrating VRE systems into isolated grids raises stability concerns. From a technical standpoint in the transition of the electricity sector, a key consideration for isolated grids is that as the capacity of variable renewable energy sources like photovoltaic and wind increases, a subsequent need arises for additional capacity from a stable and readily available source. This supplementary capacity is essential for meeting peak demand hours or addressing periods when solar PV and wind power alone are unable to fulfill the island's electricity requirements. This study presents several applications on islands in Greece that undergo green transition in respect of VRE installations (Ag. Efstratios) and e-mobility (Astypalaia) and highlights the drawbacks of RES penetration. The interesting case of Lesvos Island is presented, and this study explores the potential for biomass and biowaste utilization in the context of the green energy transition. Lesvos has 11 million olive trees and more than 40.000 tonnes of pruning are readily available every year that can support a 5 MW biomass gasification facility. In addition, for every hour of operation of olive mills on Lesvos, 100 tonnes of olive mill wastewater are produced. Liquid biowaste can undergo anaerobic digestion to produce biogas. Leveraging biomass and biowaste for energy production can contribute to the grid stability during the transition to higher VRE utilization, effectively serving as a "gas-battery" to address any supply shortfalls. Therefore, we introduce the concept of "μgas-to-grid," wherein various biomass sources are converted into gaseous fuels and injected into a small-scale natural gas grid. This μgas design entails localized, small-scale conversion of biomass and biowaste into gaseous fuels, with centralized upgrades to the gases before injection into a small natural gas grid. This concept can support the second stage of the energy transition, as isolated island grids become integrated with central grids while also meeting the demand for greener heating fuels in buildings and the transportation sector. This study delves into the pivotal role that biomass can play in both stages of the energy transition.
Dr. Stergios Vakalis is an Assistant Professor at the Department of Environment / University of the Aegean in the field of "Energy Management and Low Carbon Technologies". He works in the Energy Management Laboratory and his research focuses on the production and analysis of fuels, and the energy efficiency of energy systems. He teaches courses on Renewable Energy Technologies, Energy Modeling & Analysis (LCA / MCA / Aspen Plus / Cantera-MATLAB) and Thermodynamics (Heat and Mass Transfer). He supervises one postdoctoral fellow, two doctoral students and two postgraduate students. From 2018 to 2109 Dr. Vakalis worked as an Assistant Professor of Research at the Libera Università di Bolzano in the field of thermodynamic analysis and in the production of electricity from renewable sources. In 2016, in the framework of his Postdoctoral dissertation, he was awarded the "National Scholarship of Academic Excellence" by the State Scholarship Foundation. A notable point of his research was the development of the 3T energy efficiency method for the holistic evaluation of waste-to-energy plants. Also, in collaboration with Robert Heimann he has developed the innovative method of frictional pyrolysis which produces biocarbon and bio-oil from agricultural waste and biomass only with the use of friction and without the addition of external heat. Dr. Vakalis is a reviewer for more than 25 scientific journals and has received awards for "Outstanding Contribution to Review" from the following journals: Journal of Cleaner Production (Elsevier), Renewable Energy (Elsevier), Journal of Environmental Management (Elsevier), Energy ( Elsevier), Waste Management (Elsevier), Journal of Analytical and Applied Pyrolysis (Elsevier). He is a permanent member of the Organizing Committee of the annual "International Conference on Sustainable Solid Waste Management" and is a reviewer and evaluator of proposals for the General Secretariat for Research and Technology. Since 2018, Dr. Vakalis is a member of the WtERT (Waste Energy Research and Technology Council) World Council in collaboration with the Earth Engineering Center of Columbia University in New York.
Keynote: Knowledge Graphs in the Energy Sector: Challenges to Enhance Transparency and Trustability in Energy Data Ecosystems by prof. Maria-Esther Vidal, Leibniz University of Hannover and TIB-Leibniz Information Centre for Science and Technology, Hannover, Germany (link)
Abstract: Knowledge graphs (KGs) have momentum as expressive data structures to represent the convergence of data and knowledge spread across various data sources. Although coined by the research community for several decades, KGs are increasingly relevant in scientific and industrial areas. In particular, the rich amount of encyclopedic knowledge in KGs like DBpedia and Wikidata, or domain-specific KGs (e.g., Transparent Energy Knowledge Graph and the PLATOON Knowledge Graph) demonstrate the feasibility of integrating factual domain-specific knowledge following the Linked Data principles.
Energy data integrated into existing KGs are collected in heterogeneous formats or physically distributed over multiple sites (e.g., wind power systems, solar power systems, conventional power plants, cooling, heating, lighting systems, and smart grids). Years of research on semantic data management and knowledge engineering have led to merging heterogeneous data as factual statements into a KG. Despite accepting data management systems as crucial data processing tools for industrial and scientific database applications, the scenario differs for KG-driven solutions. Real-world applications require a complete understanding of all the decisions made during data management. Unfortunately, the absence of algorithmic methods to account for KG transparency considerably affects trustability and prevents their full acceptance as reliable solutions for decision-making.
This talk will present the challenges faced at data integration, query processing, and knowledge engineering levels to empower the pipelines of KG creation with transparency. Solutions for query processing and data management over data integration systems represent the baselines. Moreover, we will explain the role of knowledge extraction, mapping languages, integrity constraints, and provenance towards data transparency and traceability. We will further discuss knowledge-driven data ecosystems as reference architectures to provide the foundations for transparent KG-driven frameworks to enhance trustability. We will illustrate our proposed approach with existing KGs in the energy sector, where data transparency is crucial for building trustable solutions to support decision-making.
Prof. Dr. Maria-Esther Vidal is the head of the Scientific Data Management Research Group at TIB and a member of the L3S Research Centre at the University of Hannover. She is also a full professor (on-leave) at Universidad Simón Bolívar (USB) Venezuela. Her interests include Big data and knowledge management, knowledge representation, and semantic web. She has published more than 170 peer-reviewed papers in Semantic Web, Databases, Bioinformatics, and Artificial Intelligence. She has co-authored one monograph, and co-edited books and journal special issues. She is part of various editorial boards (e.g., JWS, JDIQ), and has been the general chair, co-chair, senior member, and reviewer of several scientific events and journals (e.g., ESWC, AAAI, AMW, WWW, KDE). She is leading data management tasks in the EU H2020 projects PLATOON, iASiS, BigMedylitics, and QualiChain, and has participated in BigDataEurope, BigDataOcean; she is a supervisor of MSCA-ETN projects WDAqua and NoBIAS. She has been a visiting professor in different universities (e.g., Uni Maryland, UPM Madrid, UPC, KIT Karlsruhe, Uni Nantes). In the past, she has participated in international projects (e.g., FP7, NSF, AECI), and led industrial data integration projects for more than 10 years (e.g., Bell South, Telefonica).
