The progress toward more sustainable energy, water and environmental systems approaches and applications

This editorial provides an overview of ten scientific articles published as the Special paper selection in Thermal Science. The papers were selected from almost six hundred contributions, presented at the 16th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES 2021), held on October 10-15, 2021 in Dubrovnik, Croatia. The topics covered in the Special paper selection include economics of electricity markets, nuclear technology, repowering of the coal-based power plant, hybrid renewable energy system, sustainable biomass handling and conversion, post-combustion emissions control, and efficient cooling technology. The editorial also emphasised the papers recently published in the Special Issues of leading scientific journals dedicated to the series of SDEWES Conferences

Innovation and advancement of thermal processes for the production, storage, utilization and conservation of energy in sustainable engineering applications

This vision article accompanies a special issue of Applied Thermal Engineering dedicated to the 16th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES) held in Dubrovnik in 2021, and summarizes a selection of papers presented at the conference. At the focal point are a range of topics related to thermal processes as these arise in energy production, storage, utilization and conservation, covering fundamental research, the development of technical solutions for diverse sustainable engineering applications, technoeconomic analyses, and issues relating to the potential and integration of technologies from higher-level approaches. Thermal processes are the basis of numerous sustainable engineering applications and their understanding and improvement are increasingly required in the context of improved resource use efficiency and reduced environmental impact. Applications of interest include thermal systems used in buildings, thermochemical processes, seawater treatment, thermal storage solutions and renewable energy resource use. Emerging challenges in this space have given an opportunity to scientists, researchers and engineers to actively contribute to the development of relevant technological solutions, which are covered briefly in the present article

Innovation and advancement of thermal processes for the production, storage, utilization and conservation of energy in sustainable engineering applications

This vision article accompanies a special issue of Applied Thermal Engineering dedicated to the 16th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES) held in Dubrovnik in 2021, and summarizes a selection of papers presented at the conference. At the focal point are a range of topics related to thermal processes as these arise in energy production, storage, utilization and conservation, covering fundamental research, the development of technical solutions for diverse sustainable engineering applications, technoeconomic analyses, and issues relating to the potential and integration of technologies from higher-level approaches. Thermal processes are the basis of numerous sustainable engineering applications and their understanding and improvement are increasingly required in the context of improved resource use efficiency and reduced environmental impact. Applications of interest include thermal systems used in buildings, thermochemical processes, seawater treatment, thermal storage solutions and renewable energy resource use. Emerging challenges in this space have given an opportunity to scientists, researchers and engineers to actively contribute to the development of relevant technological solutions, which are covered briefly in the present article

A long-term capacity investment and operational energy planning model with power-to-X and flexibility technologies

In this research, we present a new long-term energy planning model that considers endogenous capacity investment, energy dispatch, Power-to-X, and demand response technologies. A thorough literature review of existing energy planning models is also presented, allowing to present the distinctive characteristics of the proposed model. The proposed model considers an energy system with the objective of minimizing the total capacity investment cost, throughout all technologies, and the operational cost faced by the system in satisfying energy demand. The model also considers the links among different demand sectors, including the links between the electricity, industry, heat, transport, and electro-fuels (e.g., Hydrogen) sectors. The proposed model is used to study the decarbonization of the Croatian energy system under distinct policies associated to RES levels and CO2 emissions goals. We demonstrate that Power-to-X technologies can certainly provide the flexibility that is required by new capacity investments in variable renewable energy sources, obtaining systems with lesser levels of critical excess of energy production. Higher usage of battery storage and Power-to-heat technologies are adopted primarily for variable renewable shares and CO2 reductions of close to 80%, while below such levels, the adoption of such technologies is limited. Additionally, Power-to-heat flexibility options become the major technologies when limits on CO2 emissions from the heating sector are imposed and, particularly, when the variable renewable energy shares in the electricity sector gets close to levels of 60%.s

Paving the way for the Paris Agreement: Contributions of SDEWES science

Today, coal is responsible for 40% of annual CO2 emissions. At the same time, global warming causes climate changes accompanied with catastrophic meteorological phenomena all over the world. After the 2015 Paris Agriment many countries set ambitious energy policy to reduce the annual greenhouse gas emission. The 2021 UN Climate Change Conference, COP26 - Glasgow, ended with the adoption of a less stringent resolution than some anticipated: countries only agreed to “phase down” rather than “phase out” coal. Is possible the realization of the Paris Agreement after COP-26? For achieving this ambitious targets in such conditions, the support of the multi-disciplinary scientific knowledge is needed. Since 2002 a series of SDEWES Conferences were founded. This paper presents an overview of published researches in special issues of leading journals dedicated to the series SDEWES Conferences, including also the papers in current special issue presented on Conferences held in 2020: 2nd LA SDEWES Conference - Buenos Aires, 1st AP SDEWES Conference - Gold Coast, 4th SEE SDEWES Conference - Sarajevo and 15th SDEWES Conference - Cologne. The focus is on five main fields: (1) energy system analysis; (2) energy savings in the building sector; (3) district heating; (4) electrification of transport and (5) water-energy nexus. Undoubtedly, the researches presented in this special issue as well as in previous ones, will contribute to the achievement of the goals of the Paris Agreement in difficult conditions after COP26

Thermogravimetric and kinetic analysis of biomass and polyurethane foam mixtures Co-Pyrolysis

Alternative fuels are crucial for the decarbonisation of high-energy demanding processes. The utilisation of waste materials to produce alternative fuels is especially interesting since, the co-pyrolysis of waste plastics and biomass was lately introduced as promising method since the synergistic effect might enhance the product properties compared to those from individual pyrolysis. Furthermore, the utilisation of waste biomass, like sawdust, is interesting since it does not influence the sustainability of biomass consumption, and even more, it avoids the usage of raw feedstock. Thermogravimetric analysis is per -formed to determine the thermal degradation behaviour and kinetic parameters of investigated mixtures to find the most appropriate utilisation method. Co-pyrolysis was conducted for three mixtures with the following biomass/polyurethane ratios: 75-25%, 50-50%, 25-75%, over a temperature range of 30-800 degrees C, at three heating rates 5,10 and 20 degrees C/min, under an inert atmosphere. Obtained results were subjected to comprehensive kinetic analysis to determine effective activation energy using the iso-conversional model-free methods and provide a detailed analysis of the samples' thermal degradation process. This work aimed to identify the main thermal decomposition stages during co-pyrolysis of biomass and polyurethane mixtures and provide the mixture composition's influence on the considered thermochemical conversion process