• Energy Research
• CZ close
• Sustainability close

Building on the planetary boundaries (PB) concept and recent studies on assessing the PB at the national level, this paper proposes a new method for addressing the growing need to conceptualize the national environmental limits in the global perspective. The global and national limits for the climate change PB are set using the GDP-adjusted model that represents an innovative and fairer CO2 emissions distribution mechanism. It elaborates on the equity principle and distributes the remaining global emission budget to countries on the basis of their past, current, and future population; past emissions; and current state of economic development. The results point to insufficient global efforts to reduce the CO2 emissions to avoid a global temperature rise of more than 2 °C by 2100. When examining the data in accordance with this climate change scenario, we see that some countries have already spent their CO2 budget and most high-income countries will spend their remaining budget by the end of the decade. This is also the case for the Czech Republic, which exceeded the limit for the period from 2017 onwards in 2018. While the result clearly points to the urgency of the decarbonization process, it also shows that some high-income countries, including the Czech Republic, are currently emitting at the expense of other countries. On the policy level, the findings could contribute to the re-evaluation of the GHG reduction plans as well as setting more appropriate and fairer national targets.

Introduction: Energy return on energy invested (EROEI) of fossil fuels has been declining sharply, while modern renewable energy sources generally have even lower EROEI than fossil fuels. It has been repeatedly proven that economic growth expressed in the form of growth of real Gross Domestic Product (GDP) is closely related to intensified energy consumption and escalated usage of natural resources in general. This problem remains scarcely explored in pure economic modelling. Objectives: This study presents a novel model titled Energy Extended Neoclassical Growth Model (EENGM), which focuses on the consequences of declining quantity and quality of extractable fossil fuels and lower quality of the succeeding renewable energy technology for economic growth. Method: The Neoclassical growth model is translated into a system dynamics format and is extended by important feedback mechanisms, which are identified as important from the literature and mostly missing from the analyzed system dynamics models with a similar scope. Two scenarios assess the EENGM performance: business as usual (BAU) and the sustainability strategy (SUS). Results: Sensitivity analysis is performed for the Energy Return on Energy Invested (EROEI) parameter and results in the investment share in GDP varying between 27 and 40%, while the energy sector investment largely displaces investment in other economic sectors. The EENGM is associated with new behavior whereby the underperforming energy sector limits GDP growth and seizes most of the available investment. The adoption of the SUS strategy causes 28% lower cumulative fossil fuel aggregate consumption which still corresponds to higher than 1.5 °C global warming compared to the preindustrial levels. Conclusion: The share of consumption in the GDP of an economy undergoing energy transition can approach levels previously seen only in totally war-oriented economies. Even omitting other negative environmental feedback, the feasibility of the successful energy transition of the system in its contemporary form, with the currently available renewable energy technology, seems to be highly uncertain.

The knowledge of a grinder structure, its performance parameters and characteristics of biomaterials breakage are crucial for this research whose aim is to determine the dependencies between performance parameters and comminution indicators. The aim of this study is to investigate the relationships between multi-disc mill performance parameters such as discs angular speed, batch dosing speed and comminution characteristics: power consumption, specific energy consumption, throughput and size reduction ratio. To achieve these goals, an experiment was conducted on a five-disc mill with a special monitoring system. The research program was established, with disc angular speed at different configurations and different batch dosing speeds. The results show that power consumption, specific energy consumption and size reduction ratio depend on the total increase in angular speed of discs SΔω in such a way that an increase in SΔω causes an increase in the abovementioned comminution indicators. In turn, an increase in batch dosing speed W causes an increase in throughput. The fitting curves of comminution indicators in dependence of selected performance parameters are also presented in this study.

Brazil plays a major role in the global biofuel economy as the world’s second largest producer and consumer and the largest exporter of ethanol. Its demand is expected to significantly increase in coming years, largely driven by national and international carbon mitigation targets. However, biofuel crops require significant amounts of water and land resources that could otherwise be used for the production of food, urban water supply, or energy generation. Given Brazil’s uneven spatial distribution of water resources among regions, a potential expansion of ethanol production will need to take into account regional or local water availability, as an increased water demand for irrigation would put further pressure on already water-scarce regions and compete with other users. By applying an environmentally extended multiregional input-output (MRIO) approach, we uncover the scarce water footprint and the interregional virtual water flows associated with sugarcane-derived biofuel production driven by domestic final consumption and international exports in 27 states in Brazil. Our results show that bio-ethanol is responsible for about one third of the total sugarcane water footprint besides sugar and other processed food production. We found that richer states such as São Paulo benefit by accruing a higher share of economic value added from exporting ethanol as part of global value chains while increasing water stress in poorer states through interregional trade. We also found that, in comparison with other crops, sugarcane has a comparative advantage when rainfed while showing a comparative disadvantage as an irrigated crop; a tradeoff to be considered when planning irrigation infrastructure and bioethanol production expansion.

This paper analyzes the possibility of using the thermal energy of discharged environmentally friendly mine water for the heat supply of a selected locality. There are few cases of industrial use of geothermal water in the Czech Republic, but mine water has never been the source. Based on this fact, an analysis of the usability of mine water at the Rožná I Mine was carried out. The analysis showed that the energy output of this pumped water was sufficient for the selected location of the municipality of Dolní Rožínka, where long-term annual average consumptions are at a level of 4350 GJ. The theoretical maximum output of this source is calculated as 837.4 kW; therefore, it exceeds the output required to satisfy the energy needs of this location several times over. Based on this input information, a technical and economic model of the heating system installation project was developed with three options. The case study aimed to find and propose an optimal alternative solution to replace the current unsatisfactory state of heat supply in the village of Dolní Rožínka. In the final part of this paper, the most optimal option is identified by a comparative method, which replaces the existing central district heating based on the production of heat energy from natural gas, i.e., fossil fuels. This study was motivated by a strategy to replace fossil energy sources with renewable energy sources wherever conditions are suitable.

In order to compare the maximum potential environmental impact savings that may result from the implementation of innovative biorefinery alternatives at a regional scale, the Territorial Metabolism-Life Cycle Assessment (TM-LCA) framework is implemented. With the goal of examining environmental impacts arising from technology-to-region (territory) compatibility, the framework is applied to two biorefinery alternatives, treating a mixture of cow manure and grape marc. The biorefineries produce either biogas alone or biogas and polyhydroxyalkanoates (PHA), a naturally occurring polymer. The production of PHA substitutes either polyethylene terephthalate (PET) or biosourced polylactide (PLA) production. The assessment is performed for two regions, one in Southern France and the other in Oregon, USA. Changing energy systems are taken into account via multiple dynamic energy provision scenarios. Territorial scale impacts are quantified using both LCA midpoint impact categories and single score indicators derived through multi-criteria decision assessment (MCDA). It is determined that in all probable future scenarios, a biorefinery with PHA-biogas co-production is preferable to a biorefinery only producing biogas. The TM-LCA framework facilitates the capture of technology and regionally specific impacts, such as impacts caused by local energy provision and potential impacts due to limitations in the availability of the defined feedstock leading to additional transport.