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Biomass is expected to play an increasingly significant role in the ‘greening’ of energy supply. Nevertheless, concerns are rising about the sustainability of large-scale energy crop production. Impacts must be assessed carefully before deciding whether and how this industry should be developed, and what technologies, policies and investment strategies should be pursued. There is need for a comprehensive and reliable sustainability assessment tool to evaluate the environmental, social and economic performance of biomass energy production. This paper paves the way for such a tool by analysing and comparing the performance and applicability of a selection of existing tools that are potentially useful for sustainability assessment of bioenergy systems. The selected tools are: Criteria And Indicators (C&I), Life Cycle Assessment (LCA), Environmental Impact Assessment (EIA), Cost Benefit Analysis (CBA), Exergy Analysis (EA) and System Perturbation Analysis (SPA). To evaluate the tools, a framework was constructed that consists of four evaluation levels: sustainability issues, tool attributes, model structure, area of application. The tools were then evaluated using literature data and with the help of a Delphi panel of experts. Finally, a statistical analysis was performed on the resulting data matrix to detect significant differences between tools. It becomes clear that none of the selected tools is able to perform a comprehensive sustainability assessment of bioenergy systems. Every tool has its particular advantages and disadvantages, which means that trade-offs are inevitable and a balance must be found between scientific accuracy and pragmatic decision making. A good definition of the assessment objective is therefore crucial. It seems an interesting option to create a toolbox that combines procedural parts of C&I and EIA, supplemented with calculation algorithms of LCA and CBA for respectively environmental and economic sustainability indicators. Nevertheless, this would require a more comprehensive interdisciplinary approach to align the different tool characteristics and focuses.

Abstract This contribution experimentally evaluates and compares the performance of an ORC (organic Rankine cycle) system for stationary bottoming WHR (waste heat recovery) application operating with two different working fluids, SES36 and R245fa. The test rig is a regenerative cycle equipped with a single screw expander modified from a standard compressor characterized by a nominal shaft power of 11 kW. A total of 36 and 43 steady-state points are collected for SES36 and R245fa respectively, over a wide range of operating conditions by changing the expander rotational speed, the pump frequency and the cooling condenser flow rate. The performances of the ORC components are individually evaluated. A maximum expander isentropic efficiency of 60% is reached using SES36 at 3000 rpm, and a value of 52% is reached with R245fa at 3000 rpm. However, for a given pressure ratio the expander output power is higher with R245fa than with SES36. The overall performance of the ORC unit are investigated in terms of first and second law efficiencies and net output power for the two fluids. The results experimentally demonstrate the correlation between the working fluid critical temperature and the ORC unit working characteristics for low temperature waste heat recovery applications. Open experimental data are provided for both fluids.

Abstract The use of bio-energy crops for electricity production is considered an effective means to mitigate the greenhouse effect, mainly due to its ability to substitute fossil fuels. A whole range of crops qualify for bio-energy production and a rational choice is not readily made. This paper evaluates the energy and greenhouse gas balance of a mixed indigenous hardwood coppice as an extensive, low-input bio-energy crop. The impact on fossil energy use and greenhouse gas emission is calculated and discussed by comparing its life cycle (cultivation, processing and conversion into energy) with two conventional bio-energy crops (short rotation systems of willow and Miscanthus). For each life cycle process, the flows of fossil energy and greenhouse gas that are created for the production of one functional unit are calculated. The results show that low-input bio-energy crops use comparatively less fossil fuel and avoid more greenhouse gas emission per unit of produced energy than conventional bio-energy crops during the first 100 yr . Where the mixed coppice system avoids up till 0.13 t CO 2 eq./GJ, Miscanthus does not exceed 0.07 t CO 2 eq./GJ. After 100 yr their performances become comparable, amounting to 0.05 t CO 2 eq./ha/GJ. However, if the land surface itself is chosen as a functional unit, conventional crops perform better with respect to mitigating the greenhouse effect. Miscanthus avoids a maximum of 12.9 t CO 2 eq./ha/yr, while mixed coppice attains 9.5 t CO 2 eq./ha/yr at the most.

Urban residents are exposed to higher levels of heat stress in comparison to the rural population. As this phenomenon could be enhanced by both global greenhouse gas emissions (GHG) and urban expansion, urban planners and policymakers should integrate both in their assessment. One way to consider these two concepts is by using urban climate models at a high resolution. In this study, the influence of urban expansion and GHG emission scenarios is evaluated at 100 m spatial resolution for the city of Brussels (Belgium) in the near (2031-2050) and far (2081-2100) future. Two possible urban planning scenarios (translated into local climate zones, LCZs) in combination with two representative concentration pathways (RCPs 4.5 and 8.5) have been implemented in the urban climate model UrbClim. The projections show that the influence of GHG emissions trumps urban planning measures in each period. In the near future, no large differences are seen between the RCP scenarios; in the far future, both heat stress and risk values are twice as large for RCP 8.5 compared to RCP 4.5. Depending on the GHG scenario and the LCZ type, heat stress is projected to increase by a factor of 10 by 2090 compared to the present-day climate and urban planning conditions. The imprint of vulnerability and exposure is clearly visible in the heat risk assessment, leading to very high levels of heat risk, most notably for the North Western part of the Brussels Capital Region. The results demonstrate the need for mitigation and adaptation plans at different policy levels that strive for lower GHG emissions and the development of sustainable urban areas safeguarding livability in cities.

The European Union is currently in the process of transformation toward a circular economy model in which different areas of activity should be integrated for more efficient management of raw materials and waste. The wastewater sector has a great potential in this regard and therefore is an important element of the transformation process to the circular economy model. The targets of the circular economy policy framework such as resource recovery are tightly connected with the wastewater treatment processes and sewage sludge management. With this in view, the present study aims to review existing indicators on resource recovery that can enable efficient monitoring of the sustainable and circular solutions implemented in the wastewater sector. Within the reviewed indicators, most of them were focused on technological aspects of resource recovery processes such as nutrient removal efficiency, sewage sludge processing methods and environmental aspects as the pollutant share in the sewage sludge or its ashes. Moreover, other wide-scope indicators such as the wastewater service coverage or the production of bio-based fertilizers and hydrochar within the wastewater sector were analyzed. The results were used for the development of recommendations for improving the resources recovery monitoring framework in the wastewater sector and a proposal of a circularity indicator for a wastewater treatment plant highlighting new challenges for further researches and wastewater professionals.

Abstract A linear economy approach results in many environmental challenges: resources become depleted and end up as waste and emissions. One of the key strategies to overcome these problems is using waste as a resource, i.e. evolving toward a circular economy. To monitor this transition, suitable indicators are needed that focus on sustainability issues whilst taking into account the technical reality. In this paper, we develop such an indicator to quantify the circular economy performance of different plastic waste treatment options. This indicator is based on the technical quality of the plastic waste stream and evaluates resource consumption by using the Cumulative Exergy Extraction from the Natural Environment (CEENE) method. To illustrate the use of this new indicator, it was applied in a case study on post-industrial plastic waste treatment. The results show that the indicator can be a very useful approach to guide waste streams towards their optimal valorization option, based on quality of the waste flow and the environmental benefit of the different options.

Since 2015, the intended climate actions of the Paris Agreement signatories have been reported as nationally determined contributions (NDC). These climate actions are fully aligned with the 13th Sustainable Development Goal (SDG) which calls for urgent action to combat climate change. The same, however, cannot be said for their relation to the other 16 SDGs of the 2030 Agenda for Sustainable Development, since climate action can either enhance or compromise the prospects for SDG implementation. In light of this challenge, this paper proposes a simple method for quantifying the synergies and trade-offs between national climate actions and the SDGs. The method, referred to as Q-SCAN, makes use of a seven-step scale and the SDG Climate Action Nexus tool. The effectiveness of the method has been demonstrated on a case study of North Macedonia, a non-Annex I, Western Balkan country with a coal-intensive energy system. Based on the experience in the preparation of the country’s enhanced NDC, the paper elaborates how the method can be used to contribute to the alignment of the national climate actions with the SDGs and how it can be used to improve stakeholder engagement.

AbstractIn large parts of Europe, the Chernobyl accident of 1986 caused fallout of Cs-137. This led to the uptake of Cs-137 in trees or other materials used for bioenergy production or as firewood for domestic purposes. This Cs-137 may concentrate in the ashes of the combustion process in such a way that the clearance level of 100 Bq per kg, defined in Directive 2013/59/Euratom (EU BSS), may consequently be exceeded. There is currently no clear consensus in Europe regarding the regulatory approach to this issue: should the import and use of Cs-137 contaminated biomass and its ashes be considered as a planned exposure situation or rather as an existing exposure situation? If considered as an existing exposure situation, which reference level should be applied? We compare the approaches in various European countries, such as Finland, Norway, Sweden, Belgium and the Netherlands. Results of a recent measurement campaign performed in Belgium on firewood imported from Belarus, Ukraine and other countries show a quite large range of Cs-137 activity concentration in firewood. Analysis of samples from biomass combustion confirms that the clearance level of 100 Bq per kg Cs-137 may be exceeded even when the activity concentration in the initial pellet is trivial. A review of dose-assessment studies performed by STUK and from the literature is presented. The general context of biomass energy production is sketched: for instance, in the Netherlands, 40 large biomass firing plants (capacity > 10 MW) are operational and some 20 more are already planned. The fly ashes from the biomass combustion may be a valuable resource for the construction industry, and the issue of Cs-137 contamination is connected with the requirements of the EU BSS regarding the natural radioactivity of building materials. Assessing the impact of Cs-137 contamination and clarifying regulations in the frame of a graded approach are important elements in this context.

The number of natural disasters is growing. A considerable number of them derives directly from climate changes and generates a deep impact on cultural heritages. As a result, the need for solutions able to cope with uncertain weather conditions and increased natural disasters is getting urgent. STORM is a European Research and Innovation Action co-funded in the H2020 framework that is aimed at creating intelligent tools which will gather data from libraries, sensors and crowd-sensing techniques in order to enable cultural heritage stakeholders (e.g., the organisations which have to manage the sites) to implement the most appropriate actions in the prevention, response and recovery phases of emergencies which could impact on cultural heritages. More specifically, the project aims at addressing those risks deriving from climate change, which in the near future is going to worsen most of the present hazards, as flash floods, heat waves and forest fires. As such, the approach adopted by the project is particularly fit for the purpose of being integrated with smart city systems which are increasingly growing in number and variety. Even if safety issues are not considered central in the overall concept of smart city, it’s plain that the huge quantity of data that can be gathered and processed in any future STORM-like urban cultural heritage compound should feed into the available smart city systems. On the other way round, the mass of data produced or processed by smart city systems have the potential to impact dramatically on emergency management and prevention activities to be implemented by cultural heritage stakeholders. The paper will illustrate the approach that the STORM project is adopting to mitigate the impact of climate changes on cultural heritages and the mutual benefits which could derive from an integration of the STORM outcomes with smart cities systems through the use of standard emergency data exchange protocols and an integrated framework aimed at improving existing processes related to the three identified areas: Prevention, Response and Policy