• Energy Research
• 11. Sustainability close
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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.

COVID-19 reaffirms that we are living out the consequences of the Anthropocene. In terms of education this affirmation has considerable implications: we must overcome the profound divisions between the fields of Natural Sciences and the Social Sciences while at the same time recognizing the political character of educational and scientific practices.Sustainability is an idea that potentially embodies the elements that respond to these two challenges, but only distancing ourselves from a technocratic-instrumental approximation and assuming a political approach to the idea. Post-normal science provides an adequate framework for this because the emerging problems present democratic challenges that demand other academic and educational treatment.Our intention with this text is to contribute didactic material that incentivizes the introduction of this conceptual debate into the classroom setting. Far from proposing a confrontation between the dominant mode of thought, in this paper we propose an argument that seeks to untangle the basic components of our thesis and show the arbitrariness of all the theoretical constructions that result from that. We hope, in this way, to contribute to a transdisciplinary environmental and sustainability education that consists in uncovering the political dimension of this issue, to repoliticize education, transcend the division between relativism and objectivism and, encourage theoretical positioning without determinisms. 

Spatial data on Low-and-Middle-Income-Country (LMIC) cities, and deprived areas within cities, are often not readily available in support of local and global information needs. To address this information gap, we propose the systematic semi-automated SLUMAP framework that provides policy-relevant information on deprived urban areas in Sub-Saharan Africa (SSA), based on free open-source software (FOSS). First, we assess user needs for spatial information on deprivation (ranging from local communities to global research and policy support). Second, we show how free or low-cost image datasets can be used for mapping the location of deprived areas at the city scale and providing an overall assessment of their spatial patterns. This is implemented as a grid-based approach using machine learning and assessing the contribution of a large number of spectral and spatial features derived from open or low-cost imagery. Third, we show how higher (spatial and spectral) resolution data can provide a detailed characterization of such areas, with a GEOBIA/machine-learning workflow and deep learning techniques. We illustrate the experiments and results on the city of Nairobi (Kenya)and discuss transferability to SSA cities.

The environmental footprint of photovoltaic electricity is usually assessed using nominated power or life cycle energy output. If performance degradation is considered, a linear reduction in lifetime energy output is assumed. However, research has shown that the decrease in energy output over time does not necessarily follow a linear degradation pattern but can vary at different points in the module’s lifetime. Further, photovoltaic modules follow different degradation patterns in different climate zones. In this study, we address the influence of different degradation aspects on the greenhouse gas (GHG) emissions of PV electricity. Firstly, we apply different non-linear degradation scenarios to evaluate the GHG emissions and show that the differences in GHG emissions in comparison to a linear degradation can be up to 6.0%. Secondly, we use the ERA5 dataset generated by the ECMWF to calculate location-dependent degradation rates and apply them to estimate the location-specific GHG emissions. Due to the reduction in lifetime energy output, there is a direct correlation between the calculated degradation rate and GHG emissions. Thirdly, we assess the impact of climate change on degradation rates and on the respective GHG emissions of photovoltaic electricity using different climate change scenarios. In a best-case scenario, the GHG emissions are estimated to increase by around 5% until the year 2100 and by around 105% by 2100 for a worst-case scenario.

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.

AbstractThe first year commissioning activities in 4 multi-family buildings from a zero-carbon neighbourhood is presented, with focus on the operation of the ventilation systems, the indoor climate and user acceptance. The key parameters to detect the main system failures are identified and the effect of the detected defects and failures on the energy performance of the dwellings is explored using dynamic simulations and monitoring data. It is concluded that commissioning of the building systems during occupancy is a vital part of the operational lifetime of a building project in order to achieve the high building performance targets in reality.