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Buildings in private and domestic use are responsible for about 30% of the global greenhouse gas emissions attributable mainly to their need for heating and cooling energy. This corresponds to about 40% of the global final energy consumption. Therefore, a viable implementation of building energy efficiency policies is inevitable to realize a transformation of the energy system to mitigate climate change. Within the building sector lies a huge potential for emission reduction consisting in the renovation of the existing building stock and climate-friendly building guidelines applicable to new constructions, both adapting CO2-neutral technology solutions. However, as there are several different pathways leading to a decarbonized energy system, there is always the question which political and technological solutions are most efficient, effective, and feasible. This paper aims to analyze building efficiency policy measures and instruments and the related technological solutions in two front-runner countries of the energy transition, possessing different structural conditions: Germany and Norway. We hence apply a comparative approach which allows us to present and assess the policies in place. The paper answers three research questions: (1) Which policies prevail in Germany and Norway to foster the deployment of energy efficient and decarbonized solutions for residential buildings? (2) How do these policies respond to country-specific barriers to the energy transition in the building sector, and (3) What effects do they have on the actual implementation of technological and societal solutions? This research provides a new insight to the highly relevant topic of energy efficiency in buildings in the context of international Intended Nationally Determined Contribution benchmarking and discusses some unsolved trade-offs in the translation of the global climate governance into the national building sector.

Buildings in private and domestic use are responsible for about 30% of the global greenhouse gas emissions attributable mainly to their need for heating and cooling energy. This corresponds to about 40% of the global final energy consumption. Therefore, a viable implementation of building energy efficiency policies is inevitable to realize a transformation of the energy system to mitigate climate change. Within the building sector lies a huge potential for emission reduction consisting in the renovation of the existing building stock and climate-friendly building guidelines applicable to new constructions, both adapting CO2-neutral technology solutions. However, as there are several different pathways leading to a decarbonized energy system, there is always the question which political and technological solutions are most efficient, effective, and feasible. This paper aims to analyze building efficiency policy measures and instruments and the related technological solutions in two front-runner countries of the energy transition, possessing different structural conditions: Germany and Norway. We hence apply a comparative approach which allows us to present and assess the policies in place. The paper answers three research questions: (1) Which policies prevail in Germany and Norway to foster the deployment of energy efficient and decarbonized solutions for residential buildings? (2) How do these policies respond to country-specific barriers to the energy transition in the building sector, and (3) What effects do they have on the actual implementation of technological and societal solutions? This research provides a new insight to the highly relevant topic of energy efficiency in buildings in the context of international Intended Nationally Determined Contribution benchmarking and discusses some unsolved trade-offs in the translation of the global climate governance into the national building sector.

NOx emissions and their intermediate species NO, HCN, and NH3 have been investigated in an industrial waste-to-energy plant for the first time. Therefore, an innovative gas probe was designed accordingly to meet the challenging requirements of HCN and NH3 measurement. The N intermediates were measured in three different sample positions close to the grate. The highest concentrations were detected on the front side of the grate where the lowest local excess air ratio occurs. The NOx reduction potential, which is defined as the ratio of HCN and NH3 to NO, was above 1 during most of the relevant position sampling; hence, the selective high-temperature reduction does not seem to be a suitable technology for a further reduction of NOx emissions. The operating points investigated were conventional operation, flue gas recirculation (VLN-GM), air staging, and air staging with improved mixing. Conventional operation leads to emissions of about 450 mg/m3, which could be reduced to 200 mg/m3 by VLN-GM. Since the emissions are strongly dependent on the primary air ratio λ1, they show an almost linear correlation. The pretreatment of waste by shredding stabilizes the combustion and simplifies NOx control. The lowest emissions (around 100 mg/m3) were achieved during air-staged operation with additional air injection, due to improved mixing and the additional staging.

NOx emissions and their intermediate species NO, HCN, and NH3 have been investigated in an industrial waste-to-energy plant for the first time. Therefore, an innovative gas probe was designed accordingly to meet the challenging requirements of HCN and NH3 measurement. The N intermediates were measured in three different sample positions close to the grate. The highest concentrations were detected on the front side of the grate where the lowest local excess air ratio occurs. The NOx reduction potential, which is defined as the ratio of HCN and NH3 to NO, was above 1 during most of the relevant position sampling; hence, the selective high-temperature reduction does not seem to be a suitable technology for a further reduction of NOx emissions. The operating points investigated were conventional operation, flue gas recirculation (VLN-GM), air staging, and air staging with improved mixing. Conventional operation leads to emissions of about 450 mg/m3, which could be reduced to 200 mg/m3 by VLN-GM. Since the emissions are strongly dependent on the primary air ratio λ1, they show an almost linear correlation. The pretreatment of waste by shredding stabilizes the combustion and simplifies NOx control. The lowest emissions (around 100 mg/m3) were achieved during air-staged operation with additional air injection, due to improved mixing and the additional staging.

A numerical model is presented for the precise prediction of carbon monoxide (CO) emissions in gas turbine combustors. All models are based on Computational Fluid Dynamics (CFD). This work starts with an introduction of fundamental mechanisms, which are responsible for CO emissions. As we will show, there is a need of CO-models as standard combustion models fail to predict CO-emissions precisely. For the purpose of validation, experiments are conducted. High ratios of secondary air is bypassing the burner in order to induce interaction of the flame front with secondary air, as the flame brush gets diluted and decreases in reactivity. Note, this is an important mechanism for elevated CO emissions in multi-burner systems with high staging ratio. Five operating points with each having a different adiabatic flame temperature were measured. They include equilibrium (complete burnout) and superequilibrium CO (incomplete burnout). In summary, it is shown that the prediction of CO with the presented models lead to a significant improvement as it captures the transition from equilibrium to superequilibrium CO. Furthermore, the strong underestimation of CO predicted by standard combustion models is shown.

A numerical model is presented for the precise prediction of carbon monoxide (CO) emissions in gas turbine combustors. All models are based on Computational Fluid Dynamics (CFD). This work starts with an introduction of fundamental mechanisms, which are responsible for CO emissions. As we will show, there is a need of CO-models as standard combustion models fail to predict CO-emissions precisely. For the purpose of validation, experiments are conducted. High ratios of secondary air is bypassing the burner in order to induce interaction of the flame front with secondary air, as the flame brush gets diluted and decreases in reactivity. Note, this is an important mechanism for elevated CO emissions in multi-burner systems with high staging ratio. Five operating points with each having a different adiabatic flame temperature were measured. They include equilibrium (complete burnout) and superequilibrium CO (incomplete burnout). In summary, it is shown that the prediction of CO with the presented models lead to a significant improvement as it captures the transition from equilibrium to superequilibrium CO. Furthermore, the strong underestimation of CO predicted by standard combustion models is shown.

Drought is one of the natural hazards that have negatively affected the agricultural sector worldwide. The aims of this study were to track drought characteristics (duration (DD), severity (DS), and frequency (DF)) in South Africa between 2002 and 2021 and to evaluate its impact on wheat production. Climate data were collected from the South African Weather Service (SAWS) along with wheat yield data from the Department of Agriculture, Forestry and Fisheries (2002–2021). The standard precipitation index (SPI) was calculated on 3-, 6-, 9-, and 12-month time scales, and the trend was then tracked using the Mann–Kendall (MK) test. To signify the climatic effects on crop yield, the standardized yield residual series (SYRS) was computed along with the crop-drought resilience factor (CR) on a provincial scale (2002–2021). The output of the SPI analysis for 32 stations covering all of South Africa indicates a drought tendency across the country. On a regional scale, western coastal provinces (WES-C and NR-C) have been more vulnerable to meteorological droughts over the past 20 years. Positive correlation results between SYRS and wheat yield indicate that the WES-C province was highly influenced by drought during all stages of wheat growth (Apr–Nov). Historical drought spells in 2003, 2009, and 2010 with low CR = 0.64 caused the province to be highly impacted by the negative impacts of droughts on yield loss. Overall, drought events have historically impacted the western part of the country and dominated in the coastal area. Thus, mitigation plans should be commenced, and priority should be given to this region. These findings can assist policymakers in budgeting for irrigation demand in rainfed agricultural regions.

Drought is one of the natural hazards that have negatively affected the agricultural sector worldwide. The aims of this study were to track drought characteristics (duration (DD), severity (DS), and frequency (DF)) in South Africa between 2002 and 2021 and to evaluate its impact on wheat production. Climate data were collected from the South African Weather Service (SAWS) along with wheat yield data from the Department of Agriculture, Forestry and Fisheries (2002–2021). The standard precipitation index (SPI) was calculated on 3-, 6-, 9-, and 12-month time scales, and the trend was then tracked using the Mann–Kendall (MK) test. To signify the climatic effects on crop yield, the standardized yield residual series (SYRS) was computed along with the crop-drought resilience factor (CR) on a provincial scale (2002–2021). The output of the SPI analysis for 32 stations covering all of South Africa indicates a drought tendency across the country. On a regional scale, western coastal provinces (WES-C and NR-C) have been more vulnerable to meteorological droughts over the past 20 years. Positive correlation results between SYRS and wheat yield indicate that the WES-C province was highly influenced by drought during all stages of wheat growth (Apr–Nov). Historical drought spells in 2003, 2009, and 2010 with low CR = 0.64 caused the province to be highly impacted by the negative impacts of droughts on yield loss. Overall, drought events have historically impacted the western part of the country and dominated in the coastal area. Thus, mitigation plans should be commenced, and priority should be given to this region. These findings can assist policymakers in budgeting for irrigation demand in rainfed agricultural regions.

Like other forms of debris in terrestrial and marine environments, space debris prompts questions about how we can live with the material remains of technological endeavors past and yet to come. Although techno-societies fundamentally rely on space infrastructures, they so far have failed to address the infrastructural challenge of debris. Only very recently has the awareness of space debris as a severe risk to both space and Earth infrastructures increased within the space community. One reason for this is the renewed momentum of interplanetary space exploration, including the colonization of the Moon and Mars, which is part of transhumanist and commercially driven dreams of the so-called New Space age. Understanding space infrastructures as inherently linked to earthly infrastructure, we attend to the ways in which space debris, a once accepted by-product of scientific-technological progress, economic interests, and geopolitics, increasingly becomes a matter of concern. Drawing on qualitative interviews with European space sector representatives and work in Science and Technology Studies on infrastructures, we argue that their discursive efforts and visual representation strategies coproduce space debris as a boundary infrastructure. We suggest considering this boundary infrastructure as relating orbital environments and the planet through enacting sustainability and responsibility for beyond-planetary environments.