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Abstract This paper examines the effects of foreign trade and foreign direct investment (FDI) on CO 2 emissions in Turkey. We consider linear and nonlinear ARDL models and find significant asymmetric effects of exports, imports and FDI on CO 2 emissions per capita. However, FDI has no statistically significant long-run effects. In the long run, decreases in exports reduce CO 2 emissions per capita but increases in exports have no statistically significant effects. Increases in imports push up CO 2 emissions per capita, while decreases in imports have no long-run effects. On the other hand, CO 2 intensity, which measures CO 2 emissions per unit of energy, is not influenced by exports and imports, nor by FDI. Instead, it is affected positively by financial development and urbanization. Also, we find that an environmental Kuznets curve is present for both CO 2 measures so that increases in real GDP per capita have led to reductions in CO 2 emissions for at least the most recent decade, controlling for other confounding factors. Furthermore, the sectoral shares of CO 2 emissions in total CO 2 emissions change asymmetrically with foreign trade for two of four sectors, with export increases leading to lower CO 2 shares and imports having the opposite effect.

In industrialized countries, large amounts of mineral wastes are produced. They are re-used in various ways, particularly in road and earth constructions, substituting primary resources such as gravel. However, they may also contain pollutants, such as heavy metals, which may be leached to the groundwater. The toxic impacts of these emissions are so far often neglected within Life Cycle Assessments (LCA) of products or waste treatment services and thus, potentially large environmental impacts are currently missed. This study aims at closing this gap by assessing the ecotoxic impacts of heavy metal leaching from industrial mineral wastes in road and earth constructions. The flows of metals such as Sb, As, Pb, Cd, Cr, Cu, Mo, Ni, V and Zn originating from three typical constructions to the environment are quantified, their fate in the environment is assessed and potential ecotoxic effects evaluated. For our reference country, Germany, the industrial wastes that are applied as Granular Secondary Construction Material (GSCM) carry more than 45,000 t of diverse heavy metals per year. Depending on the material quality and construction type applied, up to 150 t of heavy metals may leach to the environment within the first 100 years after construction. Heavy metal retardation in subsoil can potentially reduce the fate to groundwater by up to 100%. One major challenge of integrating leaching from constructions into macro-scale LCA frameworks is the high variability in micro-scale technical and geographical factors, such as material qualities, construction types and soil types. In our work, we consider a broad range of parameter values in the modeling of leaching and fate. This allows distinguishing between the impacts of various road constructions, as well as sites with different soil properties. The findings of this study promote the quantitative consideration of environmental impacts of long-term leaching in Life Cycle Assessment, complementing site-specific risk assessment, for the design of waste management strategies, particularly in the construction sector.

Abstract The present analysis was conducted as the first study to investigate the biochemical methane potential of four different agro-industrial wastewaters originating from chocolate, slaughterhouse, gum, and beet sugar industries under the same anaerobic fermentation conditions. To the best of our knowledge, no previous study has specifically attempted to pinpoint a hybrid programming strategy for making a quantitative description of the anaerobic biodegradability of these waste streams. Thus, considering the scarcity of the literature in this field, a comprehensive study was conducted to evaluate the amount of bio-methane obtainable from the investigated organic wastes and to predict their kinetics using three different sigmoidal microbial growth curve models (modified Gompertz equation, transference function (reaction curve-type model), and logistic function) within the framework an original MATLAB®-based coding scheme. The results showed that methane productions started immediately after 4 h of incubation for all substrates and reached their maximum rates of 118, 116, 108, 34 mL CH4/g VS/day, respectively, for wastewaters from chocolate, slaughterhouse, gum, and beet sugar industries. The corrected mean steady state methane contents were 61.7%, 73.4%, 62.8%, and 62.1% in the respective order. The highest methane yield (943 mL CH4/g VS) was obtained from the slaughterhouse wastewater, and this value was 1.32, 1.58, and 4.56 times higher than those obtained in the anaerobic digestion of chocolate, gum, and beet sugar wastewaters, respectively. Among the three kinetic models tested, the logistic function best explained the behavior of the observed data of all substrates using a Quasi-Newton cubic line search procedure (R2 = 0.987–0.996) with minimum number of non-linear iterations and function counts. Deviations between the measured and the outputs of the best-fit kinetic model were less than 4.3% in prediction of methane production potentials, suggesting that the proposed computational methodology could be used as a well-suited and robust approach for modeling and optimization of a highly non-linear biosystem.

Fossil fuel substitution with biomass is one of the measures to reduce carbon dioxide (CO2) emissions. This paper estimates the cost-effectiveness of raising industrial steam and producing materials (i.e. chemicals, polymers) from biomass. We quantify their long-term global potentials in terms of energy saving, CO2 emission reduction, cost and resource availability. Technically, biomass can replace all fossil fuels used for the production of materials and for generating low and medium temperature steam. Cost-effective opportunities exist for steam production from biomass residues and by substitution of high value petrochemicals which would together require more than 20 exajoules (EJ) of biomass worldwide in addition to baseline by 2030. Potentials could double in 2050 and reach 38-45 EJ (25% of the total industrial energy use), with most demand in Asia, other developing countries and economies in transition. The economic potential of using biomass as chemical feedstock is nearly as high as for steam production, indicating its importance. The exploitation of these potentials depends on energy prices and industry's access to biomass supply. Given the increasing competition for biomass from several economic sectors, more resource efficient materials need to be developed while steam production is already attractive due to its high effectiveness for reducing CO2 emissions per unit of biomass.

Abstract The aim of this study is to evaluate the incremental innovation performance of nuclear energy projects. Within this context, a novel model is generated which consists of two different stages, and large nuclear reactors are taken into consideration. Firstly, the Pythagorean fuzzy DEMATEL is used to weight the phases of technology S-Curve for nuclear energy projects. Moreover, the second stage includes the ranking two-generation technology S-curve with integer patterns for nuclear energy projects. In this framework, the best combinations are selected for innovation life cycle pattern with the integer code series. The findings demonstrate that the nuclear energy companies need to consider the two-generation technology S-Curve because continuous technological developments are occurring for nuclear power generation. It is also determined that aging in the first generation is the most significant period of two-generation technology S-Curve for nuclear energy projects. In this process, critical decisions should be made regarding future technological investments. In addition, the growth phase in the second generation is also important for the effectiveness of the nuclear energy technology. Conducting effective evaluations in these processes will contribute to increasing the efficiency of companies.

To decarbonise Europe in the post-COP26 era, current policies must be adjusted to account for the cross-border consequences of its consumption pattern. Using consumption-based Kaya identity metrics adjusted for emissions and energy embodied in traded goods and services, this study examines the nexus between technological factors defining energy transition progress, specifically energy and carbon intensities of the consumption mix, and carbon dioxide (CO2) emissions, in a sample of 20 European countries from 1995 to 2019. The empirical steps rely on panel-data estimators that are robust to cross-sectional dependence and allow for heterogeneous slope coefficients. The results show that energy and carbon intensities of the consumption mix have a positive rela tionship with CO2 emissions but a negative relationship with renewable energy consumption. The findings also verify an inverted U-shaped relationship between affluence and CO2 emissions through the energy and carbon intensity metrics. Additional tests show a unidirectional causality from carbon intensity of the energy mix to CO2 emissions and from renewable energy to the carbon intensity. Also, bidirectional causality exists between CO2 emissions and per capita GDP and energy intensity, and between renewable energy and energy intensity. By implication, renewable energy provides the technological path to mitigating consumption-induced emissions in Europe.

This study deals with the manufacturing process of compost production, followed by the release of large amounts of heat. The wheat straw and manure of broilers were the basic components of the raw mixture, monitored during the 80 h period. The simplified assessment method was developed along with suitable mathematical model. The potential for recovery of the heat released to the surroundings was evaluated indirectly based on compost temperature measurements during the one full production cycle. Temperature-time mathematical model was developed and used as time indicator for the analysis of distribution of energy that was generated in exothermic processes. The emissions of N (<1% dry basis) and C through CO2 (∼3% dry basis) was neglected in mass balances. During composting treatment material temperatures were in range 80 ± 2 °C, making it a reliable heat source of constant temperature. The amount of total generated heat during the 80 h time period was calculated to be 1325 kJ·106, of which 76.4% was released to surroundings. The specific value of generated heat was 1.32 kJ g−1 of raw mixture, of which 1.01 kJ g−1 was available for recovery. The results pointed to the existence of significant amounts of released energy available for recovering.

Torrefaction is a promising bioenergy pre-treatment technology, with potential to make a major contribution to the commodification of biomass. However, there is limited scientific knowledge on the techno-economic performance of torrefaction. This study therefore improves available knowledge on torrefaction by providing detailed insights into state of the art prospects of the commercial utilisation of torrefaction technology over time. Focussing on and based on the current status of the compact moving bed reactor, we identify process performance characteristics such as thermal efficiency and mass yield and discuss their determining factors through analysis of mass and energy balances. This study has shown that woody biomass can be torrefied with a thermal and mass efficiency of 94% and 48% respectively (on a dry ash free basis). For straw, the corresponding theoretical energetic efficiency is 96% and mass efficiency is 65%. In the long term, the technical performance of torrefaction processes is expected to improve and energy efficiencies are expected to be at least 97% as optimal torgas use and efficient heat transfer are realised. Short term production costs for woody biomass TOPs (torrefied pellets) are estimated to be between 3.3 and 4.8 US$/GJLHV, falling to 2.1–5.1 US$/GJLHV in the long term. At such cost levels, torrefied pellets would become competitive with traditional pellets. For full commercialisation, torrefaction reactors still require to be optimised. Of importance to torrefaction system performance is the achievement of consistent and homogeneous, fully hydrophobic and stable product, capable of utilising different feedstocks, at desired end-use energy densities.