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Abstract Many countries committed themselves in the Kyoto protocol to reduce greenhouse gas (GHG) emissions. Some of these targeted emission reductions could result from a switch from coal-fired to gas-fired electricity generation. The focus in this work lies on Western Europe, with the presence of the European Union Emission Trading Scheme (EU ETS). For the switching to occur, several conditions have to be fulfilled. First, an economical incentive must be present, i.e. a sufficiently high European Union Allowance (EUA) price together with a sufficiently low natural gas price. Second, the physical potential for switching must exist, i.e. at a given load, there must remain enough power plants not running to make switching possible. This paper investigates what possibilities exist for switching coal-fired plants for gas-fired plants, dependent on the load level (the latter condition above). A fixed allowance cost and a variable natural gas price are assumed. The method to address GHG emission reduction potentials is first illustrated in a methodological case. Next, the GHG emission reduction potentials are addressed for several Western European countries together with a relative positioning of their electricity generation. GHG emission reduction potentials are also compared with simulation results. GHG emission reduction potentials tend to be significant. The Netherlands have a very widespread switching zone, so GHG emission reduction is practically independent of electricity generation. Other counties, like Germany, Spain and Italy could reduce GHG emissions significantly by switching. With an allowance cost following the switch level of a 50% efficient gas-fired plant and a 40% efficient coal-fired plant in the summer season (like in 2005), the global GHG emission reduction (in the electricity generating sector) for the eight modeled zones could amount to 19%.

Space travel, often used by the authors as an equivalent to ‘space tourism’, and outer-space migration should become part of the sustainability discourse – that is the most tempting argument of the...

Global emission inventories with 1°x 1°resolution were compiled for nitrogen oxides (NO + NO2, together denoted as NO(x)), ammonia (NH3) and nitrous oxide (N2O) emissions. For NO(x) the estimated global anthropogenic emission for 1990 is about 31 million ton N year-1. The major anthropogenic sources identified include fossil fuel combustion (70%, of which the major sources are road transport and power plants) and biomass burning (20%). Natural sources contribute about 19 million ton N year-1, mainly lightning and soil processes. For NH3the estimated global emission for 1990 is about 54 million ton N year-1. The major sources identified include excreta from domestic animals and wild animals, use of synthetic N fertilisers, oceans and biomass burning. About half of the global emission comes from Asia, and about 70% is related to food production. For N2O the major sources considered include fertilised arable land, animal excreta, soils under natural vegetation, oceans, and biomass burning. The global source of N2O is about 15 million ton N2O-N year-1of which about 30% is related to food production. All three inventories are available on a sectoral basis on a 1°x 1°grid for input to global atmospheric models and on a regional/country basis for policy analysis.

Abstract Megacities in emerging markets are a relatively new phenomenon. The size of these cities combined with the high growth rates provides substantial sustainability challenges. Urban freight transport (UFT) contributes to these challenges. Despite its relatively low share as part of total traffic, the negative impact of UFT is disproportionate. Improving the sustainability in this context is inevitable in the light of further prospected urbanization. To study this topic, a theoretical framework is developed which is subsequently applied on literature. This allows characterizing the UFT system in a city. Such a framework is currently lacking. The framework is developed around the components of a UFT system (demand, supply and context) and the factors influencing these components. Factors include the different supply chains (demand), vehicles used (supply) and traffic measures (context). It is applied to analyze the UFT system in megacities in emerging markets. Results show that demand in different supply chains is fragmented as well as the transport. Uncontrolled sprawl and the existence of an informal economy further contribute to the complexity to regulate UFT. Based hereupon, we discuss efforts to move to more sustainable UFT in this context.

Abstract Several strategies based on a two steps organosolv pretreatment followed by enzymatic hydrolysis of sugarcane bagasse (SCB) were evaluated with the objective of selecting operational conditions suitable to promote an efficient and low cost production of ethanol. Initially, the influence of six variables used for the organosolv pretreatment was studied. The variables included the time of the first organosolv pretreatment step, the use of 45% ethanol as pulping solution, solid-to-liquid ratio of the ethanol solution used during the first pretreatment step, time of second organosolv pretreatment, concentration of ethanol and concentration of NaOH solution used in the second pretreatment step. Further assays of enzymatic hydrolysis were carried out to promote additional reduction in the costs of the process and improve the results of cellulose conversion to glucose. Eliminating the milling step of the pretreated SCB, using a commercial tensoactive (composed of esters and several surfactants), and recycling 50% of the slurry obtained during the second step of organosolv pretreatment as reaction medium proved to be feasible for use during the enzymatic hydrolysis. Fermentation of the glucose medium produced under the selected pretreatment conditions to ethanol by Saccharomyces cerevisiae occurred with 81% efficiency and a cost of 102.88 $/hL of ethanol.

The large thermal potentials with geothermal gradient of abandoned wells provide the possibility and opportunity for carbon-neutrality transition of district heating systems, whereas energy harvesting from abandoned geothermal wells is full of challenges, due to the considerable initial investment in economic cost, system performance degradation, and so on. In this chapter, a systematic and comprehensive review on the application techniques of abandoned wells is presented, in terms of advanced thermal/power conversions, renewable integrations for district heating, and strategies for performance enhancement. Discussions on real applications have been conducted and future prospects presented, from perspectives of lifetime system performance, techno-economic feasibility analysis, and potential assessment of abandoned wells for carbon-neutrality transition. The results of this chapter can provide preliminary knowledge and cutting-edge technologies on renewable integrations with abandoned wells, so as to demonstrate techno-economic-environmental potentials of abandoned wells and contributions toward carbon-neutrality transition. Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. Design & Construction Management

Leachate from the source separated organic fraction of municipal solid waste (OFMSW) was evaluated as a substrate for polyhydroxyalkanoates (PHA) production. Initially, the enrichment step was conducted directly on leachate in a feast-famine regime. Maximization of the cellular PHA content of the enriched biomass yielded to low PHA content (29 wt%), suggesting that the selection for PHA-producers was unsuccessful. When the substrate for the enrichment was switched to a synthetic volatile fatty acid (VFA) mixture -resembling the VFA carbon composition of the leachate-the PHA-producers gained the competitive advantage and dominated. Subsequent accumulation with leachate in nutrient excess conditions resulted in a maximum PHA content of 78 wt%. Based on the experimental results, enriching a PHA-producing community in a "clean" VFA stream, and then accumulating PHA from a stream that does not allow for enrichment but does enable a high cellular PHA content, such as OFMSW leachate, makes the overall process much more economically attractive. The estimated overall process yield can be increased four-fold, in comparison to direct use of the complex matrix for both enrichment and accumulation.

• Premise of the study: Fungal endophytes are symbionts that inhabit aboveground tissues of most terrestrial plants and can affect plant physiology and growth under stressed conditions. In a future faced with substantial climate change, endophytes have the potential to play an important role in plant stress resistance. Understanding both the distributions of endophytes and their functioning in symbiosis with plants are key aspects of predicting their role in an altered climate.• Methods: Here we characterized endophytes in grasses across a steep precipitation gradient to examine the relative importance of environmental and spatial factors in structuring endophyte communities. We also tested how 20 endophytes isolated from drier and wetter regions performed in symbiosis with grass seedlings under high and low soil moisture in the greenhouse.• Key results: Environmental factors related to historical and current precipitation were the most important predictors of endophyte communities in the field. On average, endophytic fungi from western sites also reduced plant water loss in the greenhouse compared to fungi from eastern sites. However, there was substantial variability in how individual endophytic taxa affected plant traits under high and low water availability, with up to two orders of magnitude difference in the plasticity of plant traits conferred by the different fungal taxa.• Conclusions: While species sorting appears to largely explain local endophyte community composition, their function in symbiosis is not predictable from local environmental conditions. The development of a predictive framework for endophyte function will require further study of individual fungal taxa and genotypes across environmental gradients.

Biosorption of ochratoxin A (OA) onto yeast biomass appears to be a reasonably low cost decontamination method. In vitro adsorption of OA onto three yeast industry by-products: a vinasse containing yeast cell walls (EX16), a purified yeast beta-glucan (BETA) and a yeast cell wall fraction (LEC) was examined at 25 degrees C. Seven classical adsorption models were tested to provide the best description of toxin adsorption. A comparison of these models was performed using the magnitude of the coefficient of determination R(2) for the linear models and the value of the sum of normalised errors (SNE) for linear and non-linear models. Based on the R(2) and the SNE values, Hill, Freundlich and Brunauer-Emmett-Teller equations produced the best models for OA biosorption onto respectively, EX16, BETA and LEC. For these best models, the values of isotherm constants were consistent when measured using both linear and non-linear calculations. The SNE calculation procedure presented in this paper in association with the linear equation analysis method is an appropriate approach for designing a better adsorption isothermal model.