[en] The study develops an algorithm for valuating static substratum - biofilm systems used in biogas reactors. This valuation method permits coupling the service value of static substratum - biofilm systems as derived from individual quality factors with the costs of the substratum. Beyond this the cost-related value thus obtained is of principle value for comparing different variants. (orig.)

[en] The unicellular green alga Chlamydomonas reinhardtii is able to produce hydrogen, using water as an electron donor, and sunlight as an energy source. Although this property offers interesting biotechnological perspectives, a major limitation is related to the sensitivity of hydrogenase to oxygen which is produced by photosynthesis. It had been previously shown that in conditions of sulfur deprivation, C. reinhardtii is able to produce hydrogen during several days (Melis et an. 2000). During this process, two pathways, one direct depending on photosystem II (PSII) activity and the other involving only the PSI, are involved, starch reserves being supposed to play a role in both of these pathways. The purpose of this phD thesis was to elucidate the mechanisms linking starch catabolism to the hydrogen photoproduction process. Firstly, the analysis of mutants affected in starch biosynthesis (sta6 and sta7) showed that if starch reserves are essential to the functioning of the indirect pathway, they are not involved in the direct one. Secondly, in order to identify metabolic steps and regulatory processes involved in starch breakdown, we developed a genetic approach based on the search of mutants affected in starch reserves mobilization. Eight mutant (std1 to std8) diversely affected in their ability to degrade starch after an accumulation phase have been isolated from an insertional mutant library of 15,000 clones. One of these mutants, std1, is affected in a kinase related to the DYRK family (dual-specificity tyrosine regulated serine threonine kinase). Although the targets of this putative kinase remain to be identified, the analysis of the granule bound proteome displayed profound alterations in the expression profile of starch phosphorylases, potentially involved in starch breakdown. STD1 represents the first starch catabolism regulator identified to date in plants. (author)

[en] The fundamental aim of this work is biomass utilization for gas production, which will be used ecologically and with efficiency for obtaining energy. For this reason, a pilot plant was constructed for biomass gasification in a fluidized bed reactor. The practical solution to fluidization of inert material, to fuel supplying, to ash removing and the system for analyzing of produced gas, were presented. The pilot plant is tested on rise hulls from the Kocani region and the fluidization was carried out with air under pressure and the quartz sand was used as inert material. The influence of the temperature and the height of fluidized bed on the minimum fluidized velocity was examined in different working conditions. Also, the influence of the working parameters (granulation and height of the inert bed material, pressure of the gas for fuel supply and the fuel supply) on the composition of gas produced by gasification, was examined. Mathematical model for the complete process was developed and all material flows were calculated. According to the calculated coefficient of over air it can be concluded that the process is carried out with partial fuel combustion i.e. the process of gasification is performed in the reactor. From the obtained results and their analyses, it can be generally said that the aim of this doctoral thesis is accomplished. (Author)

[en] Gasification is presented as a concept that can assist municipalities and private companies to reduce the amount of solid waste generated and to utilize the cellulosic fraction of such waste as a biofuel. The technical and economic feasibility of cellulosic waste gasification is examined along with the implications associated with the environmental, social, and regulatory issues within a planning context. Study methods included a literature review, survey research employing nonstructured interviews, and a case study analysis. Opportunities for gasification are focused on regional governments in Ontario. The case study concentrated on the Regional Municipality of Waterloo. Regional governments in Ontario can benefit from utilizing the gasification concept to achieve a substantial reduction in the waste stream in an environmentally sound manner and contribute to solving worldwide problems associated with fossil fuel utilization. However, provincial and public acceptance will affect regional government decisions regarding gasification. Separate legislation should be enacted distinguishing gasification from incineration. In addition, the effectiveness of the environmental approval process must be improved; present procedures consume excess time and resources and act to discourage the involvement of public and private proponents. Public acceptance is likely to be affected by negative experiences associated with solid waste combustion. Nonbiased, reliable information is needed to clarify doubts and stress gasification's potential benefits. 85 refs., 15 figs., 26 tabs

[en] Fossil resources are limited and will run short. Moreover, the extensive usage of fossil resources is discussed as a key driver for climate change which means that a changeover in basic economic and ecological thinking is necessary. Especially for energy production, there has to be a movement away from the usage of fossil resources and towards renewable resources like wind, water, sun, or biomass. Within the first part of this work a structured review of recent literature on the long-term, strategic planning of biomass-based supply chains is provided. Therefore, in the first step, the overall research field “bioeconomy” by means of the various utilization pathways of biomass is structured and the demand-oriented view of supply chain management models and the supply-oriented view of bioeconomy are combined. In the second step, a literature review of operations research models and methods for strategic supply chain planning in biomass-based industries are provided. Thirdly, trends are identified and conclusions about research gaps are drawn. One of the identified research gaps is to make biomass-based supply chains profitable on their own, i.e., without governmental subsidies. Therefore, new optimization models are necessary, which should be as close to reality as possible, by for example considering risks and actual surrounding constraints concerning the legal framework. Within the second part of this work, an approach for strategic optimization of biogas plants considering increased flexibility is developed. Biogas plants can produce their energy flexibly and on-demand if their design is adjusted adequately. In order to achieve a flexibly schedulable biogas plant, the design of this plant has to be adapted to decouple the biogas and electricity production. Therefore, biogas storage possibilities and additional electrical capacity are necessary. The investment decision about the size of the biogas storage and the additional electrical capacity depends on the fluctuation of energy market prices and the availability of governmental subsidies. This work presents an approach supporting investment decisions to increase the flexibility of a biogas plant by installing gas storages and additional electrical capacities under consideration of revenues out of direct marketing at the day-ahead market. In order to support the strategic, long-term investment decisions, an operative plant schedule for the future, considering different plant designs given as investment strategies, using a mixed-integer linear programming (MILP) model in an uncertain environment is optimized. The different designs can be evaluated by calculating the net present value (NPV). Moreover, an analysis concerning current dynamics and uncertainties within spot market prices is executed. Furthermore, the influences concerning the variation of spot market prices compared to the influence of governmental subsidies, in particular, the flexibility premium, are revealed by computational results. Besides, the robustness of the determined solution is analyzed concerning uncertainties. The focus of the third part of the work is to consider variable substrate feeding in the mentioned optimization approach because it is expected that variable substrate feeding and thus a demand-oriented biogas production can influence the optimized plant design. In order to support this extension, an operative plant schedule for the future, considering (non-) linear technical characteristics of the biogas plant and the legal framework is optimized. Therefore, mixed-integer linear programming models with integrated approximation approaches of non-linear parts, representing the biogas production rates, are constructed. Furthermore, the influences of fluctuating spot market prices, governmental subsidies, and biomass feedstock prices on the decisions are analyzed for a fictional case example, which is based on a biogas plant in southern Germany. These numerical experiments show that variable substrate feeding can play a decisive role during the optimization of a biogas plant schedule as part of a long-term design optimization. However, the size of the strategic optimization problem makes the use of a heuristic solution algorithm necessary.

[en] The thesis deals with aspects of the competitiveness of bioenergy. The central aim is to develop a number of concepts that enables an extended analysis. The thesis is composed of four studies. In study 1 and 2 the emphasis is put on two institutional frameworks within the forest company, i.e. the framework around the forest fuel operations and the framework around the industrial timber operations. Depending on which of the two institutional frameworks that makes up the basis for the understanding of forest fuel operations, the forest fuel operations will be given different roles and different priorities. Different goals and the process of integrating the forest fuel operations into the forest company will therefore be carried out with different means, different feelings and different resources. Study 3 examines the conceptions that the actors of the energy system uphold. The study presents the concept of logic, which is an institutionalised conception of the competitiveness of bioenergy. Logics can be seen as the dominating conceptions within the energy system and are decisive in determining the factors and parameters that state the competitiveness of different forms of energy. Study 4 argues that the strategical work concerning the competitiveness of bioenergy in the long-run to a great extent is about understanding, shaping and utilising the conceptions that affect the bioenergy system. The study problematises strategies that are used to develop bioenergy by introducing the uncertainty of the future into the analysis. The uncertainty of the future is captured in different scenarios

[en] Polarimetric Synthetic Aperture Radar Interferometry (Pol-InSAR) is an active radar remote sensing technique based on the coherent combination of both polarimetric and interferometric observables. The Pol-InSAR technique provided a step forward in quantitative forest parameter estimation. In the last decade, airborne SAR experiments evaluated the potential of Pol-InSAR techniques to estimate forest parameters (e.g., the forest height and biomass) with high accuracy over various local forest test sites. This dissertation addresses the actual status, potentials and limitations of Pol-InSAR inversion techniques for 3-D forest parameter estimations on a global scale using lower frequencies such as L- and P-band. The multi-baseline Pol-InSAR inversion technique is applied to optimize the performance with respect to the actual level of the vertical wave number and to mitigate the impact of temporal decorrelation on the Pol-InSAR forest parameter inversion. Temporal decorrelation is a critical issue for successful Pol-InSAR inversion in the case of repeat-pass Pol-InSAR data, as provided by conventional satellites or airborne SAR systems. Despite the limiting impact of temporal decorrelation in Pol-InSAR inversion, it remains a poorly understood factor in forest height inversion. Therefore, the main goal of this dissertation is to provide a quantitative estimation of the temporal decorrelation effects by using multi-baseline Pol-InSAR data. A new approach to quantify the different temporal decorrelation components is proposed and discussed. Temporal decorrelation coefficients are estimated for temporal baselines ranging from 10 minutes to 54 days and are converted to height inversion errors. In addition, the potential of Pol-InSAR forest parameter estimation techniques is addressed and projected onto future spaceborne system configurations and mission scenarios (Tandem-L and BIOMASS satellite missions at L- and P-band). The impact of the system parameters (e.g., bandwidth, NESZ, ambiguities) and the operation scenario (e.g., temporal decorrelation due to a repeat-pass orbit) is evaluated and discussed with respect to the retrieval of the forest parameters. The study is supported and validated by using repeat-pass Pol-InSAR data at L- and P-band acquired by DLR's E-SAR system over Remningstorp (BioSAR 2007, hemi-boreal forest), Krycklan (BioSAR 2008, boreal forest) and Traunstein (TempoSAR 2008 and 2009, temperate forest) test sites. The simulated spaceborne data sets generated during the BioSAR 2007 campaign are used to carry out the performance analysis.

[en] This work addresses the transport planning of raw material supply chains for biomass power plants. It considers the need of generating sustainable solutions by analyzing relevant sustainability frameworks to propose a novel approach. It proposes a novel approach which consists of an architecture to tailor a proposed base model, and to process the relevant data needed to generate sustainable solutions. The special characteristics of the biomass transport problem and power plant requirements are captured in a formal problem definition in the form of a data model. The architecture consists of five combined models (called modules). Each module contributes with methods from different disciplines to enrich the solutions with distinct perspectives. The considered modules include elements from the social, weather, geographic information systems (GIS), life cycle impact assessment (LCIA), and mathematical optimization disciplines. An integrated solution is generated combining the results of all the modules. Important implementation elements for specific potential users are discussed to support a system prototype. A case study in Chile is used to gain related primary information of a real supply chain, test the architecture, and provide results about the performance, and allows a deeper discussion. The architecture generates optimized transport plans that make impacts visible in the considered sustainability dimensions and give the decision makers a better understanding of the effects of the considered solutions.

[en] Since the implementation of the EEG in Germany the biogas production becomes an independent branch of industry in the agriculture. At this time more than 90 percent of the biogas plants work with co-generation plant for heat and power with a thermal engine efficiencies of more than 50 percent. Because of the location in the rural area heat costumers with a continuous demand of heat over the whole year are rare. This research had a closer look how to use the heat of biogas production efficiently and also generating profit. The aim of the study was to use heat over the whole year, a profitable heat concept without counting the KWK-bonus and an added value on the farm. During the study the following concepts were analyzed: asparagus production using soil heating, drying equipment for different products, the production of fish in aquaculture, the poultry production and the heated production of tomatoes. The results showed different concepts using heat of biogas plants as efficient for farmers. However with only one concept the aims - to use the heat over the whole year, generating a profitable heat concept without counting the KWK-bonus, add an value on the farm - mostly can not be achieved. The combination of different heat concepts is necessary. In this analysis the poultry production in combination with the dryer can be considered as the most efficient concept. Bearing in mind the benefit which can be generated with a heat concept as well as the higher income and the higher technical efficiency of biogas plants operators should implement an individual concept for their heat.

[en] The objectives of this research were to assess the black carbon and mass concentration levels in ambient air fuel to the use of biomass for cooking and also to facilitate awareness creation on biomass burning and its effects in the Kassena-Nankana East District through the generation of relevant scientific information. The Gent air sampler was used to sample airborne particulate matter in the Kassena-Nankana East District of the Upper East Region. These particulates were collected on nuclepore polycarbonate filters for a period of six months. In addition to determination of particulate mass in the two fractions by gravimetrical method, the aerosol filters were also analyzed for black carbon (BC) concentration levels using the black carbon method. The average fine fraction mass concentration determined was 134.59 μgm^-3 (with a minimum of 9.28 μgm^-3 and a maximum of 338.11 μgm^-3) and that of coarse fraction (CF) was 355.04 μgm^-3 (with a minimum of 61.73 μgm^-3 and a maximum of 1117.43 μgm^-3). The black carbon concentration in fine, average was 6.29 μgm^-3 (with a minimum of 1.68 μgm^-3 and a maximum of 35.35 μgm^-3) and that of the coarse was 7.62 μgm^-3 (with a minimum of 1.76 μgm^-3 and a maximum of 22.61 μgm^-3). The results were compared with some literature values and World Health Organisation guideline values (which are 50 μgm^-3 for coarse fraction and 25 μgm^-3 for that of fine) and they are higher than both. The values obtained for coarse to fine ratio and for difference between the coarse and fine concentrations, suggest that, the aerosol was not only largely made up of combustion generated carbonaceous particles but also particulate matter emissions from natural activities. (au)