Browsing by Author "Braun, Martin"

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Environmental external costs from power generation by renewable energies
(2004) Braun, Martin
In the following decades there will be a fundamental structural change in the European power supply system. This structural change is forced by several factors, e.g. the European Union Greenhouse Gas Emission Trading Scheme, the strategic goal for the European Union of a more sustainable development, energy policy targets to double the share of renewable ener-gies, the phase out or moratoria of the nuclear industry in some European Union member states, and the need of more than 200 GW of new power plant capacities in EU-15. The struc-tural change has to be embedded into an economic, social and ecological framework. Within this framework, there is a variety of possible options to create a future power supply which fulfils the multiple criteria. Generally, different technologies can be chosen which all have their own advantages and disadvantages. It is a challenging decision-making process because fossil-fired power plants tend to be economically advantageous and ecologically disadvanta-geous whereas renewable energy systems tend to be ecologically advantageous and economi-cally disadvantageous. This study gives a comparison of the estimated external costs (environmental aspects) and internal costs (economic aspects) of different power generation technologies in the year 2010 in order to support the decision-making process of future power plant investments in the framework of a sustainable development. A life cycle analysis gives considerable life cycle data for photovoltaic systems, wind turbines, fuel cells, bio-fuelled combined heat and power plants, biomass, water, solar thermal, geothermal, coal-fired, lignite-fired and natural gas-fired power plants as well as nuclear power plants. This database is used for the estimation of external costs which is based on updated factors of damage and avoidance costs for selected emissions. The damage factors are calculated with the software tool EcoSense following the impact pathway approach. Global warming and discounting are considered to be the hot spots in the external costs discussion. An avoidance costs approach is applied which is assumed to fulfil sustainability criteria. The comparison of the external costs of the technologies analysed shows that external costs of power generation technologies using renewable energies and nuclear power plants are in the range of 0.03-3.79 €-Cent/kWhel whereas the external costs of power generation technologies using organic fossil fuels are in the range of 3.37-27.98 €-Cent/kWhel. However, the comparison of the internal costs shows that fossil-fuelled power plants have the lowest internal costs compared to the other technologies analysed. This trade-off between external and internal costs requires a comparison of the social costs which are the sum of internal and external costs. The comparison of the social costs shows five social cost clusters for the ana-lysed technologies for the year 2010. Nuclear power plants have social costs of less than 10 €-Cent/kWhel. Wind turbines and river power plants have slightly higher social costs of 10-15 €-Cent/kWhel. Biomass power plants, bio-fuelled combined heat and power plants, solar ther-mal power plants, geothermal power plants and natural gas-fired power plants have social costs in the range of 15-20 €-Cent/kWhel. Photovoltaic systems in Spain, fuel cells, coal-fired power plants and lignite-fired power plants have social costs in the range of 20-35 €-Cent/kWhel. The highest social costs are caused by Photovoltaic systems in Germany with more than 35 €-Cent/kWhel.
Open Access
Models for transient simulations of decentral power generation : implementation and verification in PowerFactory
(2005) Braun, Martin
As part of the Institut für Solare Energieversorgungstechnik (ISET) e.V. in Kassel, the Design Center for Modular Supply Technology (DeMoTec) has the facilities for testing a variety of low-voltage power grid configurations. These configurations consist of decentralized power generation components in the kilowatt range. Transient simulations of components and grid configurations with MATLAB/Simulink, ATP-EMTP and SIMPLORER support research activities in this field. The aim of this work is to add a fourth tool - PowerFactory - which offers additional features for this application. All four simulation tools have their own specific characteristics which make them most suitable for particular applications. This work investigates the features of PowerFactory developed by DIgSILENT. The investigation uses components for grid configurations which are available in DeMoTec in order to verify the results of the simulations by measurements. The island grids which are investigated comprise three components: a bi-directional battery inverter which is able to form a grid, an asynchronous generator which simulates the feed-in of wind power, and a load which represents consumers and their consumption behaviour. In order to allow these components to be used in PowerFactory, this work presents the following three parts for the implementation of the components' models: 1) PowerFactory does not comprise a generic model for a battery inverter. However, single phase models in MATLAB/Simulink and ATP-EMTP are available which deliver details for the development of a PowerFactory model. For the implementation, the available models are enhanced to a three phase model and adjusted to the simulation environment of PowerFactory. 2) PowerFactory comprises a model for asynchronous generators. This generic model is adjusted to the considered asynchronous generator in DeMoTec. The electrical parameters of the analysed asynchronous generator are measured for this adjustment process and an optimisation process is performed to determine best fitting parameters. 3) A generic model for loads is available in PowerFactory. It is adjusted to correspond to the loads used in DeMoTec. The models implemented in PowerFactory form different configurations of island grids. Within these island grids, PowerFactory simulates characteristic load changes. The selected components enable measurements of the same load changes in the same grid configurations in DeMoTec. A comparison of the measured and simulated data shows a good congruence with few deviations. This thesis uses the power system analysis tool PowerFactory from DIgSILENT for transient simulations of decentralised power generation components in low-voltage grids which operate with a variable frequency and a variable voltage. Moreover, this thesis verifies the simulation results and illustrates their quality by comparing measured data at DeMoTec with simulated data using PowerFactory. Finally, one of the advantages of this simulation tool is presented by simulating a large grid configuration which is not available in the limited laboratory environment of DeMoTec.