Micro gas turbines
The micro gas turbine has been developed from gas turbine combustion systems in the 200-kilowatt range.
The turbine inlet temperature is to be increased to 1,300 °C from typical current values of 950 °C in order to improve the electrical efficiency. To achieve this, ceramic components that are designed for use with hot gases must be developed. In addition, researchers are working to optimise the power electronics with regard to efficiency, stability, and the efficiencies and pressure drops of individual components.
The research activities here are focusing on the minimisation of harmful substances and the analysis of the reliability of technical combustion systems. Another focus of research is combustion flexibility with regard to conventional, alternative, liquid and gas fuels. The experimental data measured under actual engineering conditions are being used to validate numerical simulations. The micro gas turbine at the German Aerospace Center also serves as an important test unit for research on and implementation of various plant design concepts for sustainable, decentralised energy supply and of a hybrid power plant consisting of high-temperature fuel cells and a gas turbine.
The German Aerospace Center and Energie Baden-Württemberg AG are working on an efficient heat-controlled, low-emission combined heat and power plant (CHP) that is based on gas turbines for decentralised cogeneration using natural gas. They are developing and evaluating various power plant concepts based on gas turbines, the design of a demonstration plant, and the optimisation of an efficient, low-emission combustion chamber system for natural gas of varying qualities. In parallel, a suitable location is being selected for the installation of the power plant and the implementation, test operation and permanent operation of the demonstration power plant.
The planned power plant concept has excellent potential for series production and would be suitable for installation in Germany or for export, too. Cooperations are planned with small- and medium-sized companies in Germany that will then commercially manufacture the plant components that have been developed and integrate them into the overall energy system.
Preliminary investigations are also currently being conducted on hybrid concepts with high-temperature fuel cells (SOFCs) and a micro gas turbine. As a subsequent step, these components will then actually be linked up in practice. A megawatt-scale demonstration plant is to be built by the year 2014. Work on the SOFC/gas turbine hybrid at the German Aerospace Center is concentrating on a combination of a micro gas turbine with a high-temperature fuel cell, with special focuses on the modification of the micro turbine and the development of operating concepts. The goal is to combine two technologies that have differing characteristics in an optimal manner.
Originally, the micro gas turbine was only used to generate emergency and peak-load power without waste heat utilisation. However, it is a relatively new item of equipment in the area of cogeneration. Over the last ten years, engineers have developed these turbines to a stage where they can now be used commercially. There are only a few commercial manufacturers of micro gas turbines worldwide. A few thousand systems have been installed and put into operation in the sub-100 kWel power range. A few hundred systems have been constructed in the 100 kWel range.
The German Aerospace Center and EnBW initiated a research platform for decentralised energy in 2008. The first project to be started involved the development of a micro gas turbine for the use of biogas. The tasks here included the adaptation of the combustion chambers of current micro gas turbines for the use of biogas, the optimisation of the plant to use the fuel more effectively, and the improvement of the economic viability of decentralised energy generation on a small power scale. Specific research projects are being prepared for three further plant concepts based on natural gas, biogas and wood gas.
Current research project
Combined heat and power plant with micro gas turbine using natural gas for decentralised energy supply
Organisations carrying out research:
German Aerospace Center (DLR) - Institute of Combustion Technology (EN-VT)
EnBW Energie Baden-Württemberg AG
Project numbers: 0327837B, 0327837C