As for generating district heating from CHP sources, gas engine-driven power plants offer numerous advantages over classic gas combined-cycle power plants, a comparative study by the Essen-Duisburg University and MAN Diesel & Turbo shows. Engine-driven CHPs were found to be “operationally superior”, both in terms of energy efficiency as well as cost-effectiveness.
The study compares data of a conventional CCGT with two different configurations of an engine-power plant (multiple gas engines arranged in combination). A multitude of parameters were compared, such as the heat yield, electricity production, fuel consumption, fuel utilisation and financial yield of the systems.
All of the systems provided the necessary heat demand and met the legally required efficiency of more than 80 percent”, explains Tobias Vogel, research assistant in the Department for Environmental Process and System Technology at the Essen-Duisburg University, who provided support for the study. “But in the end, it must be noted that the engine combined systems have proven themselves more favourable than gas combined-cycle power plants and were opportune in terms of their energy efficiency and cost-effectiveness.
“The economic optimum was shown to be achieved with a mix of engines in simple CHP mode and others with downstream coupled water- or steam-cycles,” he pointed out.
Apart from industrial use of CHPs, the main application for CHP plants in the multi-digit megawatt range is the supply of district heating. Owing to the oftentimes very specific requirements for heat supply that industrial CHP plants face, the study analysed the needs of a district heating network of a small city – a typical example for district heating production in Germany. The full study can be found here.
Potential for additional revenues
Both industries and utilities in Germany and beyond have for long made use of large-scale CHP plants. In contrast, the concept of engine combined power plants is not very well established in Germany yet, according to Dr. Thomas Polklas, development engineer at MAN Diesel & Turbo.
Yet, considering the constantly rising feed-in of renewable energies to the grid, this technology offers further advantages, he underlined, suggesting that “as well as ensuring the supply of a municipal power network, engine combined power plants can be used for grid support in the residual load market due to their flexibility and modular construction. There is a substantial potential for additional revenues here.”
As one of the few producers in the market, MAN Diesel & Turbo manufactures both gas and diesel engines, as well as gas and steam turbines – a comprehensive offer.