Abstracts - VGB PowerTech Journal 4/2020

Maintenance in times of corona crisis

Uwe Grobermann

Yes, these are truly extraordinary times that this virus brings with it! Not only do we have to keep our distance to our best friends and the children can only communicate with grandma and grandpa via media, no, the Covid-19 disease does not stop at the power industry![more...]

80 % effectiveness of renewable energy by innovative sector coupling and re-electrification with green hydrogen

Thomas Neuenhahn, Thomas Thiemann, Alexander Tremel and Uwe Neiß

A solution for a CO2-free electricity and heat supply system including sector coupling was developed and evaluated in a feasibility study co-funded by the Ministry of Economic Affairs, Innovation, Digitalization and Energy of the State of North Rhine-Westphalia (MWIDE). Starting point for these investigations are the local generation profiles of wind turbines and solar cells as well as the electrical and heat load profile of the grid or the end-user, respectively. Based on these boundary conditions an economical optimized solution for a CO2-free energy supply system has been developed, covering each hour of the year. Several storage technologies (hydrogen generation, storage and re-electrification by a gas turbine, batteries and heat storage) have been combined to achieve an economical optimal solution. Additionally, opportunities by sector coupling like leveraging electric energy for heating as well as for mobility applications have been investigated. The developed system solutions represent a holistic approach, which covers the electricity as well as the heat supply in addition to the sector coupling and the optimization of each system component’s operation. Thus, the Power-to-X-to-Power efficiency of typically 30 % to 40 % for electricity storage and re-electrification is increased to a renewable energy effectiveness for electricity and heat of about 80 %. This investigation is also intended to support the development of future concepts especially in consideration of the energy transition in Germany.

Accident-free through everyday life with a steam turbine, regularly checked, safe in operation!

Christian Scharfetter, Kristin Abel-Günther, Mario Schenzer and Wulf von Karstedt

The safe and reliable operation of a turboset has an important role in the safety of the plant and the employees. The reliability of the unit has a considerable influence on the profitability of the plant. Regular checks of the safety-relevant control elements is therefore of particular importance. These tests are intended to show that the turboset is capable of safely coping with malfunctions, while at the same time being designed with such care that its service life is not negatively affected. Steam turbines from MAN are ready for the future with security of supply and operation.

Cleaning hard-soiled tube bundle heat exchangers – A field report

Hans-Jürgen Kastner

As operators of shell and tube heat exchangers with hard crusts and such closures are usually not aware of the advantages and disadvantages of individual cleaning processes, this article presents alternative possibilities for the removal of such fouling. The contribution is intended to enable operators of shell and tube heat exchangers to make the decision to opt for alternative cleaning methods if the current cleaning methods no longer guarantee the required heat transfer that is close to the project to maintain a process. The use of these cleaning processes can result in considerable economic and other advantages and make the scrapping of shell and tube heat exchangers superfluous.

Benefits of Big Data and Machine Learning for the life cycle of wind turbines

Christian Pagel

To optimize their economic efficiency, the technical availability of wind turbines has to be kept at as high a level as possible, at low costs. Systems for the online monitoring of important operating parameters of wind turbines make consistent use of the progress of digitalization and thus of the strong points of AI methods, among other things on the basis of Big Data and machine learning. By intelligently analyzing data of operation management and condition monitoring, such systems not only allow to implement more cost-efficient maintenance strategies during wind farm operation but offer many and various benefits already during the development as well as in the course of the installation and commissioning of wind farms. Thus the inclusion of experiences available from monitoring installed plants from other wind farms provides valuable decision support in selecting an optimal plant type and, in addition, can significantly contribute to decreasing the levelized cost of energy. Moreover, the online monitoring of wind farms creates a valuable plant history in the form of a digital service life record that enables reliable support in assessing the residual lifetime with regard to the ongoing operation. The potentials of the solutions described in this paper thus range across the entire life cycle of wind turbines, from the development of the wind farm right up to the ongoing operation of the plants after the 20th year of operation.

Experience with the T24 steel in GKM, unit 9 after 5 years of operation

Klaus Metzger and Karl Maile

The steel T24 (1.7378, 7CrMoVTiB10-10) has been used in the boiler area in various new power plants in the Federal Republic of Germany since 1998. During the commissioning of these new buildings numerous leakages occurred due to cracks in the welded joints of the boiler tubes. As a result, intensive research work was carried out by scientific institutes and by the manufacturers, suppliers and operators. Due to the sluggish progress in the analysis of the causes of the damage, delays, some of them considerable, occurred in the completion and commissioning of the planned power plant units. In the technical discussions, the processability and practicability of T24 steel were questioned. In the Grosskraftwerk Mannheim (GKM), Block 9, this steel has been in operation for around 30,000 hours, with approx. 160 starts. The causes of the sporadic damage that has occurred in the GKM to date are discussed below.

Download [2.3 MB]

Dynamic simulation of flexibility measures for coal-fired power plants

Marcel Richter, Gerd Oeljeklaus and Klaus Görner

Improving the flexibility of conventional power plants is one key challenge for the transformation of the energy system towards a high share of fluctuating renewable energies in electricity generation. In this context, dynamic simulation models offer an efficient tool to evaluate possible flexibility measures and the resulting highly transient power plant operation. In this article, selected flexibility measures for coal-fired power plants are evaluated with regard to their flexibilization potential and the thermodynamic effects on the power plant process. For this purpose, a detailed dynamic power plant model has been built up using the Modelica library ClaRa. The first flexibility measure evaluated with the dynamic power plant model is the one-mill operation, resulting in a potential of reducing the minimum load to 10 %. Next, the possible load flexibilization by installing an indirect firing system is evaluated, showing the potential of doubling the achievable load change rates. A further innovative measure is the integration of a thermal energy storage into the power plant process. Within this context, the integration concept of a steam accumulator is presented. The results of the dynamic simulations show an improved load flexibility with regard to a temporary reduction of the (minimum) load by charging the Ruths storage as well as to the possibility of activating additional net power of 4.3 % very quickly (e.g. to participate on the quarter-hourly intraday market).

Download [2.5 MB]

Arbeitsgemeinschaft Energiebilanzen presents report on energy consumption in 2019

Arbeitsgemeinschaft Energiebilanzen

In 2019, energy consumption in Germany fell to 12,832 petajoules (PJ) or 437.8 million tonnes of hard coal units (million tonnes of coal equivalent), 2.1 percent below the level of the previous year. As AG Energiebilanzen explains in its now published Annual Report 2019, the drop in consumption was caused by further improvements in energy efficiency, shifts in the energy mix and a cyclically induced decline in energy consumption in industry. Consumption was boosted by the somewhat cooler weather and the increase in the population. However, the consumption-reducing factors had a much stronger impact than the consumption-increasing factors. Adjusted for the influence of the weather and changes in inventories, energy consumption would have fallen by as much as 2.4 percent according to calculations by AG Energiebilanzen.

A journey through 100 years VGB | The 1960ies

  • Research and technology as the basis of life
    Walther Gerlach
  • Technology and society in 2000
    Karl W. Steinbuch
  • Status of power plant technology in the USSR
    M.A. Styrikowitsch