Abstracts - VGB PowerTech Journal 8/2020

VGB – Energy is us!

Dr. Oliver Then

Energy is us – this is the mission under which VGB PowerTech is taking the way to the energy system of the future. This year our association celebrates its 100th anniversary. Our more than 430 VGB members from 33 countries are united in the knowledge that valuable impulses for the development of their own companies are created from the joint work of our association. These added values result from the exchange of experience, knowledge transfer, standardisation and innovations, which are only possible through a joint platform such as VGB PowerTech.[more...]

Can e-fuels close the renewables power gap? A review.

Thorsten Krol and Christian Lenz

A major challenge in the decarbonization efforts of governments across the world is to maintain the high availability of electric power during times of renewables unavailability. One option currently under discussion is to use renewable excess power to generate and store e-fuels. In this paper, the availability of excess renewables power at the example of Germany is discussed considering re-dispatches and Tip Capping. The power demand to produce e-fuels, the production processes of e-hydrogen, e-methane, e-methanol or e-ammonia as well as a cost estimation including a projection of the costs to 2030 will be detailed out as a result and summary of several studies. The physical properties of the fuels are listed resulting from several sources. Finally, based on the total cost of the processes and their efficiency, the possible future storage and use of excess renewable power as a fuel to secure power supply during dark doldrums is discussed. In addition, their potential in sector coupling to decarbonization the industry and transportation sectors as well as the impact on operation of current generation technologies like gas turbines and reciprocating internal combustion engines are outlined.

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Know-how and capacity assurance for the maintenance of conventional power plants

Thomas Porsche, Gerald Weiß and Nadine Müller

Maintenance Management of the Lausitz Energie Kraftwerke AG plans and provides all technical services that are necessary for the safe and economical operation of power plants. The majority of industrial maintenance services are carried out by external, competent service partners. Due to economic pressure, the increasing demand for flexibility and the noticeable decrease in the number of skilled workers, securing of know-how and capacities in terms of quantity and quality becomes increasingly important. This applies both to LEAG’s own personnel and to the personnel of its service partners. The presentation describes the current situation in the company and the region and its effects on maintenance of the power plant facilities. On the basis of first ideas and examples, possible courses of action for reacting to the changed framework conditions are shown.

Excitation of torsional oscillations in the grid by feeding in sub-synchronous currents

Matthias Humer

In the following article results of the investigation on the effect of feeding subsynchronous currents from the electric grid in the generator are presented. In the end, torsional oscillations of the shaft train are excited, which can reach very high amplitudes in case of resonance. In time with the torsional oscillations, the synchronous generated voltage induced in the stator winding oscillates, which leads to the feed in of subsynchronous currents from the generator into the electrical network. The focus is directed to the effect of these currents in the system “generator- grid”. Therefore, different analytical approaches to subsynchronous power excitation are presented and evaluated. In particular, the analytical equations of generator power generated by subsynchronous electric currents are derived.

Efficiency and lifetime optimization for bearings and gearboxes through innovative phyllosilicate-based additives

Stefan Bill and Petr Chizhik

A lifespan of 20 years is envisaged for all common wind turbines, although an attempt is of course made to extend this by a few years or even up to 30 years. During this period of use, both the gearbox and the bearings are affected by wear, so that these components have to be replaced in many systems (sometimes even several times), which is associated with very high costs. The REWITEC technology helps to significantly reduce or even prevent such damage, whereby an application is recommended for both new and already damaged systems. The technology is an innovative lubricant additive with a protective and repairing effect, which mainly consists of phyllosilicates in the form of micro and nanoparticles. The particles use lubricant as a carrier to reach the rubbing metal surfaces and to cover them by adsorption. The new, modified surface is optimized and protected from a tribological point of view, so that surface roughness, friction, wear and temperature in the system are reduced. This leads to a significant improvement in efficiency and lifespan.

First experiences with the application of heating surface coatings from coal-based energy generation in the MHKW Berlin-Ruhleben and MHKW Iserlohn

Andreas Salamon, Peter Grebe and Falk Olaf Ewert

The processes of corrosion and erosion in steam boiler plants for the generation of heating energy and electrical energy represent an important problem. These processes strongly influence the safety and economy of the operation of these plants. In order to ensure reliable and economical operation of these systems, taking environmental protection into account, protection against corrosion and erosion protection became a necessity. Suitable, known protective coatings were tested and new ones developed. The first experiences quickly showed that the investment costs for corrosion and erosion protection pay for themselves relatively quickly. The processes of corrosion and erosion in wasteto- energy (WtE) plants that burn very inhomogeneous and highly polluted fuels are much stronger compared to coal-based power plants. For this reason, it cannot be assumed from the basic point of view that the protective coatings from coal-based energy production can also be used in the WtE plants with corresponding success. This article presents protective coatings that are already established in Polish coal-based energy generation. Based on the positive experience, attempts were made to test these protective layers in WtE plants in Germany. The first experiences with test applications in waste incineration plants in Iserlohn and Berlin-Ruhleben are presented here.

The Biofficiency Project | Part 2:
A Blueprint Design for the Next Generation of Biomass-Fired Cogeneration Plants

Thorben de Riese, Lynn Hansen, Despina Magiri-Skouloudi, Konstantinos Braimakis, Liisa Clemens, Christian Bergins, Sebastian Fendt, Sotirios Karellas and Hartmut Spliethoff

The EU-funded Biofficiency project developed a design for the next generation of biomassfired combined heat and power plants using low quality fuels and ensuring safe and virtually carbon-neutral electricity generation. In the first part of this publication (published in VGB PowerTech Journal 7 (2020)) a summary of the experiments to overcome ashrelated problems in biomass-fired boilers was presented. In this second part, the new CHP concept designed in the Biofficiency project is introduced. The 300 MWth pulverized coalfired boiler shown here has an overall efficiency of 92.9 % and meets the ambitious emission targets of the Renewable Energy Directive RED II and the LCP-BREF. Subsequently, this article presents the technological improvements, reduced operational risks and the reduced environmental impact during power generation made possible by the project. Finally, the remaining research needs are outlined.

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VGB on the Way to the Future Energy System

VGB PowerTech

VGB, the International Association of Energy Plant Operators, outlines in its White Paper the important fields of action for designing the future energy system and which contributions VGB can make to implement this new energy system. [more...]

A journey through 100 years VGB | Gas turbines

  • Planning principles, technical implementation and intended mode of operation of the plant with combined gas-steam process of Neckarwerke AG
    S. Bernhardt
  • Technical possibilities of combined cycle power plants with high-temperature gas turbines
    D.G. Johnson
  • Gas turbines for power plants
    S. Wittig