Abstracts - VGB PowerTech Journal 1-2/2015

The 2030 framework for climate and energy policies

Mechthild Wörsdörfer

In the light of experiences and lessons learnt from current energy and climate policies and the changing economic and energy market context, the Commission proposed a new framework for climate and energy policies for the period until 2030 on which the European Council reached an agreement on October 24, 2014. The framework is structured around four headline targets: a binding EU level target for domestic reduction of greenhouse gas emissions of at least 40 % compared to 1990 levels; a binding EU level target for the share of renewable energy of at least 27 %; an indicative EU level target for energy efficiency improvements of at least 27 % and an objective for electricity interconnections of 15 % in 2030.

Maintenance without money – Challenge for changes

Leon Westhoeve and Maciej Brzoskowsi

Recent years have seen the energy industry facing a seemingly endless string of new challenges. While the industry managed to meet Europe’s ambitious climate protection targets in the good times, subsequent public policies have created huge burdens culminating in the exit from nuclear and fossil fuels. An initial response to stagnating or sinking profits was and still is the need to drive costs down and maintenance contractors have not been immune to the impact of shrinking budgets. But how can they cope with these rising demands when even previous budgets were stretched? The current situation is more than critical, and yet there are some real opportunities to ease the squeeze.

Renewable wind and solar energy – Future technical development

Hermann-Josef Wagner

Germany is an international leader in the development and introduction of renewable energy, i.e. wind and solar (photovoltaic) energy. Both technologies already contribute more than 13 % to national electricity generation. The political support of renewable energies resulted in a variety of different technologies the development of which has not yet been exhausted. The paper describes the state of the art of these technologies as well as selected development tendencies. New technologies can be introduced in a highly developed society only if questions according to their environmental impact are also answered.

Flexibility options in the electrical power system

Christian Rehtanz and Jan Teuwsen

The future energy system requires several flexibility options for balancing renewable energy. The high potential of wind and solar power prioritises these generation options for the power industry. The balancing mechanisms and flexibility options will be an economical and technical feasible combination of demand side management, supply side management, storages, coupling with other energy sources (power to gas, power to heat) and grid extension.

Pump storage – Requirements and comparison with other storage technologies

Albert Ruprecht

The use of renewable energy sources has strongly increased in recent years. Because of the high volatility of these sources, an appropriate energy storage capacity as well as the provision of fast and flexible regulating power is necessary. Both can be supplied by pump storage power plants. The pump storage situation is Germany is discussed. The demand of energy storage is roughly estimated and the status quo of pump storage in Germany is described. Pump storage is compared to other storage technologies (compressed air storage, mobile batteries, hydrogen storage and power-to-gas storage) in terms of efficiency, response time and costs.

The new 200 MWe wood-fired CFBC at Polaniec/Poland

Frans van Dijen and Héloise Gennart

GDF SUEZ ENERGY operates a new CFBC plant with a capacity of about 200 MWe at the Polaniec site in Poland. The main fuel is wood, especially wet wood chips. The boiler was supplied by Foster Wheeler and was connected to the exiting/upgraded steam turbines, generator and condenser. First operating experience is presented and proposals are made as regards the future and potentials of CFBC which can be further improved and advanced. Particularly existing experience is to be incorporated into new designs and constructions. Besides, new R&D projects are to be realised.

Flexibility improvement and technical optimisation at the boiler of the new lignite-fired unit Boxberg R power plant

Thomas Brunne, Günter Heimann and Jürgen Stosch

The lignite-fired unit Boxberg R power plant was designed and planned from 2004 to 2007 as base load unit. The increasing as well as fluctuating feed in of electricity from renewables is going to alter plant operation. In cooperation with the boiler manufacturer potentials for optimisation were developed in 2012. Optimisation at the boiler mainly aims at increased output, reduction of the technical minimum load in pure coal-firing mode, improved load change gradients and shorter start-up times.

Coal feeding system BoA 2&3 – Neurath Power plant – Concept and operational experience

Michael Lansen, Andreas Mowe and Frank Huth

With the erection of BoA 2&3 at the Neurath site, RWE has broken new ground with many plant components like the coal feeding system and a newly designed slot bunker that is supplied with lignite by rail and can be filled in three separate sections, an automatic and variable mixing of the pure lignite varieties delivered to obtain blended coal, a two-stage crushing concept using roller crushers, a conveyor bridge concept reflecting the latest fire protection findings and a speed-controlled, fully automatic conveyor system operation adjusted to boiler load. Since commissioning in early 2012, experience in the operation of the coal feeding system has been gathered for some three years now.

Additional revenues of wind farms by enhanced data analysis

Martin Stephan, Urs Steinmetz and Jury Schinsky

Volatile external influences impact on the operation of wind turbines causing heavy loads on the components. They often degrade power production in the long-term or even stop power production by severe damage. To identify degradation or upcoming defects early, the produced power output should be continuously compared with a calculated value that takes into account current environmental conditions. For thermal power plants, specialised IT tools are in operation to detect such situations. Their potential for use in the wind power sector has been investigated.

Efficiency of agricultural biogas plants using energy crops and liquid manure

Elmar Fischer, Jan Postel, Jan Liebetrau and Michael Nelles

Biogas plants are complex systems, combining biological processes with technology for power generation. An approach for an overall efficiency assessment for agricultural biogas plants is presented which is based on the gross calorific value of the input as key parameter to fix the energy potential which is subsequently converted to methane and electrical and thermal power. To identify energy losses, flows were calculated and visualised in Sankey diagrams. Examples underline that the concept of a plant and the amount of heat used are the major factors for efficiency.

Component life assessment under creep-fatigue loading

Patrick Buhl, Daniel Hüggenberg and Andreas Klenk

There is an increasing demand on lifetime assessment of components which are subjected to creep-fatigue stress due to more flexible operation of power plants. Assessment routes of the international standards ASME and RCC-MR respectively the recommendation R5 are described with respect to necessary data input and calculation methods. In addition to these approaches, a complex phenomenological model which is able to consider the direct interaction of creep and fatigue damage is introduced. The lifetime assessment approaches are applied to components made of martensitic steels and nickel base alloys.

Development, experiences and qualification of steel grades for hydro power conduits

Horst Cerjak, Norbert Enzinger and Milan Pudar

The development and experiences made with the application of high-strength steels for penstocks and steel lined shafts for stored and pumping stored hydropower plants is described. The evaluation of dramatic failure cases showed that high-strength steels have to be treated very carefully to assure safe fabrication and service conditions. In this connection welding plays a significant role. The dramatic change of the requirements on the service programme of stored power plants and pumping stored power plants coming from the power grids, the increasing use of high-strength steels in the recent years, the item of dynamic loading on penstocks and steel lined shafts became nowadays one of the main issues for the design of new as well as for the life time assessment of existing penstocks.

On the potential of using an extrapolation method in combination with a constitutive material model for creep fatigue assessment of components

Christian Kontermann, Alfred Scholz and Matthias Oechsner

Using constitutive material models has become a kind of standard regarding research topics. Such models are widely applicable to simulate the deformation and damage evolution under creep fatigue loading. However, the application of such kind of models is typically very time consuming. Calculation time can be cut by the application of an extrapolation method. The paper also presents observations found at notched specimens which might influence component assessment approaches.

Detection and sizing of stress corrosion cracks in austenitic components using ultrasonic testing and synthetic aperture focusing technique

Sandra Dugan, Sabine Wagner, Alexander Dillhöfer, Hans Rieder and Martin Spies

Flaw detection and sizing using NDT techniques is an important factor for reliably assessing the integrity of components. In the case of dissimilar metal welds and austenitic stainless steel welds, the grain structure of the weld in combination with the elastic anisotropy of the material will present major challenges for UT. A study on austenitic base metal test blocks with artificially grown IGSCCs has shown that the Synthetic Aperture Focusing Technique (SAFT) can improve the signal-to-noise ratio, particularly for crack tip signals. In welded test blocks, the influence of the inhomogeneous, anisotropic weld has to be considered.