Abstracts - VGB PowerTech Journal 9/2017

Welcoming address to the VGB Congress 2017 - Generation in Competition

Dr. Hans Bünting and Erland Christensen

“Generation in Competition” is the motto of this year’s VGB Congress in Essen, to which we invite you on 13 and 14 September 2017. National and international developments in power generation are leaving their impressive mark in the form of a transformation of the energy sector driven by technology, economics and politics. On the European electricity market, the EBIT for conventional power generation fell by 70 % from 2008 to 2015, and the EBIT for generation as a whole by 28 %. [more...]

Status and future of hydro power in the Alpine region

Nicolaus Römer, Herfried Harreiter, Gundula Konrad and Orkan Akpinar

The most important region in the field of hydroelectric power in Europe is the Alpine area, which has more than 1,000 hydroelectric power stations in eight countries. A generation system is provided, which is characterised by high reliability and high flexibility. The large number of storage and pumped storage plants is one of the important substructure to increase the integration of volatile renewable energies. Hydropower is competitive against other alternative power generation concepts, even if it is under economic pressure, caused by low electricity price, due to regulatory interventions. This makes the use of hydroelectric power unattractive, as well as the high regulatory burden, however the convincing technical and ecological advantages and considerable additional benefits should be the reason for strengthening the asset of the Alps.

Direct marketing of wind generation in Burgenland with the support of battery storage systems

Thomas Nacht, Martina Weissenbacher and Johannes Paeck

The funding of renewable energies led to an increasing number of wind turbines in Austria. Funding is expiring for the first of these wind turbines. This calls for the development and investigation of new business models for wind generation, which is the goal of the research project Windvermarktung. In this article, the approach of direct marketing of wind energy at the liberalised electricity market is discussed. At the liberalised market the uncertainties of the of the forecasts result in additional costs for balancing energy. Analysing different direct marketing approaches will illustrate, if economic feasibility (grid parity) can be reached and if the profitability of wind direct marketing can be increased by adding a Li-Ion battery storage system.

Download [2.3 MB]

Higher requirements for electric pitch systems in onshore and offshore applications ? More powerful wind turbines involve new system designs

Helmut Reinke

Wind energy turbines (WTGs) are becoming increasingly powerful, with regard to both onshore and offshore use. The investment in the development of new turbines is immense. At the same time, wind energy is facing massive cost pressures – through the tendering model when it comes to financing new onshore projects or, more generally, due to the persistent degression of feed-in remuneration for renewable energy production. As a result, the demands placed on state-of-the-art pitch systems for onshore and offshore WTGs are growing, both from a technical perspective and with regards to sustainable cost optimisation during development and implementation. This article provides an overview of the major variants of pitch systems, describing primarily how electric pitch systems can meet the complex current and future requirements of wind energy while meeting the challenge of continuing cost pressure.

Part-load limit reduction of a Frame 9E using a precursor for combustion dynamics

Driek Rouwenhorst, Julius Becker, Jürgen Gerhard, Jakob Hermann, Julian Niedermeier and Robert Widhopf-Fenk

The actual part-load limit of a gas turbine is variable, depending on machine state and atmospheric conditions. In order to be able to operate two Frame 9E gas turbines as close as possible to their part-load limits, a strategy is implemented to monitor the restricting phenomena in real-time, rather than retaining a conservative global minimum. A special challenge in this strategy is the monitoring of combustion dynamics. The acoustic oscillation amplitudes can arise unannounced, influencing the combustion process and ultimately leading to mechanical failure. An in real-time calculated precursor for combustion dynamics sends the thermoacoustic stability margin to the control system of the gas turbines, allowing automatic stabilisation upon reaching the part-load limit. Besides the precursor other quantities are monitored.

CFB technology stimulates distributed CHP expansion

Jaroslaw Mlonka and Grzegorz Szastok

Decarbonising Poland’s power and heat generation network is central to Poland’s energy policy framework. The policy statement requires increased diversity in the country’s fuel mix particularly with carbon neutral fuels, increased efficiency through CHP development, while simultaneously reducing CO2 emissions. The elegant solution is replacing aging coal-fired district heating plants with an integrated fuel flexible circulating fluidised bed (CFB) CHP plant burning coal-RDF biosludge and biomass mixtures. This approach increases overall scale and energy efficiency of the district heating network, produces dispatchable electricity, ensures CO2 emissions remain below winter package limits, and meets WFD RDF/biofuels reuse requirements. Waste recycled fuels when burnt locally also reduce transportation costs and emissions while extending the life of the landfill.

Joachim Rajek, Christian Hörist, Martin Schwarz and Gerald Lackner

With the continual development of the technology in the process industry, there were always accidents that were met with great interest in the media as well as the general public. But even in early years, the effort to keep the design as well as the operation of technical equipment as safe as possible also developed parallel in the industry. This applies in particular to devices such as pressure equipment and steam boilers, which inherently have a high-risk potential while in operation. In the interplay between industry and authorities it is therefore understandable that monitoring and inspection of machines and apparatus is of particular importance. In this context, the approval of “monitoring according to risk-oriented inspection, ROI” recently is-sued in 2015 in Austria in the “Druckgerätegesetz” (Federal Law Gazette I No. 161/2015) can be de-scribed as remarkable for it allows for the first time the possibility to carry out the planning of inspections by means of prior risk analysis. This article focuses on the possibilities for operators of power plants to plan the inspection based on RBI methods.

VGB-database supports performance analysis

Jürgen Aydt, Jean-François Lehougre, Ralf Uttich and Stefan Prost

A new paradigm is emerging in the electricity sector. Flexibility and adaptability are becoming the main requirements replacing traditional indicators like the operational reliability, the efficiency and the technology excellence. This can compromise the security of supply and destabilise the cost balance. Against this background, this article has been prepared by VGB Technical Group Performance Indicators (TG PI), in order to draw interest in the use and the usage of VGB-statistics. Although conventional production is losing significance and acceptance in the public perception, an actual study of VGB shows the importance of the availability of conventional power as a backup of more and more renewable based production. This will be necessary in a backup situation, at least as long as storage techniques and further new techniques are not able to supply energy in the required dimension: thousands of Megawatts for several weeks to hedge a secure supply of electricity.

Download [3.0 MB]

Long term oxidation behaviour of martensitic and austenitic steels and of Ni-base alloys at 630 – 725 °C in an operating boiler of the GKM power plant in Mannheim

Reinhard Knödler and Stefan Straub

The oxidation behaviour of martensitic and austenitic steels and of Ni-base alloys was investigated by exposing samples in the steam loop of a boiler in the power plant GKM in Mannheim (Germany). Exposure took place in two modules operating at different temperature cycles between 590 and 730 °C for more than 11.000 hours. In contrast to conventional lab tests with constant temperatures and low steam pressure, in the plant tests the temperature was changed frequently at high steam pressure. By this procedure very reliable data could be generated, regarding the behaviour of materials under real operating conditions after long times. This opens up the possibility to develop new steels and to optimise existing ones. In addition, oxidation resistant coatings on the basis of aluminium slurries were developed and tested. They show stable behaviour even after long exposure times at real operating conditions. These investigations will help to build and operate power plants, which can produce power at higher temperatures and thus, higher efficiencies and lower emissions for long time periods with high reliability.