Spurred on by a National Allocation Plan that encourages investment in coal plants, German utilities have initiated more than 50 new coal and gas firing projects, including several that involve as yet untried techniques to promote efficiency and carbon capture. Klaus Jopp
Like Europe as a whole, Germany has an unprecedented need for new power plants. There are three principal reasons for this: the age distribution of the existing pool of power plants, which is in urgent need of updating; the replacement needed for plants decommissioned as a result of a decision based on political consensus to abandon nuclear power; and the necessity to further reduce carbon dioxide emissions, which is also a declared political objective. Despite all the advances made in the renewables sector – Germany is one of the global leaders in the utilisation of wind power and the use of photovoltaic systems – high-efficiency, fossil fuel-fired power plants will have to remain the main pillar of a secure power supply for the foreseeable future. Coal-fired plants as well as combined cycle systems will remain a top priority in Germany’s energy planning. However, there will continue to be intensive efforts to develop higher efficiencies as a way of resolving the carbon dioxide problem. And starting in 2015, it may be possible to implement initial steps for creating CO2-free power plants.
Even though there is still heated debate in Germany over the issue of withdrawal from nuclear generation that may lead to its being prolonged for a few years, there is still a large requirement for new power plants. This is due primarily to the growing demand for electricity: a growth rate in power generation of 1.6% a year up to 2020 for the Europe of 25 states is also predicted for Germany. Twenty percent growth is expected up to 2020, equivalent to about 30 GW. By this time some coal-fired power plants in the base load range in particular will have reached the end of their service life. A capacity of 40 GW must thus be replaced. If there is no change of heart over abandoning nuclear power this would mean an additional 22 GW. “All in all, we see a need for 80 000 to 90 000 MW of new capacity over the next 15 years. We estimate investments of around 70 billion euros,” states Dr Uriel Sharef, a Siemens AG corporate executive.
Need for high efficiency
Against this background, the requirements for developers in the energy sector are clear. While gas and coal-fired power plants will retain their dominant position, the hunt for ever higher levels of efficiency must continue, for both ecological and economic reasons. Siemens PG quantifies the present situation as follows: the maximum efficiency for lignite-fired power plants blocks of the Niederaussem type is 43%, an improvement of 7 percentage points over the past 10 years, although the technology in use ten years ago dated from the early 1970s. The target for 2020 is set at an ambitious 50%. “Using new technologies for coal drying we will reach a figure as high as 53 %, which would be absolutely comparable with coal-fired blocks,” Sharef promises. At the present time, the benchmark for coal-fired plants is set by the Boxberg plant (907 MW) which holds the world record with an efficiency of 48.5%, 5.5 percentage points higher than 10 years ago. In this sector too, efficiency is also expected to rise to 53% by 2020, although this will be conditional upon economical production of the nickel-based materials needed.
As far as combined cycle power plants are concerned, Mainz-Wiesbaden holds the lead with more than 58%, up 6 percentage points on what was achieved in the mid-90s. A further increase in efficiency to more than 60% by 2020 is considered feasible. However, this will require new cooling technologies as well as new materials such as ceramics.
In the pipeline
According to a survey by the Bremen Institute for Trend and Market Research (trend:research), there are already over 50 new large-scale power plant projects in Germany, a total installed capacity of nearly 40 000 MW. This means that the number and capacity of the known projects have virtually doubled within a year. “There has also been a clear shift in favour of coal projects, which now account for a total capacity of 22 000 MW. Combined cycle plants amount to 13 000 MW, and another 3 500 MW will be installed based on the use of lignite,” explains Dirk Briese, managing director of trend:research. Nearly all projects are due to be implemented by 2012, based on the anticipated allocation of CO2 certificates. The present status of the projects varies greatly, ranging from concept studies to awarded orders.
New CCGT orders
A number of the plans for CCGTs have already turned into firm orders. In May 2005, for example, Siemens PG was awarded an order by Trianel Power Kraftwerk Hamm-Uentrop GmbH & Co. KG (Aachen) for the turnkey construction of a new natural gas fired combined cycle plant at the Hamm-Uentrop location in North Rhine Westphalia. Municipal utilities from Germany, the Netherlands and Austria are involved. PG is constructing the plant on the factory site of DuPont de Nemours (Germany) in Hamm-Uentrop.
Siemens PG is constructing another turnkey combined cycle power plant in Herdecke (NRW), where the customer is power plant operator Herdecke GmbH & Co. KG, Hagen, Mark-E Aktiengesellschaft, Hagen, and the Norwegian power supply company Statkraft, Oslo,. Each holds a 50% stake in this company. Siemens is constructing the new gas-fired plant on an existing power plant site in Herdecke.
In the Knapsack chemical park near Cologne-Hürth, a combined cycle power plant with a capacity of 800 MW is also being built for Statkraft. The delivery package from Siemens PG comprises the turnkey construction of the plant with two SGT5-4000F gas turbines (previous designation V94.3A), a steam turbine, three generators and the entire electrical and instrumentation and control system. Siemens is also responsible for the maintenance of the gas turbines for a period of 12 years. Hand over of the three plants is scheduled for summer/fall 2007.
Siemens PG is currently building a prototype plant in Irsching, Bavaria – Irsching 4 – that will incorporate the world’s largest and most powerful gas turbine. Following successful trial operations it is destined to be developed into a high-efficiency combined cycle power plant with a capacity of 530 MW, and then handed over to E.ON (further information on pages 7-8).
The latest order for Siemens PG in this sector was awarded in July 2006 for a turnkey combined cycle plant, also to be built in Irsching. The order was placed by Gemeinschaftskraftwerk Irsching GmbH, a company jointly owned by power supply company E.ON Kraftwerke GmbH, Hanover, which holds a 60% stake, and the two multi-utility companies N-Ergie AG of Nuremberg and Mainova AG, Frankfurt, which have a 25% and 15% holding respectively. The r450 million order includes a long-term maintenance contract for the plant, which will have a capacity of 800 MW.
Siemens PG is constructing the new natural gas-fired facility on the site of a previous power plant in Irsching near Ingolstadt. The contract includes delivery of the gas and steam turbines, the generators, the complete mechanical engineering with the waste heat steam generator as well as the electrical system, instrumentation, and control system. Irsching 5 is scheduled to go into service at the end of 2008.
“Irsching 5 is already the fourth order for construction of a turnkey combined cycle power plant that we’ve booked in Germany since May 2005,” said Klaus Voges, group president of Siemens PG. ” The key features of these new power plants are their cost efficiency, flexibility and environmental compatibility. Their efficiency will be well in excess of 57%”.
RWE new build
The projects described demonstrate that renewal of the pool of power plants in Germany is already underway. RWE Power has inaugurated several new construction projects in a single tranche. “In the interests of a balanced energy mix and with a view to providing a reliable supply, the programme includes base-load and peak-load power plants, such as the construction of a lignite-fired double block at the Neurath location, construction of a coal-fired power plant as a double block at the Westfalen location, and the option for a combined cycle plant,” states Dr Manfred Kehr, head of Power Plant Planning and Approval at RWE Power.
RWE Power has earmarked j2.2 billion for developing the use of lignite. At the beginning of 2006 construction work began on two lignite-fired power plant blocks with optimised plant technology (BoA blocks 2/3) of the 1100 MW class in Neurath. This work is progressing on schedule and the main foundations for Block F have already been poured. These two blocks are scheduled to go into commercial service in 2010. The new BoA power plant will emit up to six million metric tons less CO2 per year than the old plants replaced by BoA blocks 2 and 3.
At the Westfalen site, RWE Power’s coal fired double block plant will be of the 800 MW class. The aim is to build a modern coal-fired power plant optimised in terms of both technology and economy. An investment of j1.5 billion is needed for this, and start of commercial operation is planned for 2011. “We have also decided to develop a special concept for coal-fired power plants that can be easily transferred to other blocks, including the Westfalen coal-fired double block,” says Kehr.
Lignite drying at RWE Neurath
RWE Power is also applying state-of-the-art technology in the field of fossil fuel-fired power generation to achieve greater efficiency and lower emissions (see pages 12-13). In the case of the BoA blocks 2/3, for example, there is potential for optimising the plant technology to further increase efficiency. Due to the steam temperature of over 600°C, higher grade materials are needed for the convective heating surfaces. Apart from the high strength requirements. the materials must also be sufficiently resistant with regard to their oxidation and corrosion characteristics, for which reason austenitic materials are used in the area of the superheater and 25 % Cr-steel HR3C for the end stages. A titanium end stage has also been chosen for the steam turbine of the BoA blocks 2/3. Thanks to its outstanding strength and relatively low weight, the titanium blade offers a way of increasing the blade dimensions and the efficiency of the end stage itself. As a result it is possible to implement exhaust steam cross sections in the 1100 MW capacity class that allow a condenser of 48 mbar with only two double-flow low pressure sections.
The predrying of lignite is of considerable interest for RWE Power, as this results in further increases in efficiency. With fluidised bed drying with internal use of waste heat (WTA), the lignite is predried in a separate process before burning in the boiler. The effect of this is to boost power plant efficiency by about four percentage points. RWE Power has already been working for more than ten years on the development of its own drying process suitable for power plants. In a final phase before the process is ready for use, a prototype system is currently under construction at the Niederaussem location for the precommercial 1:1 testing of the WTA fine grain drying process with combustion of the dry lignite produced as well as other fuel in the BoA block 1.
The plant is designed to supply 110 metric tons of dry lignite per hour for firing in BoA block 1. This is equivalent to about 28% of the total furnace heat output. Construction work for the j50 million project began in July 2006, and the pilot is due to go on stream at the end of 2007. After successful completion of testing, the results will be incorporated in the planning of a dry lignite-fired power plant that will be ready to start operation some time after the middle of the next decade. A number of power generating companies in central and eastern European as well as in Australia that use lignite to fuel their plants have already shown considerable interest in this technology.
Zero CO2 IGCC
Looking ahead to a third wave of innovation, RWE is actively promoting the development of what it believes will be the world’s first large-scale, CO2-free coal-fired power plant (see pages 12-13). RWE Power is planning to put a coal-fired power plant of this type with a gross capacity of approximately 450 MW into service in 2014. Parallel to this, CO2 scrubbing will be used for conventional steam power plants to separate the CO2 from the flue gases. The estimated investment costs for the CO2-free power plant and for the transport and storage of carbon dioxide amount to approximately one billion euros. The goal is to concentrate on climate-compatible power generation from coal using this pioneering technology for separating and disposing of carbon dioxide. RWE Power is well positioned in this respect, with its own power plant and gasification expertise combined with basic know-how from the upstream CO2 storage business at RWE Dea. The rapid implementation by 2014 requires parallel development of power plant and storage. Among all the options available for CO2-free coal fuelled power plant technology, the so-called IGCC technology (integrated gasification combined cycle) – in this case that means integrated coal or lignite gasification – is the only solution that is regarded as already viable on a large scale. This involves separating CO2 before combustion of the syn-gas in the downstream gas turbine. The development and implementation of safe, long-term CO2 storage for approximately 2.3 million tons of CO2 a year is one of the great challenges of this project.
Vattenfall’s oxyfuel and other ventures
Vattenfall Europe is also already intensively involved in Germany with the creation of CO2-free power plants. It is planning to build the first pilot system for a lignite-fired power plant based on the so-called oxyfuel process for enhanced carbon dioxide capture. A 30 MW pilot block is being constructed at the Schwarze Pumpe location in the Lausitz region for approximately j40 million and will go into operation by mid-2008. The results from the test phase are then to be incorporated into the planning and construction of a 300 MW demonstration plant in order to perfect the technology for series use on a large scale. “The risks of climate change require resolute action by business and industry alike,” stated Lars G Josefsson, president and CEO of Vattenfall AB, when presenting the project in Berlin.
In the oxyfuel process, lignite is burned with a mixture of pure oxygen and recirculated flue gas. The purpose of this new technology is to provide a method of isolating the carbon dioxide that is created during combustion in a pure enough form for capture and storage. The emphasis is on testing the interaction between all components, verifying the attainable level of precipitation of CO2, and determining whether the design can be transferred to the next stage of a demonstration power plant. Other focal points include studying material requirements, plant availability and purity requirements for the CO2 and calculating the expected investment and operating costs.
Vattenfall favours the oxyfuel process because it is based on familiar power plant components, and other integral parts such as air separation are already to a large extent technically perfected . When the dried lignite dust is burned in an oxygen/carbon dioxide atmosphere, the processes taking place in the furnace are different from conventional combustion with ordinary air. One of the principal objectives of operating the pilot plant is to test the combustion characteristics and optimise them for later use in large power plants.
The construction of the pilot plant at the Schwarze Pumpe power plant location offers a number of advantages. For example, the steam it produces can be used in nearby industrial plants. Moreover, there are synergies that can be utilised with respect to supply and disposal and local technical personnel. Start-up in 2008 will be followed by a three-year test operation period. The findings from this test phase will then be used to plan a demonstration power plant with a power output of 250 to 300 MW. The focus will be on optimising the efficiency of the entire process and on studying cost effectiveness. In the last phase of development, construction of commercial power plants with outputs of up to 1000 MW is planned. It is anticipated that use of the new technology will become economically viable some time between 2015 and 2020.
Apart from the innovative oxyfuel power plant, Vattenfall is also constructing block R at the Boxberg location for which planning approval is expected to be granted in November 2006. The new lignite-fired power plant is designed for a capacity of 675 MW. Construction of a coal-fired double block with a total capacity of 1640 MW in the Hamburg district of Moorburg directly on the Elbe is also planned. Start-up of blocks A and B is planned for 2010.
E.ON plans for CC and coal plants
E.ON Kraftwerke is one of the largest producers of electricity in Germany, with a total power plant capacity of about 15 000 MW. In Irsching, it is planning along with N-Ergie Aktiengesellschaft and Mainova AG, as already noted above, to construct a combined cycle power plant (Irsching 5) with a capacity of 800 MW. The investment volume is expected to total around 450 million euros and the power plant would employ up to 40 people. Irsching 4 is also being built on the same site in co-operation with Siemens PG. It will incorporate the new 340 MW H-class gas turbine from PG (see above and pages 7-8), and when proven is to be expanded into a combined cycle plant with a capacity of 530 MW .
E.ON Kraftwerke is also planning a high-efficiency coal-fired power plant at the Datteln location, with a gross electrical capacity of 1100 megawatts, to replace the existing units 1-3. It has already applied to the regional government in Münster for permission to construct a monoblock, which it is hoped will go into commercial service in 2011. Total investment amounts to about 1.2 billion euros. In Datteln the most efficient coal-fired power plant in the world is planned with an efficiency of 46 %. This plant betters the European average by 10 percentage points. The Datteln location is specially suited for construction of this coal-fired plant owing to the possibility of linking to the canal and rail network and the proximity of the A2 autobahn.
In looking to the longer term E.ON is planning a PC plant with an efficiency, remarkably, of over 50%. It announced at the end of October plans to build such a plant in 2010, using new high temperature materials being developed as part of the COMTES700 programme described below.
The RAG subsidiary STEAG also sees new possibilities for power plants in Germany. The first project is Walsum 10 with a gross capacity of 750 MW and an efficiency of more than 45%, which will be sited directly on the Rhine adjacent to the existing block 9 in Duisburg-Walsum. The boiler is of the forced circulation type with intermediate superheating. The steam data for the live steam are 600°C and 275 bar, and after intermediate superheating 620°C and 67 bar. The cooling water is recooled in a 180 m (590 ft) high cooling tower. STEAG will start construction in October and put the plant into service at the beginning of 2010. The investment has a volume of about j800 million. STEAG is being partnered in this project by the Austrian power supply company EVN, which holds a 49% share.
Another concrete new construction project is Herne 5. The design data are virtually identical with those of Walsum 10, which is to be the template for both projects. The gross capacity is 750 MW at a net efficiency of greater than 45 %, and the plant will be fuelled with imported coal. According to the plan, construction is scheduled to begin in the autumn of 2007 so that the plant can go into service in 2011.
Component test facilty
With the materials in use today, coal-fired power stations can be operated at steam temperatures of up to 600°C and pressures of up to 300 bar. With the use of nickel-based materials it is expected that these values can be increased to approximately 700°C and 350 bar respectively. Today’s coal-fired power plants in the European Community have an average efficiency of 36%. The 700 °C technology would raise the efficiency to 50% and cut CO2 emissions by more than a third. For this reason, the German power plant industry is working jointly with foreign partners on the next generation of power plants. A test facility known as COMTES700 (Component Test Facility for a 700°C Power Plant) has already been incorporated in block F of the Gelsenkirchen-Scholven coal-fired power plant at an investment cost of over 15 million euros.
COMTES700 receives funding from the European Commission. An international consortium made up of nine European power supply companies (E.ON Energie AG, EDF, Electrabel, Elsam Kraft, EnBW, Energi E2, PPC, RWE Power, Vattenfall) and four manufacturers (Alstom Power Boiler, Babcock-Hitachi Europe, Burmeister & Wain Energy and Siemens PG) is involved in implementing the project. VGB PowerTech (Essen) has taken over co-ordination as an international association of power and heat generating companies. German industry is thus making an important contribution by taking further steps towards environmentally compatible power generation even after the current wave of new construction. This also includes the development of CO2-free coal-fired power plants. A combination of both these approaches could substantially reduce Europe’s dependence on imported fuel – and open up a new future for the large coal reserves in Germany.
Planned and proposed new fossil power plant in Germany. Sources – VDEW, RWE, and various.