Laying the foundations for a new generation of hard coal plants in Germany1 January 2009
In the past few months foundation stone laying ceremonies have been held for a further two large supercritical hard coal plants in Germany, RDK 8 and Hamm Westfalen. These boast efficiencies of about 46%, compared with the present European average efficiency for hard coal power plants of about 36%.
With construction now underway on EnBW’s 912 MWe RDK 8 and RWE’s 2 x 800 MWe Hamm Westafalen plants, some nine large hard-coal fired units can currently be considered to be in the building phase in Germany, the others being Walsum 10 (Steag/Evonik), Datteln 4 (E.On), twin-unit Moorburg (Vattenfall) (assuming final agreement can be reached with the Hamburg authorities), GKM 9 (Grosskraftwerk Mannheim), and Wilhelmshaven (Electrabel).* The technology for all these plants is supercritical, with claimed efficiencies of around 46% (750 gCO2/kWh) – the benchmark specified in the German NAP II, which aims to encourage the building of new, more efficient, fossil plants and the closure of old and inefficient units. A driver for getting these new build projects moving is the fact that to qualify under NAP II you need to be in commercial operation by the end of 2011, but working against that is the inevitable reappraisal of major investments that is going on in the wake of the world economic downturn. Interestingly, in a statement on 27 November, Wulf H Bernotat of E.On – which has a very large power plant investment programme underway, around 23 GWe, 20 units (including Datteln 4 and gas fired units, Irsching 4 and 5, under construction in Germany) – said: “Even if we chose to reassess the economic significance of each of our projects in the light of the current economic crisis, we are confident of delivering our ambitious investment programme which will make an important contribution towards stabilizing the economy and creating jobs.” He also pointed out that “in the current crisis, investments in the real economy have a particularly anti-recessionary effect.”
Meanwhile, on the River Rhine at Karlsruhe Rheinhafen, Baden-Württemberg, on 19 September 2008, the foundation stone was laid for for EnBW’s new RDK 8 hard-coal power station (see map above).
At the RDK 8 ceremony, Hans-Peter Villis, CEO of EnBW (Energie Baden-Württemberg) declared “Our investment of over one billion euros in the new power station is the visible expression of our commitment to our corporate headquarters of Karlsruhe, our home market of Baden-Württemberg and Germany as an industrial nation. We regard conventional power stations, nuclear power and renewable energy not as contradictions, but as equal elements in a future-oriented, safe and cost-effective energy mix. EnBW is accordingly planning to invest one euro in the expansion of new renewable energies for every euro which we invest in conventional power stations.”
Federal Minister for Economics and Technology Michael Glos stressed, “If we intend to maintain an equivalent level of security of supply to that which we have established in the past, we will need to expand our fleet of conventional power stations significantly, and coal will play a key role here as a source of energy. Today, by laying the foundation stone for this new power station here in Karlsruhe, we have made significant progress along this path. But further steps must follow. Security of supply, cost-effectiveness and the demands of climate change must all be accommodated, and to do this we need modern conventional power stations.”
At the ceremony, Prime Minister Günther Oettinger emphasised, “Safe, secure energy supply where it is needed is a key location factor for the dynamic economy of Baden-Württemberg. For this reason, we need adequate power generation capacity in the region, close to the sources of consumption, because we cannot and must not become dependent on imported energy. EnBW’s construction of this new power station demonstrates the company’s willingness to take responsibility and to invest in added value and employment in the region.”
The efficiency of RDK 8, like Hamm Westafen, will be over 46% (net electrical), with further efficiency gains coming from cogeneration for district heating networks.
“Karlsruhe Rheinhafen has a long tradition as a site for power stations, in which the decision to construct RDK 8 is the latest chapter. With a gross output of 912 MW and up to 220 MWt district heat extraction, the new coal power station will make a significant contribution to securing power supply and supporting the area as an industrial location...”, stated Dr. Hans-Josef Zimmer, Corporate Technical Officer at EnBW.
The EnBW Supervisory Board agreed in December 2006 to the Managing Board’s decision to construct the new unit at Karlsruhe Rheinhafen. EnBW submitted the planning application documents to the City of Karlsruhe in April 2007, and the application for approval in line with the Federal emissions control act to the Karlsruhe regional council in May 2007. The plans were approved by a large majority of Karlsruhe City Council in December 2007, and in May 2008 approval under the Federal emissions control act was granted.
Commissioning of RDK 8 is scheduled for the end of 2011.
The plant is being built with the recognition that carbon capture might have to be fitted at some point in the future, if “technically and economically feasible”, and consideration has been given to the space that might be needed to site a carbon capture plant (see site plan), with the utility reserving a “precautionary site near the unit for a CO2 capture plant.” The utility also says that the concrete shaft of the chimney has been designed in such a way that an additional clean-gas duct can be added at some stage in the future. Presumably some thought has also been given transport of the carbon dioxide and possible geological disposal sites.
When dealing with carbon dioxide a highly efficient plant, which RDK 8 will be – with a guaranteed gross electrical efficiency of over 50% – is always a good starting point of course. The steam conditions are 600°C/275 bar (HP) and 620°C/58.4 bar (reheat), with a condenser pressure of 30 mbar (at 13°C Rhine temperature).
A single train configuration (see diagram left) is being adopted to achieve maximum benefits from economies of scale.
Alstom is power plant EPC (engineering, procurement and construction) contractor on RDK 8, its scope including plant engineering, global procurement and logistics, construction and commissioning. It received the notice to proceed in April 2008 and will be supplying the pulverised coal boiler (once-through, forced flow), with bowl mills and deNOx equipment (selective catalytic reduction), as well as the steam turbine (STF 100), Gigatop generator, main steam and condensate systems, feedwater heating systems, cooling systems and component related electrical and I&C equipment for the turbine hall and boiler house.
The fan assisted cooling tower for RDK 8 is being supplied by Hamon under a contract worth about r25 million.
Particular attention has been paid to the “cold end” of the plant, which will operate either as a once-through system or, when the Rhine water temperature rises above 22.6°C, with the fan assisted natural draft cooling tower. The cooling tower will have a height of 80 m, a base diameter of 94 m and a diameter at the top of 54 m. The additional draft generated by the 28 fans located around the base of the towers allows a considerable reduction in the size of the cooling tower’s concrete shell, the aim being to strike a balance visual impact and efficiency.
The flue gas cleaning systems downstream of the deNOx system are being provided by Austrian Energy & Environment. They include an electrostatic precipitator, induction draft fan, desulphurisation equipment and gypsum processing systems. AE&E will also supply ancillary systems such as silos for limestone, fly ash and gypsum, conveyors and truck loading systems.
RDK 8 is aiming for emissions well below current German legislation (13.BlmSchV, which stipulates 200 mg/Nm3 (dry) for NOx and SO2, and 20 mg/Nm3 (dry) for particulates. EnBW also reports that “in addition to the limits of 13.BlmSchV the following annual mean limits (AML) were applied for and approved (mg/Nm3):
PM NOx CO SOx
6% O2 9 90 90 100
4.27% O2 10 100 100 110
RDK 8 is being built to the north east of existing units at the RDK (Rheinhafen-Dampfkraftwerk) site. The existing plants include three closed down hard coal units (RDK 1-3), a CCGT, the result of a repowering project (RDK 4S), two gas/oil units currently in cold reserve (RDK 5/6) and an operating hard coal unit (RDK 7).
As well as allowing the closure of older low-efficiency fossil units in the EnBW fleet, the new generating capacity represented by RDK 8 will also help compensate for the loss its nuclear units Philipsburg 1 and 2, schedule to close in the coming years.
Three weeks before the RDK 8 foundation laying ceremony a similar event took place to mark the start of construction for RWE’s new 2 x 800 MWe hard coal power plant at Hamm Westfalen, north western Germany – a r2 billion investment. Here the dignitaries included the German Federal Chancellor Angela Merkel and North Rhine-Westphalia’s State Premier Juergen Ruettgers, alongside Juergen Grossmann, CEO of RWE, Johannes Lambertz, CEO of RWE Power, RWE’s Central Works Council Chairman Guenter Reppien and Manfred Huelsmann representing the GEKKO Group - a stakeholder consortium formed by 23 municipal utilities from the states of North Rhine-Westphalia, Hesse, Lower Saxony and Rhineland Palatinate, who effectively own 350 MWe of the new plant’s capacity under a contract that will run for 25 years. All highlighted the importance of coal in Germany’s energy supply.
Acording to RWE the new power plant will, like RDK8, be “capture ready”, with downstream provision for CO2 scrubbing. Should “carbon capture and storage technology (CCS) be commercially available, potentially from 2020, the carbon dioxide emissions could then be captured and stored.” “Actions speak louder than words,” said Juergen Grossman, “when it comes to preventing climate change. This is why we are replacing older power plants with new ones and at the same time forging ahead with CCS technology.”
As at RDK 8, Hamm Westfalen will also employ Alstom supercritical boiler technology. In April 2008 the company announced it had won a contract to supply the boilers for the two new 800 MW units to be built at the existing Westfalen coal-fired power station. Under the terms of the contract, the value of which is approximately r500 million, Alstom will supply the complete boiler islands and auxiliary equipment, including contruction and commissioning.
The technology to be deployed at Hamm is very similar to that to be used at RWE’s 2 x 800 MWe hard coal project at Eemshaven in the Netherlands, which will also be “capture ready.” Another feature of both projects is that provision has been made for steam extraction to allow future supply of steam for district heating or process heat.