Opole power station to be top of its class23 April 2014
Alstom is to provide two 900 MW USC units for what will be the largest hard-coal-fired power plant in Poland
Alstom has signed contracts worth approximately €1.25 billion with Polimex, Rafako and Mostostal Warsawa, members of the consortium managing the supply of two 900 MW units to major Polish utility PGE (Polska Grupa Energetyczna). This $3.7 million project involves the supply of two ultra-supercritical coal-fired power plants. They will be units 5 and 6 of Opole power station in south-western Poland. Once operational, it will, at 3290 MW, be the country's largest hard-coal-fuelled facility, overtaking the 2.82 GW coal/biomass Kozienice power station. PGE reports that it has already started work at the site. Unit 5 is due to enter commercial operation in 2018 and unit 6 in 2019.
The decision to proceed came soon after PGE's former chief executive, Krzysztof Kilian, left his job at the head of Poland's biggest utility. Rumour at the time suggested that the company was being put under political pressure to proceed with the expansion despite having rejected it in April 2013 as unprofitable.
The Polish factories of Elblag and Wroclaw will manufacture core components including the Alstom STF-100 steam turbines and the generators.
Alstom's scope of supply includes the provision of its proprietary ultra-supercritical technology, including the supply of USC boiler islands, the steam turbine generator islands including the turbine hall equipment, and the air quality control systems as well as some balance of plant equipment. At this stage the power islands are envisaged as being based on the Alstom pulverised coal tower boiler (Figures 1 and 3, Table 1).
Alstom will be responsible for overall project management and general design for this part of the contract. They will also support the consortium members in their scope of work and contribute to the construction and commissioning of the plants.
Selection of ultra-supercritical technology
PGE has selected ultra-supercritical technology to reduce its environmental impact and meet regulatory requirements. This is particularly important in Poland, where around 90% of the fuel used for electricity generation is coal or lignite.
Alstom has a large roster of steam plant in Poland. This includes the retrofitting of units 2, 3 and 4 at Opole to upgrade their efficiency, and the 910 MW Karlsruhe unit 8 which started up in 2012. In 2013 it successfully completed the ultra-supercritical unit 14 at the 5.35 GW lignite firing Belchatów plant, reputedly Poland's most efficient fossil-fired power station.
The Alstom tower boiler comes in three versions, subcritical (below 800 MWe rating), supercritical and ultra-supercritical.
Main features of its design (Figure 3) include a tangential firing system for effieient fuel/air mixing and wider tolerance to fuel fluctuations. The advanced burner design and staging ensure that the furnace volume is empoyed in the most efficient way, which results, says Alstom, in very efficient combustion. As a result, it achieves low NOx and reduced slagging which dramatically reduce cleaning and maintenance times, allowing the system to work at maximum efficiency over a sustained period.
The design's tilting burners deliver what Alstom describes as outstanding operational flexibility by allowing the highest cycle efficiency over the widest load range. They give the operator the ability to control reheat steam temperature by regulating the furnace outlet temperature. As a result, there is no need for additional spray attemperation and therefore no associated reduction in the boiler's overall efficiency.