The two required solution scenarios, retrofitting and a major overhaul proposed by Doosan Škoda Power, came out on top when evaluated by the customer; it was preferred to tenders submitted by other tenderers, including Alstom and Siemens. The customer finally opted for the retrofitting scenario, also taking into account the recent reference for a similar ST part renovation conducted for another Finnish power plant in Seinäjoki.
'Naantali 3' is a heating plant with installed electrical capacity of 125 MW in condensation mode and 175 MWt in heat generation mode, and is used to supply heat to the three towns of Naantali, Raisio, Turku and Kaarina. It was commissioned in the early 1970s. The supplier of the original turbine was the former German KWU, today Siemens.
The contract for the retrofitting of the ST part of the set includes replacement of the flow-through part and the frontal body of the ST part including installation and testing. It is scheduled to be commissioned in September 2015.
The power plant operator, TSE Naantali Oy, is owned by the aforementioned municipalities and by Fortum Power and Heat Oy, i.e. the customer, with regard to whom Doosan Škoda Power is already a supplier of renovation works for the VT parts for the Loviisa Nuclear Power Plant.
The retrofitting of the turbine set will allow a marked increase in the internal thermodynamic efficiency of the ST part, from the existing 88% up to 94%.
Winning the Naantali project is yet further proof that Doosan Škoda Power, with its long-term retrofitting strategy for not only its own steam turbines, but also those of other manufacturers, may succeed in the demanding Scandinavian markets despite the global competition.