A major refurbishment project at the 2100 MWe Portile de Fier I (Iron Gate I) hydroelectric power station – the largest run-of-river plant in Europe – will increase its output by about 10 per cent.
Portile de Fier I is located on a stretch of the Dunube shared by Serbia and Romania. Six of the station’s Russian-built 12 Kaplan vertical turbines are on the Serbian side and six on the Romanian.
The units on the Romanian side were commissioned in 1970-1971. Although past their prime they remain a key contributor to the Romanian electricity supply. A decision was therefore taken by utility CONEL to embark on a major rerfurbishment and upgrading programme, increasing the installed capacity of each unit from 175 MWe up to about 190 MWe.
On 31 October 1997 a turnkey refurbishment contract was signed with Sulzer Hydro of Switzerland, as consortium leader, with ABB Schweiz as subcontractor.
At certain times of the year Romania is able to export power, eg to Switzerland, and this will help to finance the modernization project
Among the reasons Sulzer was selected was that it was able to guarantee the shortest refurbishment period, namely 90 months (of which 20 months are allocated to preparatory works before shut down of the first hydro unit to be refurbished).
Work on the first unit will be carried out in 2000 and the five remaining units will be refurbished at the rate of one per year until 2005, when the project is due to be completed. During the project the work will be phased so that in April and May of every year (the high flow season) there are always six units available for operation.
Since the contract signing the following preparations have been done:
Model tests in Sulzer Hydro’s Zurich laboratory and Astro laboratory, Graz.
Design work and production of project documentation.
Manufacture of cast and forged parts for the first unit.
Drawing up of contracts with the Romanian sub-contractors (UCM Resita and SAEM Bucharest, the latter being responsible for dismantling and reassembly).
As well as raising insatalled capacity from 1050 MWe to 1140 MWe (deriving from increase of the installed discharge from 725 m3/s to 840 m3/s per turbine), the rehabilitation will yield the following other benefits:
Extension of operating life by 30 years.
Increase in efficiency, decrease in maintenance costs.
Improved quality and performance in several areas (eg reduced cavitational erosion, elimination of cracks in stay vanes, less maintenance for thrust bearings, shaft seals.