Visit to Vianden pump storage scheme
A group of 15 ICE members and others, largely comprising existing or ex-European Investment Bank staff, visited the development of new capacity at the Vianden pump storage scheme in northern Luxembourg on Friday 19th October 2012.
The visit was arranged with Société Electric de l’Our (SEO), the owners and operators of the Vianden scheme; Engineer Tonino was our guide. SEO is jointly owned by the Luxembourg State (80%) and RWE, the German utility. This large scheme is essentially to support and optimize the supply on the German grid as it far exceeds the needs of the Grand Duchy. It is the second largest pump storage scheme in Europe after Dinorvic in Wales.
The project comprises the addition of 200 MW of capacity with a single turbine-generator group to the existing 1100 MW, most of which were installed in the 1960ies. It is to be constructed separately from the existing units requiring extensive tunneling for access and for the water ways. The rock is fairly well know and is mainly schist.
Works started over two years ago and are expected to be complete at the end of 2013. The coffer dam at the downstream end on the River Ours, the tunneling and the installation of the pipe to the storage lake are now all complete. Installation of the equipment in the turbine room deep in the heart of the mountain is ongoing.
This is a larger and complex project with a need to keep the existing works operating during construction. Particular technical challenges have been linked to the steel quality of the pipes, which required special attention to the welding to ensure their appropriate longevity, and the design of the intake and exit chambers on the river to keep the environmental impact to the minimum.
The total outturn cost of the operation is expected to be Eur 160 m and the project makes use of a substantial sunk cost investment in the existing dams and facilities which needed only limited changes. Using off peak and low cost energy including renewable (particularly wind power) should ensure that the project is particularly viable as well as being environmentally friendly, allowing peak demand to be more easily met in the future with an optimization of resources. The impact of a lower proportion of Nuclear generated energy, as recently proposed by Germany, is not clear, but the scheme should remain well justified. The overall energy losses between gross input and gross output are forecast at 24%.
Overall, a very interesting visit with an excellent guide.
Andrew Allen CEng, ICE Member in Luxembourg