photo credits: Ossberger
HYDRO
A powerful machine group in the Skra power plant in northern Greece: The Ossberger crossflow turbine is dimensioned for a design output of 1,320 kW.
A NEW CROSSFLOW TURBINE CONVINCES ALL ALONG THE LINE IN GREECE The new Skra power plant in the northern Greek province of Kilkis was connected to the grid in Spring 2020. It is the first hydropower plant owned by the operating company Karpi Energeiaki A.E., using the hydro-energetic potential of the River Kotza Ntere, not far from the famous Skra waterfalls. The electromechanical heart of the plant is the hydrodynamically advanced crossflow turbine from the German market leader, Ossberger GmbH; configured for a design output of 1,320 kW. The powerhouse has already generated more than 2 million kWh of electricity during its first year of operation – despite extremely dry weather and extended low flow conditions.
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ommissioning of the new Skra power plant marked the final milestone in a long project development history that began 15 years ago. "The project was originally developed in 2006 by the company Nigel O.E., which also obtained the production licence for it in 2008. This was subsequently acquired in 2012 by a specialist in renewable energies, the investor Karpi Energeiaki A.E., who then ultimately brought the project to fruition", explains Ioannis Garatziotis from the planning office Marsa Services. The engineer explains that the approval procedure took about a decade and was one of the main challenges for the project realisation. "Basically, the permit consists of three parts: the production licence, the installation licence and the operating licence. In addition, these licen-
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ces are subdivided into various sub-licences – around 40 in number. This makes gaining a licence both lengthy and onerous." But the patience of the developers was to eventually pay off. In 2016, the permits were all finally issued, and the construction could begin. TOLERANT OF WIDE WATER FLOW VARIATIONS The construction schedule commenced with the water intake and the penstock, and the construction work generally went very smoothly, as Ioannis Garatziotis confirms: "Only the powerhouse was a little delayed, as the building permit for it arrived a little later. It was then completed in 2019." Basically, the Skra power plant is a diversion power plant that uses the natural head of almost 80 metres. Up to 2,200 l/s can be drawn at the water
Connection of the steel pressure tube to the supply line into the new turbine house.
May 2022
KW Skra zek HYDRO Eng.indd 26
03.05.2022 16:37:25
