Reversible hydroelectric power station

The capacity of the reversible hydroelectric plant is up to 16 MW (depending on the height of the stored water). The complex has a storage capacity of 70 MWh, which corresponds to four hours of electricity generation at nominal power by the hydroelectric plant or more than five hours of operation of the storage system (considering operation at nominal power for all wind turbines).[16]​.

Each of the four towers has an independent upper tank made of prefabricated concrete pieces. These, in turn, are divided into two subtanks that allow water to be impounded at different heights. The first of these corresponds to the cylindrical foundations of the towers; These have a height of 40 meters and a diameter of 16 meters and can store a height of water of 31 meters.[16]​[17]​ These subtanks are called Aktivbecken (active tanks). Under the foundations of the towers is a cylindrical tank 63 meters in diameter, called Passivbecken (passive tank). The height of the latter depends on the wind turbine in question, and their maximum reservoir height reaches between 8 and 13 meters.[16] Both subtanks are filled and emptied successively.[18] In total, the tanks can impound a total of 160,000 m³ of water.[16] It should be noted that the terms Aktivbecken and Passivbecken have not been used. previously in the literature relating to reversible hydroelectric plants and its use was introduced in this project. From a technical point of view, both fulfill a reservoir function.

In July 2017 it was decided that the WEA2 tower, in principle, would not be equipped with an upper tank.[19]​.

A system of pressure pipes, approximately 3.2 kilometers long, connects the upper tanks with the power house and the lower tank, located in the valley of the Kocher River&action=edit&redlink=1 "Kocher (river) (not yet drafted)"), about 200 meters below the upper level.[20]​ The DN1800/DN1600 polyethylene pipes (provided by Egeplast[21]​), were installed as of March 2018. The distribution pipe (known as Trifurcator) that allows distribution from the pressure pipes to the turbines, is a prefabricated part manufactured by Bilfinger VAM Anlagentechnik GmbH.[22]​ The system of pipes and turbines allows a flow of 9.5 m³/s.[23]​.

The powerhouse is located on the east side of the Kocher River&action=edit&redlink=1 "Kocher (river) (not yet drafted)") and is connected to the lower tank (located on the west side of the flow) by an inverted siphon.[23]​ The powerhouse is provided with three reversible Francis turbines, developed by Voith Hydro, with a total capacity of 16 MW.[1]​ During the reservoir phase, water will be pumped from the lower tank to the upper tanks using pumping turbines. During periods of electrical demand, water flows back to the lower tank through the turbines. The change between the electricity generation phase and the reservoir phase must be possible in a time of 30 seconds and the storage is expected to have an energy efficiency close to 80%.[24]​.

A previously planned pond will be used as a lower tank as a river flood defense against floods of the Kocher River&action=edit&redlink=1 "Kocher (river) (not yet drafted)").[25]​ This pond is designed for a return period of 10 years. The volume of the pond is designed in such a way that in maximum use condition, it maintains a retention capacity (as a river defense) of 30,000 m³. In case of use as a flood defense, it is necessary to stop the use as part of the generation system for cleaning work. For initial filling, as well as for subsequent fillings after maintenance work, it is approved to divert a flow of up to 2 m³/s from the Kocher River&action=edit&redlink=1 "Kocher (river) (not yet drafted)"), as long as the river maintains a minimum flow of 10 m³/s.[23]​.

Electrical substation

To the south of the power house, an electrical substation will be built to connect to an existing 110 kV line. The network operator is Netze BW").[15]​.

Reversible hydroelectric power station

The capacity of the reversible hydroelectric plant is up to 16 MW (depending on the height of the stored water). The complex has a storage capacity of 70 MWh, which corresponds to four hours of electricity generation at nominal power by the hydroelectric plant or more than five hours of operation of the storage system (considering operation at nominal power for all wind turbines).[16]​.

Each of the four towers has an independent upper tank made of prefabricated concrete pieces. These, in turn, are divided into two subtanks that allow water to be impounded at different heights. The first of these corresponds to the cylindrical foundations of the towers; These have a height of 40 meters and a diameter of 16 meters and can store a height of water of 31 meters.[16]​[17]​ These subtanks are called Aktivbecken (active tanks). Under the foundations of the towers is a cylindrical tank 63 meters in diameter, called Passivbecken (passive tank). The height of the latter depends on the wind turbine in question, and their maximum reservoir height reaches between 8 and 13 meters.[16] Both subtanks are filled and emptied successively.[18] In total, the tanks can impound a total of 160,000 m³ of water.[16] It should be noted that the terms Aktivbecken and Passivbecken have not been used. previously in the literature relating to reversible hydroelectric plants and its use was introduced in this project. From a technical point of view, both fulfill a reservoir function.

In July 2017 it was decided that the WEA2 tower, in principle, would not be equipped with an upper tank.[19]​.

A system of pressure pipes, approximately 3.2 kilometers long, connects the upper tanks with the power house and the lower tank, located in the valley of the Kocher River&action=edit&redlink=1 "Kocher (river) (not yet drafted)"), about 200 meters below the upper level.[20]​ The DN1800/DN1600 polyethylene pipes (provided by Egeplast[21]​), were installed as of March 2018. The distribution pipe (known as Trifurcator) that allows distribution from the pressure pipes to the turbines, is a prefabricated part manufactured by Bilfinger VAM Anlagentechnik GmbH.[22]​ The system of pipes and turbines allows a flow of 9.5 m³/s.[23]​.

The powerhouse is located on the east side of the Kocher River&action=edit&redlink=1 "Kocher (river) (not yet drafted)") and is connected to the lower tank (located on the west side of the flow) by an inverted siphon.[23]​ The powerhouse is provided with three reversible Francis turbines, developed by Voith Hydro, with a total capacity of 16 MW.[1]​ During the reservoir phase, water will be pumped from the lower tank to the upper tanks using pumping turbines. During periods of electrical demand, water flows back to the lower tank through the turbines. The change between the electricity generation phase and the reservoir phase must be possible in a time of 30 seconds and the storage is expected to have an energy efficiency close to 80%.[24]​.

A previously planned pond will be used as a lower tank as a river flood defense against floods of the Kocher River&action=edit&redlink=1 "Kocher (river) (not yet drafted)").[25]​ This pond is designed for a return period of 10 years. The volume of the pond is designed in such a way that in maximum use condition, it maintains a retention capacity (as a river defense) of 30,000 m³. In case of use as a flood defense, it is necessary to stop the use as part of the generation system for cleaning work. For initial filling, as well as for subsequent fillings after maintenance work, it is approved to divert a flow of up to 2 m³/s from the Kocher River&action=edit&redlink=1 "Kocher (river) (not yet drafted)"), as long as the river maintains a minimum flow of 10 m³/s.[23]​.

Electrical substation

To the south of the power house, an electrical substation will be built to connect to an existing 110 kV line. The network operator is Netze BW").[15]​.