Assessment permit

The Koralm pumped storage hydroelectric power plant will be constructed in Styria, Austria. With a bottleneck output of about 1 megawatt, it will be one of the most powerful hydropower plants in Austria.

Assessment permit

The Styrian state government issued an assessment permit stating that the Koralm project did not require an environmental impact assessment. In the assessment permit, the authority assessed the project as a closed pumping system with a lower and upper reservoir. Each reservoir will be constructed with a dam and filled once by water from a small river. That water will then be pumped from the lower reservoir to the upper reservoir. The flow (from the upper reservoir to the lower reservoir) will be used for electricity generation. These plants do not produce energy, only store it. As such, they operate with high energy losses. In the assessment permit, the authority declared that the Koralm plant was not a 'hydroelectric power plant' under the definition set out in Appendix 1(30) of the Environmental Impact Assessment Act because of its closed pumping system.

Further, the project does not meet the benchmark (10 million cubic metres or 2 million cubic metres) set out in Appendix 1(31) of the act for the permanent storage of water.

A non-governmental organisation recently objected to the assessment permit, stating that pump operations in closed systems fall within the scope of Appendix 1(30) of the act.


In its ruling, the Federal Administrative Court stated that a pumped storage hydroelectric power plant which has a closed pumping system and is filled with abstracted water over the course of the first two-and-a-half years falls under Appendix 1(3) of the act because:

  • while Austrian law contains no exact legal definition of a 'dam', both reservoirs and pumped storage hydroelectric power plants require the use of dams; and
  • all relevant measurements in relation to an abstraction of water must be understood regardless of their purpose.

According to the court, the three hydroelectric power plants set out in Appendix 1(30) of the act – that is, dams, river barrages and diversions – are not the only types of power plant. Instead, the three listed power plants were the most common types when the act came into force. The EU Environmental Impact Assessment Directive refers to hydroelectric energy production without naming specific types of hydroelectric power plant.

The Federal Administrative Court also referred to a Supreme Administrative Court decision which found that the modification of a storage hydroelectric power plant into a pump storage hydroelectric power plant falls under Appendix 1(30) of the act because the storage of water is used to produce electricity.


The Federal Administrative Court found that the Koralm project fulfils the relevant legal prerequisites for a hydroelectric power plant, as it:

  • uses water for the production of electricity;
  • requires a dam for the storage of water; and
  • requires the abstraction of water for the first two-and-a-half years to fill the reservoir.

Therefore, the court found that an environmental impact assessment was required.

The Federal Administrative Court granted an appeal to the Supreme Administrative Court because no clear decision has been issued regarding whether a project that uses water in a closed pumping system to produce electricity falls under Appendix 1(30) of the act.

For further information on this topic please contact Christian Schmelz or Dieter Wohlmuth at Schoenherr by telephone (+43 1 5343 70) or email ([email protected] or [email protected]). The Schoenherr website can be accessed at