Balancing Service Providers representing Dispatchable hydro Generating Units are required to notify the HETS Operator of a forecasted change in any components affecting mandatory hydro management as soon as possible after the occurrence of the event. In particular, they are required to inform the HETS Operator with regard to:

a) the water level in the reservoir of the Dispatchable hydro Generating Units and the expected changes therein, especially if a violation of the Safety Maximum Reservoir Level is ascertained or forecasted,

b) the water supply in the reservoir of the Dispatchable hydro Generating Unit (instantaneous or average for a specific period),

c) any necessary measures taken for the safety of the reservoir dams when increased water supplies are observed,

d) the modification of irrigation needs,

e) special works and third-party claims or

f) other safety reasons (Force Majeure).

Balancing Service Providers representing Dispatchable Hydro Generating Units are required to submit daily mandatory hydro injection declarations to the HETS Operator before 09:30 ΕΕΤ on the previous Dispatch Day. Furthermore, they are also required to submit daily mandatory hydro injection declarations to the HETS Operator as soon as possible after the occurrence of any event affecting the management of hydro resources subject to mandatory reporting.

A deviation of the daily mandatory hydro injection declaration from the weekly mandatory hydro management declaration is allowed only in the following cases:

a) modification water supply needs,

b) modification of irrigation needs,

c) avoidance of overflow,

d) special works and third-party claims and

e) other safety reasons (Force Majeure).

Any deviation of the daily mandatory hydro injection declaration from the weekly mandatory hydro management declaration shall be fully substantiated by the Balancing Service Provider. The HETS Operator may request additional information at a later stage if in its judgment the justification is not complete. In case of amendment of the weekly mandatory hydro management declaration, the HETS Operator shall notify the Participants as soon as possible.

If an amended daily mandatory hydro injection declaration is submitted during the Dispatch Day to which the declaration refers, the HETS Operator shall:

a) depending on the extent of the amendment, decide if an execution of an ad-hoc ISP is required,

b) include the amended daily mandatory hydro injection declarations in the Balancing Energy Market, and

c) have the possibility to allocate the additional quantities within the Dispatch Day, so that the operation of the HETS is ensured and the operation of the Balancing Market is not disturbed to the extent possible.