The Balancing Service Providers representing Dispatchable Hydro Generating Units, including Dispatchable Pumped-Storage hydro Generating Units shall submit to the HETS Operator the following hydro management declarations:

a) Yearly ahead hydro usage declarations,

b) Weekly mandatory hydro management declarations and

c) Daily mandatory hydro injection declarations.

The Balancing Service Providers representing Dispatchable Hydro Generating Units are required to:

a) submit to the HETS Operator annual curves regarding reservoir reserves for the last ten (10) years, on a monthly basis. As for the new power stations of Dispatchable Hydro Generating Units, given that the historical data on water levels are limited, they must submit the estimated curves and shall take into account any available historical data.

b) inform the HETS Operator about the reservoir water level of the Dispatchable Hydro Generating Unit and any changes expected, and about the water supply to the reservoir of the Dispatchable Hydro Generating Unit (instantaneous or average for a specific period), one day before the Dispatch Day or on an ad hoc basis, as the HETS Operator deems appropriate.

c) take into account the current level of the relevant water reserves, any forecasts for the evolution of these reserves, their obligations for water supply, irrigation and ecological supply, and ensure that the Safety Minimum Reservoir Level is constantly maintained, when planning the operation of these Units and, in particular, at the time of submission of hydro management declarations and at the time of submission of Techno-Economic Declarations, which include information on the maximum daily energy injection for the Generating Units in question.

d) notify the HETS Operator of the forecasted changes in any components affecting mandatory hydro management as soon as possible after the occurrence of the emergency.

e) notify the HETS Operator, on a weekly basis, of the daily quantity of water in cubic meters and the corresponding energy in MWh that came through the spillway for each reservoir.

The Maximum Reservoir Safety Level and the Minimum Reservoir Safety Level are determined for each Dispatchable Hydroelectric Generation Unit by the RAEWW following a proposal from the respective Balancing Service Provider and the recommendations of the HETS Operator.

The Balancing Service Providers representing Dispatchable hydro Generating Units that are connected to the reservoir may:

a) submit mandatory hydro injection declarations for the above Units to avoid an overflow only when the water level in the relevant reservoir is expected to be equal or higher that the Safety Maximum Reservoir Level.

b) submit declarations of maximum daily energy injection constraint for the above Units only when the water level in the relevant reservoir is expected to be equal or higher that the Safety Minimum Reservoir Level.

Upon expiration of the Dispatch Day, the HETS Operator shall immediately publish the quantity of energy injected by each Dispatchable hydro Generating Unit for each Imbalance Settlement Period of the Dispatch Day.

The HETS Operator shall submit a report to the RAEWW on a monthly basis, containing requests submitted for amendment of weekly mandatory hydro management declarations, outlining the reasons for submission, the supporting documentation provided by the Balancing Service Providers, and the acceptance or rejection of these requests by the HETS Operator, and any other relevant information. 

The HETS Operator shall send a report to the RAEWW by the end of the following month, which shall include at least the following information per day for each Dispatchable Hydro Generating Unit. 

a) the water level in the relevant reservoir,

b) curves on reservoir reserves,

c) total injected energy,

d) mandatory hydro injection declarations with distinct reference to the quantities by reason of overflow,

e) pumping energy.

The HETS Operator shall inform the Energy Exchange with regard to the mandatory hydro injection declarations in accordance with the provisions of the Day-Ahead & Intra-Day Markets Trading Rulebook.

Details on hydro resources management may be specified in the Technical Decision “Integrated Scheduling Process”.

The yearly ahead hydro usage declaration refers to the upcoming twelve months and shall be submitted on a rolling basis up to five (5) days before the start of the first month to which it refers. The yearly ahead hydro usage declaration shall be submitted to the HETS Operator, accompanied by the evidence on the maximization of the hydro resources value and the overall benefit of using the Dispatchable hydro Generating Units for the electricity sector.

The yearly ahead hydro usage declaration shall determine for each month of the following twelve-month period, as a sum for all Dispatch Periods of the Dispatch Days of the month, as a sum for all Dispatchable hydro Generating Units of each Balancing Service Provider, and for three (3) hydrological scenarios (high, low and intermediate total inflows) the following:

a) the schedule of forecasted energy injection due to mandatory operation,

b) the schedule of forecasted generation of additional energy,

c) the expected water inflows in the reservoirs, and

d) the forecasted water reserves in the reservoirs at the end of the month.

Within one (1) month of the end of each year, the Balancing Service Providers representing Dispatchable Hydro Generating Units shall submit a report to the HETS Operator and the RAEWW regarding hydro resource management during the previous year. The report shall include: 

a) The accounting statements pursuant to paragraph 1 of this Article, 

b) a comparison with the corresponding yearly ahead hydro usage declarations and evidence on the imbalances and

c) evidence on the maximization of the hydro resources value and the overall benefit of using the Dispatchable hydro Generating Units for the electricity sector.

The weekly mandatory hydro management declaration shall be submitted by the relevant Balancing Service Providers every Thursday by 12:00 ΕΕΤ and shall refer to a period of seven Dispatch (7) Days in total starting on the following Saturday. The weekly mandatory hydro management declaration shall specify the estimated quantity of mandatory energy injections for each Dispatchable hydro Generating Unit and for each Dispatch Period of the Dispatch Days to which the declaration refers and shall correspond to the following mandatory operations:

a) water supply,

b) irrigation, and

c) ecological supply.

The Balancing Service Providers representing Dispatchable Hydro Generating Units must substantiate the energy quantity declarations for the mandatory operations on a weekly basis, by submitting data on the said operations and on the inflow-outflow water balance in the reservoirs. The data substantiating the declarations shall be both actuarial and budget data and shall be published on the website of the HETS operator. The weekly mandatory hydro management declarations for each Dispatchable Hydro Generating Unit are binding and cannot be amended for energy quantities corresponding to paragraph 1, item (c), of this article. 

Balancing Service Providers representing Dispatchable Hydro Generating Units may submit a request for amendment of the weekly mandatory hydro management declaration with regard to the information as per paragraph 1 of this Article for emergency reasons, which include cases of violation of the Maximum Reservoir Safety Level, other safety reasons or special works and third-party claims. The Balancing Service Provider shall fully substantiate the request for amendment. 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.

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.