Dealing with Negative Inflows in the Long-Term Hydrothermal Scheduling Problem

Round 1

Reviewer 1 Report

This paper proposes an approach to deal with the negative wather inflow that is found in a long-term hydrothermal scheduling (LTHS) problem. For that, the Stochastic Dual Dynamic Programming (SDDP) algorithm is used as well as the Time Series Model (TSM) of the river inflows. Although this is an interesting dicussion, some points shoud be clarifyed:

1- What is the contribution of the paper? The authors wrote from line 61 that “Optimal Value process” is one of the contribution. The penalty described from line 66 and Truncation methods are another contributions of the paper? 
2- In another part of the paper, it was possible to verify that the penalty and truncation methods are already used in the literature. From the point of view of this reviewer, they just complete the contribution of the work called "Optimal value process". This aspect needs to be made clear at the beginning of the work.
3- As consequence of previous questions, the Optimal value process has been discussed in a short way. The autors should improve this section.
4- Using some statistical process, negative wather inflow can be avoided by some technique. Then, the authors shoud clarify  this question and present some advantage and disadvantage.
5- Line 166 presents an error.
6- Figure 9 is confuse because capacity is generally constant and is not variable with the time horizon. It shoud be clarifiyed.
7- Figure 10: The authors can display som parto f the figure (zoom) to show the negative wather inflow.
8- Figure 11: All methods converged. The zoom and some expalin can be done to clarify this figure.
9- Figure 15: Why the truncation method discrepancy appears only at the end of the horizon?

Finally, this reviewer suggest these improvements in the paper.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

1. In line 166, there is some error message. It is an oversight from the authors and has to be corrected.
2. The exact contribution and work is not exactly highlighted.
3. The single diagram of the test system has to be shown.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript presents research related to the optimal control of water resources in the electricity system. The topic is very relevant in view of the rising prices of electricity worldwide, as well as the need for balanced and optimal management of energy flows in electricity generation systems in order to obtain a minimum price and maximum efficiency. To prove the advantages of the proposed approach, many results of numerical experiments with developed models are presented. The recommendations to the authors are the following:
- to strengthen the overview of the manuscript by including additional manuscripts on the subject, including those from the MDPI Publishing Group;

- it would be useful for the authors in the conclusion to present, in addition to the advantages of their proposed method, its disadvantages in comparison with other methods used for these purposes;
- as the forecasting of weather and in particular of precipitation is quite advanced and is performed with a high degree of accuracy, it would be useful to include in the data for analysis and management decisions with some weight the data from precipitation forecasts and respectively from future water supplies. 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

This reviewer considers that the authors' answers clarified the points suggested by this reviewer.