Review of Recent Developments in Microgrid Energy Management Strategies

Round 1

Reviewer 1 Report

The authors proposed a review addressing the overall aspects of Energy Management Systems (EMS) in microgrids (MG) and how they influence MG functionalities. The review also deals with the common challenges to sustain MG project (economic and environmental goals).

A large number of references (248) is proposed to illustrate the different points with a significant number published in the last 5 years. Some references have been grouped without analysis (for instance [33–41]) but this rarely occurs and does not compromise the paper quality. Most references (~ 80%) focus on the overall aspects of EMS and the remainder on the MG implementation challenges. This second part is an interesting topic, not often investigated, and for which we still have a lack of visibility. It thus brings some novelty in relation to the usual EMS reviews. It should also be noted that the authors have made significant efforts to present recent developments, also introducing not commonly known techniques such as proactive control.

One general comment is that it may be unclear whether the case study results presented in this review came from simulations or experimentations. As feedbacks of experimental microgrids are less common but highly valued, authors are encouraged to put emphasis on them when results came from actual MGs. Many EMS appear to show their limits when used under real conditions.

Specific comments:

L 59-60: Please clarify what is the “Worldwide MG power capacity” which is excepted to rise from 6 GW to 20 GW. According to [14] the total MG capacity was already at ~25 GW in 2020 (Chart 3). The figures you mentioned seem to be the annual additional capacity which is expected to be installed every year (Chart 1).

L 61-63: I agree with your definition of a microgrid and the precision added at line 53. An important point raised by the DOE (which is an authoritative source in this field) is that “A microgrid can connect and disconnect from the grid to enable it to operate in both grid-connected or island-mode”. With this in mind, is it fair to say that the global leader in the microgrid market focuses on “remote microgrids”, which are not considered as true microgrids for many authorities? A small paragraph about the different types or definitions of microgrids could be useful to clarify this point for the readers. Later, it seems clear that your review focuses on grid-connected ones, as evidenced by the frequent references to the electricity price in the EMS.

L 153: Please reword the sentence “Critical loads must run loads, and these are the loads […]”.

L 209: I suggest changing the title to “Power Generation Management”. The term “Energy” is better suited for the part about EMS.

L 237: I would not say that [100] used a MILP “to predict power production curves of PV and wind farms”. They used it to take into account the stochastic nature of wind and PV. Wind and PV forecasting is a whole different work which is not directly addressed in this study.

L 269: For commercial batteries, BMS are usually included at the system level and cannot be easily controlled by the MG owner. EMS generally controls the batteries (mainly charging and discharging currents) with respect to the BMS constraints. In this paragraph, it is unclear if the authors focus on a short literature review of BMS or if there is a link with the microgrid’ EMS. This ambiguity comes mainly from the last sentence when mentioning the “power management to RESs that helps to determine the operational costs of microgrid”.

L 354: “A rule-based solution approach is utilized for grid-connected and islanded modes of MG in [127]”. This sentence does not fit well this paragraph. Rule based control is introduced at line 364, it seems better to add this reference in this part.

Table 3 summarizes the classical techniques but Rule based control is missing. It is classic enough to be added in this table.

L 547: Subsection “Protection” should briefly discuss the issue of DC microgrid (or hybrid DC/AC microgrid). This subject is quite popular in research papers but brings difficulties such as DC circuit breaker.

Conclusion is quite short and does not reflect the quality of the review. It should be improved to better highlight the main results. Aside from a brief overview of the topic, the only comment concerns the fact that metaheuristic optimization approaches can be more effective compared to the classical approaches in case of complex optimization EMS formulations. More findings of this type should be presented.

 

Author Response

Please go through the attached document.

Author Response File: Author Response.pdf

Reviewer 2 Report

This work provides a review of microgrid implementation considering the strategies for its management, the optimization approaches and the main challenges. The paper has good support based on other works and is in general well written and to some extent easy to follow. Nevertheless, the actual contributions to the literature are quite limited and can be improved. Thus, some suggestions for its improvement follow:

1 – There are several review papers available that perform similar reviews to the one presented. Therefore, the contributions stated by the authors are somewhat redundant. In this way, authors should improve the par in such a way that provides a real contribution to the literature.

2 – Check acronyms throughout the paper, some of them are initiated more than once, others are initiated after the first acronym, other are not initiated, different acronyms refer to the same thing, etc. a careful review of the acronyms should be performed.

3 – Chapter 3 states the enumeration of several works proposing different microgrid energy management systems, and therefore is inconclusive. There is no critical review on this chapter, so gaps are not identified. In addition, in most of the text, there is no clear flow and connection between the research works that are described.

4 – In section 4.3, it is presented a summary of the several metaheuristic methods, and some comparisons are stated. This should be carefully reviewed as many papers state that one metaheuristic is performing better than the one proposed by the authors, and in the end, tunning parameters of these methods are key for the performance. A critical review should be provided.

5 – A picture summarizing the main challenges for MG implementation can be included in chapter 5.

6 – Throughout chapter 5, several challenges for microgrid implementation have been provided, yet for each subsection, it is not so clear the identification of enablers and barriers. This should be improved.

7 – In the conclusions chapter, the authors state that “The metaheuristic optimization approaches were found to be more effective compared to the classical approaches in case of complex optimization EMS formulations”. Do you really mean effective or efficient? And in what terms?

8 – Though the paper is in general well written, there are still some sentences that could be improved. Some suggestions can be found in the enclosed file.

Author Response

Please go through the attached document.

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper consolidates a significant amount of information about microgrids with a focus on controls / energy management strategies. It will likely be useful for researchers to have the information presented in this paper.

There are a few minor recommendations to consider, including:

1. There is a broken reference link on line 627.

2. The use of English language throughout is generally good and the paper is readable; it could still benefit from a detailed copy edit for grammar.

3. There is an opportunity to more clearly separate optimization objectives between optimizing the configuration of a microgrid (i.e. the size of each component included), and optimizing the operation of a microgrid (i.e. given a microgrid configuration, how to optimize how each component contributes). The paper mostly focuses on the second but does mention the first, so more clearly stating when each type of optimization is being discussed would be helpful.

Author Response

Please go through the attached document.

Author Response File: Author Response.pdf

Reviewer 4 Report

This paper shows a good review comparing and summarizing the use of Microgrid Energy. Some issues need to address:

- I believe this review would benefit from a table that could compare and provide an overview of the discussed approaches. The table should include the advantages and limitations of each approach as well as findings.

- The language of the paper needs to be improved. There are some grammatical errors, please carefully check the whole manuscript.

- The introduction should be rewritten to show the highlights and novelty of the work. Also, authors can cite the following work in the introduction which is related to their work and recently reported:

-  "A review of the methods of modeling multi-phase flows within different microchannels shapes and their applications." Micromachines 12, no. 9 (2021): 1113.

- section of drawbacks and future could be increased the quality of the manuscript.

- It is recommended to add a statement to clearly separate the current work from these similar references and also define the review period (e.g. last five years). Also, prepare statistical data (such as the number of documents, documents per country) about your used references by creating databanks such as Scopus, Google Scholar, and web of science.

- Maybe at the beginning of the article, there should be a list of abbreviations?

- A review paper not only should summarize recently published works, but also should contain critical and comprehensive discussions. Therefore, check the writing for the whole manuscript. The review should not be presented by listing what have done by others.

 

- sections “5.4. Security Challenge of AMI “ and “5.5. Regulatory and Policy Issues” need more details!

Author Response

Please go through the attached document.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors took care of every points raised during my first review.

I therefore consider the manuscript is suitable for publication.

 

Reviewer 2 Report

The paper has been significantly improved, as well as the authors have considered most of this reviewer's suggestions. No further comments.

Reviewer 4 Report

The manuscript quality has been improved.