Economic Methods for the Selection of Renewable Energy Sources: A Case Study

Number

Comment

Response

1

Are there the latest data and policy background to better introduce the real-world issues and the research topic of the article?

The data used are the most recently published contemporary data for the different technologies.  We accept that the situation is dynamic, but our aim is to investigate the effectiveness of different approaches, not to make a statement about the difference between technologies.

2

Please summarize the innovations and main contributions of the article, and refine its practical and theoretical significance.

Described in the conclusions

3

The introduction mentions energy policy and decision-making. Relevant literature [J. Loss Prev. Process.  Vol 2005 p105523] should be cited. Additionally, the article considers carbon emissions and energy decision-making issues, so relevant literature [Applied Thermal Eng. Vol 264 p125371, 2025] should be cited. Please further check the format of the references.

We have identified and included new references [43-46] in the discussion that we feel cover your point but are more relevant to our example.

4

What are the selection criteria for several indicators, and do they account for impact of current world-wide scenarios, such as the influence of carbon neutrality policies and the impact of digital technologies?

We’ve added a couple of paragraphs (lines 259-272)

5

The article considers issues related to subsidies and carbon taxes.  Do these government incentives take into account the policy environments of different regions?  Are these two measures decided jointly or separately?  If there are corresponding policies in different countries, they should be supplemented in the discussion section.

Included in discussion

6

Please supplement more management insights and suggestions in the analysis section of the paper.

We’re afraid with the time constraints we did could not address this issue.

Line

Comment

Response

please be careful to the title editing `Economic methods for the selection of renewable energy sources; a case study.`

We feel the paper is an examination of economic methods of comparing different energy sources and uses the UK as an example.  The methods can be used for other fuels and in different locations

49-50

- please be careful to the information and editing `However, as with all comprehensive metrics the devil is in the detail and there are components at multiple levels as indicated in Figure 1 `

Sorry, the phrase ‘devil is in the detail’ is a colloquial expression (commonly used in English in both Britain and the US).  We have modified the phraseology.

51

- explain the content from figure 1 please ?

I have added a description of Figure 1

57-58

please try to express the information more usual "Whilst academics discussed the intricacies and capabilities of the approach, early users were administrators, such as the California Energy Commission [2]."

I have modified the sentence (lines 62-64)

- what "whilst " means? (is used more in the text )

‘Whilst’ is a conjunction in this case meaning ‘at the same time’ but carrying a sense of contrast (‘whereas’).  It used to be very commonly used in English, but in the 20^th century it became less popular.  In the 21^st century it is rising in use,

113-114

please give more information to your suggestion/goal, why is this selection made is also important to explain   "Thus, one tidal range scheme is compared with two consecutive nuclear schemes or four consecutive CCGT power stations. "

The explanation has been modified to make it clearer (lines 118-120)

Fig 2 138

- please add the metrics of the Capacity and AEP

   - the diagrams need  to show a correlation ? Capacity shoud be bigger than AEP or else, please explain?

Metrics added to the caption, but it is the relative difference that is of interest (the pie chart literally shows the proportion).  The metrics are different, so cannot be compared

The diagrams do not need to show a tight correlation as one shows the ability to generate power (GW) the other the amount of power generated in a year (TWh a^-1).  The difference is time.  We think the problem is with the use of the word capacity; total capacity for the period of the AEP would be GW multiplied by 8,760 (number of hours in a year) and would be higher than the AEP.  The different sources are used selectively (availability, demand, costs, etc.).  That is what we are trying to highlight.

158 -159

please rephrase , is not clear  "The load factor indicates the efficiency of the system by comparing the maximum actual use or efficiency at energy  conversion with its capacity"

 - maybe a mathematics expression is needed to clarify the load factor indicator

      - careful that the large hydro with accumulation including the pumping storage ones are the most efficient, cost friendly and available from all types of energy sources, so which is the correlation with the loading?

Rephrased (lines 169-171)

Equation added and explained (lines 171-178)

The loading describes the use of different technologies in the UK indicating how much of the capacity is used.  Hydro here combines both natural flow (e.g. run of river) and pumped storage.  There is only limited capacity at large scale in UK (at present).

Fig 3 168

-  check please your information about hydro https://en.wikipedia.org/wiki/Hydroelectricity_in_the_United_Kingdom

-  maybe a better overview is needed

The figures are UK Government data.  The reason hydro looks insignificant is that the capacity (2% of UK) and production (1% of UK).  Pumped hydro is not included as it would be double counting (i.e. the power is generated from multiple sources, the excess is used to pump water and then power regenerated when needed).

207 - 209

can you please add large hydro (including pumped storage) type in your list "We selected seven of their technologies for our analysis to represent a mixture of existing and emerging technologies. They include the commonly used combined cycle gas turbines (CCGT), an assortment of renewable technologies, and are shown below: "?

Hydro is not included as, at the moment, the UK is not contemplating any additional major hydro power schemes (as primary sources).  The aim of the paper is to demonstrate techniques used to help select power sources in the UK.  The approach could be used to examine any technology (the Government publish figures for over 40 types) and can be applied in other geographic locations.  Paragraph added (lines 268-280)

364 - 366

please add information about your database and explain the accuracy "All spreadsheets are included in the supplementary data or can be obtained from the corresponding author. Each column in the spreadsheets represents one year of costs, and for the IRR analysis revenue is included. Costs are handled the same as revenue and are indexed linked to assumed inflation rates. "

The data in the spreadsheets are obtained, for most technologies from Government reports and are therefore the same data as those being used to make the policy judgements we are describing.  They are not qualified by statistical error terms or other methods of assessing their accuracy, but that is missing the point.  We are attempting to mimic the analyses used by Government to make decisions.  We have added a statement into the text addressing the issue. (lines 416-418)

483- 485

please can you explain"Thus, two nuclear stations will be needed consecutively, four offshore wind farms and CCGTs, five tidal stream stations, and six wave farms."?

Text modified. (lines 534-536)

Fig 8

can be better presented and explained, is difficult to follow the results "Figure 8 The ranking of different generation sources from three different metrics (LCOE, IRR and SCOE) with three different levels of discounting. The size of each marker represents the frequency of the rank, the shade the dominant metric."

   -  where do you think is the hydro placed in this ranking? 

Text modified.

At the moment, major large-scale hydro is not being considered by UK Government (primarily on environmental grounds as the British public feel that large dams and reservoir production are damaging to existing natural systems – they are therefore politically unpopular).

630-633

take please in account the hydro with pumping- storage, because they are one of the most peaking of all "Using the UK Government’s figures for the cost of hydrogen and carbon tax, only offshore wind, solar, nuclear and tidal range are viable at current electricity prices. Of these, offshore wind and solar are the most cost effective, but none of them are capable of responsive generation as peaking plants."

We agree with your sentiment, but we cannot put pumped storage in as it is not a primary power source.  We are not considering batteries, compressed gas (both of which are being investigated by UK Government) because their source is electricity.

conclusions

the power sources type explored in the paper need an extension to include hydro type

Our results are not intended to be definitive, but to demonstrate how different sources are currently assessed and a new potential analysis.  The inclusion of tidal range demonstrates how other technologies (not included in the Government’s data) can be included.  We accept that hydro would be interesting, but so too are different forms of bioenergy and other technologies.  We don’t believe it is necessary to make our point.

a suggestion is to start/take in consideration the sources selection for the analyse using each source energy price (MWh), so an extended and more real analysis can be made

The price is the nux of the problem!  The three methods we present each attempt to estimate the cost per unit of power (£ MWh^-1).  It is possible to makes estimates for every technology and have some confidence in them.  Unfortunately, the costs are not comparable, hence the idea of levelising.  For ranking of systems the comparative costs are essential.

references - can be completed according with the indications above

Accepted.

Number

Comment

Response

1

Formatting: The manuscript contains tracked changes, inconsistent formatting, and structural issues. Please align it with the journal’s submission template.

Addressed.

2

Figures and Tables: Improve the resolution, consistency, and labeling of figures and tables. Visual clarity is currently insufficient for accurate interpretation

The tables have all been redrafted to match the journals format.  We have looked at trying to improve the resolution of the figures, but the only way seems to be by making them larger and we’re not sure you would want that.  The material (as raw data) is supplied to the editor along with some minor modifications in case further adjustment is needed.  Please come back to us if you need other options.

3

Literature Review and Referencing: Expand the review to include more recent works (2020–2024). Several claims lack proper citations and must be appropriately referenced.

We’ve added more recent papers, reports and databases.

4

Methodology: Clearly justify assumptions in the SCOE model, especially the operational lifespan and discounting structure. A sensitivity analysis would be helpful

Addressed in additional text describing both LCOE and SCOE.

5

Results and Validation: Strengthen the discussion with a comparative assessment of SCOE performance against existing metrics in published studies.

We fear in the time we have not managed to fully address this issue.

6

Structure and Flow: Avoid over-fragmentation caused by excessive use of short subsections. Merge and streamline for better narrative continuity.

We accept that in places the text appears to be fragmented, but the authors feel that the structure gives a greater feel for the comparison than with larger amorphous blocks of text.  To improve the flow of the text we have added a paragraph linking the sections at the end of the Introduction.  We have also reduced the use of bulleted lists.

7

Language: While readable, the manuscript would benefit from a professional English language revision for technical clarity and coherence.

We are always happy to have our English proofed and improved, but in this instance, we don’t think there is time and, speaking personally as a pensioner, funding things out of my own pocket, I cannot justify the expense.