Climate Change Effects on Hydropower in Mozambique

Round 1

Reviewer 1 Report

The paper “Climate change effects on Hydropower in Mozambique” written by M. M. Uamusse, K. Tussupova, K. M. Persson presents a study on the impact of global warming on Hydroelectricity production in the next decades. The topic is very interesting nevertheless the quantitative and qualitive analysis are a bit light. Please find below some recommendations to improve the rigor of this article.

General comments

In the introduction, it could be nice to precise numbers such as GWh of production, MW installed as well as numbers for the potential . A table with the list of installed power plants and future one (like Table2) should be included there.

A map of the country with the position of existing power plants classified by installed power, for instance small circle for P<1MW, medium circle for 1MW<P<10MW and large circle for 10MW<P<100MW and super large circle for higher power. The positions of the Hydropower plant could be kept on the map with temperature increased figure 1. Some figures should be add to explain the change in temperature and precipitation according to scenarios, it will be understandable than text only.

In part 2, again some figures should be added to complete the text. This is quite complicated to identify the region mentioned for people who don't know the geographical characteristics of this country.

Part 3 is very short compared to the two first ones, it could be included as first part of Methodology part. Again a map with the selected region and the existing or potential power plants concerned is needed.

Part 4 : Figures including the data and interpolation precising the error and standard deviation must be included. A comparison of the 5 GCM's or the three scenarios must be represented on a graph. A graph to explain the extrapolation from Table 1 should be provided.

 

Comments :

L39 : renewable sources of electricity

L45 : % of the total population ?

Figure 1 : the quality should be increased, the text of the legend colored is not lisible

Figure 2 : please indicate the approximation law and discrepancies with the data

Figure 4 : part of the legend is in yellow. For precipitation, instead of representing point for each year, ten years could be considered with min value, max value and mean value represented as a rectangle ?

 

Reference

Please indicate the journal name, series, pages for all the references.

Author Response

1. In the introduction, it could be nice to precise numbers such as GWh of production, MW installed as well as numbers for the potential . A table with the list of installed power plants and future one (like Table2) should be included there. Yes i have done, the potential yes should be presented by Megawatt(MW)

2.A map of the country with the position of existing power plants classified by installed power, for instance small circle for P<1MW, medium circle for 1MW<P<10MW and large circle for 10MW<P<100MW and super large circle for higher power. The positions of the Hydropower plant could be kept on the map with temperature increased figure 1. Some figures should be add to explain the change in temperature and precipitation according to scenarios, it will be understandable than text only.

Yes, i have add mor figuer to show this explanations of some project of hydropower and some old project

3.Part 3 is very short compared to the two first ones, it could be included as first part of Methodology part. Again a map with the selected region and the existing or potential power plants concerned is needed.

Sure, i have add new picture and thank you again

4. I have revise the reference and thank you

Reviewer 2 Report

General comments:

Many parts of the manuscript are not sufficiently clearly exposed and need to be reviewed. The references are not correctly cites in the paper text, like „author et al., year” or reference number in the references list like: [xx]; please verify and complete;

Specific comments:

In Abstract, pag. 1, row 14: „To fulfill the SDG goals and ....”; please explain the abbreviation SDG.

In chp. 1. Introduction, pag. 2, row 47: „Climate variation impacts the use of hydropower and represents high challenges to the water...”; the most common term in the literature is „climate variability”, please consider to use it in the manuscript.

In chp. 1. Introduction, pag. 3, rows 65 – 67: the statement expressed in the phrase „The future projections for temperature are expected to increase up to +1.4°C by 2030 and 1.0 to 66 2.8°C by 2060 (minimum ranging)” has to be more documented; e.g. what are the future climate projections, which you refer to.

In chp. 1. Introduction, pag. 3, rows 67-68: „A continued increase is expected of +2.2°C by 2070 and 67 1.4 to 4.6°C up to the 2090s (maximum ranging) shown in Figure 1 [3].”. Similar with the previous observation, the statement need more ducumented explanation. Also the statement is not in full correlation with the data presented in fig.1; for example in the figure 1, the time domain for the projected change in temperature is till 2070, not till 2090.

In chp. 1. Introduction, pag. 3, rows 68-70: „In addition, under a single emissions scenario, the projected changes from different models have shown that the temperature will be up by 1.8°C.”. The sentence is unclear and need more documented expalntion regarding the cited climate change scenarios and models.

In chp. 1. Introduction, pag. 3, rows: 73-75: „Rainfall projections show that the substantial change in total annual rainfall on the national level is projected to be between - 8 and +14% from 1975 to 2100”. Like the previous comments the statement need more information about the climate projections referred to in the sentence, supported by graphs, figures etc.

In chp. 1. Introduction, pag. 3-4, rows: 75-80: „Regional and seasonal changes are however more pronounced: A rainfall increase of 1-8% (2010-2090) is expected for the north of the country, mainly in the rainy season between December to February; A decrease is projected for the west, south and central regions of the country (including Zambezi valley) during the onset of the rainy season, with a strong decrease of up to 31% projected for September and October; Another decrease for the south of the country is expected for the main rainy season. [7,9]”. The statement need more information about the climate projections referred to in the sentence, supported by graphs, figures etc.

In chp. 1. Introduction, pag. 4, rows: 95-98: „The precipitation is estimated to be reduced by 15% and the evaporative losses increased up to 25%. The runoff could be reduced with 30-40%. This may to a large extent be applicable for all the major river basins in Mozambique”. The presented statements have to be supported by documented papers/references.

In chp. 1. Introduction, pag. 5, rows: 106-107: the sentence „Spalding-Fecher [6] implies a need for policy development in the energy sector, not only in 106 Mozambique but within the entire region of southern Africa” is unclear, please refrase it.

In chp. 1. Introduction, pag. 6, row 123: the title of the figure 1 „Figure 1 Projected increase in temperature and precipitation in Mozambique by 2050 [From 3]” is not well corelated with the figure content and with the related comments made in the manuscript (chp. 1. Introduction); in the figure the analysed time period is 2030 to 2070.

In chp. 2. Climate characteristic in Mozambique, pag. 7, rows 143-146: „ The climate change scenario in southern Africa projected using GCMs models in IPCC report number four (AR4) show the temperature will increase 1 - 2.8oC until the 2060s and 1.4 - 4.6oC until the 2090s 145 while the precipitation will decrease”.Please include in the refenece list the IPCC Report 4.

In chp. 2. Climate characteristic in Mozambique, pag. 7, rows 146-147: „With higher temperature comes higher evaporation, and for Mozambique lower precipitation, which affects the potential for hydropower generation.”The sentence is unclear, please reprase it with more reliable explanation.

In chp. 2. Climate characteristic in Mozambique, pag. 7, rows 148-151: „Mozambique is extremely vulnerability to climate change or climate variation because of the location and geography conditions and large areas of the country are exposed to tropical cycloanes, droughts and every three to four years the phenomena is repeating and river, coastal area suffering of flooding”. The sentnce is unclear, please reprase it.

In chp. 4. Methodology , subchp. 4.1. Data collections, pag. 8, rows 179-181: „The data collations concerning climate in the central region of Mozambique (Chimoio, Beira and Tete) was collected from Ara-Centro and provided by The Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) in Manica by February 2017 (Zambeze, 2003).”Zambeze, 2003 is not included in the Bibliography list.

In chp. 4. Methodology , subchp. 4.2 Statistical recreations method, pag. 8, row 186: The meaning of the term „Statistical recreations” is not clear and have to be explain.

In chp. 4. Methodology , subchp. 4.2 Statistical recreations method, pag. 9, rows 199-200: „For the time series where significant linear trends were established, projections were made based on these trends until 2050 and 2100”. Please explain more in details the scientific reason and the assumptions used for this approach.

In chp. 5. Results, pag. 10, rows 223-226: „In Figure 2 the trends for the three chosen periods are presented. For the years 1902-1957 no clear trend can be seen from the linear regression analysis. For the years 1957-2012, a small increase in temperature can be detected. For the years 1973-2012, a significant temperature 225 increase is present.” The presented statements have to be supported by examples of the significances of the linear regressions (e.g. the p-value from the author’s t-test on the slope coefficients).

In chp. 5. Results, pag. 12, row 239: the title of the figure 4 „Figure 4. October to March precipitation for the Ara-Centro region (Zambeze, 2003)” is not clear; it has to be more specific about the precipitation data, e.g. mean average monthly data.

In chp. 5. Results, pag. 12, row 241-242: „For precipitation for October to March, as seen in Figure 4, no significant trend was visible 241 for the dataset.”. The statement is based only of simple visual observation of the graph; a trend curve has to be included and analysed.

In chp. 5. Results, pag. 12, row 244-245: „ Extrapolating data from Figure 1a indicates an increase in temperature of 3.6oC in 2100, as presented in Table 1.”. Figure 1a is not clear indicated in fig 1.

In chp. 5. Results, pag. 12, row 242-244: „Climate change scenarios do suggest an increase in precipitation due to warmer climate, yet with a faster increase in temperature, the evapotranspiration will grow faster than the precipitation.” The statement has to supported by some specific examples (e.g. values of  estimated evapotranspiration compared with precipitation) .

In chp. 5. Results, pag. 12-13, row 252-256: „In the climate scenarios projected in GCM (CSIRO 3.0, CGCM3.1, ECHAM5, CCSM3.0, HACDM3), a 10% decrease in runoff during the rainy season and a 12% decrease during the dry season is estimated for the coming 10 years; until 2100 the runoff will decrease even further, down to - 18% in the rainy season and -20% in the dry season.” The statements have to be more clear and presented more in detailed.

In chp. 6. Discussion, pag. 14, row 288: „The total hydropower potential for Mozambique is approximately 18000 MW according to 287 EDM and hydrological studies of the large river basins in the country [1].”. EDM abbreviation has to be explained.

Author Response

1. In Abstract, pag. 1, row 14: „To fulfill the SDG goals and ....”; please explain the abbreviation SDG.

Yes is ther now Sustainable Development Goals (SDGs)

2. In chp. 1. Introduction, pag. 2, row 47: „Climate variation impacts the use of hydropower and represents high challenges to the water...”; the most common term in the literature is „climate variability”, please consider to use it in the manuscript.

Ther is diference between climate variations and climate change

yes i have mentions and now is clear

3.

In chp. 1. Introduction, pag. 3, rows 67-68: „A continued increase is expected of +2.2°C by 2070 and 67 1.4 to 4.6°C up to the 2090s (maximum ranging) shown in Figure 1 [3].”. Similar with the previous observation, the statement need more ducumented explanation. Also the statement is not in full correlation with the data presented in fig.1; for example in the figure 1, the time domain for the projected change in temperature is till 2070, not till 2090.kNow the figuere is there and is clear. thank you

In chp. 1. Introduction, pag. 3, rows 68-70: „In addition, under a single emissions scenario, the projected changes from different models have shown that the temperature will be up by 1.8°C.”. The sentence is unclear and need more documented expalntion regarding the cited climate change scenarios and models.

n chp. 4. Methodology , subchp. 4.1. Data collections, pag. 8, rows 179-181: „The data collations concerning climate in the central region of Mozambique (Chimoio, Beira and Tete) was collected from Ara-Centro and provided by The Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) in Manica by February 2017 (Zambeze, 2003).”Zambeze, 2003 is not included in the Bibliography list.

is corected

In chp. 6. Discussion, pag. 14, row 288: „The total hydropower potential for Mozambique is approximately 18000 MW according to 287 EDM and hydrological studies of the large river basins in the country [1].”. EDM abbreviation has to be explained.

Thank you, EDM yes is abreviations and is Electricidade de Mocambique. Done

 

Round 2

Reviewer 2 Report

General comments:

The authors have still to verify the figures titles, to be cited in the manuscript text and to be well corelated with the figures content as well as with the related comments made in the manuscript.

Specific comments:

In chp. 1. Introduction, pag. 4, row 72: „Figure 2. Shows the three main grid systems in Mozambique with existing or planned large 72 power plants. Source: own illustration with information from [1, 2, 5, 8]”. Please avoid the term shows in the figure title.

In chp. 1. Introduction, pag. 5, row 81: „Figure 3. Shows the greatest holograph in Mozambique. Source: own illustrations”. Please avoid the term shows in the figure title.

In chp. 1. Introduction, pag. 5, row 81: „Figure 3. Shows the greatest holograph in Mozambique. Source: own illustrations”; please explain the meaning of the term holograph. The figure 3 is a digital elevation model  of the basin, in which the altitudinal levels are expressed by colors. Also this figure is not cited in the manuscript text.

In chp. 1. Introduction, pag. 6, rows 104-105: ”A continued increase is expected of +2.2°C by 2070 and 104 1.4 to 4.6°C up to the 2090s (maximum ranging) shown in Figure 1 [3].”. The figure 1 – (Currently electricity scenarios in Mozambique, Productions, Domestic consumptions and 47 import.) has no relation to the content of the sentence; please corect.

In chp. 1. Introduction, pag. 6-7, rows 112-119:” Regional and seasonal changes are however more 112 pronounced: A rainfall increase of 1-8% (2010-2090) is expected for the north of the country, mainly in the rainy season between December to February; A decrease is projected for the west, south and central regions of the country (including Zambezi valley) during the onset of the rainy season, with a strong decrease of up to 31% projected for September and October; Another decrease for the south of the country is expected for the main rainy season. [7, 9]. Climate change is projected to alter the frequency of precipitations, floods and drought events in Mozambique”. The statement need updated information about the climate projections referred to in the sentence. The reference [7] and [9] are quite old (2012).

In chp. 1. Introduction, pag. 9, row 160: the title of the figure 4 „Figure 4. Projected increase in temperature and precipitation in Mozambique by 2050 [From 3]” is not well corelated with the figure content; in the figure the analysed time period is 2030 to 2070.Please correct.

In chp. 5. Results, pag. 15, row 284: „Figure 7. October to March precipitation for the Ara-Centro region. Source: own illustrations”; the figure does not appear in the manuscript.

In chp. 5. Results, pag. 15, row 285: „For precipitation for October to March, there is no significant trend was visible for the dataset”; the grammar of the phrase must be revised; the figure that has to support the statement is missing (may be figure 7).

In chp. 5. Results, pag. 15, row 288 - 289: „Extrapolating data from Figure 5 indicates an increase in temperature of 3.6^oC  in 2100, as presented in Table 1.”. It’s difficult to accept the estimated increase in temperature in 2100, based only on exptrapolated the linear trend of  a short data series (1973 – 2012). Please comment.

In chp. 2. Climate characteristic in Mozambique, pag 9, rows 184-186: „Mozambique is extremely vulnerability to climate variation because of the geography location and large areas of the country are exposed to tropical cyclones, droughts and every three to four years the phenomena is repeating and river, coastal area suffering of flooding.” The sentence is unclear... the country are exposed to tropical cyclones, droughts... and finnaly it is mentioned that every three to four years the phenomena is repeating and river, coastal area suffering of flooding... what about droughts ??. Please reprase it.

Author Response

1. Author with information from [1, 2, 5, 8], Corrected
2. Corrected and removed.
3. Now the figure is cited, and no more owen ilustrations
4. is Figure 4....is corrected
5. The reference [7] and [9] are quite old (2012).Yes the reference 7,8 is hold but i think is fine
6. In chp. 1. Introduction, pag. 9, row 160: the title of the figure 4 „Figure 4. Projected increase in temperature and precipitation in Mozambique by 2050 [From 3]” is not well corelated with the figure content; in the figure the analysed time period is 2030 to 2070.Please correct. corrected
7. In chp. 5. Results, pag. 15, row 284: „Figure 7. October to March precipitation for the Ara-Centro region. Source: own illustrations”; the figure does not appear in the manuscript. Corrected

8. In chp. 5. Results, pag. 15, row 285: „For precipitation for October to March, there is no significant trend was visible for the dataset”; the grammar of the phrase must be revised; the figure that has to support the statement is missing (may be figure 7).Not necessary Figure 

9. n chp. 2. Climate characteristic in Mozambique, pag 9, rows 184-186: „Mozambique is extremely vulnerability to climate variation because of the geography location and large areas of the country are exposed to tropical cyclones, droughts and every three to four years the phenomena is repeating and river, coastal area suffering of flooding.” The sentence is unclear... the country are exposed to tropical cyclones, droughts... and finnaly it is mentioned that every three to four years the phenomena is repeating and river, coastal area suffering of flooding... what about droughts ??. Please reprase it. Yes also is one of the fenomena