Assessment of Sectoral Greenhouse Gas Emission Reduction Potentials for 2030
, Angélica Afanador 2, Irina van der Hoorn 3, Tom Berg 3, Oreane Y. Edelenbosch 4,5 and Detlef P. van Vuuren 5,6Round 1
Reviewer 1 Report
The article aims to provide an overview of GHG emission reduction potentials for 2030 based on the assessment of sectoral studies. Although the analysis could have been performed in more depth, the current level is anyway an important contribution to the literature. It is also well written and structured. I recommend acceptance with minor revisions.
My specific comments are as follows:
Page 4, Line 171 – I wonder which value is assumed for autonomous development and what is assumed additional EE potential? Are these values assumed differently for each sector? Please state the assumptions.
Page 6, Table 1 – The no. of categories considered for each sector is rather low in my view. For example, for the industry sector, my past experience suggests that cross-cutting measures related to motor systems, or heat integration (direct) are largely cost-effective.
Page 8-9, Section 3.2 – For buildings, I don’t see the potential application of heat pumps for energy supply. It is one of the hot topics for decarbonizing the building sector. I wonder if heat pumps were studied in the assessment.
Page 9, Lines 289-291 – You talk about the required rate of building renovation i.e. 3-5% p.a. Isn’t it too low? This makes me wonder, what the current rate is? What are the barriers in this regard and what stakeholders need to do to accelerate retrofits?
Page 9, Lines 325 – Why Solar PV potentials are « notoriously » difficult to estimate? The sentence is too general and doesn’t provide any insight.
Page 10, Line 347 – As I understood, the emission reduction as a result of switching from fossil fuel power plants to nuclear plants is included in the potential. In many countries, especially developed countries, there are debates to shut down nuclear plants and plug in other sources. I think nuclear power doesn’t make a lot of sense for long-term energy and emission targets.
Page 10, Line 359 – Certainly, the CCS potentials cannot always be realized at costs below 100 USD/tCO2. Infact, these technologies are still very expensive. I wonder, what is the rationale applied then?
Page 9-11, Section 3.3 – In this section, an important measure i.e. Power-to-X/gas is missing. To my knowledge, it is another topic that is highly debated for low-carbon energy supply.
Page 12, Line 420 – What about the emissions reduction potentials in inorganic chemical industries, other metal, food, and textile industries? The list of sub-sectors is rather incomplete. There are significant potentials associated with e.g. refineries or breweries or dairy and chocolate industries.
Page 14, Figure 1 – It is difficult to believe that the building sector has the lowest emission reduction potential compared to the emissions gap in 2030. Does this mean that the building sector is improving extremely well or the emission targets or projections for 2030 are very conservative and not ambitious? Please clarify and improve the discussion of Figure 1.
Page 15 – Typo: It is Table 2, not 1.
Author Response
Please see the attachement
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper on the global GHG emission reduction potentials by sector for 2030 is well written, clearly organized, and easily digested. It is extremely well supported by a large amount of literature and estimates are well substantiated. The introduction provides a good justification of the knowledge gap that this work fills. I also appreciate the focus on interventions that are cost effective.
The only two issues I see with the paper are the legend and color scheme of figure 1 -- the meanings of "emission gap" is not clear and the marking between it and basic and additional potential does not come through when the article is printed in black and white. Also line 719-721 could use clarification.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
