Evaluating the Potential Contribution of District Heating to the Flexibility of the Future Italian Power System
Round 1
Reviewer 1 Report
Please improve the paper by writing logically.
Comments for author File: 
Comments.pdf
Author Response
The authors thank the reviewer for the feedback and the constructive comments.
The suggestions were addressed as described in the Word file.
Author Response File: 
Author Response.docx
Reviewer 2 Report
In this work, the authors investigated how measuring the diffusion of district heating (DH) coupled with thermal energy storage (TES) units can contribute to the overall system flexibility and the provision of operating reserves for energy systems with high RES penetration. The deployment of two different DH supply technologies (combined heat and power units and large-scale heat pumps) was modeled and compared in performance for the Italian energy context. The research results showed that: (i) the large deployment of DH systems coupled with TES units could offer an important contribution to the power system flexibility and (ii) the higher integration of renewables allows to reduced costs (up to 50% savings) and significantly lower GHG emissions.
This paper is very interesting; however, before publication, a minor revision is suggested. In particular, some suggestions are listed below:
- Please, improve the introduction including in the scientific literature additional works such as:
- Rahaei, R. Rafee, M. R. Zargarabadi, (2021) A photovoltaic thermal system with a complete contact between water and PV modules suitable for district heating and electric power generation. SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS, vol. 47, 101325;
- Mi, J. Zhang, Y. Han, X. Guo, (2021). Study on energy efficiency and economic performance of district heating system of energy saving reconstruction with photovoltaic thermal heat pump. ENERGY CONVERSION AND MANAGEMENT, vol. 247, 114677
- Arabkoohsar, A. S. Alsagri, (2020). A new generation of district heating system with neighborhood-scale heat pumps and advanced pipes, a solution for future renewable-based energy systems. ENERGY, vol. 193, 116781;
- Rosato, A. Ciervo, G. Ciampi, M. Scorpio, S. Sibilio, (2020) Integration of Micro-Cogeneration Units and Electric Storages into a Micro-Scale Residential Solar District Heating System Operating with a Seasonal Thermal Storage. ENERGIES, vol. 13, article number 5456;
- ur Rehman, J. Hirvonen, R. Kosonen, K. Sirén, (2019). Computational comparison of a novel decentralized photovoltaic district heating system against three optimized solar district systems. ENERGY CONVERSION AND MANAGEMENT, vol. 191, pp. 39-54;
In addition, at the end of section “1.3. Rationale of the work” and before the description of the structure of the paper, the authors should clearly address the research's novelty with respect to the research results reported in the analyzed literature.
- Line 347: please introduce Table 5 before showing it;
- Line 555: please introduce Table 6 before showing it;
- Line 418: Figure 4 should be Figure 5;
- Line 513: please introduce Figure 11 before showing it;
- Some minor typos should be checked and corrected, i.e.: Line 50: “…their participation in DR programs has been” should be “…their participation in DR programs have been”; Line 157: “…of reserves. The paper assess” should be “…of reserves. The paper assesses”; Line 308: “…by a constraint which guarantees” should be “…by a constraint that guarantees”…;
- Please improve the section “Conclusion” remarking the importance of this study and highlighting the research's novelty of this research.
Author Response
The authors thank the reviewer for the feedback and the constructive comments.
The suggestions were addressed as described in the Word document.
Author Response File: Author Response.docx
