International Journal of Sustainable Energy Planning and Management Vol. 30 2021 1 *Corresponding author - e-mail: poul@plan.aau.dk International Journal of Sustainable Energy Planning and Management Vol. 30 2021 01–04 ABSTRACT This editorial introduces the main findings from the 30th Volume of the International Journal of Sustainable Energy Planning and Management. This volume probes into analyses of the technical interactions between multi-energy carrier energy hubs and the role and feasibility of cogeneration of heat and power in a Portuguese context. It moves on to analyse the framework for implementing photo voltaic technology and decision processes for implementing PV technology. Lastly, it presents work on the role of renewable energy sources in meeting carbon dioxide emission reduction goals in Iran. Editorial - International Journal of Sustainable Energy Planning and Management Vol 30 Poul Alberg Østergaard* and Rasmus Magni Johannsen Department of Planning, Aalborg University, Rendsburggade 14, 9000 Aalborg, Denmark Keywords Energy hubs; Cogeneration of heat and power; Implementation of photo voltaics; Emission reductions; URL: https://doi.org/10.5278/ijsepm.6506 1. Technology transition In their work on multi hubs in the article Planning of multi-hub energy system by considering competition issue [1], Farshidian et al. investigate the interplay between series of connected multi-carrier energy sys- tems. This is in line with Kienberger’s work published in this journal [2]. In their work, Farshidian and co-authors focus on the methodological development of an assess- ment framework based on Karush–Kuhn–Tucker conditions. Ferreira et al. investigate the prospects of cogenera- tion of heat and power (CHP) in their work Application of a cost-benefit model to evaluate the investment viabil- ity of the small-scale cogeneration systems in the Portuguese context [3]. The authors follow up on an IJSEPM focus area of Iberian energy system transition [4–7] as well as on studies on district heating [8–10] and cogeneration of heat and power [11–13]. In this work, Ferreira et al. analyse different types of CHP in buildings, finding that economic viability requires subsidies for energy-efficient electricity production in the Portuguese context. 2. Systems for implementation Based on a PESTLE (Political, Economic, Social, Technological, Legal, and Environmental factors) frame- work, Schaefer & Siluk assess the potential implementa- tion of PV technology based on network analyses of the players in their article An Algorithm-based Approach to Map the Players’ Network for Photovoltaic Energy Businesses [14]. Among other conclusions, Schaefer & Silluk find that there is a need to establish clear business models representing all technical aspects along with all interrelations between players, and establishing gover- nance of the sector facilitating both coordination and standardization. Miraj & Berawi analyse PV investment decision pro- cesses in their work Multi-Criteria Decision Making for https://doi.org/10.5278/ijsepm.6506 2 International Journal of Sustainable Energy Planning and Management Vol. 30 2021 Editorial - International Journal of Sustainable Energy Planning and Management Vol 30 Photovoltaic Alternatives: A Case Study in Hot Climate Country [15]. Using an Indonesian case-study and fac- toring in a range of criteria from the cost of energy, via CO2 emissions to operation and maintenance established through a respondent survey, the authors continue to investigate optimal decisions. This follows up on previ- ous work published in the IJSEPM on decision-support systems [13,16,17]. 3. Country scenarios Godarzi and Maleki analyse Optimal Electrical Energy Supply to Meet Emissions Pledge Under Paris Climate Accord [18]. Based on a non-linear model of the Iranian energy system, the authors find that Iran can meet its CO2-emission reduction pledge through a 25 USD/t carbon tax, 10–20 % renewable energy and conversion of combined cycle power generation. This follows up on previous studies on Iran [17,19,20] published in the IJSEPM, focusing on photo voltaics/wind power, desali- nation and policy issues as well as other studies investigating strategies to meet Paris Agreement com- mitments [21–23]. 4. Special section Lastly, the this issue contains a contribution from the European Conference on Renewable Energy Systems held in Istanbul, August 2020. In this contribution Karipoğlu and coauthors investigates site selection methods and cases for wind power development in Turkey [24]. References [1] Farshidian B, Rajabi-Ghahnavieh A, Haghi E. Planning of multi-hub energy system by considering competition issue. Int J Sustain Energy Plan Manag 2021;30. http://doi.org/10.5278/ ijsepm.6190 [2] Kienberger T, Traupman A, Sejkora C, Kriechbaum L, Greiml M, Böckl B. Modelling, designing and operation of grid-based multi-energy systems. Int J Sustain Energy Plan Manag 2020;29. http://doi.org/10.5278/ijsepm.3598 [3] Ferreira AC, Teixeira S, Teixeira JCF, Nebra SA. Application of a cost-benefit model to evaluate the investment viability of the small-scale cogeneration systems in the Portuguese context. Int J Sustain Energy Plan Manag 2021;30. http://doi.org/10.5278/ ijsepm.5400 [4] Østergaard PA, Soares I, Ferreira P. Energy efficiency and renewable energy systems in Portugal and Brazil. Int J Sustain Energy Plan Manag 2014;2. http://doi.org/10.5278/ ijsepm.2014.2.1 [5] da Silva RR, Dias MF, Madaleno M. Iberian Electricity Market spot and futures prices: comovement and lead-lag relationship analysis. Int J Sustain Energy Plan Manag 2019;19. http://doi. org/http://dx.doi.org/10.5278/ijsepm.2019.19.6 [6] Figueiredo NC, da Silva PP. The price of wind power generation in Iberia and the merit-order effect. Int J Sustain Energy Plan Manag 2018;15. http://doi.org/10.5278/ijsepm.2018.15.4 [7] Teixeira JCF, Østergaard PA. Development in efficiency, cost, optimization, simulation and environmental impact of energy systems. Int J Sustain Energy Plan Manag 2019;22. http://doi. org/10.5278/ijsepm.3359 [8] Margaritis N, Rakopoulos D, Mylona E, Grammelis P. Introduction of renewable energy sources in the district heating system of Greece. Int J Sustain Energy Plan Manag 2014;4:43– 55. http://doi.org/10.5278/ijsepm.2014.4.5 [9] Zhang J, Lucia L Di. A transition perspective on alternatives to coal in Chinese district heating. Int J Sustain Energy Plan Manag 2015;6:49–69. http://doi.org/10.5278/ijsepm.2015.6.5 [10] Büchele R, Kranzl L, Müller A, Hummel M, Hartner M, Deng Y, et al. Comprehensive Assessment of the Potential for Efficient District Heating and Cooling and for High-Efficient Cogeneration in Austria. Int J Sustain Energy Plan Manag 2016. http://doi.org/10.5278/ijsepm.2016.10.2 [11] Ferreira AC, Nunes ML, Teixeira S, Martins LB. Technical- economic evaluation of a cogeneration technology considering carbon emission savings. Int J Sustain Energy Plan Manag 2014;2:33–46. http://doi.org/10.5278/ijsepm.2014.2.4 [12] Sorknæs P, Lund H, Andersen AN, Ritter P. Small-scale combined heat and power as a balancing reserve for wind – the case of participation in the German secondary control reserve. Int J Sustain Energy Plan Manag 2014;4. http://doi.org/10.5278/ ijsepm.2014.4.4 [13] Zugno M, Morales JM, Madsen H. Decision support tools for electricity retailers, wind power and CHP plants using probabilistic forecasts. Int J Sustain Energy Plan Manag 2015;7:19–36. http://doi.org/10.5278/ijsepm.2015.7.3 [14] Schaefer JL, Siluk JCM. An Algorithm-based Approach to Map the Players’ Network for Photovoltaic Energy Businesses. Int J Sustain Energy Plan Manag 2021;30. http://doi. org/10.5278/ijsepm.5889 [15] Miraj P, Berawi MA. Multi-Criteria Decision Making for Photovoltaic Alternatives: A Case Study in Hot Climate Country. Int J Sustain Energy Plan Manag 2021;30. http://doi. org/10.5278/ijsepm.5897 [16] Brange L, Sernhed K, Thern M. Decision-making process for addressing bottleneck problems in district heating networks. Int J Sustain Energy Plan Manag 2019;20. http://doi.org/10.5278/ ijsepm.2019.20.4 http://doi.org/10.5278/ijsepm.6190 http://doi.org/10.5278/ijsepm.6190 http://doi.org/10.5278/ijsepm.3598 http://doi.org/10.5278/ijsepm.5400 http://doi.org/10.5278/ijsepm.5400 http://doi.org/10.5278/ijsepm.2014.2.1 http://doi.org/10.5278/ijsepm.2014.2.1 http://doi.org/http http://doi.org/http http://dx.doi.org/10.5278/ijsepm.2019.19.6 http://doi.org/10.5278/ijsepm.2018.15.4 http://doi.org/10.5278/ijsepm.3359 http://doi.org/10.5278/ijsepm.3359 http://doi.org/10.5278/ijsepm.2014.4.5 http://doi.org/10.5278/ijsepm.2015.6.5 http://doi.org/10.5278/ijsepm.2016.10.2 http://doi.org/10.5278/ijsepm.2014.4.4 http://doi.org/10.5278/ijsepm.2014.4.4 http://doi.org/10.5278/ijsepm.2015 http://doi.org/10.5278/ijsepm.5889 http://doi.org/10.5278/ijsepm.5889 http://doi.org/10.5278/ijsepm.5897 http://doi.org/10.5278/ijsepm.5897 http://doi.org/10.5278/ijsepm.2019.20.4 http://doi.org/10.5278/ijsepm.2019.20.4 International Journal of Sustainable Energy Planning and Management Vol. 30 2021 3 Poul Alberg Østergaard and Rasmus Magni Johannsen [17] Saleki S. Introducing Multi-Stage Qualification for Micro- Level Decision-Making (MSQMLDM) Method in the Energy Sector – A case study of Photovoltaic and Wind Power in Tehran. Int J Sustain Energy Plan Manag 2018;17. http://doi. org/10.5278/ijsepm.2018.17.6 [18] Godarzi AA, Maleki A. Optimal Electrical Energy Supply to Meet Emissions Pledge Under Paris Climate Accord. Int J Sustain Energy Plan Manag 2021;30. http://doi.org/10.5278/ ijsepm.5896 [19] Caldera U, Bogdanov D, Fasihi M, Aghahosseini A. Securing future water supply for Iran through 100% renewable energy powered desalination. Int J Sustain Energy Plan Manag 2019;23. http://doi.org/10.5278/ijsepm.3305 [20] Godarzi AA, Maleki A. Policy Framework for Iran to Attain 20% Share of Non-Fossil Fuel Power Plants in Iran’s Electricity Supply System by 2030. Int J Sustain Energy Plan Manag 2020;29. http://doi.org/10.5278/ijsepm.5692 [21] Osorio-Aravena JC, Aghahosseini A, Bogdanov D, Caldera U, Muñoz-Cerón E, Breyer C. Transition toward a fully renewable-based energy system in Chile by 2050 across power, heat, transport and desalination sectors. Int J Sustain Energy Plan Manag 2020;25. http://doi.org/10.5278/ijsepm.3385 [22] Singh MK. A planning perspective on Hydropower Development in the Indian Himalayan Region. Int J Sustain Energy Plan Manag 2020;28. http://doi.org/10.5278/ijsepm. 4304 [23] Momodu AS. Energy Use: Electricity System in West Africa and Climate Change Impact. Int J Sustain Energy Plan Manag 2017;14. http://doi.org/10.5278/ijsepm.2017.14.3 [24] Karipoğlu F, Genç MS, Koca K. Determination of the most appropriate site selection of wind power plants based Geographic Information System and Multi-Criteria Decision- Making approach in Develi, Turkey. Int J Sustain Energy Plan Manag 2021;30. http://doi.org/10.5278/ijsepm.6242 http://doi.org/10.5278/ijsepm.2018.17.6 http://doi.org/10.5278/ijsepm.2018.17.6 http://doi.org/10.5278/ijsepm.5896 http://doi.org/10.5278/ijsepm.5896 http://doi.org/10.5278/ijsepm.3305 http://doi.org/10.5278/ijsepm.5692 http://doi.org/10.5278/ijsepm.3385 http://doi.org/10.5278/ijsepm.4304 http://doi.org/10.5278/ijsepm.4304 http://doi.org/10.5278/ijsepm.2017.1.3