**1. Introduction**

The world has been struggling with the coronavirus disease (COVID-19) pandemic since March 2020, which has damaged the world economy—including the Association of Southeast Asian Nations (ASEAN). The global economy is being pushed into a recession by the COVID-19 pandemic due to preventive and containment measures such as country lockdowns, travel restrictions, and slow or even negative growth in many sectors such as tourism, retail, and industry. The magnitude of the economic impacts is hard to predict as it depends on the success of the pandemic containment efforts around the world. The International Monetary Fund (IMF) projected the world economy and the ASEAN 5 (Indonesia, Malaysia, the Philippines, Singapore, and Thailand) to contract sharply by −4.9% and −2.5% respectively in 2020, much worse than during the 2008–2009 financial crisis (IMF, 2020) [1]. Such an economic downturn is contracting energy demand and energy-related carbon dioxide (CO2) emissions around the globe, but this crisis is seen as temporary and both energy demand and CO2 emissions will bounce back once the economy starts to recover. Global energy demand increased 10 times from 1999 to 2019, and keeps increasing (IEA, 2017) [2]. The gravity of energy demand has shifted to Asia, and emerging economies account for half of global growth in gas demand. Many of the Organisation for Economic Co-operation and Development (OECD) countries will see energy demand peak, while some countries will experience negative growth due to energy

**Citation:** Phoumin, H.; Kimura, F.; Arima, J. ASEAN's Energy Transition towards Cleaner Energy System: Energy Modelling Scenarios and Policy Implications. *Sustainability* **2021**, *13*, 2819. https://doi.org/ 10.3390/su13052819

Academic Editor: George Xydis

Received: 28 January 2021 Accepted: 1 March 2021 Published: 5 March 2021

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**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

efficiency and other factors such as population growth and industrial structures. However, ASEAN will be the opposite, as it will need more energy to steer its economic growth [3].

To reconfirm the present situation of ASEAN's high reliance on fossil fuel, this study also estimates the energy demand and supply in ASEAN. It found that ASEAN will see strong growth in fossil fuel demand to steer economic growth from 2017 (The energy modelling uses 2017 for the baseline information as it is the most up-to-date baseline data in the ASEAN Member States (AMS)) to 2050 in which fossil fuels (oil, coal, and gas) had the dominant share in the primary energy mix in 2017, at 78.0%, while their combined share is projected to increase to 81.7% in 2050 (Tables A1–A8). Oil will be the largest energy source in the primary energy mix in 2050, at 39.6%, down from 36.9% in 2017. Coal was the second largest energy source after oil in 2017, at 21.6%, and is projected to have a 22.4% share in 2050. Natural gas is projected to have the second largest share of the primary energy mix in 2050, at 24.7%, overtaking coal. Thus, this is a real concern as to whether ASEAN's energy transition will be achieved or not within the context of Climate Change timeframe in which the net zero emission should start from the mid of this century?

Elsewhere, especially the OECD, moves away from fossil fuel dependence to a system based on cleaner energy through a higher share of renewables, but ASEAN will continue to rely on the fossil fuel, and it tries to find ways on how to use fossil fuels more cleanly in an energy transition. For instance, coal use has been drastically reduced in the OECD and more developed countries due to the role of gas, renewables, and advanced technologies. However, as the most abundant and reliable energy resource in ASEAN, coal use will continue to be the second largest energy source in power generation after gas in the foreseeable future, to meet fast-growing electricity demand [4]. The increase in coal use for power generation in ASEAN countries will lead to the widespread construction of coal-fired power plants, which will result in increased greenhouse gas (GHG) and CO2 emissions if the best available clean coal technology (CCT) is not employed (Phoumin, 2015) [5].

Meanwhile, the climate narrative which has prevailed since the Conference of the Parties (COP) 21 in 2015 and is likely to continue at the upcoming COP 26, promotes the banning of public coal financing throughout the world, through financial instruments and influence over multilateral development banks and OECD member countries. Based on the Greenhouse Gas Emissions Data (United States Environmental Protection Agency, 2020) [6], emissions from fossil fuel combustion and industrial processes contributed about 78% of the increase in GHG emissions from 1970 to 2011. China, the United States (US), Europe, and India are the largest emitters, contributing 30%, 15%, 9%, and 6% of global GHG emissions, respectively [6]. With substantial new generation capacity required to generate power, unabated coal-fired power generation plants are increasingly being constructed in developing Asia. Therefore, these trends reflect the urgent need to address the environmental sustainability of powering emerging Asia's economic development.

The Economic Research Institute for ASEAN and East Asia (ERIA) held a round discussion on "ASEAN's Future Energy Landscape" on 10 September 2020 [7], whose leaders in ASEAN expressed that managing the energy transition in ASEAN will need to consider the presence of fossil fuels (coal, oil, and natural gas) in the short- and medium-term energy system. At that round table discussion [7], ASEAN's leaders and experts expressed that it will be crucial to explore ways in which to use fossil fuels in an environmentally sustainable manner to act as a bridge to a carbon-free energy future, rather than simply ruling out them completely. For successful implementation of the energy transition and climate change policy objectives, policymakers also indicated the need to balance the other equally important policy objectives of energy security, energy access, and affordability.

For climate friendly, ASEAN's position to shift towards a cleaner energy system will have fundamental impacts on environmental sustainability and emission reduction. The evidence has been shown elsewhere in New York's power generation mix in which the drastic reduction of emissions came from the shift of fossil fuel dependence to increasing share of onshore and offshore wind power (Isik, M.; Kaplan, P.O., 2021) [8]. Here at ASEAN, the

pace at which ASEAN Member States (AMS) have adopted national power development plans and policies has created a drastic change in the energy system, as more renewables have penetrated the electrical grid. For instance, the recent development of accelerating pace of share of solar in power mix in Cambodia and Vietnam is achievably remarkable surprises for ASEAN [9]. However, one of the greatest challenges in all countries in ASEAN of increasing the share of variable renewable energy (e.g., wind and solar) in the power mix is the high cost of upgrading and integrating the systems that need more investment in grids, the internet of things, technological know-how, and quality energy infrastructure [10]. In a recent virtual conference on Asia—Carbon Capture, Utilization, and Storage (CCUS)—organised by ERIA on 18 February 2021 [11], experts in Asia generally expressed that ASEAN would need to create an energy bridging from the current fossil based energy system to a cleaner energy system that will need to consider the role of cleaner use of fossil fuels through innovative technologies such as clean coal technologies and CCUS, the technology that can remove carbon dioxide from flue gas and atmosphere, followed by recycling carbon dioxide for utilization and further determining safe and permanent storage options. In this way, the CCUS can reduce CO2 and GHG emissions. Therefore, urgent steps need to be taken to decarbonise the energy sector through pathways to a low-carbon economy which require the rapid deployment of the clean use of fossil fuel technologies, renewable energy development, and a doubling of energy efficiency, given that the energy sector accounts for two-thirds of global GHG emissions.

As ASEAN as well as developing countries around the world are embarking on energy transition, it is very crucial to ensure everyone is not left behind or become victims of the energy transition as they may be denied access to energy. In this regard, McCauley, D., and Heffron, R. (2018) [12], called on researchers to explore the multiple implications of the transition to a post-carbon society through the application of their proposed new triumvirate of tenets (distributional, procedural, and restorative), as this just transition framework enables researchers to more explicitly reflect upon the intersectionality of environment, climate, and energy, assess justice issues from a truly interdisciplinary perspective and ultimately contribute to meaningful long-term solutions. Details of Energy Justice Metric has been developed to facilitate the decision-makings to formulate energy policy with respect to the difficulties faced in balancing between the competing aims of economics, politics and the environment which form the trilemma of energy policy (Heffron, R, et.al., 2015) [13].

Thus, the paramount of climate change awareness and policy towards energy security and affordability will need to be flexible in the context of ASEAN, considering the role of fossil fuels in an energy transition. In the minds of ASEAN's leaders as expressed through various conferences as mentioned above, meeting the growing energy demand would need appropriate energy policies and cooperation that can help facilitating energy-related infrastructure investments. These common energy challenges need to be addressed through concerted efforts—including collective measures and actions—to rapidly deploy energy efficiency and energy savings, highly efficient and low-emissions coal-fired power plant technology, and nuclear safety; and to double the share of renewable energy in the overall energy mix for inclusive and sustainable development.

This study aims to analyses the potential impacts of proposed additional energysaving goals, action plans, and policies in ASEAN on energy consumption, by fuel, sector, and greenhouse gas (GHG) emissions as to whether under various policy commitment and targets will ASEAN be able to achieve climate neutrality by 2050? In addition, the study results will support ASEAN's energy policy directions to achieve the followings:


Therefore, this study will explore the best energy mix under various Alternative Policy Scenarios (APSs) and the associated emissions. Under the APSs, key considerations are realistic assumptions in terms of technologies, resource endowment, energy efficiency, and system integration challenges, when the power generation mix has a higher share of intermittent renewables such as wind and solar energy. The study employs the energy outlook by each country and ASEAN under the ERIA's Energy Outlook and Energy Potentials in ASEAN and East Asia. However, for the purpose of ASEAN's scope of study, only aggregated ASEAN' data is shown. The paper is organized as follows. Section 2 reviews the literature, Section 3 discusses the research methodology, Section 4 describes the results and discussion, and Section 5 is the conclusion and policy implications.
