Bioenergy updates and prospects for decarbonization in the ASEAN region: A review on logistical concerns and potential solutions

Association of Southeast Asian Economies (ASEAN's) logistical concerns and support for bioenergy production from biomass waste are consolidated to discuss the updates and the areas needing modification/improvement to sustain the increasing trend of bioenergy production and consumption amidst food security and other ecological issues in the region. A systematic narrative review was conducted to address the current information scarcity on bioenergy logistics and discuss methods for moving forward. Regardless, the biofuels supply chain primarily supports biofuels and has numerous logistical concerns, including feedstock, conversion, and generation. The ASEAN Plan of Action for Energy Cooperation has coordinated the ASEAN's present bioenergy development that shows slow yet determined steps. As a result of policies and mandates, bioenergy production has progressed steadily, as well as a continuous improvement of current energy logistics (mostly fossil fuel‐based) to increase biofuel deployment. The current logistics for bioenergy is still lacking and technologically ill‐equipped, with significant inefficiency and sub‐optimality issues. Huge support to re‐engineer and retool bioenergy logistics is necessary to make bioenergy competitive with fossil fuels in ASEAN countries with varying economic and modernization status. Regional cooperation is key in developing an efficient and optimal logistical system for bioenergy in ASEAN, which needs to be supported with intensified R&D, smart solutions, green financing, incentive system, risk management, and policy frameworks. Green logistics is advocated to push forward decarbonizing the future across the ASEAN region with bioenergy.

The predominance of agriculture and forestry in most of the Association of Southeast Asian Economies (ASEAN) member-countries (e.g., Indonesia, Malaysia, Thailand, Philippines, Vietnam, Cambodia, and Laos) makes the ASEAN region a potentially leading source of biomass waste from which a clean bioenergy is produced for world consumption (Erdiwansyah et al., 2019;Lau, 2022).Indonesia and Thailand are already in the world's top 10 countries in bioethanol and biofuel production (OECD/FAO, 2020), which is advantageous in expanding bioenergy deployment and use across the ASEAN.Relative to the Sustainable Development Goal 7 (SDG 7-Affordable and Clean Energy) and other pivotal global guidelines to restore environmental health, bioenergy is quintessential to achieve decarbonization and net zero emission in the future at a faster rate (United Nations Environment Programme [UNEP], 2018; Yusoff et al., 2021).Climate change and extreme weather events have already produced sustained alarming levels of natural disasters and epidemics that have challenged the frontiers of science for effective solutions to get the global conditions back in shape.Recent man-made and natural catastrophes (e.g., floods, drought, and landslides) have shown losses of lives, livelihoods, and properties of seemingly apocalyptic proportions.Vidinopoulos et al. (2020) reported these catastrophes to leave behind irreversible effects and damages.To restore imperatively the environment by keeping global temperature rise below 2 C, controlling greenhouse gas (GHG) emissions, and inducing circular economy strategies, bioenergy must be pursued as an essential energy solution because it is a clean, carbon-neutral, and renewable energy (Sasaki et al., 2021;UNEP, 2018;Yusoff et al., 2021).It had been explored in the past until this time when the need to decarbonize economies and institute net zero emissions to the atmosphere has become more pressing than ever (Handayani et al., 2022;Vidinopoulos et al., 2020;Yusoff et al., 2021).The abundance of the biomass/bioresource in both the land and the sea for energy/power is a clear indication that bioenergy is largely possible for a sustainable future in the ASEAN.To date, the current capability of bioenergy worldwide can substitute 10% of the primary energy produced for world consumption (UNEP, 2018).
Due to bioenergy's characteristics (ecologically clean, biodegradable, carbon-neutral, and renewable) and increasing environmental concerns, bioenergy has increasingly replaced fossil fuels in running machines, infrastructures, industries, and households through gradual increase of blending rates (ASEAN Centre for Energy [ACE], 2022; Yusoff et al., 2021).As an ideal complement to the current greening efforts (Li et al., 2020;Memari et al., 2018;Yusoff et al., 2021), the Conference of the Parties (COP) 26 identified bioenergy as a strategic solution to climate change because of decarbonization primarily via permanent carbon capture and storage as well as replacement of fossil fuels in the foreseeable future (IETA, 2021).The ASEAN region comprised of 10 developing countries in the Pacific is strategically capable to pursue rapid bioenergy development with the abundance of raw/feedstock materials from biomass and the implementation of its bioenergy plans, programs, and policy instruments (ACE, 2015; The Renewable Energy Support Program for ASEAN, 2016).However, recent advances in bioenergy research and production involving the global leaders (e.g., United States, China, Japan, and the European Union (EU)) indicated the ASEAN to be lagging behind.Yet, the ASEAN has kept on catching up by putting in place plans and policies toward the necessary energy transition for net zero emissions in the long run.The ASEAN region can particularly harness the available various sources of bioenergy from traditional and nontraditional biomass in addition to hydropower and geothermal power (ACE, 2015;Diaz-Rainey et al., 2021).In this regional energy initiative, the ASEAN Plan of Action for Energy Cooperation (APAEC) has provided substantial guidance and directions in which the renewable energy sources of hydro-based, geobased, and bio-based types are programmed to be increased in the next few years in aid of decarbonizing industries and societies (Lau, 2022;Pranadi et al., 2018;The Renewable Energy Support Program for ASEAN, 2016).
Indonesia, Malaysia, the Philippines, Thailand, and Vietnam are yet the leading countries in bioenergy development across the ASEAN based on their renewable energy programs and accomplishments (Ying et al., 2020).These countries have aggressive policy instruments to induce progress through the achievement of bioenergy targets, the schemes for awarding incentives and for imposing tariffs, the financing, and the acquisition of permits, licenses, and the required technical support (The Renewable Energy Support Program for ASEAN, 2016).For instance, the ASEAN countries have been working to achieve the renewable energy share of 60% by 2050 (Vidinopoulos et al., 2020), which the Philippines particularly has tried to shorten until 2040 especially the achievement of the targeted increases in bioenergy production and use (DOE, 2018).In the pursuit of bioenergy development across the ASEAN, logistics is a critical aspect to examine (Memari et al., 2018), because the readiness of the logistical resources for bioenergy determines the progress of the bioenergy pursuits across the ASEAN region.Largely, the countries in the ASEAN still have more than 50% in energy share from fossil fuels (Phoumin et al., 2021), which means their full transition to the eco-friendly bioenergy takes considerable time to happen.Thus, the ASEAN countries can yet be laggards in bioenergy development (ACE, 2016).
Logistics as a crucial component in the bioenergy supply chain deals with biomass collection, transportation, storage, and conversion to energy critical in terms of time (leads and lags) and cost/economy.This work examines the logistical support for bioenergy production and distribution from biomass waste in the ASEAN countries.Published sources are reviewed to discuss the logistical issues and opportunities along the bioenergy supply chain wherein through the logistical endowments the biomass waste is converted to bioenergy to be used in the decarbonization process and the ways forward are determined for the strategic bioenergy deployment across the ASEAN region.

| METHOD
Published articles in 2018 to 2022 from the ScienceDirect and the Google Scholar databases were accessed online and downloaded for this work of systematic narrative review.Updated information specifically about the status, concerns, opportunities, and potential solutions regarding bioenergy logistics across the ASEAN region is the reason for the choice of the recent articles within the period specified.The two academic databases were used to ensure extensive search for relevant articles to be included in the review.In the selection of articles, keywords related to bioenergy (from biomass waste) logistics, the countries in the ASEAN region, and bioenergy research in the ASEAN were used.Figure 1 shows the process of selecting the articles following the PRISMA framework of identifying, screening, and finally, including articles for review.Initially, the process yielded 258 articles identified with the keywords used.Upon quick examination, 52 articles were excluded due to eligibility issues (e.g., non-ASEAN and general renewable energy).The remaining articles were further examined for their quality and their relevance to the review topic that is about the bioenergy logistics in the ASEAN region for bioenergy deployment and development.
F I G U R E 1 The process of selecting articles for review.
The examination and screening of articles made use of an inclusion/exclusion criteria that were concerned on: (1) the logistics and/or logistical requirements/resources/support for bioenergy and specific bioenergy products from biomass waste (e.g., biofuels, bioethanol, biodiesel, and biomass) in part or in whole; (2) the ASEAN region's and its member-countries' bioenergy development programs, including production and distribution; (3) the discussion of logistics in part or in whole across the bioenergy supply chain and its chain activities; and (4) the date of publication from 2018 to 2022.Removing the duplicates after screening, the process resulted to the selection of 42 related articles for reference in this review (Figure 1).However, this work also included the reports produced by the UNEP and the ACE.The reports from these agencies have provided essential directions and policy frameworks for the development of bioenergy in the ASEAN.As shown in Figure 1, most of the reviewed articles were published in journals.Only a few were from books, technical reports, discussion papers, and conference papers.Of the journal articles used in this review, most of them were from journals hosted by the Elsevier, followed by Multidisciplinary Digital Publishing Institute (MDPI), Springer, Wiley, BioMed Central (BMC), Taylor & Francis, and Cell Press as academic publishers, which had been indexed in Clarivate Analytics and Scopus (Table 1).

| THE BIOENERGY DEMAND, ISSUES, AND LOGISTICAL IMPLICATIONS
The energy demand across the ASEAN region is generally increasing due to increasing population and modernization and sustained economic growth.It is estimated that energy consumption in the region grows at an annual rate of at least 4% due to these factors (IRENA, 2016 as cited by Nepal et al., 2021;Phoumin et al., 2021).To catch up with the increasing energy demand, the major oil-producing countries in the ASEAN (Indonesia, Malaysia, and Thailand) ramped up the production of energy from both fossil fuels and renewable energy (e.g., hydropower and bioenergy; Nepal et al., 2021).However, the significant proportion of increase is not on bioenergy and other renewable energy sources but on the fossil fuels estimated at around 80% of the 2000 level of energy consumption, despite the bioenergy and renewable energy targets as environmental commitments of the countries in the ASEAN (Nepal et al., 2021).
Renewable energy as a whole has only provided 15% of the energy demand in the region mainly from hydropower and bioenergy, in which the uses are yet limited to heating and transport (Louis, 2020 as cited by Nepal et al., 2021).Renewable energy such as that of bioenergy is yet produced to supplement the available power supply dominated by the fossil fuels.Economic and technological reasons explain the continued dominance of fossil fuels despite the increased targets for bioenergy and other renewable energy as well as the urgency of decarbonization and net zero emissions.Currently, the infrastructure and technological endowments in the ASEAN are yet more suitable to produce energy from fossil fuels than from the renewable energy sources such as biomass, solar and hydro power, making fossil fuels still more preferable to produce than bioenergy and other renewable energy forms.On the demand side, industrial plants, machines, and vehicles are yet not engineered to run fully on bioenergy across the ASEAN.Reportedly, the ASEAN is still challenged with pursuing bioenergy at a cost competitive level, especially that biofuels are more expensive to produce than fossil fuels aside from the huge biomass volume required to produce it (Blair et al., 2021).Coal is much cheaper, more reliable, and more abundant than the renewable counterpart, aside from the fact that some of the ASEAN nations have rich oil reserves for energy production (IEA, 2018 as cited by Ali et al., 2021;Lau, 2022;Li et al., 2020).At the rate bioenergy production is going relative to the fossil fuel production, the ASEAN region is expected to fall short of its target comprising of 70% (bioenergy and renewable energy) of the energy mix, which is needed to fulfill the SDG commitments by 2040 especially on decarbonization and net zero emission targets (Lau et al., 2022;Nepal et al., 2021).Energy transition toward the renewable energy sources is potentially to be weighed down by an energy dilemma in the ASEAN, especially that the economical energy form and energy preference in the ASEAN is yet in favor of the fossil fuels (Lau, 2022;Lau et al., 2022), but for environmental reasons, bioenergy is continually promoted as an imperative option to be taken seriously.With this, fossil fuels will still remain an essential part of the ASEAN's energy mix in the coming years (Lau, 2022;Lau et al., 2022), despite the environmental commitments based on the SDGs.In fact, the member countries of the ASEAN are predicted to increase their demand for fossil fuels even more in the near future due to the pressure of growing population and economies (IEA, 2018 as cited by Ali et al., 2021;Lau, 2022;Li et al., 2020), which is a huge challenge to settle with the increasing pressure to decarbonize as well.Thus, despite the difficult energy dilemma, the energy opportunities are kept open in the ASEAN wherein increasing bioenergy for the future is continued for the necessary climate actions.Apparently, the ASEAN is struggling to address both energy and environmental concerns, but it has opted to remain relentless on bioenergy.Indonesia, a new addition to the G-20 nations, has targeted a much higher increase in blending rates for both biofuels and bioethanol, which are reportedly ambitious across the ASEAN with B30 and E30 blending targets.This means across the ASEAN the increase in bioenergy demand is continually worked out, which is currently unstoppable in coordination with the international community for global climate action to reduce further losses in key economic sectors such as agriculture, fisheries, and forestry in Southeast Asia (Venkatappa et al., 2021).The 2025 outlook of 142 Mtoe of renewable energy utilization shows a significant share for bioenergy for power, heating, and transport purposes, which Pranadi et al. (2018) had reported to be a proof of stressing bioenergy importance in the renewable energy portfolio for the ASEAN.
The forward steps to increase bioenergy production have been identified and laid out in the ASEAN's bioenergy roadmaps, in which volume-based, the priority is set yet on biofuels (bioethanol and biodiesel; Figures 2 and 3).These roadmaps describe the interventions that each country in the ASEAN have to coordinatively pursue from the upstream (generation) to the downstream (deployment) level or across the entire bioenergy supply chain (e.g., from biomass yield improvement to processing facility development to engine modification; Figures 2 and 3).Meanwhile, the projected increase in bioenergy demand in the ASEAN is rather government/policy driven than market driven (Erdiwansyah et al., 2019;Jusoh et al., 2021;Memari et al., 2018Memari et al., , 2021;;Salleh et al., 2020), wherein the targets are set based on the nationally determined contributions (NDCs) of the member countries toward decarbonization and reduction of GHG emissions (ACE, 2022).In these NDCs, Myanmar is the only country that did not declare multiple GHG coverage with carbon dioxide as its only GHG priority to address (ACE, 2022).The countries determined to reduce their GHGs inclusive of carbon dioxide, methane, and nitrous oxide are Brunei Darussalam, Cambodia, Indonesia, and Lao People's Democratic Republic (Lao PDR) (ACE, 2022).The wider GHG coverage in the NDCs is observed in Vietnam with the addition of hydrofluorocarbons, and the Philippines with hydrofluorocarbons and perfluorocarbon (ACE, 2022).
Thailand is the country that has a much wider coverage than Vietnam and Philippines with the inclusion of carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbon, and Sulfur hexafluoride (ACE, 2022).Malaysia and Singapore have the biggest GHG coverage in their NDCs with the addition of nitrogen trifluoride to the GHGs included in Thailand's GHG targets (ACE, 2022).
Since bioenergy is nationally induced in the ASEAN, its progress would continually improve and be monitored based on the environmental commitments/targets of the ASEAN member countries particularly in terms of the fulfillment of decarbonization and net zero emissions in 2050 (ACE, 2022).In addition, in biofuels deployment, Indonesia, Malaysia, the Philippines, Thailand, and Vietnam are the five countries that have been using biodiesel, while the Philippines, Thailand and Vietnam are the three countries that have been consuming bioethanol as of 2020 (ACE, 2022).With the emissions targets pinned on bioenergy, the ASEAN member nations have to ensure the readiness of their logistical resources to attain the necessary energy mix changes.The cost aspect is important to be examined here because the needed energy transition for decarbonization and net zero emission is challenged heavily by the availability of the cheaper non-bioenergy and nonrenewable energy sources at present, aside from the uncertainty of sustainable supply for biomass waste and other bioenergy issues.As an important cost component, logistics needs to be competitive, which means that the transition to clean bioenergy is dependent on the ease of adjusting the current energy logistics for bioenergy production and deployment.The ease of doing it at present is hampered by the diversity of the bioenergy sources, which apparently demands distinctive ways and materials for handling.Cost-saving bioenergy logistics is considered an important target to attain in order to hasten the uptake of bioenergy by industries and households (Malladi & Sowlati, 2018).It can be achieved by not only keeping logistics establishment costs down (especially for location-based logistics) but by designing the logistics with wide-ranging versatility in terms of use and in locating them close to the center of bioenergy supply chain operations.This aspect particularly needs tools for examination and simulation exercises, where geographic information system (GIS), digital twins, internet of things (IoT), and network analysis, among others, can be used to project the potential operational efficiency of the logistical networks for bioenergy (Malladi & Sowlati, 2018).To date, power plant installations for bioelectricity, energy connectivity/cooperation improvement through multilateral power trade schemes (e.g., Lao PDR-Singapore and Lao PDR-Malaysia power trades), power integration projects (e.g., Lao PDR-Thailand-Malaysia-Singapore Power Integration Project), and strategic financing for bio-based and renewable energy are ramped up for the eventual energy transition (ACE, 2022).

| THE LOGISTICAL CONCERNS IN BIOENERGY DEVELOPMENT ACROSS THE ASEAN
In the developing countries across the ASEAN, food security is an outright priority, which puts bioenergy in critical but debatable importance.The land and the raw material requirements for bioenergy are also necessary for food and fiber production (Jusoh et al., 2021;Panoutsou & Singh, 2020).Therefore, all of them (food, fiber, and bioenergy) compete over more or less the same land, water, land-based logistics, and material inputs for their respective production processes (Erdiwansyah et al., 2019;Lau, 2022).To minimize the competition of these equally important commodities for sustainable development, the biomass waste is highly advocated for bioenergy, which is obtained from agricultural and forestry sources.The availability of which follows the usual production cycle or cropping seasons that vary according to crops and tree species.Seasonality is high in biomass production for energy because of production timing and/or time lags in agricultural and timber production (Jusoh et al., 2021;Ying et al., 2020).The forest-based biomass can be comprised of left-overs from timber harvesting and processing that have longer production cycles than that of agriculture (Malladi & Sowlati, 2018).While big plantations provide most of the biomass for energy across Indonesia, Malaysia and Thailand, farms are the major biomass source for Cambodia, Lao PDR, the Philippines, Myanmar, and Vietnam (Jusoh et al., 2021).The expanded four generations or categories of raw materials and biomass waste/by-products for bioenergy is a strategy to avoid compromises with the equally essential food and fiber products.Particularly, the second (crop residues) and the third (algae) generations/categories of bioenergy raw materials are promoted to resolve the competition issue among food, fiber and bioenergy in resource use (Agustina et al., 2018;Erdiwansyah et al., 2019;Lau, 2022;Yadav et al., 2022).These generations/categories of raw materials exhibit potential value addition and smart use of biomass wastes/by-products (Yadav et al., 2022).For the biomass waste, the added value is formed by the reusability of the biomass that is normally left to rot in the field after harvest operations.When used as feedstocks, biomass waste is valorized to produce bioenergy without compromising the food and fiber industry, forest conservation, air and soil quality, and environmental commitments (Du et al., 2016;Yadav et al., 2022).
Meanwhile, the different characteristics between the major sources of biomass waste among the ASEAN member nations like plantations for the relatively richer developing nations (Indonesia, Malaysia, and Thailand) vis-à-vis farms among the poorer nations (Cambodia, Lao PDR, the Philippines, Myanmar, and Vietnam) implies an underlying efficiency gaps and development constraints in logistical operations particularly in the collection of biomass waste for feedstock and raw materials for bioenergy (biofuels and bioethanol).Apparently, the plantations have more organized and concentrated operations than scattered farms especially in the consolidation and transport of biomass waste.The seasonal availability and the diversity of the biomass waste as well as the scattered farm locations in the poorer nations in the ASEAN complicate the development of the logistical support through efficiency and cost issues.Differences in levels of bioenergy logistics development are reflected on the slow deployment of bioenergy across the ASEAN nations as the bioenergy advancements in the richer ASEAN nations are weighed down by the slow action of the poorer ASEAN nations on bioenergy development despite the urgency with climate change vulnerability.Other issues have also complicated the transition process to bioenergy.Erdiwansyah et al. (2019) had pointed out the negative impacts of bioenergy on biodiversity, farm output use, and atmospheric emissions, besides the income-disparity-based issue on energy where low-income families can hardly do away from the use of traditional energy from fuelwood.Vidinopoulos et al. (2020) had expressed similar ecological concerns over bioenergy production due to the potential of losing forest ecosystems, soil quality, and air quality due to emissions from burning biomass waste.Bioenergy is faced with a potential sustainability problem, especially that the current energy systems in the ASEAN are yet not fully modified according to the requirements of bioenergy systems, resulting to intermittency and unreliability of bioenergy supply due to unstable production (Vidinopoulos et al., 2020;Ying et al., 2020).In comparison to Europe, United States, Japan, and other advanced nations where hydrogen is continually explored for bioenergy, the ASEAN is yet focused on increasing biofuels (bioethanol and biodiesel) production to utilize most of its existing energy logistics and to save resources for the transition to clean energy form.
Also, the sources of bioenergy raw materials across the ASEAN show the diversity of crop-and forest-based organic materials utilized for energy production.Table 2 shows these specific sources of bioenergy raw materials obtained from the farms and the plantations of the member nations, except for the relatively advanced level of Singapore that harnesses already microbial resources for energy.Agricultural and wood residues are the most common sources, in which for agriculture, the residues for energy are commonly obtained from sugarcane, oil palm, cassava, rice, and coconut.The diversity of agricultural crops is advantageous for reducing the build-up of agri-waste and extending the use of the agricultural residues in the fields, but it can pose a potential issue in the efficient operation of the current bioenergy logistics.Some of the biomass materials can be consolidated, transported, and processed together, while some others apparently cannot be mixed together (e.g., woody and dense materials vs. moist materials).This runs the risk of applying less proven and costly technologies, which can slow down bioenergy uptake in the future (Vidinopoulos et al., 2020).Technologies that can modernize logistics is critical because such can ensure cost-effective and competitive levels of operation for economies of scale (Khan et al., 2022).An efficient logistics system for the reutilization of biomass waste/by-products is a useful incentive in the advocacy of clean energy for the restoration of the environment in the ASEAN.
Research reports about the bioenergy logistics in the ASEAN are scarce, in which the logistical facilities can be grouped into feedstock, conversion and distribution logistics to perform the essential functions of collection, storage, transportation, and pretreatment of biomass waste across the bioenergy supply chain.Figure 4 illustrates the critical phases and logistics of bioenergy across the ASEAN's bioenergy supply chain, which shows the requirements from source point (raw material) up to the deployment of bioenergy based on the works of Yatim et al. (2018) and Harahap et al. (2020).The feedstock logistics entails the acquisition phase of the biomass waste from plantations and farms to ensure the regular and adequate supply of raw materials for feedstock.Feedstock logistics is responsible for the activities occurring before biorefinery and power plant operations, which include collection, storage, pretreatment, and transport of biomass waste volume to the biorefinery (Yatim et al., 2018).Strategically located spaces, storage facilities, and road network infrastructure are key to an incentivizing feedstock logistical operation.The conversion and generation logistics ensures the technical conversion of the biomass waste into the various forms of bioenergy.In the case of the ASEAN, the major forms of bioenergy include the biofuels (bioethanol and biodiesel), biogas, and bioelectricity.The distribution logistics is comprised of resources, spaces, and infrastructure for the efficient distribution of the generated bioenergy to the various consuming units (e.g., households, institutions, and industries).Energy storage, pipeline F I G U R E 4 The bioenergy logistical system (modified from Harahap et al., 2020;Yatim et al., 2018).
systems, shipping and trucking facilities, power grids, and road networks are essential for the efficiency of bioenergy distribution.Optimizing and converting the current energy logistics (mostly used for fossil fuels) and identifying the logistical improvements for bioenergy in the ASEAN can be examined through these core logistical requirements (feedstock, conversion and generation, and distribution logistics) as influenced by the biomass waste materials.Across the bioenergy logistics system in the ASEAN, there are several issues and concerns that need to be resolved for a smooth transition to bioenergy in the future.Table 3 shows them to be distributed across the major logistical groupings, while some others are identified with the general logistical system for bioenergy.These concerns and issues are the reasons for the inefficient and uncompetitive bioenergy, and imply the huge requirement for financial, technical, and infrastructural investments to enable the ASEAN to make a significant turnaround in the bioenergy transition process.The problems reverberate the need to ensure adequate and stable supply of raw materials through a definite land allocation, the need to establish the infrastructure and the upgrades to the current logistics through efficient technologies, and the need to have reliable quality of bioenergy.Based on the identified concerns and issues in Table 3, bioenergy cannot yet compete with the fossil fuels because of inefficiency across the current energy logistics aside from the seasonality and unreliability of biomass supply and the traditional logistical systems.The current logistical system particularly the conversion logistics has problems of fitting it to the processing requirements for bioenergy.Thus, the competitive advantage of the fossil fuels persists unless the said issues and concerns are addressed over a short run period.

| POTENTIAL OPPORTUNITIES AND SOLUTIONS TO BIOENERGY DEVELOPMENT'S LOGISTICAL CONCERNS IN THE ASEAN REGION
The present bioenergy supply chains need to be re-examined for optimal design revision to be competitive with fossil fuels and to expedite the needed energy transition in the next few years.Comprehensive innovations are extremely necessary particularly in the upgrading and strengthening of the current bioenergy logistics to significantly increase the share of renewable bioenergy in the current forms of energy consumed (Phoumin et al., 2021).Interconnectivity of bioenergy and fossil fuel energy systems across the ASEAN is highly necessary to aid in the transition process for bioenergy.However, with the disparity between or among the member nations in terms of economic and modernization status, bioenergy transition is likely to proceed slowly especially with the dilemma of most countries in the ASEAN regarding the national priorities on food security and clean energy stability as well as the complex and costly modification of the current energy facilities and logistics for bioenergy from biomass waste.The bioenergy supply chains need to have the logistical systems capable to meet the requirements for stable operations with efficiency, cost-effectiveness, inclusivity, sustainability, interconnectedness, seamless system integration, and capability for uncertainty management.It can be achieved by overcoming the current bottlenecks, concerns and setbacks in bioenergy logistics and supply chains (Phoumin et al., 2021).Regional cooperation in the ASEAN is the key strategic approach to do this in which the member nations have to work together in determining their roles based on their strengths and opportunities in the proliferation of bioenergy and in determining the strategic bioenergy actions (e.g., pooling and sharing of technologies and resources, establishing efficient market networks, and updating energy policies) so that the ASEAN can altogether move for a seamless integration of bioenergy in the future.
In terms of inclusivity, bioenergy can potentially foster a game-changing inclusion of the farming or agriculture sector (especially the smallholder farmers) due to the opportunities of having an expanded range of marketable farm outputs including the biomass waste as well as supply chains (Phoumin et al., 2021).This outcome produces economic repercussions, which the ASEAN nations have to also prepare especially for the soaring food prices due to the crops converted to energy use.However, across the ASEAN, the following strategies can be explored across the bioenergy supply chain through regional cooperation/collaboration efforts:

• Smart bioenergy logistics
Well-coordinated actions across the bioenergy supply chain need fast-paced innovations and well-timed processes.The use of the second-generation crop residues as raw materials of bioenergy is already a smart move to ensure food and fiber sustainability for human and industry consumption in the wake of increasing bioenergy production and consumption.This particularly harmonizes the sustainability agenda considering that food and fiber are not compromised even if the bioenergy advocacy is intensified.In developing smart bioenergy systems, computer and internet/web systems and infrastructures are necessary especially with the innovations on artificial intelligence, IoT, machine learning, block chain technology (Loy et al., 2022), digital twin for virtual optimization analysis (Huynh & T A B L E 3 The issues and concerns in the current bioenergy logistics in the ASEAN.Zondervan, 2022), and other smart technologies.These are examples of innovations to be integrated into the current bioenergy production and distribution systems to be efficient and cost-effective.These can establish the efficiency with traceability and accountability across the bioenergy supply chain and help ensure the quality of bioenergy to be used for various purposes.Computer-based and internet-/web-based facilities are extremely useful globally to come up with smart and secure troubleshooting and decisions for efficient operation.

• Intensifying R&D for bioenergy systems
Bioenergy in the ASEAN is yet a work in progress.The challenges listed in Table 3 imply that so much needs to be done for the ASEAN to sustain the current bioenergy efforts and catch up with the advanced nations in terms of accomplishments.These challenges are also the ones that can slow down the progress toward the proliferation of bioenergy and the needed energy transition for decarbonization and net zero emission.However, the same challenges have the opportunities for R&D, which the ASEAN member nations can consider in their coordination and collaboration efforts.The long list of challenges in Table 3 shows the areas where R&D is substantially needed, wherein examining efficiency is relatively in demand across the bioenergy supply chain.R&D is also important in the interconnectivity of the current energy logistics with that of the bioenergy, so that the ways to make the energy transition economical/cost-effective can be determined.Some of the current energy infrastructures can be used for bioenergy especially for biofuels (bioethanol and biodiesel), while some others need to be modified to fit with the bioenergy system requirements to handle the various types of biomass waste (e.g., woody, and moist materials).R&D and simulations can also help in determining the potential benefits against potential costs for bioenergy infrastructure and logistical investment purposes, for impacts of bioenergy to other sectors, and for the futureproofing of bioenergy in the ASEAN.Research on the alternative sources for bioenergy remains important to resolve the food and fiber versus bioenergy issue.Currently, research on bioenergy in the ASEAN shows substantial interest on optimization.These are demonstrated by the optimization studies of Harahap et al. (2020) for the technical configuration of biorefineries, Lim et al. (2019) on optimal bioenergy supply chain operation by addressing biomass supply issues, Ling et al. (2019) on bioelectricity supply chain, and Akbarian et al. (2022) on gasification of lignocellulosic biomass for circular bioeconomy.In anticipation of potential setbacks, bottlenecks, barriers, and challenges, research is used to prepare for the scenarios and eventualities that may slow down the progress of bioenergy from biomass waste and the transition process toward clean and renewable energy.Research efforts has looked at the bioenergy logistical issues as well for improvement in the bioenergy supply chain.Works on this matter include that of Jusakulvijit et al. (2022) on Thai's bioethanol production system, of Yatim et al. (2018) on feedstock logistics in palm oil biomass industry, and of Ubando et al. (2020) on the review about biorefineries.Intensifying R&D for bioenergy will expedite the advocacy and transition process for clean energy in the ASEAN.• Pursuing green financing and risk management for bioenergy's logistics Logistical improvement for bioenergy development needs to be pursued with adequate funding support and incentive program (Shrestha, 2021).This is to attract interests to invest and fast track bioenergy projects for upscaling, Costly transportation systems Memari et al. (2018) commercialization, and mainstreaming.With the bioenergy system in the ASEAN at the fledgling stage, there are numerous aspects to explore that need funding support especially from venture capitalists to further bioenergy exploration and commercialization.Business models for bioenergy are among the potential areas to experiment to chart the logistical implications and opportunities for optimal bioenergy system operations and competitiveness.Bioenergy pursuits may slow down without adequate funding, incentives, and risk protection, which can contribute to delays in bioenergy mainstreaming and energy integration.Phoumin et al. (2018) reiterated that the potential bottleneck of renewable energy projects is about the low investment level.This low investment level can also explain the slow transition to clean energy across the ASEAN.Phoumin et al. (2018) noted the high upfront capital requirement and slow investment returns among the clean renewable energy projects as a downturn.High investment and slow recouping of invested capital are a disincentive and disservice to venture capitalists and investors.Thus, for bioenergy logistical projects to carry on meeting the needs for an efficient, cost-effective, and competitive bioenergy system, adequate funding support and risk management programs have to be accessible to provide reasonable incentives and to protect the major lines of support for bioenergy development in the ASEAN (Zhai et al., 2021).Social innovations and enterprises are potential solutions to explore for bioenergy's logistical development.Its application in the renewable energy sector has been discussed in the work of Lizarralde et al. (2021) particularly, where the driving factors were determined to gain insights on the possible areas to manage for an effective transition to clean energy regime.Crowdfunding is another avenue in which funding for such eco-friendly energy solution is socially sponsored.The study of Kropelnytska and Mayorova (2021) had explored on the potential of crowdfunding for financing green and renewable energy projects in Ukraine, which is a potential financial platform for renewable energy development in the ASEAN.• Providing strong policy frameworks and support for bioenergy development The current progress of bioenergy in the ASEAN is a result of a committed political action that is translated into policies supporting the development of bioenergy across the region.Mandated increases in production and blending have paved the way to the expansion of raw material sources for the production and integration of bioenergy in the current energy systems and supply chains.Strong policy frameworks have made possible the determined albeit slow progress toward changing the energy landscape to decarbonize the future.For the logistical system to catch up with the requirements of an efficient bioenergy system, policy frameworks are still the aspects to turn to (Sandu et al., 2019) so that the desired logistical support capable to achieve the bioenergy targets in the ASEAN will be accessed and established.These policies will provide guides in pursuing regional cooperation to set plans and achieve the level of logistical development for the bioenergy pursuits in the ASEAN.These policies will significantly provide directions for the future of bioenergy and drive the technological innovations related to its comprehensive planning and sustainable development (Salleh et al., 2020;Yusoff et al., 2021).

• Ramping up green logistics for bioenergy development
The use of biomass waste in the production of clean energy is already a notable example in integrating green technologies in bioenergy production and logistical performance.Such particularly minimizes the release of harmful gases into the atmosphere, which can potentially increase global warming.Another perspective that set upon the biomass waste is its potential for a value-adding product of (bio) hydrogen power called green hydrogen that is likewise renewable, eco-friendly, and innovative form of bioenergy.Providing logistics that can potentially further the value of biomass waste and enhance its environmental performance put emphasis on the imperative of transitioning to bioenergy and/or renewable energy.Decarbonizing the future is sustainable with greening the bioenergy logistics that further elevates the environmental performance and secure the value addition to the reprocessing of biomass waste.

| CONCLUSION
The imperative to transition to a decarbonized future through clean and renewable energy use is inevitable.The ASEAN has made small but determined steps toward it through policy support and strong political will to take part and keep up.Bioenergy development is pushed for this matter because of the abundance of biomass sources from agriculture and forestry and the need to strengthen climate actions through decarbonization and net zero emission in the long run.It is apparent that ASEAN's approach to bioenergy development is focused on strengthening its capability to produce biofuels.However, there are accompanying issues to confront while strengthening bioenergy and the consequent transition to a clean energy source.The member nations in the ASEAN are not in equal footing in terms of economic performance and modernization status.The leading countries in the ASEAN such as Singapore, Malaysia, Indonesia, Thailand, and Vietnam have been developing and upscaling bioenergy, while the rest of the countries have issues to resolve with bioenergy production.The countries where food security is prioritized have an issue to balance with bioenergy/renewable energy because of the similar crops and inputs used in the production of both food and bioenergy.
The second-generation/category of biomass sources as raw materials of bioenergy is an eco-friendly innovation that promotes the extended uses of biomass waste materials.Even with the alternative sources of biomass for bioenergy through the later generations of biomass sources, there is a need to ensure the competitiveness of bioenergy production vis-à-vis fossil fuel production.The transition is yet slow to cleaner energy sources due to the cheap coal and fossil fuels, especially that the current logistics is built based on these energy types.The ASEAN region even the leading countries in it have dilemmatic energy situation because of the less cost-effective ways of producing bioenergy compared to the fossil fuels.The ASEAN has still much to work on making bioenergy and other clean energy sources really competitive to fast-track the needed energy transition.Particularly, research on bioenergy particularly on its logistics is scarce, because bioenergy in the ASEAN is yet young and developing.The bioenergy supply chain and its logistical system, although making progress, needs to be fully established for a significant bioenergy deployment.
The institutional platform of regional cooperation called APAEC is motivational and instrumental for the furtherance of renewable energy initiatives among the ASEAN member countries.Through APAEC, regional cooperation is coordinated through core planning actions for the future plans and roadmaps of bioenergy production and deployment over the next few years, which have already been made clear and worked on by the member-countries.The ASEAN member countries have to attain their bioenergy targets as set in their individual plans and to settle with their role as net producers or net consumers of bioenergy based on the member nations' varied economic status.Based on the member-countries' status, some of them can proceed to making significant progress in bioenergy, while some others cannot due to cost and technology issues.This disparity can leave some of the member countries net producer and net consumer of bioenergy in the near future, which needs to be examined under regional cooperation.The massive adjustments in the current energy logistics for bioenergy may depend on the aspects of regional cooperation such as that of being a net producer or a net consumer of bioenergy.Member countries can potentially make significant progress on their bioenergy targets based on this.Logistically, there are numerous areas and aspects across the bioenergy supply chain, which needs re-examination, reengineering, and retooling to match with the desired level of performance of the bioenergy supply chain.The thrust of the ASEAN to focus yet on biofuels allows the maximized use of the current energy logistics that currently cater to the production of fossil fuels.However, in the gradual establishment of logistics for bioenergy, even in the conversion of the current logistics for the same reason, R&D needs to be ramped up through a handholding approach or partnerships (richer + poorer nations) between or among the member countries to make significant progress in addressing the logistical issues and concerns, especially with regional cooperation, commitment to bioenergy policies and targets, and sharing of technological innovations and investments.Logistics that is efficient/ optimal, cost-effective, capable to manage uncertainty, and integrable to the coexisting energy systems and facilities is ideal for the bioenergy to take off as a major energy source in the future.The reengineering and retooling process has to consider those qualities in the application of web-based and computer-aided solutions that can function the bioenergy system with smart interfaces.Such solutions have been linked to advanced/bio manufacturing that allows virtual optimization based on ecological guidelines and SDGs.Therefore, the ASEAN through APAEC has to intensify R&D, green financing, incentive, and risk management programs to keep the increasing production and consumption of bioenergy going particularly.

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I G U R E 2 The R&D roadmap for bioethanol in the ASEAN.Source: ACE (2022).

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I G U R E 3 The R&D roadmap for biodiesel in the ASEAN.Source: ACE (2022).
cost-effective technologiesLi et al. (2020),Vidinopoulos et al. (2020) Land used for biofuel could be repurposed for other renewable energy sources that have higher energy conversion capacities Vidinopoulos et al. (2020) Land acquisition and social conflicts Widayati et al. (2022) Lack of institutional capability Vidinopoulos et al. (2020) Lack of experience among the engineering service companies Widayati et al. (2022) High financial and technical risks Widayati et al. (2022) Lack of familiarity with energy efficiency projects Widayati et al. (2022) Political situations Widayati et al. (2022) Need of upgrading and integrating the energy systems Phoumin et al. (2021) Need of more investments in grids, the internet of things, technological know-how, and quality energy infrastructure Erdiwansyah et al. (2019), Phoumin et al. raw material supply Lim et al. (2019), Ying et al. (2020), Akbarian et al. (2022) Insufficient biomass for feedstock Lim et al. (2019), Ying et al. (2020), Rashidi et al. (2022) Raw material supply issues/uncertainties Junginger et al. (2020), Lo et al. (2021), Akbarian et al. (2022), Widayati et al. (2022) Existing technologies have biomass feed lower in process efficiency compared to coal Lim et al. (2019) Required several tank lorries and trips of lorries Rashidi et al. (2022) Costly procurement systems Memari et al. (2018) Lack of reliable collection, storage, transport and pre-processing technologies, facilities, and infrastructure Yatim et al. (2018), Ubando et al. (2020), Jusakulvijit et al. (dependent on biomass type and quantity as well as environmental and financial standards) Agustina et al. (2018) Lack of scientific and technical local expertise (technology design and construction, and biomass power plant operation and maintenance) .(2022), Lim et al. (2019) Lack of access to biodiesel production chains for small-scale producers Widayati et al. (2022) Lack of infrastructure readiness for blending Widayati et al. (2022) Lack of production infrastructure and feedstock for ethanol blending Harahap et al. (2020) Slow installation of biogas plants (Malaysia) Rashidi et al. (2022) Suboptimal biorefinery processes Akbarian et al. (2022), Ubando et al.
Journals included in the review.
Note: Figures in parentheses are % share of the publishers in the number of journal articles reviewed.a Includes the Journal of Environmental Treatment Techniques and the Journal of Advanced Engineering and Computation.
Bioenergy sources across the ASEAN.