Low-carbon emission development in Asia: energy sector, waste management and environmental management system
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Mitigation of greenhouse gases (GHG) emissions is desirable without compromising the economic growth. This paper reviews the recent trends to mitigate GHG emissions in the key sectors of energy and solid waste. The energy sector is the key admitter for global GHG emissions, and a range of optimisation and modelling tool has been developed to minimise the GHG emissions and overall cost, especially for the implementation of renewable energies such as biofuel and biogas. A few carbon sequestration technologies such as the carbon capture and storage (CCS) and biochar application have been reviewed. The review included the challenges and knowledge gaps regarding the utilisation of CCS, such as the storage capacity, long-term policy framework, high costs and the potential risk. Although solid waste contributes about < 5% of the global GHG emissions, effective solid waste management remained a great challenge in many fast-growing cities in Asia. Considering the high organic portion (> 40%) in the municipal solid waste for many developing countries in Asia, composting has been proposed as a viable treatment technology to convert waste-to-wealth. A range of waste management tools, including scenario analyses on different waste technologies, optimisation of waste collection routes, multi-criteria decision tools, is reviewed to support the decision-making for solid waste management. A range of environmental management system (EMS) has been adopted by organisations to improve product quality, reducing production cost and improves reputation of firms. An environmental policy such as tax exemption could be helpful to promote the adoption of EMS that could be costly. CO2 and material flow footprint tools, such as water–energy–materials nexus, are applicable at a city and regional level. The tools are used to mitigate GHG emissions by developing the mechanisms with shared markets of virtual resource flows (carbon, water, food, energy) between the trading partners regionally and internationally.
KeywordsGreenhouse gases emissions Energy sector Solid waste management Environmental management system
Energy is an important element for social and economic development. Increased world population will intensify the growing global energy demand. It is vital to address the issues of sustainability and other related economic and environmental implications in establishing sustainable energy systems. The planning and optimisation for energy sector involve finding a set of sources and conversion procedures to meet the energy requirements, at minimal cost and environmental impacts (Hiremath et al. 2007).
The growth in global primary energy consumption has been the lowest (171, Mt CO2 Eq. 0.1%) in 2016 over the previous 10 years (BP 2017). The fuel mix shifted away from coal towards lower carbon (low CO2 emission) fuels, i.e. to natural gases and other renewable energies such as wind and solar energy in China and the USA. Most of the emissions (about 72%) consist of CO2, followed by methane (CH4), nitrous oxide (N2O) and fluorinated gases (F-gases) (19, 6 and 3%) (Olivier et al. 2017).
The GHG emissions by sector can be divided into fuel combustion and fugitive emissions from fuels (without transport), transport, industrial processes and product use, agriculture, as well as waste management (Eurostat 2017). Various clean and innovative technologies are under intensive research to mitigate the emission from the sector related to the fuel consumption.
In Asia, up to two-thirds of the total emissions are contributed by fossil fuels (ADB 2016). In Europe, 78% of the emission is from the fuel combustion and transportation sector (Eurostat 2017). The technologies to improve the energy sustainability of transport fuel, power, heating and cooling sector are by enhancing the energy efficiency (e.g. integrated system, use of waste heat, improved brake system). A range of renewable energies (RE) is available, e.g. biomass, geothermal, hydropower, ocean energy, solar photovoltaics, concentrating solar thermal power, solar thermal heating and cooling, wind power. Half of the Asia emissions reduction through 2050 is contributed by low energy production and another third from energy efficiency measures, with the rest achieved by curtailing emissions from forest deforestation, land degradation and other non-energy sources (ADB 2016). Energy sector remains the key emissions source and the best potential for Asia’s transition to low emission growth (Lee et al. 2018).
The overview structure
The presented overview reviews three groups of papers that are relevant to the low CO2 emissions developments, including the mitigation of GHG from the energy sector, sustainable solid waste management and the environmental management system (EMS). Apart from the low CO2 emission development in all three aspects, the review also concerns the sustainability of the cleaner process or technologies concerning their economic impacts.
The first part reviews the mitigation of CO2 emissions for the energy sector with the focus on the approaches to improve energy efficiency using optimisation and modelling tools. This part also reviews the development of carbon sequestration via carbon capture and storage (CCS).
The second part reviews the current research in sustainable solid waste management (SWM) to mitigate GHG emissions. Although waste sector contributes relatively low percentage of global GHG emissions (typically < 5%), the resultant environmental impacts such as the eutrophication and water source pollution can post adverse impacts in the long run. Improved waste management is a key area of intervention for sustainable development. It has been estimated that 10–15% reduction in global GHG emissions can be achieved through landfill mitigation and diversion, energy from waste, recycling and other improved solid waste management (UNEP 2015). The waste prevention can further increase the contribution to 10–20%. The individual waste treatment technology (treatment to reduce volume, recycling, composting, waste to energy) can be considered as mature. However, the high variation of the waste characteristics could challenge the appropriate decision-making. The waste composition, source of the waste, location of treatment plants, climate and investment cost are affecting the efficiency of the selected technologies to a certain extent. A proper management and an integrated waste system are needed towards sustainable solid waste management.
The last part reviews the environmental management system (EMS) that has been affecting policymakers, markets and is among the most discussed topic nowadays. Many new environmental regulations, policies and strategies have been adopted to support environmental sustainability.
Potential mitigation for the energy sector contributed from different technologies.
Reproduced with permission from Yang et al. (2016)
Energy efficiency improvements
Alternative energies and carbon sinking
Carbon capture and storage or sequestration (CCS)
Optimisation and modelling tools for energy sector
Many computer optimisation and modelling works have considered the supply and demand chain of the energy system, notably for biogas and biofuels where the site selection and logistics of biomass collections, energy storage and distribution are among the critical cost factors to be optimised. Minimisation of the overall cost and GHG emissions is the typical goals of the optimisation studies.
Han and Kim (2017) suggested an optimisation model for the design and planning of a complex RE sources-based energy supply system. A model formulated using the mixed integer linear programming (MILP) was developed to minimise the total cost. Among the constraints considered in the model were the resource availability, demand satisfaction, energy flow conservation and the limited capacity of technologies.
Carbon capture and storage or sequestration (CCS)
CCS is a relatively recent approach where more development is needed. CCS involved the separation/capture technology of CO2, compressed and transport to the suitable geological storage where liquid CO2 is injected into the deep underground. The sustainability remains an open question. Improvement is anticipated for the capture technology (costly and energy intensive); reservoir flow modelling; geologic storage and integrity modelling; and assessing well seal integrity and storage capacity of oil and gas reservoirs, aquifers and coal beds for potential storage use (ExxonMobil 2017). Rahman et al. (2017) summarised that the following key criteria must be applied in CCS: (1) the storage period should be prolonged (100–1000 years), (2) the cost including storage and transportation from the source to the storage site should be minimised, (3) the risk of accidents should be eliminated, (4) environmental impact should be minimised and (5) the storage method should not be against any national or international laws and regulations. Asia is the biggest continent in the world and plays a significant role in contributing towards the climate change mitigation plan, i.e. the below 2 °C temperature increment target. Gasser et al. (2015) suggested that the target could only be achieved through negative emissions. (0.5–3 Gt of C per year and storage capacity of 50–250 Gt C are required.)
Acceleration in the development of negative emissions technologies has been highlighted. The potential of flue gas injection into gas hydrate reservoirs for methane recovery and CO2 sequestration was demonstrated by Yang et al. (2017). Unmineable coal because of geologic, technological and economic factors is potential for CO2 storage.
In Japan, the development of the Tomakomai CCS demonstration project has been published in 2013 and updated recently (Tanaka et al. 2017). The technical viability has been demonstrated and discussed. The demonstration facilities comprise the CO2 capture facility, CO2 injection facility, two injection wells, three observation wells and various onshore and offshore monitoring systems. It is expected to capture and store 100 kt/year of CO2 (Tanaka et al. 2017). The individual technologies have already been established in Japan, but there is also concern on the leakage particularly where there are many earthquakes and volcanic eruptions (Watanabe 2016). Liu et al. (2016) highlighted the pressing need to formulate environmental management regulation to be in parallel with the development of CCS projects. There are many uncertainties, challenges and knowledge gaps regarding the development and utilisation of CCS technology, including the lifecycle effects, storage capacity, storage permanence, the power penalties, long-term policy framework and high implementation costs (Rahman et al. 2017).
CCS is in line with the idea where CO2 in the atmosphere represents a liability, but in the soil or land, it is an asset. In contrast to the advanced technology, the objective can also be achieved by photosynthesis (planting) as well as the application of biochar or compost. It was suggested that plants alone are no longer able to deal with the increased amount of CO2 in the atmosphere due to the rapid industrial development. The C sequestration capacity of China’s Grain for Green Program, a large-scale ecological restoration program, can only offset about 3–5% of China’s annual C emissions and about 1% of global C emissions (Deng et al. 2017). Application of biochar or compost returns the carbon resource (CO2 emission) to the soil by transforming the wastes (composting, pyrolysis) that were conventionally disposed to the landfill, as a soil amendment. Lehman (2007) classified biochar as a lower-risk strategy than other sequestration options. Smith (2016) analysed various negative emission technologies and concluded that soil C sequestration and biochar have a lower impact on land, water use, nutrients, albedo, energy requirement and cost. It has the negative emission potential of 0.7 Gt C eq. year−1. The other potential conversion products from CO2 are methanol, methane, light alkanes, ethanol, syngas and a cyclic carbonate.
Sustainable solid waste management (SWM)
Many recent studies focus on the scenario analyses for sustainable SWM, where intensive analyses on the economic and environmental impacts are conducted. A different mix of waste treatment technologies, such as landfill, incineration, recycling, composting and other waste-to-energy (options) technologies, are modelled through scenario analyses. Some studies also considered a multiple-period planning to provide varied scenarios at different time frames, taking into consideration the demand and supply side of the waste inputs (e.g. increased waste volume of different waste types), outputs (e.g. energy, compost, recyclables) and policy implication with time (Tan et al. 2014). Guerrero et al. (2013) determined the stakeholders’ role in the waste management process and to analyse influential factors on the system. More than thirty urban areas in 22 developing countries in four continents were evaluated in the attempt to facilitate the planning, changing or implementing waste management systems in cities.
Optimisation of waste collection routes is vital to reduce the operating cost for SWM. Das and Bhattacharyya (2015) propose a scheme for the optimal waste routing between the transfer stations and processing plants of a city in India. The integrated SWM and the optimal path offer low emission and transportation cost. Similar studies were conducted by Malakahmad et al. (2014) in a city of Malaysia and Xue et al. (2015) in Singapore by using the geographical information system (GIS). Waste recovery technologies together with localised management (collection route, collection system) minimised the burdening footprints of waste handling.
Composting is a relatively low-cost waste treatment that could minimise the disposal of organic waste to landfill and encourage the re-utilisation of waste as resources to produce compost. It is one of the preferred treatment options in Korea (37%), Indonesia (15%), Thailand (10%), Philippines (10%) and India (10%) (UNEP 2017). Organic waste comprised about 40–60% in many fast-developing countries in Asia, and composting could be promoted as a viable technology to recycle the excess nutrients in food waste back to the planting ecosystem. Most developing countries in Asia have a reported low rate of composting, about 10% or less. Various challenges remained for recycling the organic portion in the municipal solid waste including lack of funding and outreach to promote behavioural change for consumers to recycle organic or food waste, lack of an institutional framework to enforce the waste reduction policies that are already in place in many developing countries. Based on the best practices of SWM in the Taipei city, the high recycling rate (over 50%), and the achievement of “zero-landfill” (zero waste to landfill) goal in 2010, was driven by various collective efforts as driven by Taiwan Environmental Protection Agency (EPA) since 1987. Among the key policies were the “Extended Producer’s Responsibility requesting product producer” where producers (the responsible enterprises) are responsible for waste recycling and disposal; the “4-in-1” program which combines communities, recycling firms, local governments and recycling fund in the implementation of resource recycling and the cradle-to-cradle principle implemented in 2010 to promote circular economy in Taiwan (Houng et al. 2014).
Promoting a circular economy could create an ecosystem where virtually different types of wastes would become recyclables. The ongoing challenges for improving organic waste recycling through composting include establishing the steady demand for the compost market, and developing mechanisms to support accurate recording and reporting of waste diversion rates.
The sustainability of composting technology highly depends on the quality (which decides compost selling price), assessment and utilisation of compost. Fan et al. (2016) proposed the economic quality assessment system, which classified compost analyses into five major groups. Minimum analyses are proposed for different composting systems fed with different feedstocks, to enhance the sustainability of composting. The studies can enhance the economically feasible of composting as many composting facilities/plants reported the low or no profit (Chen 2016).
Other than municipal solid waste, other solid wastes include biomedical waste, hazardous waste, plastic waste, electronic waste, construction and demolition waste. Although the composition of e-waste in Asia is only 1% (UNEP 2017), with the increasing interest on the application of internet of things (IoT), the management of electronic waste would become crucial in the future.
Environmental management system (EMS)
EMS was initially proposed by the European Commission to provide a series of policy tools that allow companies to pursue their environmental objectives while maintaining their business operations (Iraldo et al. 2009). There is an increasing trend of customers demanding the green products and processes, to avoid risk stemming from the less environmentally conscious suppliers.
Three key elements namely the environmental sustainability, economic sustainability and social sustainability were fully integrated into the framework development. Insights from the framework provide vital guidelines for facility managers to implement action plans for cleaner production and sustainability. To achieve sustainable development, Zhou et al. (2018) constructed an integrated two-stage system that links the environmental management and industrial production using a new data envelopment analysis model. Results from a China’s case show that over the span of 9 years the efficiency gap between the environment management and industrial production has been reduced and lead to the overall performance improvement for the integrated system. The potential positive correlation between environmental management and future financial performance has been the main focus of the study by Song et al. (2017). More active involvement of companies in environmental protection through technological and management innovations was recommended to improve the product quality, reducing production cost and enhancing firm’s reputation (Song et al. 2017).
EMS typically refers to the footprint assessment and resources database management at the corporation level. Other CO2 footprint assessment techniques at city, regional and global levels are essential to guide an efficient long-term policy for the mitigation of GHG. These tools could guide future actions to steer regions towards self-sufficiency based on more efficient processes and to develop a mechanism with a shared market of virtual carbon trading across different regions.
White et al. (2018) developed a tele-connected Water–Energy–Food Nexus (WEFN) of the East Asia global value chain to assess competing demands of these resources and environmental outcomes. The nexus is established based on the transnational inter-regional input–output approach that monitors the activities of water–energy–food. Liddle (2018) developed the trade-carbon emissions nexus, which considered the consumption-based emissions database where the calculations are based on the domestic use of fossil fuels plus the embodied emissions from imports minus exports.
At a city level, Chen et al. (2018) developed an ecological network analysis system to probe the interaction between urban carbon metabolism and socio-economic activities. The system is capable of tracing the structural and functional changes in urban carbon flows with regard to the socio-economic development. Their analyses highlighted the need for continually improving efficiency to lessen the pressure from carbonisation in 2020 and 2030 without sacrificing the diversity of economic activities.
Central and local governments should play the role to coordinate the data management for the assessment of environmental indicator such as the GHG (CO2 eq.). EMS should not be seen as an extra workload to their existing role, but an opportunity to improve process efficiency, resource recycling and to promote the circular economy.
This paper reviews the latest development of low-carbon emissions mitigation strategies in Asia and beyond. Extended coverage has focused on the energy sector, which is the key emitter by sector. Intensive research has been reported on a range of optimisation and modelling tools to improve energy efficiency, notably for the renewable energies (RE) where the implementation is merely 3% of the global energy consumption in 2016. Process optimisation and modelling tools are expected to close the gap to reduce the reliance on the conventional petrochemical-based fuels, mainly to improve the cost efficiency of the RE. Importantly, the methods developed for the energy sectors, such as the Pinch-Analyses and LCA, can also be applied to other sectors such as waste management to reduce GHG emissions and to enhance the economic feasibility. Implementation of sustainable SWM remained slow in many fast-growing cities in Asia. Considering the high rate (> 40%) of the organic waste portion in many Asian cities, composting has been as a viable waste-to-wealth technology to reduce waste and to promote a circular economy. EMS is seen as an important database nexus to monitor and guide the management of resources (i.e. water, waste, energy, materials) towards low CO2 emission development. The current trend has witnessed the surge of EMS case studies reported at all levels, including for corporation level, as well as for city and regional level. Incentives could be given to corporations to adopt EMS as a means to fulfil the social, economic and environmental responsibilities. Various regional CO2 footprint assessment tools are used to mitigate GHG emissions by developing the mechanisms with the shared markets of virtual resource flows (carbon, water, food, energy) between the trading partners regionally and internationally.
For the continual transformation towards low GHG emission development in Asia, more concerted approaches that involve top-down and bottom-up approaches from different stakeholders are crucial. Other enablers include the policy instruments and framework, well-educated policymakers through meeting and conferences with the experts, competitive technology supported by viable economic feasibility studies, and leadership to promote consensus-building and rapid implementation.
The authors acknowledge research grants from the Ministry of Higher Education (MOHE) Malaysia with Grant Nos. S.J130000.0846.4Y042 and Q.J130000.2546.15H25; and Universiti Teknologi Malaysia Research University Grant No. Q.J130000.2546.14H65; and the EU project Sustainable Process Integration Laboratory—SPIL, Project No. CZ.02.1.01/0.0/0.0/15_003/0000456, funded by Czech Republic Operational Programme Research, Development and Education, Priority 1: Strengthening capacity for quality research, in a collaboration agreement with UTM.
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