## 3 Results and Discussion
### Requirements and Considerations for Selection of Waste-to-Energy Technologies  
Whether incineration and waste-to-energy are a net positive can depend on the efficiency of the process and the energy mix that waste-to-energy is replacing, including far better pollution and dioxin filters to protect the environment and human health [22]. Most waste-to-energy projects aim to demonstrate the full-scale utilization of municipal waste through the reduction of waste flow at disposal sites, GHG reduction, resource efficiency, energy recovery, and employment creation [42]. However, there are several requirements and considerations for the selection of suitable technologies regarding waste characteristics, plant sizes, climate and seasonal variations, and economic conditions, as described in Table 3. Waste-to-energy plants such as incineration, pyrolysis, and plasma gasification ones need huge volumes of waste--above 100 tons of waste per day and, at best, 500 tons of waste per day--to sustain the continuous combustion in the furnace of boilers to produce a consistent heat to supply to boilers for steam production [32]. For waste-to-energy production, the AD process can accept a wide range of MSW volumes starting at 25 tons of waste per day, whereas landfilling needs at least a consistent volume of MSW with a capacity of above 500 tons per day to produce a steady stream of electricity supply for the grid [34]. Some advantages of waste-to-energy technology include that when well-managed, this technology has a smaller plant footprint with a smaller area of land required to operate, a reduction of need for physical waste storage, lower carbon emissions, minimal land contamination, chemically stable by-products from incineration, a higher density of energy recovery per ton of MSW, and the utilization of a domestically-available and sustainable resources for electricity production [5,24,32]. Additionally, it is good for areas with a lack of land for landfills to adopt alternative solutions in some Southeast Asian countries such as Singapore and Brunei Darussalam [22]. For the meaningful use of the produced energy, it is very desirable to use the produced heat on site, e.g., for drying biodegradable municipal waste. Control of the electricity generator and the methods of connection to the electricity grid can also play important roles. While the calorific values of MSW in developed countries are in the range of 8.4-17 MJ/kg [52], the calorific values of the MSW in Southeast Asian countries are estimated at 5.82-10.11 MJ per kg in Malaysia [53], 5.163-6.121 MJ per kg in Thailand [37], 5.52-9.37 MJ per kg in Lao PDR [38], and 5.163-7.5 MJ/kg in Myanmar [13,46]. The calorific value of waste can vary with the composition of the waste and the country's economic development, consumption habits, educational standard, time, season, etc. [2,15]. As a result, some Southeast Asian countries have lower quality waste, with calorific values ranging from 5 to 11 MJ/kg, especially due to major portions of organic waste and the high moisture content of the waste. Hence, a country is suited for waste-to-energy process if pretreatment processes such as bio-drying and solar drying could be carried out. Additionally, a combination of systems, such as the cooperation of solar systems for the pre-preparation of biodegradable waste before its thermal treatment or the use of excess heat and electricity in the form of accumulation (power to X), could play an important role. Additionally, a combination of AD and incineration or other disposal methods could offer more benefits for waste-to-energy process in the region. Figure 8 illustrates a comparison of different waste-to-energy technologies in term of plant capacity, energy potential, capital cost, operation and maintenance (O and M) cost, and planning-to-commissioning costs, and emissions produced from each technology.