*2.4. Cost Assumptions and Methodologies*

For the analysis in this paper, LCOE consists of base plant costs, deSOx and deNOx costs, financing costs and emission costs. Base plant costs are divided into EPC, O&M and fuel costs. Similarly, deSOx and deNOx costs consist of EPC, O&M and additional fuel costs (see Table 4).


**Table 4.** Levelized cost of electricity (LCOE) breakdown costs.

The cost assumption of EPC is adopted from [23]. The EPC cost consists of generator, turbine, boiler and auxiliary machine costs, construction costs and other management costs. The standard assumption is that all coal technologies pay equivalent connection costs and land costs. These costs are thus not taken into consideration.

For the 25-year life cycle of the plant, the SC and subcritical capital costs are discounted from USC capital costs (USD 1931 million per 1000 MW), based on a cost index from [34]. Subcritical plant capital costs are indexed at 100, while SC and USC are indexed at 106.5 and 108.5, respectively. Based on these indexes, capital costs for SC are estimated at USD 1897 billion, and capital costs for subcritical are estimated at USD 1786 million. Likewise, the A-USC capital cost is an escalating cost index factor of 107.5. Therefore, the EPC costs of different types of coal combustion technologies are: A-USC at USD 2100 million, USC at USD 1931 million, SC at USD 1897, and subcritical at USD 1786. Additionally, for the cost assumption for the 20-year life cycle of the plant, the cost estimates for different types of

coal-fired power generation technologies are: A-USC at USD 2625 million, USC at USD 2413.75 million, SC at USD 2371.25 million, and subcritical at USD 2232.5 million.

Base plant O&M costs are calculated by dividing non-fuel O&M costs by annual generation (7008 GWh). The annual costs for this analysis are calculated by applying O&M cost differences from [35] to the annual O&M costs for USC from [34]. Annual O&M costs are thus estimated at: USD 0.6/kWh for A-USC, USD 0.7/kWh for USC, USD 0.72/kWh for SC and USD 0.75/kWh for subcritical power plants.

Thermal coal prices grew since the second half of 2016 due to robust Chinese demand and supply tightness at several production sites [36]. For example, free on board (FOB) Kalimantan 4200 kcal/kg gross as received (GAR) coal price rose 34% since the start of 2017 to USD 49.60/mt in January 2018. Coal prices in April 2020 dipped to their lowest level since 2010 due to the COVID-19 pandemic. Import prices of the majority of ASEAN coal reserves have seen a strong momentum since mid-November 2020 and have been trending upward due to steady economic recovery and thus high demand of coal by key consumers in China, Japan, India and South Korea. Coal demand by importing countries is expected to rise in the post-COVID-19 era due to increased economic activities and, consequently, coal prices will evolve to new high prices in the future. To assess the impact of high coal prices on LCOE values, a bandwidth is thus analyzed to reflect the situation. The annual average fuel price assumptions used in this study were: USD 50/ton, USD 80/ton, and USD 100/ton. For the breakdown of these costs and calculation methodologies, the reader is advised to refer to [23].
