*2.3. General Assumptions*

ASEAN's preference for coal is to continue in the future as it remains the most economic source of long-term base-load generation. Collectively, large scale operational coal-fired electricity generation plants around the globe are key contributors to total emissions. We thus consider large coal plants that are connected to the grid to provide base load. High-efficiency coal-fired plants are typically large and fall in the range 600 MW to 1000 MW. Since 1000 MW plants are usually grid-connected to provide base load, the cost–benefit analysis was thus targeted at 1000 MW-capacity coal-fired plants. Base-load power plants typically have annual capacity factors (CFs) that exceed 75 percent, but are usually more likely to be 90–98% [32]. All coal plants were modelled with an assumed CF of 80%. The LCOE calculation is usually performed assuming ideal conditions; a CF of 80% is thus a moderate choice. Based on plant capacity and utilization rate, total annual generation was thus 7008 gigawatt-hours (GWh).

Within a project capital structure, a project may receive equity investment from a private equity firm or group of investors, with an insurance wrap from a development financial institute (DFI). The coal-fired plant life cycle is about 25–30 years, however, investors are likely looking for faster return/payback based on 20–25-year cash flow projections. Therefore, for this reason, the return cash flow is analyzed for 20 and 25 years of the expected lifetimes for each coal technology.

The efficiency figures listed in Table 1 are based on the low heating value (LHV) of the fuel and net output (LHV, net). Coal-fired station efficiencies based on the high heating value (HHV) are generally around 2% to 3% lower than those based on LHV efficiencies. We thus added three percentage points to the higher end LHV-based efficiencies in Table 1 to get HHV-based efficiencies for different coal-fired plants and associated heat rates (See Table 2).

**Table 2.** High heating value (HHV)-based coal-fired power plant efficiencies and heat rates.


Coal has a calorific value of 4000 kcal/kg and emissions (adjusted from the Intergovernmental Panel on Climate Change (IPCC) default emission factors) of 1.43 kg-/kg-coal. The kWh generated from CO2 per kg of coal was computed by dividing the coal heat content (in Btu per kg) with HR (in Btu per kWh). Coal requirements to generate one kWh of electricity (in kg-coal/kWh) were multiplied by the emission factor to obtain levelized kg CO2 emissions per kWh.

The general assumptions for electricity generation plant specifications and coal composition are summarized in Table 3.


**Table 3.** General assumptions for cost benefit analysis.
