**3. Results**

Figures 1–4 show the LCOE sensitivity analysis results in USD cents/kWh for Scenario 1 through 4, respectively. The results of Scenario 1 in Figure 1 suggest that HELE plants are competitive against subcritical plants without coal pricing and deSOx and de-NOx costs. A comparison of the results of Scenario 1 through Scenario 4 in Figures 1–4, respectively, reveals that as carbon price and deSOx and deNOx costs are included, LCOEs increase. However, HELE plants retain their competitive edge over the subcritical plants. The study suggests that Scenario 1 offers the best economic case for HELE plants due to the lowest LCOE values for HELE plants, followed by the Scenario 3, Scenario 2 and Scenario 4.

**Figure 1.** Scenario 1: Sensitivity Analysis of LCOE for different coal prices and economic life span of the subcritical and high-efficiency, low-emission (HELE) plants.

**Figure 2.** Scenario 2: Sensitivity Analysis of LCOE for different coal prices and economic life span of the subcritical and HELE plants.

**Figure 3.** Scenario 3: Sensitivity Analysis of LCOE for different coal prices and economic life span of the subcritical and HELE plants.

In all scenarios, for different coal prices and operating life spans of 20 and 25 years, both coal technologies derive benefit from lifetime extensions and low coal prices. However, HELE coal technologies derive more benefit due to lower LCOE values compared to the subcritical technology. It is immediately apparent that, in all scenarios, A-USC offers the best economic value, followed by USC and SC.

The lower LCOEs of HELE against the subcritical technology are necessary to shift investment decisions in favor of HELE and thus expedite deployment of HELE plants in the region. We thus evaluated the difference of LCOE values between HELE and subcritical technologies for each scenario using the LCOE difference metric ΔLCOE = |LCOE*HELE* − LCOE*Subcritical*|. These differences are displayed in Figures 5–8, for Scenario 1 through 4, respectively. A close comparison of results in Figures 5–8 suggests that Scenario 2 is the best scenario causing the highest difference in LCOE values of subcritical and HELE plants. A similar observation reveals that Scenario 4 is the second-best Scenario, followed by Scenario 3. A closer analysis of results reveals that Scenarios 2 through 4 allow a shift of economics in favor of HELE technologies at the price of increased LCOE values of coal plants. However, notice that since Scenario 2 LCOE values are lower than the Scenario 4 LCOE values, Scenario 2 thus emerges as the best driver scenario to displace subcritical plants. Notice that Scenario 3 yields low LCOE prices as compared to the Scenario 4. However, as compared to Scenario 3, the difference in LCOE values of HELE and subcritical technologies in Scenario 4 is highly attractive to shift economics strongly in favor of HELE plants. Scenario 4 thus emerges as the second-best driver scenario. A similar comparison between LCOE values of coal plants, and LCOE difference in Scenario 1 and Scenario 3 suggests that Scenario 3 is the third-best Scenario.

**Figure 4.** Scenario 4: Sensitivity Analysis of LCOE for different coal prices and economic life span of the subcritical and HELE plants.

**Figure 5.** Scenario 1: LCOE differences between HELE and subcritical technologies for different coal prices and economic life span of the plant.

**Figure 6.** Scenario 2: LCOE differences between HELE and subcritical technologies for different coal prices and economic life span of the plant.

**Figure 7.** Scenario 3: LCOE differences between HELE and subcritical technologies for different coal prices and economic life span of the plant.

**Figure 8.** Scenario 4: LCOE differences between HELE and subcritical technologies for different coal prices and economic life span of the plant.
