*4.1. Potential Renewable Hydrogen from Curtailed Electricity*

ASEAN's power generation is dominated by fossil fuel (coal, oil, and gas), the share of which in the power mix was 79% (equivalent to 1041 TWh) in 2017 and is predicted to be 82% (2826 TWh) and 72% (2087 TWh) in 2050 for BAU and APS, respectively (Figure 1). The share of combined fossil fuel (coal, oil, and gas) in the power generation mix is expected to reduce drastically from 82% in BAU to 65%, 58%, and 51% in Scenario1, Scenario2, and Scenario3, respectively, in 2050 (Figure 2). The share of combined renewables is expected to increase from 18% in BAU to 35%, 42%, and 49% in Scenario1, Scenario2, and Scenario3, respectively, in 2050. The higher share of renewables in the power generation mix is desirable to decarbonize emissions in ASEAN's future energy system. However, the high share of renewables can only happen with bold policy actions to develop and deploy renewable hydrogen to support the power integration system, which has a higher penetration of renewables. Utilizing unused electricity and/or curtailed renewable electricity to produce hydrogen could be ideal to tap the maximum potential of renewables.

**Figure 1.** ASEAN's Power Generation Mix in Business as Usual and Alternative Policy Scenario by Source. BAU = business as usual, APS = alternative policy scenario. Source: Authors.

**Figure 2.** Share of Combined Fossil Fuels (coal, oil and gas) vs Renewables under Various Scenarios. APS= alternative policy scenario, BAU = business as usual. Note: Scenario1, Scenario2, and Scenario3 envision replacing combined fossil fuel (coal, oil, and natural gas) power generation with renewables (mainly variable renewable energy) at 10%, 20%, and 30%, respectively, in 2050. Source: Authors.

Scenario1, Scenario2, and Scenario3 assume the replacement of combined fossil fuel (coal, oil, and gas) power generation in 2050 with 10%, 20%, and 30% of power generation from renewables. Renewable power generation amounts in 2050 are 1016 TWh, 1224 TWh, and 1433 TWh for Scenario1, Scenario2, and Scenario3, respectively (Table 1).


**Table 1.** ASEAN's Power Generation Mix under Various Scenarios of Share of Renewables (TWh).

APS = alternative policy scenario. Note: Scenario1, Scenario2, and Scenario3 envision replacing combined fossil fuel (coal, oil, and natural gas) power generation with renewables (mainly variable renewable energy) at 10%, 20%, and 30%, respectively, in 2050. Source: Authors.

In Scenario1, Scenario2, and Scenario3, the shares of renewables in the power mix will be 35%, 42%, and 49%, respectively, in 2050. Because of higher shares of renewables in the power mix, renewable energy generation will be highly curtailed. The curtailed electricity rate could vary from 20% to 30%, depending on the power grid infrastructure in AMS. Based on this curtailed electricity, with varying shares of renewables in Scenario1, Scenario2, and Scneario3, hydrogen production scenarios are created— Scenario1H2, Scenario2H2, and Scenario3H2. Potential renewable hydrogen from curtailed electricity in scenarios in AMS range from 4.23 to 8.96 million tonnes hydrogen (Table 2).


H2 = hydrogen, Scenario1H2 = hydrogen production in Scenario1, Scenario2H2 = hydrogen production in Scenario2, Scenario3H2 = hydrogen production in Scenario3. Note: 20–30% curtailed electricity applied for combined renewable power generation in 2050. The study applied a conversion factor of 48 kilowatt-hours (kWh) of electricity needed to produce 1 kilogram (kg) H2 [10]; 1 kg of H2 could generate 33.3 kWh [10]. Source: Authors.

The higher share of renewables under various scenarios such as APS, Scenario1, Scenario2, and Scenario3 will see a large reduction in carbon dioxide emissions (CO2), which could result in decarbonizing emissions and contribute to COP commitments. Potential emission abatement ranges from −340 million tonnes carbon (Mt-C) in APS to −648 Mt-C, −710 Mt-C, and −774 Mt-C in Scenario1, Scenario2, and Scenario3, respectively (Table 3). Emissions were cut by 28% from BAU to APS, 53% from BAU to Scenario1, 58% from BAU to Scenario2, and 64% from BAU to Scenario3.


**Table 3.** Potential Emission Reduction under Various Scenarios (Mt-C).

APS = alternative policy scenario, BAU = business as usual, Mt-C = million tonnes carbon. Note: Emission abatement potential is change of emissions from BAU to APS and other scenarios in 2050 under high renewables in Scenario1, Scenario2, and Scenario3. Source: Authors.
