“The operation of thermal and combined cycle power plants requires the discharge of exhaust gases from the combustion of various fuels into the atmosphere. The company therefore places great importance and strictly controls and manages key pollutants, including SO₂, NOₓ, and particulate matter, to comply strictly with the air emission standards prescribed by law.”
Air Quality Management
Performance in 2025
Air Quality at Stack of Thailand-based Power Plants
| Data | Unit | 2025 | 2024 | 2023 |
|---|---|---|---|---|
| NOx emissions* | Tons | 1,783 | 1,650 | 2,365 |
| kg/MWh | 0.14 | 0.14 | 0.24 | |
| SOx emissions* | Tons | 25.8 | 22.9 | 160.4 |
| kg/MWh | 0.002 | 0.002 | 0.017 | |
| Opacity* | % | 3.4 | 3.28 | 6.96 |
| TSP* | Tons | 152.2 | 107.6 | 233.5 |
| VOC** | Tons | 0.81 | N/A | 2.72 |
- * Emission of RGCO, HKP, RCO, RER and RPE Group are calculated from the Continuous Emission Monitoring Systems (CEMs) and RAC used calculation method of the Queensland Department of Environment and Science
- ** Total Volatile Organic Compounds volume is calculated from the average of air quality measurement results from the Kemerton and Townsville power plants.
| Power Plant | Average concentration of pollutants from combustion | ||||
|---|---|---|---|---|---|
| NOx (ppm) | SO2 (ppm) | Secondary fuel |
|||
| Natural gas | Fuel oil | Natural gas | Fuel oil | ||
| Ratchaburi Thermal | Reserved shutdown | Bunker oil | |||
| Ratchaburi Combine Cycle * | N/A | - | N/A | - | Diesel oil |
| Target (not exceeding-Ministry of Industry Standards) ** | 120 | 180 | 20 | 320 | - |
| Hin Kong Unit 1 | 36.89 | 0 | 0.69 | 0 | Diesel oil |
| Hin Kong Unit 2 | 38.07 | 0 | 0.24 | 0 | |
| Target (not exceeding EIA-specified limits) | 59 | 99 | 10 | 20 | - |
| RATCH Cogeneration | 39.6 | - | <1.0 | - | None |
| Target (not exceeding EIA-specified limits) | 60 | - | 10 | - | - |
| RATCH Energy Rayong | 30.80 | - | <2.0 | - | None |
| Target (not exceeding EIA-specified limits) | 60 | - | 15 | - | - |
| RATCH Pathana Energy HRSG#4 | 88.32 | - | 0.83 | - | None |
| Target (not exceeding EIA-specified limits) | 108 | - | 18 | - | - |
| RATCH Pathana Energy HRSG#5 | 30.66 | - | 0.2 | - | None |
| Target (not exceeding EIA-specified limits) | 90 | - | 15 | - | - |
| RATCH Pathana Energy HRSG#6 | 37.79 | - | 0.01 | - | None |
| Target (not exceeding EIA-specified limits) | 60 | - | 10 | - | - |
- * In 2025, Ratchaburi Combined-Cycle Power Plant was in Reserved Shutdown mode and ordered to resume the open cycle mode for a short period of time.
- ** The Notification of the Ministry of Industry on the Determination of Contaminant Levels in Air Emissions from Power Generation, Transmission, or Distribution Facilities B.E. 2547.
Air quality warning system
The power plants have established warning measures and set values for alarm signals, to prevent risks from an irregularity in the combustion system. The CEMS alarm is triggered when air pollutant intensity at stack hit 80-85% of the controlled rate (High Alarm), requiring controllers to check a particular generator and its pollutant emission control device. When pollutant concentration hits 95% of the controlled rate (Very High Alarm), controllers are required to normalize the air quality. If the problem persists, they will consider reducing the electricity generation or shutting down. Generation activity will resume after the problem is solved.
Warning System
