Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 181

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 181
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 Hills wind facilities in the first quarter of 2024; and |

| • |     | Full-year production from the Garden Plain wind facility; partially offset by |

| • |     | Increased economic dispatch at the Centralia facility due to lower market prices compared to the 
 prior year in the Energy Transition segment; and                                                 |

| • |     | Higher dispatch optimization in Alberta. |

2023 versus 2022 Total production for 2023, increased by 771 GWh, or four per cent, compared to 2022, primarily due to:

| • |     | Lower planned and unplanned outages at the Centralia facility in the Energy Transition segment                        
 compared to prior year, which allowed the Company to increase dispatch during the periods of higher merchant pricing; |

| • |     | Higher availability in the Gas segment during periods of supply tightness, allowing for the Company 
 to operate during periods of peak pricing;                                                          |

| • |     | Production from new facilities, including the Garden Plain wind facility, commissioned in August 
 2023 and the Northern Goldfields solar facilities in November 2023; and                          |

| • |     | The partial return to service of the Kent Hills wind facilities in the fourth quarter of 2023, 
 partially offset by                                                                            |

| • |     | Lower than average wind and water resources in the year; |

| • |     | Lower availability in the Hydro segment due to increased planned maintenance outages compared to 
 2022; and                                                                                        |

| • |     | Relatively mild weather in the fourth quarter of 2023, compared to the same period in 2022 when 
 markets experienced tighter supply due to the extreme cold weather in Alberta.                  |

| M8 |     | TransAlta Corporation |     | 2024 Integrated Report |

Management’s Discussion and Analysis Market Pricing

| Year ended Dec. 31, 2024                |     | 2024 |      |     | 2023 |     | 2022 |
|:----------------------------------------|:----|:-----|-----:|:----|-----:|:----|-----:|
| Alberta spot power price ($/MWh)        |     |      |   63 |     |  134 |     |  162 |
| Mid-Columbia spot power price (US$/MWh) |     |      |   56 |     |   76 |     |   82 |
| Ontario spot power price ($/MWh)