Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 203

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 203
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 Gas segment;                    |

| • |     | The utilization of emission credits in the Gas segment in 2024 to settle a portion of our 2023 GHG 
 obligation;                                                                                        |

| • |     | Higher hydro ancillary services volumes due to increased demand by the AESO; and |

| • |     | Lower natural gas prices. |

2023 versus 2022 Total production for the year ended Dec. 31, 2023, was 11,759 GWh, compared to 11,476 GWh in 2022. The increase of 283 GWh, or two per cent, was primarily due to:

| • |     | The commercial operation of the Garden Plain wind facility in the third quarter of 2023; |

| • |     | Higher production from our Gas facilities due to strong market conditions in the first half of 
 2023; partially offset by                                                                      |

| • |     | Lower water resources in the Alberta Hydro Assets. |

Hedged production for the year ended Dec. 31, 2023, increased compared to 2022, primarily due to the opportunity to secure additional margins with strategic hedges for the hydro assets. Gross margin for the Alberta portfolio for the year ended Dec. 31, 2023, was $1,248 million, compared to $1,196 million in 2022. The increase of $52 million, or four per cent, was primarily due to:

| • |     | Higher power price hedges, partially offsetting the impacts of lower Alberta spot prices; and |

| • |     | Lower natural gas prices compared to 2022; partially offset by |

| • |     | Lower ancillary services revenues due to the AESO procuring lower volumes given its decision to 
 reduce the cumulative volume of imports into Alberta.                                           |

| TransAlta Corporation |     | 2024 Integrated Report |     | M31 |

Management’s Discussion and Analysis The following table provides information for the Company’s Alberta electricity portfolio:

| Year ended Dec. 31                     |     | 2024 |       |     | 2023 |       |     | 2022 |       |
|:---------------------------------------|:----|:-----|------:|:----|:-----|------:|:----|:-----|------:|
| Alberta Market                         |     |      |       |     |      |       |     |      |       |
| Spot power price average per MWh       |