Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 206

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 206
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 loss attributable to common shareholders                  |     |      | (65 | ) |     |      | (84 | ) |
| Net (loss) earnings attributable to non-controlling interests |     |      |  (4 | ) |     |      |   5 |   |

Current Year Variance Analysis (Fourth quarter 2024 versus Fourth quarter 2023) Revenuesfor the three months ended Dec. 31, 2024, increased by $54 million, or nine per cent, compared to the same period in 2023, primarily due to:

| • |     | Higher revenue in the Gas segment due to favourable contribution from hedging and the addition of 
 Heartland facilities;                                                                             |

| • |     | Higher revenues in the Hydro segment due to higher production in the fourth quarter of 2024 due to 
 water conservation in the same period of 2023; and                                                 |

| • |     | Revenue from the commercial operation of the White Rock and Horizon Hill wind facilities in the 
 current period; partially offset by                                                             |

| • |     | Lower realized power prices and dispatch optimization in Alberta; |

| • |     | Lower revenues in the Energy Marketing segment due to lower market volatility across North American 
 power and natural gas markets; and                                                                  |

| • |     | Lower revenues in the Energy Transition segment due to increased economic dispatch due to lower 
 market prices.                                                                                  |

Fuel and purchased power costsfor the three months ended Dec. 31, 2024, decreased by $29 million, or 10 per cent, compared to the same period in 2023, primarily due to:

| • |     | Lower purchased power costs driven by lower Mid- Columbia                             
 prices on repurchases of power and lower production in the Energy Transition segment. |

Carbon compliance costsfor the three months ended Dec. 31, 2024, increased by $12 million compared to 2023 due to:

| • |     | Carbon price increase from $65 to $80 per tonne; and |

| • |     | Carbon compliance costs attributable to facilities acquired from Heartland. |

OM&A expensesfor the three months ended Dec. 31, 2024, increased by $84 million, or 56 per cent, compared to the same period in 2023, primarily due to:

| • |     | Penalties assessed by the Alberta Market Surveillance Administrator for self-reported 
 contraventions pertaining to hydro ancillary services provided during 2021 and 2022;