Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 387

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 387
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229 |   |

| (1) | Basic and diluted (loss) earnings per share attributable to common shareholders is calculated in                                                                                                                                                          
 each period using the basic and diluted weighted average common shares outstanding during the period, respectively. As a result, the sum of the (loss) earnings per share for the four quarters making up the calendar year may sometimes differ from the 
 annual (loss) earnings per share.                                                                                                                                                                                                                         |

Operating results have been impacted by the following events:

| • |     | Commissioning of the Northern Goldfields solar facilities in the fourth quarter of 2023, the Mount                                                                                    
 Keith 132kV expansion in the first quarter of 2024 and the impact from the White Rock and Horizon Hill wind facilities which achieved commercial operation in the first half of 2024. |

In addition to the items described above, revenues have been impacted by:

| • |     | Higher production in all three quarters of 2025 and the fourth quarter of 2024 compared to the same 
 periods in the prior year;                                                                          |

| • |     | The effects of unrealized                                              
 mark-to-market gains and losses from hedging and derivative positions; |

| • |     | Lower realized pricing in the fourth quarter of 2024 primarily due to the impact of additions of 
 new natural gas, wind and solar supply in the Alberta market; and                                |

| • |     | Higher realized pricing in all three quarters of 2025 compared to the same periods in the prior                                                          
 year due to favourable realized hedge positions and optimization in the current period, which generated positive contributions over settled spot prices. |

| TransAlta Corporation |     | M41 |

Management’s Discussion and Analysis

Carbon compliance costs (recovery) have been impacted by:

| • |     | Higher costs of carbon per tonne, which increased from $80 in 2024 to $95 in 2025; |

| • |     | In the second quarter of 2025, carbon compliance costs were reduced by using internally generated                                                                      
 and externally purchased emission credits to settle a portion of our 2024 GHG obligation and a portion of the GHG obligation assumed in the Heartland acquisition; and |

| • |     | In the second quarter of 2024, carbon compliance costs were reduced by using internally generated 
 and externally purchased emission credits to settle a portion of our 2023 GHG obligation.         |

OM&A has been impacted by:

| • |     | Higher spending to support strategic and growth