Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 370

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 370
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 net earnings of $1 million for the same period in 2024, primarily due to lower net earnings for TransAlta Cogeneration, LP (TA Cogen) resulting from lower merchant pricing in the Alberta market.

| M14 |     | TransAlta Corporation |

Management’s Discussion and Analysis

Nine months ended Sept. 30, 2025 Variance Analysis (2025 versus 2024) Revenuesfor the nine months ended Sept. 30, 2025 decreased by $361 million, or 17 per cent, compared to the same period in 2024, primarily due to:

| • |     | Higher unrealized                                                                                                                                                     
 mark-to-market losses in the Wind and Solar segment driven by long-term wind energy sales related to the Garden Plain and Oklahoma facilities, primarily due to lower 
 forecasted power prices, partially offset by mark-to-market gains related to Big Level facility;                                                                      |

| • |     | Higher unrealized                                                                                                                                  
 mark-to-market losses in the Gas and Energy Transition segments primarily related to unfavourable changes in forward prices in the current period; |

| • |     | Lower Alberta and Mid-Columbia power prices; |

| • |     | Higher dispatch optimization in the Gas segment driven by lower power prices in Alberta; |

| • |     | Lower realized                                                                              
 mark-to-market gains on settled trades in the Energy Marketing segment; partially offset by |

| • |     | The full three quarter impact from the addition of the Heartland facilities in the fourth quarter 
 of 2024;                                                                                          |

| • |     | The impact from the White Rock and Horizon Hill wind facilities which achieved commercial operation 
 in the first half of 2024; and                                                                      |

| • |     | Higher realized                                            
 mark-to-market gains on settled trades in the Gas segment. |

Fuel and purchased power costsfor the nine months ended Sept. 30, 2025 decreased by $13 million, or two per cent, compared to the same period in 2024 primarily due to:

| • |     | Lower purchased power costs driven by higher availability, which resulted in fewer repurchases to    
 fulfill contractual obligations during outages in the Energy Transition segment; partially offset by |

| • |     | The full three quarter impact from the addition of the Heartland facilities in the fourth quarter 
 of 2024; and                                                                                      |

| • |     | Higher production in the Energy Transition segment due to higher availability. |

Carbon compliance costsfor the nine months ended Sept. 30