Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 377

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 377
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 and $1,031 
 million), to adjusted fuel and purchased power — fuel and purchased power of $119 million and $388 million for the three and nine months ended Sept. 30, 2025, respectively (Sept. 30, 2024 — $100 million and $339 million),   
 to adjusted gross margin — gross margin of $172 million and $456 million for the three and nine months ended Sept. 30, 2025, respectively (Sept. 30, 2024 — $174 million and $586 million), to adjusted OM&A —                  
 OM&A of $64 million and $188 million for the three and nine months ended Sept. 30, 2025, respectively (Sept. 30, 2024 — $43 million and $131 million), to adjusted EBITDA and adjusted earnings before income taxes —           
 earnings before income taxes of $63 million and $105 million for the three and nine months ended Sept. 30, 2025, respectively (Sept. 30, 2024 — $88 million and $318 million).                                                  |

| (4) | During the first quarter of 2025, our Adjusted EBITDA composition was amended to exclude the                                                                                                                  
 impact of realized gain (loss) on closed exchange positions and Australian interest income. Therefore, the Company has applied this composition to all previously reported periods. Refer to the Non-IFRS and 
 Supplementary Financial Measures section of this MD&A.                                                                                                                                                        |

| M28 |     | TransAlta Corporation |

Management’s Discussion and Analysis

Adjusted revenues for the three months ended Sept. 30, 2025 increased compared to the same period in 2024, primarily due to:

| • |     | Addition of gas facilities from Heartland; |

| • |     | Higher ancillary revenue due to production optimization between the Gas and Hydro segments; and |

| • |     | Favourable hedge positions settled, which generated positive contributions over settled spot prices 
 in Alberta; partially offset by                                                                     |

| • |     | Higher dispatch optimization due to lower market prices driven by milder weather and new gas 
 generation in Alberta; and                                                                   |

| • |     | Lower spot power prices in the Alberta market. |

Adjusted EBITDA for the three months ended Sept. 30, 2025 decreased compared to the same period in 2024, primarily due to:

| • |     | Higher fuel costs, carbon compliance cost and OM&A related to the