Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 378

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 378
---
 | — %   |
| Centralia mine reclamation spend(3)       |     |                         |     4 |   |     |      |     5 |   |     |        |   (1 | ) |     | (20)%  |     |                         |     12 |   |     |      |     12 |   |     |        |    — |   |     | — %   |

| (1) | All of the power produced by Centralia is sold by the Energy Marketing segment for physical                                                                                                                                                           
 market delivery, which is shown as merchant sales volumes. Power required to fulfil contractual obligations is included in purchased power. Total production from the facility includes the net result of merchant sales volumes and purchased power. |

| (2) | Adjusted revenues, adjusted gross margin, adjusted EBITDA and adjusted earnings before income                                                                                                                             
 taxes are non-IFRS measures, are not defined and have no standardized meaning under IFRS and may not be comparable to similar measures presented by other issuers. The most directly comparable IFRS measure to           
 adjusted revenues is revenues of $158 million and $385 million for the three and nine months ended Sept. 30, 2025, respectively (Sept. 30, 2024 — $165 million and $461 million), to adjusted gross margin — gross margin 
 $60 million and $138 million for the three and nine months ended Sept. 30, 2025, respectively (Sept. 30, 2024 — $60 million and $144 million), to adjusted EBITDA and adjusted earnings before income taxes — earnings    
 before income taxes of $23 million and $50 million for the three and nine months ended Sept. 30, 2025, respectively (Sept. 30, 2024 — $8 million and $31 million).                                                        |

| (3) | Highvale and Centralia mine reclamation spend, which represent the costs necessary to bring the                                                                                                                                        
 sites to their original condition, are supplementary financial measures and are included in the Decommissioning and restoration liabilities settled during the period in the consolidated statements of financial position under IFRS. |

| M30 |     | TransAlta Corporation |

Management’s Discussion and Analysis

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

| • |     | Lower Mid-Columbia prices; partially offset by |

|