Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 399

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 399
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 to common shareholders. Refer to the reconciliation of (loss) earnings before income taxes to adjusted net (loss) earnings attributable to common shareholders in the Reconciliation of Non-IFRSMeasures on a Consolidated Basis by Segment section of this MD&A. Funds From Operations (FFO) FFO is an important metric as it provides a proxy for cash generated from operating activities before changes in working capital and provides the ability to evaluate cash flow trends in comparison with results from prior periods. FFO is a non-IFRSmeasure. For a description of the adjustments made to Cash Flow from Operating Activities (the most directly comparable IFRS measure) to calculate FFO, refer to the Reconciliation of

| M56 |     | TransAlta Corporation |

Management’s Discussion and Analysis

Cash Flow from Operations to FFO and FCF section of this MD&A. Adjustments to Cash Flow from Operations

| • |     | FFO related to the Skookumchuck wind facility, which is treated as an equity-accounted investment                                                                                                                                                    
 under IFRS and equity income, net of distributions from joint ventures, is included in cash flow from operations under IFRS. As this investment is part of our regular power-generating operations, we have included our proportionate share of FFO. |

| • |     | Payments received on finance lease receivables are reclassified to reflect cash from operations. |

| • |     | We adjust for costs associated with acquisition-related transaction and restructuring costs that 
 are not reflective of ongoing operations.                                                        |

| • |     | We adjust for the items included in the cash flow from operating activities related to the decision                                      
 in 2020 to accelerate being off-coal and the shutdown of the Highvale mine in 2021 (Clean energy transition provisions and adjustments). |

| • |     | Penalties totalling $33 million were issued by the Alberta Market Surveillance Administrator                                                                                                                                                          
 for self-reported contraventions pertaining to ancillary services provided during 2021 and 2022 at our Brazeau hydro facility. The penalties were recognized in OM&A during the fourth quarter of 2024 and paid during the first quarter of 2025, and 
 have been excluded from FFO composition as they are not reflective of ongoing business performance.                                                                                                                                                   |

| • |     | Other adjustments include payments/receipts for production tax credits, which are reductions to tax 
 equity debt and include distributions from equity-accounted joint ventures.                         |

Free Cash Flow (FCF)