Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 204

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 204
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) | Hedged power price average per MWh is calculated as the average sales price for all hedges and 
 direct customer sales during the reporting period.                                             |

| (3) | Fuel cost per MWh is calculated on production from carbon-emitting generation in the Gas and 
 Energy Transition segments.                                                                  |

| (4) | Carbon compliance cost per MWh is calculated on production from carbon-emitting generation, as 
 well as power purchased, in the Gas and Energy Transition segments.                            |

2024 versus 2023 The average spot power price per MWh for the Alberta portfolio for the year ended Dec. 31, 2024 decreased from $134 per MWh in 2023 to $63 per MWh in 2024, primarily due to:

| • |     | Higher generation from the addition of increased supply of new renewables and combined-cycle gas 
 facilities into the market compared to the prior period; and                                     |

| • |     | Lower natural gas prices. |

The realized merchant power price per MWh of production for the Alberta portfolio for the year ended Dec. 31, 2024, decreased by $27 per MWh, compared to 2023, primarily due to:

| • |     | Lower average spot power prices as explained above; and |

| • |     | Lower hedge prices compared to the prior year. |

Fuel cost per MWh for the year ended Dec. 31, 2024, decreased by $2 per MWh, compared to 2023, primarily due to lower natural gas prices. Carbon compliance cost per MWh of production for the year ended Dec. 31, 2024, increased by $2 per MWh, compared to 2023, primarily due to:

| • |     | The increase in carbon pricing from $65 per tonne in 2023 to $80 per tonne in 2024; partially 
 offset by                                                                                     |

| • |     | The utilization of emission credits to settle a portion of the 2023 GHG obligation during the year. |

2023 versus 2022 The average spot power price per MWh for the year ended Dec. 31, 2023 decreased from $162 per MWh in 2022 to $134 per MWh in 2023, primarily due to:

| • |     | Moderate temperatures in the last six months of the year compared with the prior year; |

| • |     | Higher total renewable generation in the Alberta market from new Wind