Company: TSLTF
Filing Date: 2025-12-12
Form Type: SUPPL
Source: 0001193125-25-317786
Chunk: 368

Company: TRANSALTA CORP
Filing Date: 2025-12-12
Form: SUPPL
Chunk 368
---
     |                         |   47 |     |      |   50 |     |                         |   44 |     |      |   61 |
| Ontario spot power price(1)      
 ($/MWh)                          |     |                         |   64 |     |      |   34 |     |                         |   54 |     |      |   32 |
| Natural gas price (AECO) per GJ  
 ($)                              |     |                         | 0.63 |     |      | 0.67 |     |                         | 1.43 |     |      | 1.24 |

| (1) | Ontario spot power prices through April 2025 were based on the hourly Ontario energy price              
 (HOEP). Starting May 2025 prices are based on the settled day ahead hourly Ontario zonal energy prices. |

For the three and nine months ended Sept. 30, 2025, spot power prices in Alberta were seven and 34 per cent lower, respectively, compared to the same periods in 2024, driven by generally milder weather and increased supply from new renewable and gas-firedfacilities. For the three and nine months ended Sept. 30, 2025, Mid-Columbia spot power prices in the Pacific Northwest were six and 28 per cent lower, respectively, compared to the same periods in 2024, due to lower natural gas prices and the impact of a milder weather on the nine months ended Sept. 30, 2025. Ontario spot power prices were higher on average compared to the same periods in 2024, due to nuclear refurbishments occurring in 2025 and higher natural gas prices. For the three months ended Sept. 30, 2025, AECO natural gas prices were six per cent lower, compared to the same period in 2024, mainly due to higher gas production in Alberta and throughout North America. For the nine months ended Sept. 30, 2025, AECO natural gas prices were 15 per cent higher, compared to the same period in 2024, mainly due to lower storage levels in Alberta and throughout North America, as well as stronger demand.

| M12 |     | TransAlta Corporation |

Management’s Discussion and Analysis Financial Performance Review of Consolidated Information

|                                                               |     | 3 months ended Sept. 30 |      |   |     |      |      |   |     | 9 months ended Sept.