TransAlta's Sheerness Unit 1 to be mothballed April 1

Executive Summary

• TransAlta Corp. subsidiary Alberta Power (2000) Ltd. has notified the Alberta Electric System Operator that Sheerness Unit 1 will be temporarily mothballed effective April 1, 2026, for a period of up to two years.
• The mothballing is a financial decision to preserve long-term optionality while awaiting favorable market fundamentals or contracting opportunities.
• Sheerness Unit 1 will remain fully operational through the winter season, and Sheerness Unit 2 will remain fully in service.

Key Details

• Action: Notice to mothball Sheerness Unit 1 provided to the Alberta Electric System Operator.
• Effective Date: April 1, 2026.
• Duration: Up to two years.
• Operational Status: Unit remains available and fully operational through the winter season; Sheerness Unit 2 remains fully in service.
• Rationale: Prudent financial decision to preserve long-term optionality of the asset while reserving it for future economic opportunities.
• Strategic Context: CEO John Kousinioris cited continued progress on the company's data centre strategy and significant value at Alberta thermal sites.

Notable Quotes

• "We have made the prudent financial decision to temporarily mothball Sheerness Unit 1 while reserving it for future economic opportunities. There is significant value at our Alberta thermal sites and we remain very pleased with the continued progress on our data centre strategy. Today's decision ensures we preserve the long-term optionality of the asset," said John Kousinioris, president and chief executive officer.