Joint Venture Partner Sues CS Energy for Over $1 Billion Over Callide Power Station Failures

The joint venture partner of Queensland's largest power station is suing the state-owned operator, CS Energy, for more than $1 billion.

Sev.en Global Investments said a series of catastrophic failures at the Callide power station had led to the loss of more than 1,700 days of generation capacity over the last five years.

CS Energy said in a statement it would defend itself against the allegations.

The government-owned operator of Queensland's largest power plant is being sued for more than $1 billion by its joint venture partner.

Czech-based investment group Sev.en Global Investments, which owns half of the Callide power plant through its subsidiary IG Power, filed proceedings in the Federal Court of Australia on Friday against CS Energy (CSE).

In a statement, Sev.en GI said it was seeking to recover losses incurred by three separate failures at the plant which led to the loss of more than 1,700 days of generation capacity.

A catastrophic explosion at the Callide C Power Station in 2021 was the result of a failed battery back-up system at the power station's C4 unit.

The explosion led to almost 500,000 Queensland customers losing power, becoming the state's worst power outage in decades.

A subsequent report revealed long-standing issues with safety practices at CS Energy, concerns about maintenance backlogs and inadequate risk management at the site.

C4 was offline for more than three years as a result of the incident, and Sev.en GI claims repairs to the unit have cost approximately $250 million.

Less than 18 months later, in October 2022, a cooling tower at the power plant's unit C3 collapsed due to structural issues.

Sev.en said the costs to repair, demolish and rebuild the cooling towers exceeded $330 million.

Finally, in April 2025, a boiler in unit C3 exploded, sparking another investigation which handed down a scathing report detailing inadequate risk controls, gaps in operator training, and flaws in the design of the unit.

That explosion left the C3 unit offline for another 58 days.

Sev.en GI said, as a 50 per cent owner in the joint venture, IGPC had been required to pay more than $290 million in rebuild costs and had lost "many hundreds of millions of dollars in foregone profits".

The lawsuit alleged CSE failed to disclose deficiencies in its process safety procedures and that serious concerns raised as early as 2019 had not been communicated directly.

In a statement, CS Energy said it had been aware for a number of years of potential claims by Sev.en for alleged losses relating to historical events since 2021 at Callide C Power Station.

"CS Energy will defend the legal action brought by Sev.en Global Investments in relation to any such claims," a spokesperson said.