A Queensland government office has estimated the cost of diving into pumped hydro. 

The director-general of Queensland's Department of Public Works and Energy, Paul Martyn, has revealed significant cost disparities between two approaches to meeting the state's long-duration energy storage requirements for its renewable energy zones. 

According to Martyn, opting for batteries to fulfil the need would inflate costs by a staggering $18 billion compared to using pumped hydro storage.

The government had initially allocated $14 billion for the Borumba 24-hour pumped-hydro storage project, which would generate 2000 megawatts. 

Martyn stated that replicating this storage capacity with batteries would require a staggering $32 billion investment.

While acknowledging the role of batteries in the energy landscape, Martyn said pumped hydro assets like Snowy 2.0 - despite its doubled budget of $12 billion - is critical for deep seasonal storage, along with the incorporation of some gas-based solutions to address prolonged renewable energy supply shortages.

Martyn attributed Queensland's ability to manage costs and provide a more predictable transition to its public ownership of coal-fired power stations. 

This contrasts with other states that have experienced delays and budget overruns in their renewable energy zone rollouts due to privatisation of generation and transmission companies.

For instance, NSW, which privatised its energy assets, has faced considerable delays and increased costs. 

The Central West Orana renewable energy zone, initially slated for commissioning in 2025, is now expected to come online in 2027 or 2028, according to James Hay, CEO of EnergyCo, responsible for delivering REZs in NSW. 

However, Hay dismissed claims that the budget for Central West Orana had ballooned to $3 billion.