How coal-fired power stations will become clean energy hubs 

Over the next decade, Queensland will gradually become less reliant on coal-fired power stations for energy – but these stations will continue to play a crucial role in the grid. 

Traditionally, coal-fired power stations have supplied the bulk of the electricity generation in the grid. But by 2035, it’s expected that Queensland’s renewable energy generation and storage will have progressed to the point that the state will no longer need to rely on coal-fired energy. 

The challenge is that these coal-fired power stations don’t just provide power. They also provide critical services that help to keep the state’s energy system reliable and secure. 

That’s why – even when renewable energy generators, pumped hydro energy storage, batteries, and low emissions gas-fuelled plant are able to collectively replace the power currently provided by coal – Queensland’s publicly owned coal-fired power stations will continue to serve an important purpose. 

These sites, including Stanwell Power Station and the Tarong power stations, will be gradually converted into clean energy hubs that will provide critical system strength, storage and firming services. 

Why are coal-fired power stations being repurposed? 

To say that coal – a nonrenewable fossil fuel – plays a large role in generating the power that we consume would be an understatement. 

Queensland’s electricity system has traditionally consisted mainly of dispatchable generation – generation that can be increased or decreased on command to ensure supply always meets demand. This dispatchable generation can come from gas turbines and hydro-electric plants, but most of it comes from coal-fired power stations, which are designed to run 24/7 and provide a steady, affordable ‘baseload’ of power. 

There’s around 8,100 megawatts (MW) of coal-fired generation in Queensland. That’s the equivalent of roughly 880,000 average home solar installations, if those installations were able to generate solar energy day and night. 

Replacing that level of production with clean energy might seem like a tall order, but that’s exactly what Queensland is in the process of doing. By 2035, under the Queensland Energy and Jobs Plan, it’s expected that there’ll be enough clean energy and storage in the grid – including wind and solar energy, pumped hydro energy storage, batteries, and low emissions gas-fuelled plant – that Queensland will no longer need to rely on coal-fired generation.

There are two main challenges with this. The first is that, whereas coal-fired generation is dispatchable, wind and solar generation is variable – it’s entirely dependent on the weather, so it’s volatile on a day-to-day basis. 

The second is that electricity isn’t the only service that coal-fired stations provide to the grid. These units also provide system strength and inertia. 

Coal-fired power stations are synchronous generators, which means they’re purposely designed to spin at the same frequency as the power system (and resist changes to this frequency). By maintaining this frequency, they help to provide system strength and inertia. 

System strength refers to the power system’s ability to respond to disturbances, like generator outages and transmission line faults. Essentially, the more system strength there is in an energy grid, the more resilient it will be when disturbances occur. 

Similarly, inertia acts as a shock absorber, giving the grid more ability to withstand surges and imbalances in supply and demand.

These services are crucial for maintaining the reliability of the grid, and coal-fired power stations provide them as a by-product of their synchronous generation. But solar panels and wind turbines, which are connected to the grid via inverters, aren’t synchronous generators – so, as renewables gradually come to make up a larger proportion of the energy in the grid, system strength and inertia will need to come from elsewhere. 

Repurposing Queensland’s publicly-owned coal-fired power stations into clean energy hubs will go a long way towards solving these problems.

What is a clean energy hub? 

Under the Queensland Energy and Jobs Plan, coal-fired power stations will continue to serve in a back-up capacity for as long as required. But by 2035, it’s expected that Queensland’s publicly owned power stations will have become clean energy hubs, helping to replace the services that are currently provided by coal-fired generation. 

They’ll do this in two main ways. First, by ‘firming’ the output of renewable generators. For the supply of energy to match demand as the amount of variable wind and solar energy in the grid increases, there’ll need to be a flexible supply of dispatchable energy that can be called on when the sun isn’t shining and the wind isn’t blowing.

This firming capacity will take various forms, including grid-scale batteries that absorb renewable energy, store it, and discharge it when needed; and low emissions gas-fuelled generators that can start up quickly at times of peak demand or low supply. (Eventually, it’s expected these generators will be fuelled by renewable hydrogen, which generates no emissions.) 

Clean energy hubs will play host to these batteries and gas-fuelled generators, capitalising on the skilled workforces, existing infrastructure and strong network connections that are already present at these sites. 

The second way these clean energy hubs will help is by providing system strength and inertia. This will be done by converting generating units into synchronous condensers, so they continue to spin at the grid’s frequency and provide essential system services without exporting power.

To ensure the reliability of supply, the coal-fired unit conversions will be designed to be reversible, so they can return to service if needed. 

In addition to providing storage, firming, system strength and inertia, clean energy hubs are also expected to serve as maintenance hubs for nearby government-owned wind and solar farms – again capitalising on the strong network connections that have already been established at these sites. 

Which power stations will be converted into clean energy hubs? 

As Queensland’s largest energy supplier, Stanwell will enable the state’s smooth transformation by progressively repurposing Stanwell Power Station and the Tarong power stations into clean energy hubs, and developing a pipeline of renewable energy and storage projects around them.  

CS Energy – which, like Stanwell, is a Queensland Government owned energy company – will also repurpose Kogan Creek Power Station and Callide B Power Station into clean energy hubs.

Privately owned power stations will make their own decisions about their future operations, with the understanding that the system is being designed to operate without reliance on coal by 2035. 

What’s the process for converting power stations into clean energy hubs? 

The repurposing of coal-fired power stations into clean energy hubs will be carefully coordinated to ensure continued energy security, with government investment to convert existing assets and fund new technology. This includes grid-scale battery projects that have already been approved for installation at multiple power station sites. 

The Queensland SuperGrid Infrastructure Blueprint proposes a three-phase process for these stations.  

1. A gradual shift to seasonal operation or synchronous condenser conversion, which is reversible, for one or more units from 2027. 

2. Once Queensland’s first long duration pumped hydro energy storage (PHES) is online, more units will be shifted to seasonal operation or reversible synchronous condenser conversion. 

3. Once the second long duration PHES is online, further units will be shifted to seasonal operation and reversible synchronous condenser conversion. Stations in Phase 3 will operate as clean energy hubs, with potential for on-site storage, dispatchable capacity, hydrogen development, and operations and maintenance bases for publicly-owned large scale renewable energy. 

It should be noted, however, that the pathway outlined by the Blueprint is expected to adapt and evolve over time, in response to the changing market outlook, emerging risks and new opportunities. 

For that reason, the Government will establish a Queensland Energy System Advisory Board to provide expert technical advice and update the Blueprint as the system transforms. 

In the meantime, Stanwell will continue operating our power stations day-in, day-out, to provide baseload power and keep downward pressure on prices. 

How will this affect workers at these power stations? 

The energy transformation is about people working together to find solutions that bring the greatest mutual benefit. 

In that spirit, the Queensland Government has established a Job Security Guarantee for workers at publicly owned coal-fired power stations. The Guarantee is backed by a $150 million funding commitment, and an Energy Workers’ Charter between unions, government and employers, including Stanwell. 

The Guarantee provides workers with opportunities to continue their careers within publicly owned energy businesses, or pursue other career pathways. It does this by supporting workers to transfer between publicly owned energy businesses to secure new, ongoing opportunities; undertake additional training or skills development; and seek advice on their career options with dedicated future pathway managers. 

The state government has also released a Clean Energy Workforce Roadmap that outlines the steps required to develop workforce capacity and capability as part of a low-emissions economy; and released a Future Energy Jobs Guide to help workers explore new career opportunities and training pathways in the clean energy sector. 

At Stanwell, as well as building our portfolio of renewable energy and storage projects, we’re also focused on developing career pathways and opportunities for our people in Queensland’s renewable future. This includes our Future Energy Innovation and Training Hub (FEITH) at Stanwell Power Station, which will provide a real-life, hands-on training environment for our people to develop the skills needed to work on emerging energy technologies. 

Our people are at the heart of our business – and our priority is to create new opportunities for them as the energy industry evolves.