Coober Pedy: A model for the future of power generation

Energy Developments has successfully completed a world-class hybrid renewable project in Coober Pedy, South Australia.

Since 2004, Energy Developments (EDL) has supplied electricity to Coober Pedy, a remote mining community located 846km north of Adelaide in South Australia, via a diesel-fuelled power station.

After identifying an opportunity to displace diesel with renewables, Energy Developments worked with the District Council of Coober Pedy and the South Australian Government to create the Coober Pedy Renewable Hybrid Project (CPRHP).

The project was partially funded by the Australian Renewable Energy Agency (ARENA).

The project is a hybrid combination of 4MW of wind, 1MW of solar, and a 1MW/500kWh battery that uses enabling technologies to integrate the renewables with the existing 3.9MW diesel power station.

The CPRHP started supplying power to Coober Pedy in March 2017, ahead of the original schedule, when the solar array was connected to the switchboard.

The solar was constrained to 30 per cent diesel load given the integration and enabling technologies were yet to be integrated.

The diesel station had no issues in responding to the solar intermittency, confirming the 30 per cent load set point was well chosen to both ensure system stability and allow integration in minimal time and not distract from the completion of the whole project.

Since completion of commissioning of the individual system components and the integration of the control systems on July 1, 2017, the performance of the integrated hybrid system has met or exceeded expectations.

Since October, the town has run on 100 per cent renewables for approximately 46 per cent of the time.

Less than one year since commissioning, 70 per cent of the Coober Pedy’s power is being sourced from renewables.

The project is on track to have all diesels turned off for about half the negotiated 20-year power purchase agreement (PPA) and there is good reason to believe there is scope for further significant improvement in renewable penetration and, therefore, diesel displacement.

“This project is setting global benchmarks for renewable penetration in a megawatt-scale islanded grid and is demonstrating what can be achieved technically in the integration of renewables with thermal generation while retaining reliable supply and power quality,” Energy Developments chief executive officer James Harman said.

The current composition of the hybrid system provides a number of opportunities to enhance the power system and provide further benefits to the community of Coober Pedy.

The design of the system (an inherent characteristic of any high-penetration islanded hybrid system) results in a substantial amount of spilled energy which creates potential for demand side management of existing loads, and the introduction of storage to shift excess generation.

Coober Pedy station layout

These types of opportunities could increase the average renewable penetration rate significantly above the 70 per cent achieved to date.

Importantly, the technical issues faced to date have not related to the intermittency and integration controls between the renewables and the diesel thermal plant.

Rather they have related to specific system component technical issues that have not interrupted supply, and these issues have been resolved by Energy Developments in its ongoing management of the project.

Apart from an outage caused by a severe electrical storm that also disrupted the town’s distribution system, the hybrid project has supplied reliable power and improved power quality.

Beyond power generation, Energy Developments is supporting the Coober Pedy community through an Indigenous Land Use Agreement with the AMYAC, sponsoring the Annual Opal Festival and the annual Opal Trade Show, and supporting community initiatives through the District Council of Coober Pedy.

Mr Harman believes the CPRHP can be further developed and augmented, and is readily translatable to many locations in Australia.

“The challenge moving forward with projects of this type is to reduce the cost of high penetration hybrid projects,” he said.

“As such, Energy Developments is looking at ways to increase the efficiency of integration and to reduce the scale and complexity of the enabling technology while maintaining reliable power and power quality.”

Energy Developments acknowledges the support of ARENA in the development of this project.