South Australia reaping the solar harvest Tuesday, 30 January 2018

A 150 MW solar thermal power plant to be built about 300 km north of Adelaide, in the same region Elon Musk installed the world’s largest lithium-ion battery, is sure to be a beacon for engineers looking to work in the sector.

Global large-scale developer of solar projects, SolarReserve, has been given the green light to start building the plant this year - known as the Solar Aurora Energy Project - near Port Augusta. It will cost $650 million and be the biggest of its kind in the world. The company has now opened its Australian headquarters and a field office with the aim of completing the project by 2020.

The Aurora plant will deliver 495 GWh of power each year and have a lifespan of approximately 40 years without degradation and provide fully dispatchable baseload electricity to the network. SolarReserve revealed it will comprise more than 12,000 automatic, dual-axis tracking heliostats, measuring 96 m² in size each. These will cover an area of 1.2 million m² and equipped with a control unit and software to enable precise tracking of the sun.

The heliostats will be arranged in a circle around a 240-metre tall tower with a receiver on top - to increase the solar harvest. The plant will include a cold and hot salt storage tank, steam turbine and steam generator. Aurora will also be equipped with a dry cooling system that reduces water usage, saving one million litres annually.

How does it work? Liquid salt from the cold storage tank will be pumped into the receiver where it will be heated to 566°C. Once heated, the salt will flow into the hot salt tank and onto the steam generator to produce steam, and drive the steam turbine to generate electricity. The company said the plant will be connected to a 275 kV transmission network nearby and will be able to store 1100 MWh of energy for up to eight hours.

Aurora will use molten salt as a heat transfer medium as it retains heat and allows for uninterruptable electricity generation. As the salt will be circulated through the receiver during the day and stored in tanks at night, round-the-clock operation will be possible. SolarReserve said the molten salt does not need to be replaced for the entire lifespan of the plan as it can be recirculated with no loss expected, making it cost-effective, reliable and efficient.

From 2020, Aurora will supply 100% of South Australia’s electricity load, having won a competitive tender process. The state government said the project would also supply the broader market which will enhance competition and put downward pressure on electricity prices.


Image: An illustration of the Aurora project. Source: SolarReserve.