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Issues we face
South Australia’s electricity system has undergone rapid change, with strong investment and fast uptake in renewable energy sources like rooftop solar, battery storage, solar farms, and wind farms.
However, our electricity grid was not originally designed to handle these new technologies. Traditionally, electricity was generated at a power station and sent one-way through the grid to the user. With these new technologies, electricity is also now being generated by the user and sent back into the grid.
While this is making a substantial contribution to a low carbon energy supply, operating a two-way system originally built for one-way, is creating new balancing issues for our system.
On what would be considered a perfectly mild, sunny, cloudless day, South Australia’s rooftop solar network can generate more power than the entire state requires.
While this is a good thing, added to the electricity already being generated by our solar farms, wind farms and power stations, keeping a stable balance of supply and demand becomes difficult.
Combine the above with days where electricity demand is much lower than usual, like public holidays and long weekends, maintaining the balance of supply and demand becomes even harder.
To keep the electricity network secure in these situations, rooftop solar systems may need to be remotely disconnected for a short amount of time from the grid. This is known as manual generation shedding.
New solar systems that are installed on rooftops in South Australia must have the technology to be remotely disconnected/reconnected to the grid.
On extremely hot days, during a heat wave for example, electricity demand rapidly increases due to the use of air conditioning across the state. On rare occasions, demand can increase to the point where it exceeds the amount of electricity that can be generated and supplied.
To keep the electricity network secure in these rare situations, homes and businesses may be temporarily disconnected from the grid for a short amount of time. This is called manual load shedding, or more commonly known as 'rolling blackouts'. This is done to reduce pressure on the electricity network and only happens in extreme situations when there is an urgent need to prevent major damage.
Power system security
Our electricity system is secure when technical factors such as voltage and frequency are maintained within their safe operating limits.
For example, the Australian electricity system operates very tightly around 50 Hertz (50 cycles per second). To maintain this frequency, our electricity grid must instantly balance electricity supply against demand. If there is an excess of supply, frequency will rise, and if there is too little supply, frequency will decrease (and vice versa for demand). The National Energy Market can only function if frequency is maintained between 47 Hz and 52 Hz.
While we have a number of large scale battery storage facilities, there isn’t enough capacity to store the vast amount of electricity being generated at times. There also isn’t enough stored capacity to supply the network in rare occasions of peak demand.
In addition to managing supply and demand balance, the system needs to be resilient to faults and emergency events.
The major transmission system is operated so that the loss of a piece of transmission network, will not result in customers not being supplied (known as a credible contingency). The Australian Energy Market Operator (AEMO) procures a range of ancillary services (in addition to the primary energy market) to maintain the system within tight operating standards.
If multiple events were to occur simultaneously (non-credible contingencies), the system has emergency schemes in place that quickly shed either load or supply to quickly bring the system into balance.
However, as the system has been transforming with a reduction in traditional non-renewable sources while also introducing new renewable technologies to the grid, there has been a reduction in technical capability that was provided as a bi-product of traditional generation.
For example, conventional generation is synchronised with the grid to operate at 50 Hz, all spinning at the same speed. The spinning mass of the generators and turbines provides ‘inertia’ and ‘system strength’ to the system, providing a stabilising force to the system to reduce changes in frequency and voltage. New technologies, such solar and wind farms, tend not to provide these services to the same level as they are not synchronised when they connect to the grid via electronic interfaces. Accordingly, the system has had to transition to access these system services from other sources.
The shift into two-way and renewable technology brings many benefits. Decreased impact on the environment, increased electricity generation and supply, but also new ways to combat large scale faults and emergency events. A range of projects and strategies are being investigated and introduced to strive for ongoing power system security.
Projects and strategies
A series of projects are being implemented to give South Australia greater control of our electricity grid and power system security. They will also increase self-reliance and provide reliable, competitive, and cleaner power into the future.
Projects
- Overview: An interconnector between South Australia and New South Wales, with an additional spur to Victoria.
- Benefits: Will increase power system security and allow supplementary import of electricity when demand is high. It will also allow export of excess renewable energy when demand is low.
- Further details: Available on the Project EnergyConnect website.
- Overview: Solar farms are in the pipeline to be constructed in Port Augusta and in Goyder.
- Benefit: Will provide additional electricity supply to South Australia, and help with peak demand issues.
- Further details: Port Augusta Energy Park and Goyder Renewables Zone
- Overview: Four large synchronous condensers have been commissioned, two at Davenport and two at Robertstown.
- Benefits: Synchronous condensers mimic traditional generators to regulate and normalise the electricity grid in times of need. These will increase power system strength and security.
- Further details: Available on the AEMO website.
- Overview: Multiple large scale energy storage facilities have been installed in South Australia, with more in the pipeline. Current facilities include the Hornsdale Power Reserve (was the world’s largest battery when commissioned), the Dalrymple battery facility, and the Lake Bonney Battery facility.
- Benefits: As well as providing a supply of electricity when required, these storage facilities also help store excess electricity, lowering oversupply and helping with minimum demand issues.
- Further details: Information is available on the Hornsdale, Dalrymple and Lake Bonney battery websites.
- Overview: Various studies and projects are underway to explore the use of hydrogen in South Australia. Some of these include Hydrogen Park South Australia (HypSA), Hydrogren Utility (H2U) and the Port Pirie Green Hydrogen project.
- Benefits: Excess renewable electricity can be converted into a liquid hydrogen fuel, which can be stored and converted back into electricity when needed. The fuel can also be used to power other items or blended with other chemicals to create other products. There are also opportunities to export hydrogen fuel interstate or internationally.
- Further details: Information is available on our Hydrogen in South Australia webpage.
Strategies
Other strategies are under investigation, some already being implemented, to reduce demand and infrastructure costs, both nationally and within the state.
- Benefits: Provides customers with additional options and incentives to move their electricity use from peak times to the middle of the day when renewable electricity generation is at its highest.
- Further details: Available on the time of use tarrifs webpage.
- Benefits: This technology gives customers the ability to track their electricity use throughout the day. This can be used to monitor usage trends and various appliance electricity demands. This will provide greater insight on how customers can lower their power usage.
- Further information: Available on the smart meters webpage.
- Benefits: New technical standards in place to ensure all new solar systems can be remotely disconnected and reconnected to the grid to help with minimum demand issues and power system security.
- Further information: Available on the dynamic export regulation changes webpage.
