Renewable energy is rapidly increasing its penetration of Australia’s overall energy supply mix, with states like South Australia heading towards a 75 percent market share by 2025.
By 2050, almost all of the country’s coal generators will have reached the end of their technical lifecycle and will not be replaced – in a national bid to reduce carbon emissions and meet the prescribed targets of the 2016 Paris Agreement.
For environmentalists, the extinction of baseload generators and the “forced penetration of renewables” is a welcome move. But for some consumers and political parties – for whom affordability and reliability are equally (if not more) important aspects of the energy trilemma – it presents a complex challenge.
As baseload generators disappear, so too does inertia, system strength and dispatchable energy – leaving the nation exposed to price spikes and power outages, as seen in the 2016 South Australia blackout.
Replacing the current energy generation regime with a model comprised mostly of renewable resources and technologies will require a change in approach, says Andrew Kingsmill, Manager of Network Planning at TransGrid.
“There is no doubt that, as the uptake of renewables increases, there are places in the grid where reliability and stability will need to be addressed going forward. Without a co-ordinated plan, today’s electricity grid will not be sustainable,” he says.
Firming capacity, such as storage, is an imperative
Significant research and investment has been channelled into improving the ability of the power system to manage generation and load peaks into the future, as well as control instruments and long-term storage systems.
Storage solutions provide the backup generation needed for intermittent resources, like wind and solar, to maintain consistent levels of supply and reliably transmit power on a mass scale.
Pumped hydro – a method of storage which relies on vast reservoirs of water – is a large-scale solution that is suited to long-duration storage. But it requires substantial real estate and can be costly.
Batteries are showing strong technical potential, and have emerging commercial viability for short-duration storage.
In 2018 a number of utility scale batteries connected to the grid, including a 30 MWh Ballarat Energy Storage System in Victoria, a 30 MW/8 MWh Dalrymple Energy Storage for Commercial Renewable Integration in South Australia, the 25 MW/50 MWh Gannawarra Energy Storage System in Victoria and the 5 MW Alice Springs Battery Energy Storage System in the Northern Territory.
Commercial scale batteries are also gaining traction. By allowing consumers to store their own excess energy generated through solar panels, battery owners can become more energy independent. However, battery costs are still quite prohibitive for widespread commercial uptake. Some safety concerns have also been raised, with lithium ion batteries susceptible to thermal runaway, if not used properly.
Synchronous condensers are also technically promising. These can help to meet reactive power needs, boost system inertia and provide system strength and dynamic voltage recovery after system disturbances.
These technologies all have the potential to improve grid stability. However, in the absence of a sufficiently interconnected grid, their contributions may be geographically limited.
Interconnectors are another promising way to improve energy flows, deliver price reductions and share ancillary services such as system strength and inertia between states.
“Interconnectors help to share available generation between states to provide a reliable supply. When there is high demand in one state, interconnectors can supplement that with supply from adjacent states,” says Andrew.
“They can improve access to market for low cost generation and keep prices at a minimum for consumers.
“Interconnectors also share ancillary services. So, you don’t have to over-invest to provide system strength and inertia at a state level – states can share these aspects.”
Last year AEMO published an Integrated System Plan (ISP) setting out a least-regrets pathway for the NEM to adapt to the future energy system.
The ISP found that interconnector development will lead to the most efficient energy system in the future, enabling high penetration of intermittent renewable generation with firming technologies such as storage or gas peaking generation, pumped hydro.
With NSW being central in the NEM geographically, TransGrid is working with its peers in other states to deliver the interconnector projects in the ISP.
Andrew concludes by saying, interconnectors form an integral part of the suite of solutions which will keep the NEM stable for decades to come.
“Interconnectors are essential to the changing energy landscape. They are integral to a timely and well delivered transition to the energy system of the future – which is essential to reduce electricity prices, maintain the reliability of the electricity system and lower carbon emissions.
“Interconnectors will deliver a much-needed platform for renewables to deliver dispatchable electricity which is reliable, secure and affordable,” he says.
Hear more from Andrew about the role of interconnectors and other storage solutions at Informa’s Maintaining Grid Stability Forum 2019 – due to take place 2-3 December in Melbourne.
Learn more and register.