Transmission’s role in energy security and reliability

Transmission is essential to provide energy security and reliability. As Australia transitions to a clean-energy future, we need more transmission infrastructure. The Australian Energy Market Operator's 2022 Integrated System Plan sets out a path for the National Electricity Market to achieve a low-carbon electricity grid.

The ISP includes a rapid change from coal-fired generation to grid-scale wind and solar power by 2050. This happens at the same time as electricity use from the grid almost doubles.

Australia's energy transformation will need significant upgrades for renewable energies, more storage, complex network management, and, importantly, the installation of more than 10,000km of new transmission lines.

What is energy reliability?

Australians rightly expect that the lights will come on when they flip the switch at night. Electricity must be running through the poles and wires constantly, as the grid cannot currently store significant volumes of electricity.

The National Electricity Market must have enough energy to match the supply of energy with demand in real time. The standard imposed on the grid is to meet this balance at least 99.998% of the time.

While delivering electricity from the generator to the light bulb goes through several stages, transmission is a critical element to maintain a reliable and secure power supply. It is delivering. Electricity transmission standards recommend that in inner Sydney energy is available for all but 36 seconds during an entire year - 0.6 of a minute - ensuring residents in New South Wales enjoy consistent electricity supply.

But the energy reliability challenge is growing

Traditionally, the flow of electricity was straight-forward. Electricity flowed in one direction. Large-scale power plants generated the energy, and it was transmitted through high-voltage poles and wires to a transformer. The electricity then flowed through distribution lines to homes and businesses.

But transmission is becoming more complex as Australia moves rapidly to a renewables-led, low-carbon future. The rise of household solar connections - while positive to reduce costs and emissions for consumers - makes it more complex to the grid’s stability. Transmission providers are successfully managing operations to overcome technical issues such as voltage spikes or overloads when electricity is fed back into the grid at scale.

The nation’s transition to renewable energy sources is irreversible and progressing quickly. The proportion of renewable power generation has more than doubled over the last decade, jumping 126 per cent. Solar generation alone has increased almost 40 per cent since the late 2000s.

Under the AEMO forecasts, grid-scale solar and wind generation will increase nine-fold by 2050 and distributed solar will increase more than five-fold. This means more than doubling these renewable sources within the next eight years to 2030.

“From 2025, there will be moments when the National Electricity Market (NEM) has enough renewable energy to meet 100% of that demand,” the ISP says. “Investment in low-cost renewable energy, firming resources and essential transmission remains the best strategy to deliver affordable and reliable energy, protected against international market shocks.”

How does the change in generation impact grid reliability?

The rise of large-scale renewable energy production is demanding more of the transmission system. It creates two major priorities for the power system: resources such as hydro generation and gas-fired generation for “firming capacity” that can respond immediately to a dispatch signal, and modern control rooms to monitor and maintain the grid operations.

There is a need to establish alternatives to the coal generators that the system has traditionally relied on for system strength, inertia and voltage support. Coal-fired generators have already made announcements that about one-third of Australia’s current coal-fired generation (8GW from 23GW) will be withdrawn by 2030. AEMO expects the withdrawal could be as much as 14GW.

As the levels of renewables increases, so does the need to match energy inputs to consumers when and where they need it. This distributed and dynamic network of generation makes the grid more complex to operate.

Managing the transition to renewables reliably

The increasing number of projects will require more connections and major transmission lines, as well as interconnections across the national electricity grid. It is through these connections that the system can build resilience and connect geographically and technologically diverse energy generation.

If the sun is shining in regional New South Wales, for example, but not in Queensland, the electricity generated in NSW can be distributed north of the border, and visa versa. These interconnection projects will create a more resilient grid that has greater capacity to connect more renewable power sources, supply all customers when they need it, and enable Australia to grow as a clean energy superpower.

As the operator of the most important electricity transmission network in Australia, Transgrid is maintaining and upgrading the backbone of the National Electricity Market.

As Australia connects more renewables to the grid, Transgrid is building the new transmission that will deliver more reliable and low-cost energy by doubling our investment in assets by 2027 and tripling it by 2030.

Find out more about Transgrid’s Energy Vision here.