The National Electricity Market (NEM) has been in place since 1998. It brought together electricity industries in Queensland, New South Wales, the Australian Capital Territory, Victoria, South Australia, and Tasmania to drive greater efficiencies and a better utilisation of resources. It has served the nation well. But much has changed in the way we generate, consume and share energy that has implications for the way our energy services are supplied.
Addressing these implications is the core of the Post 2025 reforms.
Penetration of variable renewable energy resources is increasing
Source: ESB June 2020
Australia’s energy system is unlike any other around the world. Geographically, we’re an island continent with the world’s longest interconnected system, the national electricity market (NEM), which spans over 5,000km across our east coast.
This energy system delivers energy to Australia’s low-density population of around 25 million. The combination of large distances and low population means the challenges we face around system frequency, voltage control levels, and inertia, are highly unique compared with the global energy sector.
Much of Australia’s energy infrastructure was built from the 1950s and onwards, meaning our traditional generation resources are rapidly approaching the end of their 50-year technical and economic life.
More recently, declining costs, technology advancements, government policies and incentives, along with shareholder and consumer preferences are driving record investment in wind and solar generation, contributing to record-low wholesale energy prices.
AEMO’s 2020 Integrated System Plan (ISP) forecasts 63% of today’s coal-fired power stations will retire by 2040. The generators will be replaced by more than 30 gigawatts (GW) of wind and solar projects, 6 to 19 GW of firming generation, such as battery storage, pumped hydro and gas, along with rooftop solar PV to provide up to 22% of total energy capacity.
Historically speaking, in the 1990s it would take over 6 years to build a 200-megawatt power plant within our power system. If we fast forward to today, it now only takes 9 months to build a 200-megawatt solar plant, complete with approvals.
The pace and change in generation mix is already having significant implications for the future operation of synchronous generation units, which provide the bulk of essential power system security services. This is posing emerging operating challenges in some markets to deliver a secure, reliable and low-cost outcome for consumers.
Australia leads the world on a per capita basis in rooftop solar photovoltaic (PV) penetration at greater than 20%, with more than 2.5 million systems and 15 solar panels installed every minute on average. Penetration rates are already as high as 50% in some parts of the distribution networks in South Australia and Queensland.
Despite the growing number of connections and increased reliance on electricity, growth in electricity consumption has been in decline. Energy efficient buildings and appliances, along with the continued growth in the uptake of solar PV systems, are together contributing to record low electricity consumption and demand required from the grid.
While this can result in lower consumer costs, reverse power flows from distributed energy devices – without visibility to identify and manage – can also result in difficulties in voltage variability, which can in turn degrade power quality and adversely impact machines and home appliances.
Observed minimum operational demand in the NEM is now approaching at-risk thresholds for maintaining voltage, system strength, and inertia within secure limits. With continued rooftop solar PV installations pushing out the need for grid-scale supply (both synchronous and non-synchronous), minimum operational demand is creating real-time power system operating and planning issues.
In addition, a large proportion of rooftop PV inverters predominantly early adopters of the technology don’t have the capability to ‘ride-through’ electricity disturbances, further adding the risk during minimum demand periods of solar exports switching to demand spikes on the grid.
AEMO’s 2020 Electricity Statement of Opportunities confirms that most NEM regions now experience minimum operational demand in the daytime (SA 2016, QLD 2017, VIC 2018), with all regions expected to by 2024-25. In South Australia, minimum demand is forecast to reach close to zero by 2022-23, a world-first for a jurisdiction of its size.
As part of AEMO planning responsibility in the NEM, AEMO has recommended investment in new transmission infrastructure in the 2020 ISP to enhance the sharing of excess renewable energy and network services between states. This would help manage the emerging risk of minimum operational demand.
The decentralisation of large-scale and residential renewable generation is completely changing our approach to managing the complex and integrated characteristics of the power system to deliver a secure, low-cost outcome for consumers.
The Energy Security Board’s recommended four areas of reform address the critical needs of the energy sector: making sure we have the right mix of resources to keep the lights on; ensuring those services essential to maintain the system’s secure operation are available when needed; improving access to the grid; and providing for the integration of distributed energy (or behind the meter) resources into the overall market.
Australia’s unique combination of geography, population and influx of new generation resources means that some of the challenges our energy system is facing are years ahead of our global counterparts. The transition presents technical challenges, but also opportunities for innovation to benefit consumers with the right infrastructure, regulations and markets.
| 1998 | 2021 | IMPLICATIONS |
| Families and businesses were considered as just ‘consumers’ of electricity. Except for large industrial loads, customer relationships with energy retailers or local network businesses was limited. | Consumers concerned about affordability, responding to new tech opportunities to take control of energy consumption and bills, driving rapid uptake of distributed energy resources like rooftop solar, smart appliances, and metering. |
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| Relatively few, predominantly large thermal generating units | Increasing decentralisation of generators with more energy produced by variable renewable or small scale resources which have potential to drive down both emissions and generation costs. |
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| A mostly established transmission network. | New transmission needed to connect the new generation as the mix changes along with fast response storage and other technologies to come. |
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| Established distribution networks that were one directional with very few behind the meter, distributed energy resources in homes or businesses. | Rapid uptake of distributed energy resources and other behind-the-meter services by consumers of all types. |
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