An exploration into how electricity evolved from a local lighting service into the infrastructure underpinning modern life—and why Australia’s electricity system must now expand while simultaneously replacing much of what built it.

Electricity has become so embedded in everyday life that most of us notice it only when it stops. It powers homes, hospitals, telecommunications, transport networks, water systems, businesses, manufacturing and almost every digital service we use. Increasingly, it will also power vehicles, heating, industrial processes, artificial intelligence and the data centres supporting the digital economy.

Yet the electricity system was not originally designed for this world; it began with small generators serving a handful of streets. It grew into large, centralised networks built around coal and hydroelectricity. It then became a national market—and is now evolving into something larger, cleaner, more decentralised and far more complex. The important story is not simply that Australia is replacing coal with renewable energy. It is that this replacement must occur while electricity demand rises, consumption patterns change, and millions of households become generators and storage providers in their own right.

From the first electric lights to a national power system

One of the earliest commercial electricity systems began operating at New York’s Pearl Street Station in September 1882. It initially powered approximately 400 lamps within a small area because early direct-current systems could not transmit electricity over long distances. The real innovation was not only the light bulb: it was the complete system of generators, cables, meters and customer connections needed to deliver electricity as a service. Smithsonian National Museum of American History, US Department of Energy

Australia followed quickly; back in November 1888, Tamworth became the first Australian town or city to use municipally operated electric street lighting. Its original network powered 21.5 kilometres of streetlights—an early example of electricity being treated as essential civic infrastructure. Tamworth Regional Council

South Australia’s early electricity system developed around Port Adelaide and central Adelaide. The Grenfell Street Power Station opened in 1901 with approximately 400 kilowatts of capacity. By 1917, growing demand had pushed its output beyond 12,000 kilowatts. Electricity was no longer limited to lighting: it was powering businesses, expanding suburbs and Adelaide’s electric tramways. History Trust of South Australia . That pattern would repeat for more than a century. New electricity supply enabled new technology, and each new technology created more demand.

The electricity and demand timeline

Historical Australian generation figures are from the Australian Government’s latest national electricity dataset. Australian electricity generation, 1984–2025

The first great expansion: building modern Australia

Electricity demand increased rapidly after the Second World War as Australia industrialised, its population grew, and more households acquired refrigerators, washing machines, televisions, electric water heaters and other appliances. This was the era of large, centralised public infrastructure.

The Snowy Mountains Hydro-electric Scheme began in 1949 and was completed in 1974. It incorporated major dams, tunnels, aqueducts and power stations, providing electricity, water security and a foundation for national development. More than 100,000 people from over 30 countries worked on the scheme, making it both an energy project and an important part of Australia’s migration and multicultural history. Snowy Hydro history

Electricity systems were generally designed around a one-way model:

Large power station → transmission network → distribution network → customer

Coal and hydro generators supplied predictable electricity to passive consumers. Demand rose as homes, cities and industries added more electrical equipment, and governments responded by building larger power stations and extending networks.

The national market era

By the 1990s, Australia’s separate state electricity systems were moving towards greater interconnection and competition. The National Electricity Market began operating in December 1998, connecting Queensland, New South Wales, the Australian Capital Territory, Victoria, South Australia and, later, Tasmania through an interconnected wholesale market. Australian Energy Market Commission

Australia generated 203.8 TWh of electricity in 1998–99. By 2009–10, generation had reached 249.3 TWh. The growth reflected population, industry, air conditioning, telecommunications, computers and an expanding commercial economy. But after decades of largely consistent increases, demand growth began to slow. More efficient appliances, improved building standards, structural changes in manufacturing, and the rapid adoption of rooftop solar altered how much electricity customers needed from the grid, creating an important distinction.

Electricity use and grid demand are not the same thing

When rooftop solar powers a home during the day, that household is still using electricity—but the electricity may never pass through the transmission system.

Energy analysts therefore distinguish between:

• Underlying consumption: all electricity being used, including electricity supplied behind the meter by rooftop solar.

• Operational demand: electricity that must be supplied through the power system.

• Peak demand: the highest level the system must supply at a particular moment.

• Minimum demand: the lowest level of grid demand, increasingly occurring during sunny periods when rooftop solar output is high.

This explains why society can become more electrified while household demand from the central grid falls. Australia has now supported more than 4.2 million rooftop solar systems. AEMO reports that 36% of suitable dwellings in the NEM already have rooftop solar, while approximately 600,000 households have batteries. Clean Energy Regulator, AEMO 2026 Integrated System Plan

In October 2025, consumer and business energy resources briefly supplied more than 60% of NEM demand. This was not produced by a single power station. It came from thousands of distributed systems operating across the market.

The electricity system is becoming two-way:

Grid generation ↔ networks ↔ homes, businesses, batteries and electric vehicles

Australia’s demand and renewable generation have risen side by side

Between 1984–85 and 2025, total generation increased by approximately 140%. Renewable generation increased more than sevenfold. Solar supplied 19.6% of Australian electricity in 2025, wind supplied 14%, and hydro supplied 4.7%. On Australia’s five major grids, renewable electricity reached 42%. Australian Government electricity statistics

The latest results show the transition continuing. During the June quarter of 2026, renewable generation supplied a record 42.1% of NEM electricity, with wind, grid-scale solar and rooftop solar all increasing while coal and gas generation fell. AEMO Quarterly Energy Dynamics, Q2 2026

Why electricity demand is rising again

Efficiency and rooftop solar moderated grid demand during parts of the 2010s. The next phase looks different. AEMO forecasts operational electricity consumption in the NEM will increase from approximately 178 TWh in 2024–25 to 229 TWh by 2034–35—a 28% increase in a decade. The main drivers include data centres, business electrification and new industrial loads. AEMO reliability outlook 0 Over the longer term, AEMO expects underlying NEM electricity consumption to rise from approximately 205 TWh today to about 390 TWh by 2050.

Five forces sit behind this increase.

1. Transport is moving from oil to electricity

Electric vehicles shift energy demand away from petrol and diesel and onto the electricity system. AEMO forecasts that approximately 80% of vehicles in use could be electric by 2050. Properly coordinated charging could absorb excess solar generation during the day or charge overnight when demand is lower. Poorly coordinated charging could add pressure during existing evening peaks. The vehicle therefore becomes both a new electrical load and, potentially, a flexible energy resource.

2. Buildings are electrifying

Gas heating, gas hot water and gas cooking are increasingly being replaced by electric alternatives such as heat pumps and induction cooktops. Electric appliances can be considerably more efficient than the fossil-fuel systems they replace. Even so, widespread electrification shifts more of society’s total energy requirement onto the power system. Cooling is also becoming a larger global driver. The International Energy Agency expects air conditioning to account for more than 20% of worldwide electricity-demand growth between 2026 and 2030. IEA Electricity 2026 demand outlook

3. Industry is switching fuels

Manufacturing, mining, freight and industrial processing have traditionally used a combination of electricity, coal, oil and gas. Electrifying these activities can reduce emissions, but it can also create large new connection requirements. Some facilities may need as much power as a regional town—or significantly more. AEMO expects business and industry to require around 280 TWh of grid-supplied electricity by 2050, approximately double the current level.

4. Population and economic activity continue to grow

More people, homes, businesses, hospitals, schools, transport services and commercial facilities create additional demand. Efficiency can reduce the energy required for each individual activity, but it does not automatically cancel the effects of population growth and an expanding economy. AEMO estimates stronger energy-efficiency policies and technology could reduce underlying electricity consumption by approximately 75 TWh in 2050 compared with what it would otherwise have been. Efficiency therefore acts as infrastructure: energy that does not need to be generated, stored or transported.

5. Data centres are becoming major electricity customers

Data centres support cloud services, financial transactions, streaming, government systems, business software and artificial intelligence. AEMO estimates data centres consumed approximately 4 TWh in the NEM during 2024–25—about 2.2% of grid demand. Under its Step Change scenario, consumption could reach around 12 TWh by 2029–30 and approximately 34 TWh by 2049–50. That would represent about 12% of grid-supplied NEM electricity. AEMO data-centre forecasting The issue is not only the total electricity consumed. Large data centres can operate continuously, concentrate hundreds of megawatts of demand in one location and require extremely high reliability. Their location can therefore determine where new substations, transmission lines, generation and storage are needed.

The global demand curve is also turning upwards

The IEA describes the current period as an emerging “Age of Electricity”. Global electricity consumption reached approximately 28,600 TWh in 2025 and is forecast to reach 30,700 TWh by 2027. Demand is expected to grow by 3.6% in 2026 and 3.8% in 2027, driven by industry, appliances, electric vehicles, air conditioning, heat pumps and data centres. IEA Electricity Mid-Year Update 2026

Global data-centre electricity use is expected to rise from approximately 485 TWh in 2025 to about 950 TWh in 2030. AI-focused facilities are forecast to grow substantially faster than conventional data centres. IEA Energy and AI

Electric vehicles are another rapidly growing load. The global EV fleet used approximately 250 TWh in 2025. Under current policy settings, this could exceed 1,500 TWh by 2035. IEA Global EV Outlook 2026

These increases do not mean every country or region will experience identical growth. Demand will depend on climate, industry, population, technology, policy and economic conditions. But the overall direction is clear: more activities are moving onto electricity networks.

What Australia must build alongside growing demand

Australia is not merely adding renewable generation to the existing electricity system. It is rebuilding the system around a different operating model while much of the coal fleet retires.  In 2010, the NEM had 26 major coal-fired power stations with approximately 30 GW of capacity. At the beginning of 2026, 15 remained, providing about 21 GW. AEMO expects most remaining coal generation to withdraw by 2038 and all of it by 2049.

Under AEMO’s least-cost development pathway, the NEM would require by 2050:

• Almost 120 GW of utility-scale wind and solar

• Nearly 50 GW of utility-scale storage and hydro

• Approximately 17 GW of flexible gas-powered generation for backup

• Around 6,000 kilometres of additional transmission

• Approximately 87 GW of rooftop and other small-scale solar

• Approximately 35 GW of consumer batteries

• A more flexible distribution system capable of managing two-way electricity flows

AEMO estimates this pathway requires approximately $106 billion in utility-scale generation, storage, firming and network investment to 2050, expressed in today’s dollars. AEMO 2026 Integrated System Plan

CSIRO’s latest GenCost analysis continues to identify renewables supported by storage and transmission as the lowest-cost new-build pathway, while also highlighting falling battery costs and the importance of integrating the full system. CSIRO GenCost 2025–26

Generation alone is not enough

A power station can generate electricity only if the wider system can connect, transport, balance and use it. Growing electricity demand therefore requires coordinated investment across:

• Generation

• Transmission

• Distribution

• Substations

• Batteries and pumped hydro

• Flexible backup

• System strength and stability services

• Digital control systems

• Skilled workers and supply chains

• Demand management

• Energy efficiency

• Community and landholder engagement

Worldwide, the IEA estimates annual grid investment must increase by approximately 50% from today’s level of US$400 billion to meet electricity needs through 2030. IEA Electricity 2026: Grids

Flexibility is equally important. Batteries, demand response, coordinated EV charging, flexible industry and better price signals can move some consumption away from periods of system stress and into periods when renewable electricity is abundant. IEA Electricity 2026: Flexibility

This makes demand part of the solution—not only a number the supply system must chase.

The community dimension

The future electricity system will require more physical infrastructure across more locations. Renewable Energy Zones, transmission corridors, substations, batteries, pumped hydro facilities, wind farms, solar farms and large industrial connections all have local impacts. They affect landholders, First Nations communities, regional towns, biodiversity, landscapes, local roads, housing, employment and community services.  Demand may be created in cities, industrial centres and the digital economy, while much of the infrastructure needed to meet it is hosted in regional Australia. That makes social licence and strategic engagement central to delivering the system. Consultation cannot begin after routes and sites have effectively been decided. Communities need clear information about why infrastructure is required, how alternatives were assessed, what cumulative impacts are expected and how local benefits will be shared. AEMO now includes social licence and demand-side considerations as formal components of the Integrated System Plan. AEMO ISP Social Licence Appendix, AEMO Demand Side Factors Statement

The next electricity system will be bigger—but also smarter

The electricity system that served Australia through the twentieth century was built around large generators supplying passive customers.  The system emerging through the twenty-first century will be different. It will combine utility-scale wind and solar with rooftop systems, household batteries, large storage projects, hydroelectricity, flexible backup, electric vehicles and active consumers. Electricity will move in multiple directions, and demand will increasingly respond to when energy is available.

By 2050, Australian households could draw less net electricity from the grid even while owning more electrical appliances and vehicles. At the same time, business and industrial grid demand could double. This is the apparent contradiction at the heart of the transition:

Electricity demand is increasing—but not everywhere, not at every time and not in the same way.

The challenge is no longer simply generating enough electricity over an entire year. It is ensuring that the right amount of reliable electricity is available in the right place at the right time.

Where the timeline is heading

The first electricity networks supplied a few streets, whereas the twentieth-century grid supplied cities, industries and increasingly electrified homes. The early twenty-first-century system added renewable generation, rooftop solar, and digital technology, and the next phase will support electrified transport, industry, heating, cooling, artificial intelligence, and a far more active relationship between consumers and the grid.

Australia has already moved from 119.7 TWh of annual generation in 1984–85 to 286.8 TWh in 2025. AEMO now expects underlying consumption in the NEM to increase from approximately 205 TWh to 390 TWh by 2050—even after substantial savings from energy efficiency and consumer-owned generation. The electricity system is therefore being asked to perform two historic tasks simultaneously:

1. Replace the coal-fired generation that built much of modern Australia.

2. Expand to support an economy that will depend more heavily on electricity than ever before.

That is why the energy transition is not simply a change in how electricity is generated.

It is the next chapter in the continuing expansion of the infrastructure that powers Australian life.

Written by Tarnia Riggs.

Disclaimer: Energy 101 is an educational series designed to explain complex energy and infrastructure topics in plain English. It is intended to improve public understanding and should not be interpreted as policy, investment, engineering or legal advice.

If there is a future industry topic, infrastructure challenge or energy conversation you would like explored as part of the Energy 101 Series, feel free to reach out.

renewable energy approvals, renewable energy project delivery, stakeholder engagement renewable energy, social licence infrastructure, transmission infrastructure Australia, renewable energy planning approvals, environmental impact assessment renewable energy, cultural heritage infrastructure projects, renewable energy development Australia, grid connection renewable energy, energy infrastructure delivery, renewable energy communities, transmission project engagement, renewable energy project lifecycle, energy transition Australia

Enjoyed this article? Explore the full Energy 101 Series for practical, plain-English explanations of Australia’s evolving energy sector.
https://tarniariggs.com/writing/energy-101-series/