Australia has put itself on a realistic path to achieving what climate activists around the world have long dreamed of: running its power grid entirely on renewable energy.

The Australian Energy Market Operator oversees the nation’s power markets. Chief among them, the National Electricity Market serves about 90% of customers, minus remote areas and the west coast. At its peak, the system uses 38 gigawatts of power — more than New York state’s peak consumption. Over the last five years, AEMO has rigorously studied how the country, whose coal fleet is aging and which banned nuclear energy decades ago, can run this grid on renewables alone.

“This is not a climate-zealot kind of approach,” AEMO CEO Daniel Westerman told Canary Media. ​“Our old coal-fired power stations are breaking down; they’re retiring,” he said. ​“They’re getting replaced by the least-cost energy, which is renewable energy, backed with storage, connected in with transmission. We’ll have a bit of gas there for the winter doldrums. That is just what’s happening.”

Australia’s efforts could offer a proof of concept for how a nation with a bustling, modern economy can rapidly shift its electricity from fossil fuels — mostly coal with some gas — to wind, solar, storage, and other renewable sources like hydropower.

“There’s nothing impossible about 100% renewable supply,” said Jesse Jenkins, a Princeton University professor who has studied net-zero pathways for the U.S. ​“Australia has a better chance of this than almost anywhere.”

So far, renewables have surged to about 35% of annual electricity production, while coal still leads with 46%, according to the International Energy Agency.

Because this transition is primarily driven by market forces, rather than a legislative or regulatory requirement, Westerman couldn’t say for sure when Australia will hit the 100% mark. He does expect 90% of Australia’s coal generation will be gone by 2035, and the rest could shutter later that decade.

The more pressing milestone, though, will be the country’s first day with no coal generation on the system, which could happen far sooner due to some combination of competitive forces and mechanical trouble at the aging plants. It’s a landmark Westerman has experienced before: He operated the U.K. electricity network in 2017 when it ran without coal for the first day since the Industrial Revolution. The last British coal plant shut down seven years later, in 2024.

AEMO has developed a clear sense of what is needed to keep the lights on whenever coal power flickers out, he said. It’s a matter of getting ​“kit installed in the ground,” especially the unsexy machinery that can maintain a stable grid in the absence of big fossil-fuel-powered generators.

“It’s now a physical problem rather than an intellectual challenge, a ​‘no one knows how to do this’ challenge,” Westerman said. ​“We can deal with that.”

Unleashing renewables, large and small

Australia’s renewables outlook is strong for a few key reasons.

For one, it enjoys distinct geographical advantages, Jenkins noted: It spans a sunny, windy landmass the size of the contiguous United States, but with just 27 million people to provide for. (The U.S. has nearly 13 times more.)

It also has policy advantages. Australia has a national market governing the power sector, which allows technologies to proliferate faster than in places with patchwork regulations (like the U.S.) or strong incumbent monopoly utilities (also like the U.S.). Furthermore, Australia has avoided U.S.-style clean-energy trade protectionism, so cheap Chinese imports are plentiful.

Last month, the National Electricity Market topped out at more than 77% renewable generation for a half-hour period, Westerman said. Grid constraints kept that number from being even higher. The state of South Australia regularly generates more electricity from renewables than it consumes, shipping the excess to neighbors.

Australia doesn’t just excel at big renewables and big batteries. Four million homes produce rooftop solar; a few weeks ago, those households temporarily supplied 55% of demand on the National Electricity Market, Westerman said.

“Australians have an absolute love affair with rooftop solar,” he said. ​“We have the highest rooftop PV penetration in the world, and it’s one of the driving forces of our energy transition.”

Finding new ​“shock absorbers” for the grid

Westerman flagged one big technical obstacle to reaching 100% renewables, and it’s not what many people expect. 

The key hurdle to unlock a completely renewable system is to build up ​“rotating machines on the grid that don’t necessarily produce power,” Westerman said.

The physical spinning mass of the old coal plants’ generators delivered ​“essential system services” beyond just the kilowatt-hours. These services aren’t known to many people beyond grid engineers, but they go by names like voltage support, frequency regulation, synchronous inertia, and reactive power. Westerman describes them as ​“shock absorbers … to withstand the bumps and disturbances that we get all the time.”

“The consequence of not having system security is Spain and Portugal,” he said, referring to the nationwide blackouts this spring that have been traced to failure to control voltage levels.

If the coal plants are headed for extinction, something else needs to take on these responsibilities. Batteries can replicate some services. But Westerman worries about a service called fault current, which is necessary to operate the grid-scale version of fuses or breakers that protect equipment from issues like short circuits.

One way to do this is by building devices called synchronous condensers, which include a rotating hunk of metal that can spin without fossil-fuel combustion. But constructing new single-purpose infrastructure is expensive, especially when the energy-only markets don’t currently reward this grid service on its own.

Westerman has been talking up another option largely absent from decarbonization discourse in the U.S.: install a clutch on existing gas plants, on the shaft between the fuel-burning turbine and the spinning generator. The clutch isolates the generator, so it can keep spinning with a relatively minor jolt of electricity and without burning fossil fuels. This approach also keeps the gas plant around to produce power on what Westerman described as ​“cold, dark, and still” days, when the renewable fleet falls short. Such plants could eventually switch to biofuels or clean hydrogen instead of fossil gas.

“[The clutch] is like 1950s technology — it’s really boring,” Westerman said (“boring,” for grid operators, is the highest form of praise). ​“The marginal cost of putting this in is like nothing compared to the cost of the plant.”

A company called SSS has built these clutches for decades. One is nearly operational in the state of Queensland at the Townsville gas-fired plant, which Siemens Energy is converting into what it calls a ​“hybrid rotating grid stabilizer.” Siemens says this project is the world’s first such conversion of a gas turbine of this size.

That particular retrofit took about 18 months and involved some relocating of auxiliary components at Townsville to make room for the new clutch. So it’s not instantaneous, but far easier than building a new synchronous condenser from scratch, and about half the cost, per Siemens.

Some novel long-duration storage techniques also provide their own spinning mass. Canadian startup Hydrostor expects to break ground early next year on a fully permitted and contracted project in Broken Hill, a city deep in the Outback of New South Wales.

Broken Hill lent its name to BHP, which started there as a silver mine in 1885 and has grown to one of the largest global mining companies. More recently, the desert landscape played host to the postapocalyptic car chases of Mad Max 2. Now, roughly 18,000 people live there, at the end of one long line connecting to the broader grid.

Hydrostor will shore up local power by excavating an underground cavity and compressing air into it; releasing the compressed air turns a turbine to regenerate up to 200 megawatts for up to eight hours, serving the community if the grid connection goes down and otherwise shipping clean power to the broader grid.

But unlike batteries, Hydrostor’s technology uses old-school generators, and its compressors contribute additional spinning metal.

“We have a clutch spec’d in for New South Wales, because they need the inertia,” Hydrostor CEO Jon Norman said. ​“It’s so simple; it’s like the same clutches on your standard car.”

Transmission grid operator Transgrid ran a competitive process to determine the best way to provide system security to Broken Hill in the event it had to operate apart from the grid, Norman said. That analysis chose Hydrostor’s bid to simply insert a clutch when it installs its machinery.

The project still needs to get built, but if up-and-coming clean storage technologies could step in to provide that grid security, it wouldn’t all have to come from ghostly gas plants lingering on the system.

“It’s a different feeling [in Australia] — there’s a can do, go get ​‘em, ​‘put me in coach’ attitude,” said Audrey Zibelman, the American grid expert who ran AEMO before Westerman. ​“When you’re determined to say how best to go about this, as opposed to why it’s hard or why it doesn’t work, the solutions appear.”