Over the past two decades, solar power has been undergoing a revolution.
Billions of panels have been shipped to all parts of the globe.
Lined up in vast arrays out in the desert and tucked away on discreet rooftops, they've been turning sunlight into terawatts of power.
Climate-tech startup TransitionZero has scoured the world's surface for medium- and large-scale installations, using machine learning to pick them out of satellite imagery.
The individual farms are too small to see from a distance, so we've sliced up the globe into a 50-kilometre grid and visualised them that way here.
The data reveals how, in recent years, the installation of solar farms has accelerated into an all-out frenzy.
This massive growth spurt has propelled solar from bit player to a sizeable chunk of the planet's energy mix.
And it's taken less than two decades.
A planet-wide solar boom has been beating expectations at every turn. And it's only just the beginning.
Of the billions of panels in operation around the world, the vast majority of them have their intellectual origins in a lab in the Sydney suburbs.
A research project at UNSW, led by Professor Martin Green, developed what is called passivated emitter and rear cell (PERC) technology back in 1983.
It was a transformative moment that led to his team holding the record for the most efficient solar cells for the next 31 years.
And it seeded the coming revolution.
As the individual cells became more efficient, they also became more economical to produce at scale. Then the market did its thing, sending the cost per kilowatt of energy into freefall.
Prices have consistently fallen faster than predictions, passing several thresholds that were once thought impossible.
"People talk about a future where solar is going to be insanely cheap," says Professor Green.
"Just about every projection that's been made for solar has been exceeded by reality."
It's now the cheapest way to generate electricity.
And, as a result, it's been installed at record rates, flooding power grids with excesses of daytime electricity and quietly rewriting how entire nations are powered.
The amount of solar power in the world has been doubling roughly every three years, but because it came off a low base, it's hard to get a sense of how remarkable that growth is.
Kingsmill Bond for the Rocky Mountain Institute, which analyses the clean energy transition, says the next part of the transition will see solar become a dominant force in energy at a speed few are prepared for.
"If I do the maths, from 0.5 per cent to 5 per cent [of global power] takes about the same time as from 5 per cent to 80 per cent," he explained.
"So that's the point. You don't notice it until it gets to 5 per cent and then from 5 to 80 is actually quite quick."
At current rates, solar is on track to provide 12 per cent of global electricity in three years, 24 per cent in six years, and 48 per cent in less than a decade.
It's been a staggering ascent: no energy-producing technology has grown this quickly before.
So, which countries are driving — and profiting from — this solar revolution?
China
In the race to net zero, there is one country with more influence than the rest.
Through the 2000s and 2010s, China's fossil fuel emissions were rising at a rapid rate, largely due to increasing demand for coal as the country industrialised.
But this trend has been quietly reversing, starting about a decade ago as China invested heavily in renewable energy.
By 2017, solar farms were sprouting up all around the country, but it would only ramp up from there.
China installed more solar in 2023 than the rest of the world combined, with the majority of it coming online in the country's sparsely populated west and north.
That same year, its renewable capacity grew faster than its overall demand for electricity — meaning its fossil fuel usage actually went backwards.
Since then, two major international climate agencies are predicting that global emissions could have reached their peak in 2023 and began declining in 2024.
Located in the deserts of Qinghai Province is Golmud Solar Park, one of China's largest individual solar farms.
Larger than Sydney's Botany Bay, Golmud Solar Park has a capacity of around 2.2GW — the equivalent of two coal-fired power plants.
The scale of this one installation boggles the mind, and yet it represents less than 1 per cent of the country's solar output.
And then there's the manufacturing industry that is underpinning all this construction.
China's factories produced 80 per cent of the world's solar panels in 2024 — far more than it needed for its own solar farms.
In recent years, panels have been in oversupply, causing prices to dip and encouraging creative uses for the glut of panels.
They've become so cheap they're even being used as garden fences in the Netherlands and Germany.
While this might seem like a novelty, there is evidence that ad-hoc installs have been happening on a staggering scale in other parts of the world.
Pakistan
A few years back, solar analyst Jenny Chase caught wind of a surprising amount of panels being imported into Pakistan.
Chinese export data suggested that Pakistan could be "the sixth-largest solar market in the world", she told the ABC.
But, somehow, the outside world had barely noticed it happening.
The Pakistani government wasn't tracking these installations so it was unclear where all these panels were actually ending up.
Her team at BloombergNEF had some theories. They identified a money laundering scheme where some of the panels never existed, and they suspected that others were likely being re-exported to Afghanistan.
But neither explanation accounted for the sheer scale of imported panels.
"Gigawatts of solar modules [were] leaving China and going to Pakistan," she explains.
Transition Zero's analysis shows little medium- or large-scale solar in Pakistan, especially compared to some of its solar-rich neighbours.
Chase teamed up with Atlas Maps, another machine-learning firm, to look for the missing panels in satellite imagery.
"I think we found the modules," she says. "They're being installed on rooftops in Pakistan … on big rooftops and also sometimes small ones."
This wasn't the product of large-scale coordination, and it had nothing to do with the government.
"They're not being subsidised," says Chase. "It is very much bottom-up."
India
Just across the border in India, the situation is almost the complete reverse.
The rise of solar in the subcontinent has been all about government subsidies and massive arrays out in the desert.
"India sees the opportunity to build energy security, grid diversity and reduce their massive over-reliance on imported fossil fuels," says Tim Buckley, the director of Climate Energy Finance.
Clusters of industrial solar farms have sprung up in the north-west and south of the country in recent years, with smaller-scale operations dotting other regions.
Nestled in with a wall of existing farms near the Pakistani border, India's Adani Group is currently building what will be the largest solar farm outside China.
The under-construction Khavda Renewable Energy Park is planned to be five times the size of Paris. Once completed, it will be able to power over 16 million homes.
It's telling that Adani Group is embracing solar at such scale.
Adani is practically synonymous with fossil fuels. It's the largest private developer of coal power stations in the world, and the owner of the controversial Carmichael coal mine in Queensland.
And yet, it's set to become one of the largest solar developers outside China.
According to Mr Buckley, this is a sign of how fossil fuels are in "terminal decline".
"The solar disruption is inevitable," he says. "[Fossil fuels] are being eaten alive."
Kingsmill Bond says the embrace of solar in the global south runs counter to the narrative that only developed countries are interested in investing in renewables.
"We found that, in fact, 20 per cent of the global south has already leapfrogged what's going on in the global north," he says.
"The folks in Pakistan or Namibia or Bangladesh or Uruguay or Chile or Vietnam, they too want local cheap energy, and they too can buy cheap stuff from China and harness the sun.
"Why wouldn't they?"
On top of those 20 per cent installing solar at record rates, he says another 60 per cent of nations in the global south are adding it at the same pace as developed economies.
United States
Each day as the sun sets, and the solar farms stop producing energy, there is a peak of demand in the evening as people get home from work.
This has been the time when dispatchable fossil fuels — specifically gas — have been crucial.
But another renewable technology is changing this.
In California's grid — which has about 31 per cent of its power coming from solar — newly installed batteries are soaking up the excess power generated during the day.
And then they're selling it back to the grid when demand rises in the evening.
"First, the solar came for the gas plants that ran all day," says Jenny Chase. "And then batteries came for the evening peak."
And this isn't limited to a single state.
At the start of 2017, California was the dominant US state for solar and home to the largest solar farm in the world.
Since then, the southern states have usurped California in the speed they've been installing new capacity.
And none more so than the traditionally oil-rich state of Texas.
In March 2024, utility-scale solar in Texas overtook coal's contribution to the energy grid for the first time.
It's a familiar dynamic: fossil fuels falling into structural decline as massive new solar farms come online.
And while solar continues its march towards super-cheap, super-abundant energy generation during the day, it's over to another technology to continue the clean-energy transition into the night.
"Solar was the disruption of last decade," says Tim Buckley. "Batteries will be the disruption of this coming decade."
With all this development going on, it might sound — and look — like the world is quickly filling up with solar panels.
But, according to TransitionZero's data, the world's solar took up an estimated 19,000 square kilometres in September 2024.
To put that area into perspective, we need to zoom in a long way.
19,000km2 is roughly a third of the size of Tasmania. And you could fit all of the world's current solar infrastructure within this space.
According to analysis by the Carbon Tracker Initiative, "the land required for solar panels alone to provide all global energy is … less than the current land footprint of fossil fuel infrastructure".
Of course, that isn't going to be concentrated in one place. It works best when distributed around the globe.
Australia
With vast amounts of space, intense sunshine and a leading role in solar power's creation, Australia is an ideal candidate to take advantage of the solar revolution.
But that's not been the case so far for large-scale solar. In 2023, Australia fell out of the top 10 countries for solar installations for the first time in three decades.
We've seen mega-projects struggle to get off the ground and have been unable to fully capitalise on our geographic advantage.
As is all too common in this space, large-scale solar power has been politicised, with the Nationals calling for renewables projects in regional areas to be scrapped.
But that's not the whole story. Australia is a world leader in rooftop solar, which now powers over 10 per cent of the grid.
And this is just another manifestation of the inevitability of solar's rise.
Even when large-scale projects are stymied, the low prices and simplicity of installing solar panels make them attractive for households.
"The thing about solar is that there's always more of it than you think," says Jenny Chase.
"It will pop up in really unexpected places — you can put it on a small roof. You can put it on a big roof. You can put it on the ground. You can put it on a parking lot."
This flexibility is a large part of why, as of June 2024, solar was producing around 18 per cent of the world's renewable energy.
When Professor Green reflects on his team's contribution to the solar rush — from their technology sitting on household rooftops to industrial-scale installations — he is filled with pride.
"When you look around the houses in this area," he says, "[there's] a good chance that the solar panels use the technology that was developed at the University of NSW."
The next few years will determine whether these panels become a symbol of Australia's role as a global player in the solar revolution, or a footnote in a history that plays out elsewhere.
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