On the tiny island of Olkiluoto on Finland’s Baltic Sea coast, just over three hours drive north-west from Helsinki, a minor miracle of engineering and science, planning and governance is unfolding.

On the far western edge of the little island – just 5 kilometres across – Finland has switched on the first new nuclear reactor in Europe in the past 15 years; it is the tiny nation’s fifth reactor. The reactor now generates 1.6 gigawatts, enough to supply more than 750,000 modern Australian households.

Drive back towards the mainland a kilometre or two and you will come to the gates of Onkalo, a Finnish word meaning something like “cavity” in English, which will soon open to become the world’s first deep geological repository for the permanent storage of high-level nuclear waste.

Soon robot tractors will begin the work of transferring Finland’s spent fuel rods 450 metres down into the bedrock along the 50 kilometres of Onkalo’s tunnels to be sealed in gigantic copper cylinders, packed in bentonite – an absorbent clay that swells when exposed to water and is the main ingredient in kitty litter – and finally entombed behind vast concrete plugs to rest in safety for 100,000 years.

Or that is the plan arrived at in Finland’s parliament in 1994, when the nation’s leaders decreed that the generation that benefited from nuclear power was responsible for safely disposing of it and set a timeline to get it done.

A site would be selected by 2000, operations would begin by the mid-2020s. And so it was that a site was chosen by that date and Posiva, the company that won the contract to bury the waste, has just won a licence to start operations later this year.

“This is also important for Finnish culture that we stick to the schedule,” says Mika Pohjonen, managing director of Posiva Solutions, a subsidiary that sells the company’s expertise internationally, as he talks through the extraordinary considerations of such a project.

The timelines, he says, as we speak in his Helsinki office on an unseasonably snowy spring afternoon, are impossible for human minds to properly grapple with.

The plant will operate for 100 years before it is sealed and returned to the state.

In 100,000 years the radioactivity of the waste will have reduced to background levels, but the facility is intended to last 1 million years.

“Any human being cannot really understand what this means,” says Pohjonen. “You understand 10 years, 100 years, maybe. The Roman Empire was 2000 years ago, OK. But then 10,000 years? 100,000 years? That is beyond comprehension.”

I ask him how long the facility would remain safe if due to some unforeseen future calamity there was no one left to maintain it.

“If there is no nobody in Scandinavia or Finland? Then in fact who would care?”

Besides, he notes, the next ice age will cover the entire area with a few kilometres of ice in less than 150,000 years.

The bedrock into which Onkalo is built is 1900 million years old. “So it is relatively stable,” says Pohjonen, who is possessed of a manner of speech so dry it is impossible to know whether he is always or never joking.

The site was selected not just for its stability but for its utterly unremarkable geological make-up. The designers wanted to be sure that no future civilisation would seek to disturb it, so they selected an area that not only had no known useful minerals, but one whose geological make-up was so common that there would be no reason to mine it for materials that might one day become valuable.

Posiva’s view is that it should be left utterly unmarked, says Pohjonen. There should be no reason for anyone to disturb it. (Just as no other deep permanent facility has yet been completed, there is no international consensus on this. A report by a major US nuclear research lab went as far as proposing wording to be inscribed upon such facilities. “This place is not a place of honour,” reads the proposed text. “No highly esteemed deed is commemorated here ... nothing valued is here. What is here was dangerous and repulsive to us. ”)

However unthinkable the timelines that Onkalo’s keepers are grappling with, Climate and Environment Minister Kai Mykkänen has no doubt about nuclear’s role in Finland’s economy.

Mykkänen represents a centre-right government installed in June 2023, more than a year after Russia’s invasion of Ukraine. It is more conservative and more West-facing than its predecessors and determined that not only should clean electricity help Finland meet climate targets, cheap and abundant energy should also bolster its economy.

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Finland’s climate targets are among the most ambitious on earth. It aims to have a net-zero economy by 2035 and after that to go negative. That is, it aims to have its forests absorb more carbon from the atmosphere than its economy pumps into it. So far it is having success in reducing its emissions but struggling to improve its forest emissions sink.

By comparison, Australia’s targets are to reduce emissions by 43 per cent compared with 2005 levels by 2030, and reach zero in 2050.

To reach Finland’s ambitious goals, nuclear is crucial says Mykkänen. Nuclear power, along with the mass deployment of wind and solar, will allow it to double its electricity production so it can power electrified green export industries. It plans to ramp up the production of green steel, synthetic fuels and hydrogen.

It has also allowed Finland to sever its energy lifelines with Russia, which until the invasion of Ukraine was a source of gas, wood and biomass for Finland.

So convinced of the efficacy of nuclear power is Finland that when it adopted its ambitious targets it lobbied for the European Union to recognise nuclear as a form of green energy.

Support for nuclear comes from across the political spectrum, too. While opposition to nuclear power is woven into the creation of the early Green political movements, particularly in Germany and Australia, MPs for the Green League in Finland now support it.

Partly this has to do with Finland’s typically pragmatic approach to policymaking, says Veikko Sajaniemi, a lead consultant with the Finnish sustainability advisers Third Rock.

Finland has a population of just over 5.5 million people, which is well-educated and well governed. In one annual global report, Finland was famously named the happiest country on earth seven times running, in part because it is among the least corrupt.

In other words, Finland’s nuclear energy policies are less contested than those in some other countries simply because Finns still have a faith in government and institutions that has withered in other nations.

Mykkänen boasts that in a recent survey 68 per cent of Finns voiced support for the nation’s nuclear industry.

Environmentally minded Finns were appalled when they saw Germany switch off nuclear plants only to ramp up coal use, says Sajaniemi: “Fossil fuels are the past. We are not going back to that.”

But all this does not mean Finland’s nuclear path has been without difficulty or controversy, or that there is universal support for expanding it further.

This takes us back to the island of Olkiluoto, where the government approved the construction of the so-called Olkiluoto 3 reactor on the same site as two older reactors in 2005, expecting it to begin delivering power in 2009.

In fact, the reactor was not switched on until April 16 last year, 17 and a half years after construction began, after a series of delays, breakdowns and outages.

As far back as 2009 Finland’s then-nuclear regulator, Petteri Tiippana, explained to the BBC that one of the reasons for the delay was that even though nuclear power was a proven technology, reactors remained infernally difficult machines to build and because so few were built, there was no experienced workforce.

“When they encounter a problem on site they usually follow their previous experience,” he told the BBC, “this is how we did it on a coal power plant and that just doesn’t work on a nuclear construction project.”

In the end the plant, which the French company Areva had agreed to provide for €3 billion ended up costing €11 billion ($18 billion), driving the company into losses and legal skirmishes with the Finnish operator, TVO.

Despite these blowouts Mykkänen tells this masthead he would like to see even more nuclear plants built in Finland, though it would be up to the private sector to do so. He says one of the reasons for the delays was that Olkiluoto 3 was new technology, a so-called European Pressurised Reactor, designed to be safer and more efficient than a Pressurised Water Reactor.

But over the years of its development, competing technologies such as wind, solar and batteries, have matured to the point where their components can be churned out of factory production lines at the push of a button.

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In 2020, the International Energy Agency declared solar to provide the cheapest electricity in history, while last year alone the cost of producing solar panels in China fell by 42 per cent.

In recent years, Finland has ramped up its deployment of renewables too, especially wind.

In 2022, wind power production in Finland increased by 41 per cent to 11.6 TWh, accounting for just over 14 per cent of the country’s electricity consumption.

Given the advances of renewables and the staggering cost and construction times of nuclear, it may well be that while the obvious solution to Finland’s future power needs when Olkiluoto 3 was commissioned nearly two decades ago, it is no longer, says Tuuli Hietaniemi, a specialist in sustainability solutions with Sitra, an influential Finnish think tank.

She now believes Finland should stick to the “basic recipe” of rapidly deploying more renewables until and unless the nuclear sector manages to make available the much vaunted small modular reactors, which supporters say will enjoy the same benefits of industrial scale as renewable technology. And when might that be? Hietaniemi shrugs.

The writer’s travel was supported by the Finnish foreign ministry.

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