On the edge of the sleepy town of Figueruelas, a single, vast wind turbine spins around, casting its shadow over the buildings nearby.

It’s a reminder of the importance of renewable electricity in this windswept area of Aragón, in north-eastern Spain, whose plains are host to many of the country’s wind and solar energy farms.

Figueruela’s status as a symbol of Spain’s green transition has been further boosted recently, as work starts nearby on the construction of a vast factory that will produce batteries for electric vehicles.

Chinese firm CATL and the Netherlands-based Stellantis are investing a combined €4bn ($4.7bn; £3.5bn) in the facility. Yao Jing, China’s ambassador in Spain, described it as “one of the biggest Chinese investments Europe has ever seen”.

Luis Bertol Moreno, mayor of the town, says the area was a logical choice for the project.

“We’re in Aragón, where there’s wind all year round, there are lots of hours of sunshine, and we are surrounded by wind turbines and solar panels,” he says.

“Those [energy sources] will be crucial in generating electricity for the new factory, and I understand that was the key reason for building it here in Figueruelas.”

The factory can be seen as vindication of Spain’s energy model, which prioritises renewable sources. In 2017, renewables contributed just a third of Spain’s electricity production, but last year they represented 57%.

By 2030, the government wants them to contribute 81% of electricity output.

Earlier this year, Prime Minister Pedro Sánchez summarised his government’s approach as he delivered a riposte to US President Donald Trump’s pro-fossil fuel “Dig, baby, dig” slogan. “Green, baby, green,” said the Socialist, as he pointed to the benefits of renewable energy.

However, in recent months, Spain’s all-in commitment to renewables has come under scrutiny. This was in great part due to an 28 April blackout that left homes, businesses, government buildings, public transport, schools and universities in the dark across Spain and neighbouring Portugal for several hours.

With the government unable to offer a full explanation for the outage, the country’s energy mix became a fiercely-debated political issue. Alberto Núñez Feijóo, leader of the conservative opposition, accused the government of “fanaticism” in pursuing its green agenda, suggesting that an over-reliance on renewables might have caused the incident.

Feijóo and others on the right advocated a rethink of the national energy model.

The fact that, a week before the blackout, solar generation in mainland Spain registered a record 61.5% of the electricity mix has fuelled such claims.

Yet the government and national grid operator Red Eléctrica have both denied that the outage was linked to the preponderance of renewable energy sources in Spain.

“We have operated the system with higher renewable rates [previously] with no effect on the security of the system,” says Concha Sánchez, head of operations for Red Eléctrica. “Definitely it’s not a question of the rate of renewables at that moment.”

Ms Sánchez said the blackout was caused by a combination of issues, including an “unknown event” in the system moments before, which saw anomalous voltage oscillations.

However, Red Eléctrica and the government are still awaiting reports on the incident that they hope will determine the exact cause. A cyber-attack has repeatedly been ruled out.

Meanwhile, since April, Spain’s electricity mix has been modified somewhat, with greater reliance on natural gas, reinforcing the notion that the country is at an energy crossroads.

Spain’s nuclear industry, which currently contributes around 20% of national electricity, has been particularly vocal since the blackout, pushing back against government plans to close the country’s five nuclear plants between 2027 and 2035.

With many European countries undergoing a nuclear renaissance, the planned closures make Spain something of an outlier. The companies that own the Almaraz plant in south-western Spain, due to be the first to shut down, have requested a three-year extension to its life until 2030. That request is currently under consideration.

Ignacio Araluce, president of Foro Nuclear, an association that represents the industry, says Spain is the only country in the world that is scheduling the closure of nuclear plants that are in operation. He believes nuclear energy provides stability while being compatible with the green energy transition.

“It’s prudent to have a mix of renewables and nuclear energy,” he says.

Mr Araluce praises renewable sources because they only require natural elements to generate electricity, but points out that they are not able to operate around the clock or when weather is unfavourable.

“How can you produce energy in those hours when the renewables are not producing?” he asks. The answer, he added, is “with a source like nuclear, that is not producing CO2, that is producing all hours of the year”.

The political opposition is staunchly opposed to the nuclear shut-down. The far-right Vox, criticising what it saw as a lack of explanation by the government for the April blackout, recently described nuclear power as “a crucial source of stability”.

Ms Sánchez acknowledges that there is room for improvement for Spain’s electricity model, pointing to the Iberian peninsula’s relative isolation from the European grid compared to most of its EU neighbours. She also sees storage as an issue.

“While we have taken a good path when it comes to renewable installation, we cannot say the same regarding storage,” she says. “We need to foster storage installation.”

Spain’s political panorama adds an element of uncertainty to its energy future. The Socialist-led coalition has been mired in corruption scandals and its parliamentary majority appears to have collapsed in recent weeks, raising the possibility of a snap election in the coming months.

A right-wing government, which polls suggest would be the likely outcome, would almost certainly place less emphasis on renewables and advocate a partial return to more traditional energy sources.

But in the meantime, Spain’s renewable transition continues.

And for Figueruelas, in Aragón, that means not just cheap, clean energy, but investment. The town’s population, of just 1,000, is due to increase dramatically, with 2,000 Chinese workers scheduled to arrive to help build the new battery plant, which is expected to create up to 35,000 indirect jobs once it starts operating.

“These kinds of investments revitalise the area, they revitalise the construction sector, hostelry,” says local man Manuel Martín. “And the energy is free – it just depends on the sun and the wind.”