Japan has restarted a reactor at the world's largest nuclear plant nearly 15 years after a disaster at the Fukushima power plant forced the country to shut all its nuclear reactors. Reactor no.6 at the Kashiwazaki-Kariwa plant located northwest of Tokyo was restarted on Wednesday. It was delayed by one day because of an alarm malfunction and is expected to begin operating commercially next month.

This is the latest installment in Japan's nuclear power reboot, which still has a long way to go. The seventh reactor is not expected to come back on until 2030, and the remaining five could be decommissioned. That leaves the plant with far less capacity than it once had when all seven reactors were operational: 8.2 gigawatts.

Japan, which had always heavily relied on energy imports, was an early adopter of nuclear power. But these ambitions were scuppered in 2011 by what is now remembered as one of the worst nuclear disasters in history.

Triggered by the most powerful earthquake ever recorded in Japan, the meltdown in the reactors at Fukushima Daiichi led to radioactive leakage. It traumatized local communities that were evacuated, and many have not returned despite official assurances that it was safe to do so.

Critics say the plant's owner Tokyo Electric Power Company (Tepco) was not prepared, and the response from them and the government was not well-coordinated. An independent government report called it a man-made disaster and blamed Tepco, although a court later cleared three of their executives of negligence.

Still, the fear and lack of trust fueled public opposition to nuclear power and Japan suspended its entire fleet of 54 reactors shortly after the Fukushima disaster.

It has now spent the past decade trying to wake up those power plants. Since 2015, it has restarted 15 out of its 33 operable reactors. The Kashiwazaki-Kariwa plant is the first of those owned by Tepco to be turned back on.

Before 2011, nuclear power accounted for nearly 30% of Japan's electricity and the country planned to get that up to 50% by 2030. Its energy plan last year unveiled a tamer goal: it wants nuclear power to provide 20% of its electricity needs by 2040.

Even that may be tricky.

Global momentum is building around nuclear energy, with the International Atomic Energy Agency estimating that the world's nuclear power capacity could more than double by 2050. In Japan, as of 2023, nuclear power accounted for just 8.5% of electricity.

Prime Minister Sanae Takaichi, who took office in October, has emphasized the importance of nuclear power for Japan's energy self-sufficiency, especially as it expects energy demand to surge because of data centers and semiconductor manufacturing.

However, the costs of operating nuclear reactors have surged due to new safety checks requiring hefty investments from companies trying to restart their plants. Critics argue that nuclear power is becoming increasingly expensive, potentially harming the government amid rising public dissatisfaction with energy costs.

Public trust remains a significant issue, especially after scandals linked to Tepco's management and the fallout from Fukushima. Many citizens still actively protest nuclear power, fearing another catastrophe could devastate local communities.

The road ahead suggests a complicated path for Japan's nuclear strategy as it grapples with economic, safety, and environmental challenges.