Japan has begun a controversial return to nuclear power generation with the restart of a reactor in the country’s south-west, four and a half years after its faith in atomic energy was shattered by the triple meltdown at Fukushima Daiichi.

Kyushu Electric Power, the operator of the Sendai plant, said it had restarted one of the facility’s two reactors on Tuesday morning, in defiance of strong local opposition.

The move marks the first time Japan has generated nuclear power since a post-Fukushima shutdown of all its 44 operable reactors two years ago.

While police scuffled with demonstrators outside the plant, public broadcaster NHK showed workers in the control room as the reactor whirred into action for the first time since it was mothballed in May 2011.

Kyushu Electric said the restart had gone without a hitch. The 30-year-old Sendai No 1 reactor is expected to reach full capacity next month. The second Sendai reactor is due to restart in October.

In an attempt to keep Japan’s fledgling economic recovery on track, the prime minister, Shinzo Abe, has pushed for a return to nuclear power generation in spite of opinion polls showing that most voters oppose restarts.

Former prime minister Naoto Kan speaks to protesters gathered at the main gate of the Sendai nuclear power plant. Photograph: The Asahi Shimbun/via Getty Images

Backed by business and industry lobby groups, Abe has warned that Japan cannot afford to continue importing huge quantities of oil and natural gas, while the growing reliance on thermal power generation has stalled Japan’s efforts to reduce greenhouse gas emissions.

“There are very strong vested interests to reopen nuclear reactors. Accepting them as permanently closed would have financial implications that would be hard to manage,” Tomas Kaberger, chairman of the Japan Renewable Energy Foundation, told Associated Press.

Japan’s powerful pro-nuclear lobby is hoping a safe restart at Sendai, about 1,000km south of Tokyo, will help the public overcome the trauma caused by the Fukushima meltdown.

The March 2011 disaster, triggered by a powerful earthquake and tsunami, forced the evacuation of 160,000 people, many of whom might never return home.

“It is important to restart reactors one by one from the perspective of energy security, the economy and measures against global warming, but safety always comes first,” the industry minister, Yoichi Miyazawa, told reporters, adding that the government would “deal responsibly” should another accident occur.

Just ahead of the restart, Abe said Sendai’s reactors had passed “the world’s toughest safety screening”. He added: “I would like Kyushu Electric to put safety first and take utmost precautions for the restart.”

The Sendai plant, where more than £64m has been spent on new safety systems, was the first to meet strict new standards introduced after the Fukushima disaster.

Japan’s revamped Nuclear Regulation Authority (NRA) said the new safety checks meant there would be no repeat of the Fukushima catastrophe. “A disaster like that at … Fukushima Daiichi nuclear plant will not occur,” NRA chairman Shunichi Tanaka said in a recent interview with the Nikkei business paper. He conceded, though, that there was “no such thing as absolute safety”.

The government wants nuclear power to account for as much as 22% of Japan’s energy needs by 2030, despite continuing troubles at Fukushima Daiichi, where the removal of melted fuel from damaged reactors is not due to begin until 2022. Decommissioning the wrecked plant is expected to take 40 years.

Greenpeace said the restart “will not reverse the terminal decline” of Japan’s nuclear industry. “Even though one nuclear reactor has restarted, the nuclear industry is still fighting for its very survival in Japan,” said Mamoru Sekiguchi, energy campaigner at Greenpeace Japan.

Sekiguchi echoed local concerns that authorities in Sendai had not devised a comprehensive evacuation plan for more than 200,000 people living within a 30km radius.

Aside from the risk from earthquakes and tsunami, the Sendai plant is located in a volcanically vulnerable region, with Sakurajima, one of Japan’s most active volcanoes, just 50km away.

“The lengths to which safety issues have been ignored in the Nuclear Regulation Authority’s review process for the Sendai plant restart shows just how desperate the nuclear industry and their government allies are,” Sekiguchi said. “Rather than a nuclear renaissance, much of Japan’s ageing nuclear reactor fleet will never restart. Prime minister Abe and the nuclear regulator are risking Japan’s safety for an energy source that will likely fail to provide the electricity the nation will need in the years ahead.”

Greenpeace predicts nuclear will provide 2%-8% of Japan’s electricity generation by 2030, far lower than the government’s target.

Tobias Harris, a Japan analyst at Teneo Intelligence in Washington, said it was unlikely that Tuesday’s restart would herald a quick return to nuclear as a major source of energy.

“The Sendai restart is unlikely to trigger a cascade of restarts that significantly reduces Japan’s post-2011 dependence on imported fossil fuels,” he said. “Each nuclear power plant faces a unique set of technical, operational, legal, and political challenges, suggesting that the delays that have dogged the first restart will be seen at other locations.”

Japan’s nuclear operators have applied for approval to restart 25 reactors: so far regulators have cleared only five to go back online.