Two reactors at Japan's Sendai nuclear plant are due to become the first to be restarted in the country since the 2011 meltdown at the Fukushima facility.
The governor of Japan's Kagoshima prefecture gave his approval, marking the final hurdle for the restart, which is now likely to happen next year.
Before the accident, caused by a massive quake and tsunami, about 30% of Japan's power was nuclear-generated.
All 48 plants were shut down but PM Shinzo Abe has lobbied for a restart.
Mr Abe's government has argued that the shutdown has hurt the economy, forcing Japan to import expensive fossil fuels to make up the power shortfall.
Despite public anxiety, earlier this year Mr Abe approved an energy plan backing the use of nuclear power.
Local authorities were given the final say on whether to restart their commercial plants. The plant's host town, Satsumasendai, had already voted in favour.
"I have decided that it is unavoidable to restart the No. 1 and No. 2 Sendai nuclear reactors," Kagoshima Governor Yuichiro Ito told a news conference on Friday, reported Reuters news agency.
"I have said that assuring safety is a prerequisite and that the government must ensure safety and publicly explain it thoroughly to residents."
The reactors, operated by Kyushu Electric Power, will likely restart next year as further operational checks need to be passed.
In a vote on Friday 38 out of 47 of the Kagoshima's prefectural assembly backed the restarting of the reactors.
Protesters present in the assembly hall stood up before the vote with pink signs that said "NO restart", reported Reuters. Yelling from opponents drowned out the final vote.
In September, Japanese regulators gave the Sendai reactors their final approval saying safety standards introduced after the Fukushima disaster had been met.
Timeline: Nuclear energy in Japan
- 11 March - a magnitude 8.9 earthquake strikes off the east coast of Japan followed by a large tsunami. The Fukushima Daiichi nuclear power plant loses power leading to a meltdown of reactors.
- December 2011 - Fukushima plant shutdown is achieved.
- May 2012 - Japan's last remaining nuclear reactor shuts down leaving the country entirely nuclear-free for the first time in 42 years.
- July 2012 - Kansai Electric Power Company restart reactors at the Oi power plant in Fukui Prefecture.
- September 2012 - Japan announces that it plans to abandon nuclear power by 2030 and will not begin construction on new nuclear reactors.
- December 2012 - Shinzo Abe is elected as prime minister saying nuclear energy is needed to turn around the economy.
- September 2013 - The last reactor at the Oi nuclear power plant is shut down meaning Japan is nuclear power free.
- April 2014 - Japan approves an energy plan that backs the use of nuclear power, reversing the earlier decision.
- September 2014- Japan's nuclear regulator gives safety sign-off for two reactors at the Sendai nuclear plant to restart.