Environmental campaigners have descended from the 650ft (200m) tower at Didcot power station where they had been protesting for two days.
Greenpeace said 30 campaigners entered the site on Thursday
Operator Npower served the Greenpeace group with an injunction instructing them to leave the Oxfordshire site.
Police have made arrests at the plant on suspicion of aggravated trespass and criminal damage.
Campaigners want the coal-fuelled plant to close as they believe it makes a large contribution to climate change.
Power generation at the site was reduced by the protest, but Npower said it did not stop.
Site managers had been negotiating with the protesters who had remained camped out at the power station through the night.
Campaigners that remained at the site into the second day of protest have been arrested by police.
Supt Jill Simpson, of Thames Valley Police, said: "The protesters have made their way out of the site and all 25 are being arrested on suspicion of aggravated trespass and criminal damage.
"Our main aim was to ensure the safety of everybody involved, including the protesters, as this was, potentially, a very dangerous situation."
One man was arrested on the site on Thursday on suspicion of aggravated trespass and has been released on police bail.
Members of the Greenpeace team, who also chained themselves to equipment at the power station, said they were ending their protest so they could attend the Climate Change rally due to be held in London on Saturday.
Ben Stewart, one of the protesters, said: "All of us felt that having been up here, we have halved CO2 emissions for this power station and that's no mean feat.
"In years to come if scientists are right - and we have every reason to believe they are - then people will look back and wonder why we didn't do enough.
"I am determined not to be one of those people."
On Thursday, a spokesman for Npower confirmed 15 protesters had gained entry in the early hours, while Greenpeace said 30 were present.
Didcot Power Station provides electricity for two million homes
Kevin Akhurst, managing director of generation and renewables at Npower, said: "Regarding Greenpeace's point of view, we fully support clean energy and we're at the forefront of developing it.
"Of our three coal stations Didcot A and Tilbury are already scheduled to close over the next five to 10 years, as are many coals stations in the UK, but they can't just be switched off overnight.
"Some coal is needed to maintain secure and affordable energy and for now stations like Didcot meet that need."