Authorities arrested nine people at a South African coal-fired power station Monday after Greenpeace activists chained themselves to a gate and some climbed a crane to protest dependence on coal just weeks before the country hosts a global conference on climate change.

The protest began at dawn at the Kusile power station, and police went up after demonstrators had climbed the crane. Six people were arrested after they were persuaded to come down peacefully and safely, said police spokesman Leonard Hlathi.

Greenpeace spokeswoman Fiona Musana said a total of nine protesters, including some on the ground inside the site, were arrested and freed late Monday on bail of 500 rand (about $60) each. They were ordered to return to court Nov. 21 on charges of trespassing and malicious damage to property.

Melita Steele, a Greenpeace climate change expert, said earlier that security guards cut the chain demonstrators had used to bind themselves to the gate.

Eskom, the state-owned power company, says it needs the Kusile plant because of rising electricity demand. It is expected to be completed in 2016. Another coal plant, called Medupi, is scheduled for completion in 2015. Eskom also has renewable projects planned.

Eskom's coal-powered electricity plants are the main source of greenhouse gas emissions by South Africa.

"Construction should be stopped and investment should be shifted to renewables," Steele said in a telephone interview.

Eskom spokeswoman Hillary Joffe said the utility agrees that South Africa should reduce its greenhouse gas emissions, and is moving toward green technology and cleaner coal. But she said South Africa also needs to develop, and that cheap coal is an important part of its energy mix.

Greenpeace argues that coal would not be considered cheap if the costs of pollution, health problems, water use and climate change are factored in.

The World Bank has approved $250 million in funding for to help Eskom build solar power and wind power plants, and approved a $3.75 billion loan to Eskom for the Medupi plant.