Finland’s top refiner Neste Oil (NES1V.HE) expects its renewable diesel plant in Singapore to reach full capacity in six months, its chief executive said.

“It is a big refinery and we want to proceed slowly and see how it works and see if there are any bottlenecks,” Matti Lievonen told Reuters in an interview on Friday.

“It will take probably six months before full capacity will be reached. We are scaling up from 70,000 tonnes to 800,000 tonnes (annually),” he said.

The company has two biodiesel lines in Porvoo, Finland, and started the world’s largest renewable diesel plant in Singapore in mid-November.

It has invested some 1.4 billion euros ($2.5 billion) in renewable fuels and is building another facility in Rotterdam, Europe’s biggest port.

The plant, similar to the one in Singapore, is scheduled to start towards the end of the first half of 2011 and is seen costing less than the original 640 million euros budget.

“It will probably be below the original budget, but we have not said by how much,” Lievonen said, adding the construction had proceeded according the schedule.