"capacity left" is correct and usable in written English.
You can use it to express the amount of a resource that has not been used or consumed. For example, "We have very little capacity left in our budget this year."
It is weak and has little capacity left for renewables to connect.
According to a 1996 D.E.P. estimate, New Jersey had only eight years of landfill capacity left.
The Saudis rejected Mr Purnomo's suggestion that they had little capacity left.
It required little new investment, and used up spare capacity left over from Soviet times.
The city has enough borrowing capacity left to continue with its planned construction projects until the end of this year.
"They still have borrowing capacity left," said Peter J. Enderlin, an analyst with Ryan, Beck Southeast Research.
Spare industrial capacity left over from the Soviet era meant that firms did not have to invest to produce more.
Last year the country crushed 555m tonnes of sugarcane, with 150m tonnes of mill capacity left unused.
The reason is that the economy, having slowed down only briefly last winter, has little if any spare capacity left.
The ample productive capacity left idle by the crisis meant firms could expand without making big investments.
So freely are they still cheating that only Saudi Arabia, the kingpin of the cartel, has much spare capacity left.
