"increasing the capacity" is correct and usable in written English.
You can use it to describe a situation in which a process, person, or organization is making an effort to increase the maximum amount that can be done or handled. For example: "The company is working to increase the capacity of their production line to meet customer demand."
Musharraf underlined the importance of increasing the capacity of the Iraqi armed forces and police.
An Australian group has found a way of increasing the capacity of standard CDs and DVDs with a similar technique.
"Website crashes were far less [frequent] this year, which we believe is owed to retailers increasing the capacity of their IT platforms".
If all planes have such a system installed, they can safely fly somewhat closer to each other, landing in tighter sequence, increasing the capacity of a runway.
The Foundation's work in the area of rights to information focuses on increasing the capacity and working lives of journalists in Turkey and the Balkans.
"But actually we need a better transport system for the 21st century, and HS2 is part of increasing the capacity of our transport system".
It is difficult to measure the impact of these new donor relationships: increasing the capacity building or 'effective institutions' portion of aid sounds right.
Volvo has already demonstrated a way of packing autonomous cars together in "road trains", greatly increasing the capacity of roads while reducing traffic jams.
Bournemouth will not be increasing the capacity of their Goldsands Stadium in time for their first season in the Premier League.
By increasing the capacity of a river, dredging can help flood waters move more quickly to the next town or village.
They could co-ordinate their routes and travel in close formation, increasing the capacity of road networks, reducing congestion and saving fuel.
