Banks providing fund by way of loans (debt) is a common form of project finance.
Most major commercial banks provide a facility for project finance. For large project finance transactions, commercial banks would tend to lend on a syndicated basis. That is, a number of banks will participate in providing credit facility to the project.
Commercial banks are often more flexible than, for example, multilateral institution lenders. They are generally more prepared to structure loans to meet the specific needs of the borrowers.