Projects will typically sign an Operations and Maintenance contract with a single counterparty, which will be tasked with operating the project.
As with the EPC arrangements, the project aims to avoid interface risk by engaging with a single counterparty. Again, the Operator may still use subcontractors, but will wrap subcontractor risk.
The contract will (ideally) be for a pre-specified price so that the project will be able to ensure that its revenues less its opex will be sufficient to meet debt repayments and make an appropriate equity return for the shareholders. The price may have fixed and variable components, as well as pass-through costs.