In any public private partnership project, government contracts the private party to deliver a service to prescribed standards, and bases its payment schedules on service delivery. government is not necessarily obliged to make any payment until the service is delivered at the required standard. By purchasing outputs, government avoids immediate responsibility for risks associated with the process that produces them -from construction/commissioning risk to the longer-term risks of asset depreciation and technological obsolescence. In effect, capital expenditure on a risk-laden asset is replaced by recurrent expenditure on a service for which the private party bears a significant allocation of risk. If this can be achieved at a whole of life cost to government that is less than the risk-adjusted cost of delivering the service itself, the outcome represents value for money.