The rate of return is a function of the rate of risk transferred to an investing party. Whether the investing party is partly the Canada infrastructure bank or a private party, the rate of return will correspond to the size of its position and the risk that it would be absorbing in that project. The whole idea is to transfer risk off the public sector, corresponding to, say, revenue or volume risk, and onto that private sector investor, so that would determine the rate of investment. It has to be the value-for-money proposition of whatever that rate tends to be.
On May 16th, 2017. See this statement in context.