The first questions to ask in considering a district energy or outsourced HVAC solution are...
How important is the reliability and security of your heating and air conditioning service?
Is saving ten to fifteen percent of a project's cost important to you as a property or business owner?
Could you obtain better than "utility" rates of return on invested capital by investing in your own "core competencies?"
Do you believe you would enjoy economies of scale and reduce life-cycle costs by purchasing long-term services from a district energy or outsourced HVAC facility?

Some facts to keep in mind...
Capital Expense: A large HVAC installation is typically 50% construction or soft costs, and 50% equipment costs.

To increase the capacity of a central plant requires an investment in additional equipment and piping to distribute the energy, but a minimum in additional soft costs (assuming it has been designed accordingly).