  Multi-energy systems can provide a constant level of service to end-use
energy demands, while deriving delivered energy from a variety of
primary/secondary energy sources. This fuel-switching capability can be used to
reduce operating expenses, reduce environmental impacts, improve flexibility to
accommodate renewable energy, and improve reliability.
  This paper presents four frameworks for incentivizing energy hub equipment
investments for low-carbon operation targets. These frameworks vary in the
measures taken to achieve low-carbon operation (explicit constraint vs. carbon
pricing) and in the relationship between the hub builder and operator
(cooperative vs. uncoordinated). The underlying energy hub model upon which
these frameworks are built is an enhanced greenfield model, introducing 'energy
buses' to reduce dimensionality.
  A case study is conducted for a campus being designed in Beijing, and results
from each framework are compared to illustrate their relative costs. When the
operator cannot be trusted to cooperate in controlling emissions, the system
must be 'overbuilt' with more expensive equipment to ensure emissions target
are met. A taxation-based approach increases overall costs at moderate
emissions targets, but this effect decreases at aggressive targets. This paper
also compares the cost of less efficient institutional frameworks with the most
efficient approach, i.e. cooperation between builder and operator with
constraints on emissions.
