I am working on a LEED energy model for a small <5000sf project that has

a hot water loop served by a campus district steam loop. I am trying to
follow the "Required treatment of District Thermal Energy in LEED NC2.2"
rules, but am unclear of the requirements it is asking for. I
understand the requirements for the proposed Step 1 and Step 2, but the
baseline requirements seem quite unclear to me.

This building falls in the System 3: PSZ-AC with Fossil Fuel Furnace
heating type.

My understanding of the requirements are as follows:

- Step 1 baseline: because it is supposed to be cost neutral, I model
the systems with a hot water loop and coils served by purchased steam
rather than the normal 90.1 System 3- fossil fuel furnace.

-Step 2 Baseline (this is where I am more unclear):

Option 1: model this exactly as described in App G, system 3: with a
fossil fuel furnace with 90.1 efficiency (i.e. no hot water loop and
coils, and no steam boiler).

Option 2: model this with the hot water loop and coils as in step 1, and
put in a hot water boiler with the efficiencies listed in 90.1?

Option 3: model this with the hot water loop and coils as in step 1, and
put in a steam boiler with the efficiencies listed in 90.1?

Please let me know if I am understanding step 1 correctly and which
option should be followed for step 2.

Thank you for your help.

Ryan Del Balso, PE