Short story: you can't.

Option 1: post processing

You'll need to do some post-processing to calculate that yourself.

If you are using the DistrictHeating fuel for something else than your steam equipment, make sure you fill in the SteamEquipments' End-use subcategory, so you can easily only get the consumption for these steam equipment.

Use the consumption to calculate your natural gas consumption. The easiest way would be to calculate it with a fixed system efficiency (boiler efficiency + distribution losses).

Option 2: bump SteamEquipment consumption

Another alternative is to bump your SteamEquipment's consumption to factor in the steam system efficiency and adjust the fraction lost so you don't end up with too much extra heat in your Zone.

Here's a dummy example for you. Green=E+ inner working, Blue=Input, Red=Calculated.

Limitations prevent you from connecting your SteamEquipment to a PlantLoop:

• OpenStudio aside, this isn't possible in E+ to my knowledge: SteamEquipment cannot be linked to a PlantLoop, and I don't see any other components that could be fit for this job.

• Steam systems are not supported in OpenStudio. There is only one component you'd need that is implemented (Boiler:Steam), but others are not (PumpVariable:Speed:Condensate, Pipe:Adiabatic:Steam, all the steam components such as Coil:Heating:Steam etc). This is why the steam boiler is not yet included in the HVAC library.