This should be possible: LEAP is largely agnostic about the scale of a system it models. Lots of people have used it to model cities and states/provinces for example. (I even used it once to model my own apartment!) You can model all direct consumption and associated direct emissions associated with an institution under the demand branches. The emissions from the supply of electricity can be modeled in a simple way under the Transformation branches. I recommend you initially create simple Transformation modules that just model the average mix of fuels used in the electric system and their emissions. You can ignore the more complex features for modeling capacity expansion.

The part that LEAP cannot easily do is the so called "scope 3" emissions: indirect emissions that occur in your institution's value chain, encompassing activities beyond its direct control, such as those related to suppliers, transportation, and product use. LEAP does not cover those emissions because it is primarily set up to model a geographic system rather than an institution. Scope 3 emissions are both hard to calculate and hard to interpret. Here's a good resource with more info.

One thing to consider is whether LEAP might be overkill for what you are trying to do. You may be able to do what you want with just a spreadsheet. Usually people choose to use LEAP when they want to explore alternative policies for the future using its scenario modeling capabilities.

I hope this helps you to get started.

Best wishes,

Charlie