# Glossary

## App Concepts

* A **Project** includes a baseline and one or more decarbonization scenarios.
* A **Baseline** is a scenario for a project where no attempts have been made to reduce carbon emissions. To define a baseline, C.Scale makes a set of "business as usual" assumptions based on user inputs. When C.Scale's "business as usual" assumptions are not appropriate, they can be refined.
* A **Scenario** is a set of strategies to lower a project's carbon emissions. Scenarios are constructed individually and compared against one another in the [Compare Scenarios](https://docs.cscale.io/users-guide/compare-scenarios) tab.
* A **Portfolio** includes all active projects in your organization, allowing for an "apples to apples" comparison across the same scope categories and LCA stages.
* A **Static Collection** is a manually curated list of projects.
* A **Dynamic Portfolio** is criteria-based: created using a Primary Use Case filter, it automatically includes any new projects matching that filter.
* A **Target Scenario** is the scenario designated as the reference for [portfolio comparison](https://docs.cscale.io/users-guide/compare-scenarios/set-target-scenario) and AIA DDx reporting.

## Carbon Accounting and LCA Terms

* **EUI (Energy Use Intensity)**. Energy use by the building per unit area per year (in kBtu/sf/yr or kWh/m²/yr).
* **ECI (Embodied Carbon Intensity)**. Embodied carbon emissions from the building over the analysis period divided by building area, typically expressed in kgCO2e/m².
* **Embodied Carbon Emissions**. Cumulative emissions associated with building materials, their replacements, and landscape maintenance.
* **Refrigerant Emissions**. Cumulative emissions associated with refrigerant use in building services.
* **Electricity Emissions**. Cumulative emissions associated with energy use from the electrical grid.
* **Fossil Fuel Emissions**. Cumulative emissions associated with onsite fossil fuel combustion.
* **Reduction from Baseline**. Cumulative reduction in emissions of the current scenario as compared to the baseline.

## Electricity Grid Metrics

* **Average Emission Rate (AER)**. Annual emission factors calculated by summing total generation of all resources in a given year on a MWh basis. Includes precombustion emissions from fossil gas leakage. Described in NREL's Cambium model as "AER Load: Combustion + Precombustion."
* **Long-Run Marginal Emission Rates (LRMER)**. Emission rates of the next unit of electricity considering the grid's structure as variable. Preferable to AER for buildings, which are long-lived assets with a marginal influence on grid evolution. Described in NREL's Cambium model as "LRMER: Combustion + Precombustion."