Annual Emission constraints are specified under a top-level branch of the LEAP Tree. They are only used (and are only relevant) when running scenarios that include least cost optimization of a Transformation module.
Go to the Optimization screen of the General: Settings screen to enable display and calculation of emission constraints.
Emissions constraints can be used to specify a maximum annual level of emissions for any specified pollutant. LEAP's optimization calculation will then be used to try and identify a least cost configuration of a Transformation module that keep total emissions of pollutants (across the whole energy system) below the specified annual emissions constraint.
In LEAP, emissions of pollutants may arise from various parts of the system, including from Demand sectors, Transformation modules and Non energy sectors. The values entered for the emission constraint variable are the maximum desired value for emissions across all parts of the system. However, LEAP's optimization calculations normally only operate on a single Transformation module (typically the electric generation module).
Use the expression Unlimited if you do not wish to specify a constraint.
Note: Emissions constraints are not relevant (and will be ignored) for any scenarios calculated without least cost optimization calculations.