Firm Imports Column
Column Type = Text
A value or time series vector, input in MW, specifying the pattern of imports into the pool which can be credited as a firm resource. As such, these values will affect Pool Commitment levels, reserve margin calculations and planning reserve margin targets for long-term studies.
Firm Imports can affect unit commitment when using pool commitment. Pool commitment is used either when reliability-based commitment is selected thorough the Pool Commit switch in the Operating Pools table, or on the first day of a dynamic commitment run in order to bootstrap a reasonable commitment pattern. This variable does not impact economic dispatch or economic imports/exports.
For reserve margin accounting purposes, specified imports and exports are treated as a resource per NERC definition:
Reserve Margin = (Capacity + Firm Imports – Firm Exports) / (Peak Demand) – 1.
For long-term studies, this column is used in conjunction with the Use reserve margin capacity targets option located in the Long Term folder of Simulation Options. This value will be used to define the planning reserve margin target for the overall pool; zonal planning reserve margins will also be met. This provides the ability to specify minimum targets at the zone level, and a potentially higher level at the pool level, letting the model decide where to build additional units above zone minimums. This holds true for both zones that are members of a multiple-zone pool, and those that are not. There is no attempt to aggregate zone level imports/exports up to pool level imports/exports.
The default is zero if the column is missing, unless the pool is comprised of a single zone, in which case the zonal value will be used.
See the Knowledge Base article Long-Term Studies Using Reserve Margins for more information.
Firm Imports Column