Community Modeling and Analysis System


Brief Description

CoST (Control Strategy Tool) allows users to estimate the emission reductions and costs associated with future-year control scenarios, and then to generate emission inventories with the control scenarios applied. CoST is a component of the Emissions Modeling Framework (EMF), which is currently used by EPA to solve many of the long-standing complexities of emissions modeling. Emissions modeling is the process by which emissions inventories and other related information are converted to hourly, gridded, chemically speciated emissions suitable for input to an air quality model. The EMF supports the management and quality assurance of emissions inventories and emissions modeling-related data, and also the running of SMOKE to develop air quality model inputs.


CoST was developed primarily for performing Regulatory Impact Analyses (RIAs) for National Ambient Air Quality Standards (NAAQS). As part of the RIA development process, CoST allows EPA to identify additional emissions controls that could be applied by states and EPA to bring areas into attainment, and to estimate the emissions reductions and costs of these additional controls.


CoST tracks information about control measures, their costs, and the types of emissions sources to which they apply.

Supports preparation and analysis of future year emissions control strategies for point (primarily non-EGU), area, and mobile sources.

CoST is built on top of Control Measures Database (CMDB), a database of current information about control technologies and practices that are available to reduce emissions, the source categories to which they apply, the expected control efficiencies, and their estimated costs.

CoST is an extensible software system that provides several types of algorithms for developing control strategies:

  • Maximum Emissions Reduction
  • Multi-Pollutant Maximum Emissions Reduction
  • Least Cost
  • Least Cost Curve

Control strategy results can be exported to comma-separated-values (CSV) files, SMOKE-formatted inventory files, Google Earth-compatible (.kmz) files, or Shapefiles. The results can also be viewed in a graphical table that supports sorting, filtering, and plotting.

CoST is a component of the U.S. EPA's Emissions Modeling Framework (EMF), a client-server Java application and a PostgreSQL ( database that stores information related to emissions modeling, including emissions inventory datasets and the CMDB.

CoST reports the emissions reductions and costs associated with the co-impacts of a selected group of control measures on other pollutants.

Updates in v3.7

  • Fix end condition for least cost narrowing algorithm
  • Add option to include dataset_id column when exporting flexible format datasets from control strategies
  • Update naming for combined strategy detailed results file to use control strategy name

Updates in v3.6

  • Update control strategies to not apply controls to inventory sources with existing control efficiencies over 100%
  • Update cost equation type 2b to only apply to sources whose design capacity is less than 1500 HP
  • Add option to export multiple Strategy Detailed Results in a single file
  • Add quick search options

Updates in v3.4 & v3.5

  • Update implicit price deflators, used for cost year conversions, using values from August 2019
  • Simplify cost equation type 8 (used for non-EGU PM2.5 controls) and add a new equation type 20 (used for ICI boilers)
  • Revisions to the control measure database
  • Module export/import enhancements

Updates in v3.3

  • Now requires Java 8 or higher
  • Updated to work with Java 9 and higher, which supports HiDPI displays on Windows
  • Removed out-of-date control strategy types (Annotate Inventory and Apply Measures In Series)
  • Removed fixed 3% interest rate calculations from control strategies
  • Relabeled columns in control strategy summaries and worksheets to match FF10 inventory terminology

Updates in v3.2

  • Created a new Control Strategy Detailed Result dataset type that uses column names consistent with the Flat File 2010 inventory formats
  • Added the term "effective" to emission reduction and annual cost per ton column names in the new strategy detailed result dataset type
  • Updated all control strategy types to output the new detailed result dataset type
  • Added ability for admin users to edit dataset type column defintions for Flexible File Format-based dataset types

Updates in v3.1

  • Added a new dataset type named "Facility Closure Extended" for use with Project Future Year Inventory control strategies
  • Updated the implicit price deflator values used in cost year conversions for 2014 through 2017
  • Added 2017 as an available cost year
  • Added formatting to numbers in the CMDB export files
  • Added formatting to the cost equation parameters in the At-A-Glance report and the control measure view/edit window

Updates in v3.0

  • Purged obsolete point sector control measures from the CMDB
  • Removed all existing incremental cost-per-ton values from the CMDB; removed unused control-measure-specific capital recovery factors and discount rates
  • Added columns to the control strategy detailed results dataset to report raw emissions reduction (based on uncontrolled inventory emissions) and associated annual cost-per-ton

Updates in v2.15

  • Converted control measures using pollutants PM2_5 and PM10 to PM25-PRI and PM10-PRI
  • Updated control efficiencies and equipment life values for some NOx measures
  • Updated control measures using equation types 1, 12, and 13

Updates in v2.14

  • Fixed a bug in the calculations for Equation Type 13 caused by an order of operations error
  • Added checks for null cost equation parameters for Equation Type 2 and its variants

Updates in v2.13

  • Updated cost year conversion factors (implicit price deflators) for 2013 through 2016
  • Updated NOx non-EGU control measures based on SRA recommendations
  • Miscellaneous CMDB clean-up and fixes
  • Added the ability to upload local files to the server via the EMF client

Updates in v2.12:

  • Updated NOx non-EGU control measures with new cost data, SCC assignments, and cost equations.
  • Changed the final cost-per-ton calculations in CoST to use the net emissions reduction instead of gross; this change impacts costs when replacement controls are applied.

Updates in v2.11:

  • The control measure database has been updated based on IPM v5.15 for the ptipm sector. Updates include revised control efficiency and cost equation parameters, removal of obsolete control measures, addition of new measures, and fixes to cost equation calculations.

Updates in v2.10:

  • Conversions of dollar amounts between different years are now done using annual GDP implicit price deflator values. Previously, CoST used chained GDP values for converting between cost years.
  • Added support for cost years 2007 through 2014.
  • Updated the default cost year to 2013. Previously, the default year was 2006.

History of CoST/EMF

The Control Strategy Tool was developed as a replacement for the AirControlNET (ACN) software tool which is no longer supported by EPA. It was determined in 2006 that it was an appropriate time to replace the ACN software with newer software that could provide improved effectiveness, functionality, and transparency to support current and upcoming needs. A prototype version of the Control Strategy Tool was developed in 2006 and a fully functional version was developed in 2008. The tool has the functionality of AirControlNET but with added capabilities, including:

  • The ability to insert emissions inventories almost seamlessly from the Emissions Modeling Framework (EMF)
  • The ability to insert new control measure data
  • Easier for users to track their analyses and output
  • Quality assurance (QA) steps provided for identifying errors in emissions and control measure data
CoST Flow Chart

Latest Version: CoST/EMF version 3.7



Previous Documentation

Online Resources

System Requirements

O/S Windows, Linux, Mac
Memory 1024 Mb RAM
Software All needed CoST components are contained in the distribution package.