Version History

This page provides an archive of GridLAB-D™ version announcements.

Previous Announcements

  • GridLAB-D™ v4.3 ([Navajo (Version 4.3)]) is now available! Windows and Linux builds can be found at GridLAB-D™ downloads. The Mac release is coming soon. In the mean time, GridLAB-D™ v4.3 can be built from the source code at GridLAB-D™ GitHub Repository.

  • GridLAB-D™ v3.2 ([Jojoba (Version 3.2)]) is now available!

    Windows, Linux, and Mac can be found at GridLAB-D™ v3.2.

  • [Jojoba (Version 3.2)] candidate release (November 15, 2015)

    This candidate release is for Windows, Linux and Mac OSX. The downloads can be founds at Candidate Release Release notes are available at: [History].

  • GridLAB-D™ v3.0 is now available!

    Windows, Linux, and Mac can be found at GridLAB-D™ v3.0.

  • GridLAB-D™ v3.1 is branched

    It was branched from v3.0 and ticket 730 for completion, testing, and validation in Jan. 2014. Currently, the goal is to release v3.1 by Summer 2014. It will included expanded delta-mode and microgrid capabilities, expanded hardware-in-the-loop capabilities, DG controllers, and multi-threading support, among others. Feel free to see progress in the source tree.

  • GridLAB-D™ v3.0 Release Candidate is now available! (posted 10/1/2013)

    Release candidates for Windows, Linux, and Mac can be found at Candidate Release. Please report any bugs or concerns.

  • [GridLAB-D™ Association] Formation Authorized (posted 20 November 2011)

    The US Department of Energy has authorized PNNL to begin the legal process of forming an association of GridLAB-D™ stakeholders, including interested parties from user, vendor, academic and government communities to help direct and fund the growth of GridLAB-D™. Contact David Chassin (PNNL) for details. Update - Initial kickoff meeting was held in July 2013 - for more information or to join the GridLAB-D™ Association, please contact the GridLAB-D™ Team

  • [Grizzly (Version 2.3)] Launched (posted 10 November 2011)

    A new release of GridLAB-D™ was started by PNNL. This release is will incorporate support for microgrids and advanced multi-objective controls. Contact Jason Fuller (PNNL) for details.

  • [Four Corners (Version 2.2)] Released (posted 28 September 2011)

    A new release of GridLAB-D™ was released for general use. It supports the American Recovery and Reinvestment Act (ARRA) Smart Grid Investment Grant (SGIG) analyses performed by PNNL for the US Department of Energy. See Downloads for details.

Release Notes

For the sake of posterity we're keeping track of the major versions and releases of GridLAB-D™.

GridLAB-D™ Family Tree (Source: [1])
Figure 1: GridLAB-D™ Family Tree (Source: [1])

is a minor upgrade of GridLAB-D™ planned for Fall 2020. Changes and improvements in Navajo will be outlined here.

  • New Capabilities

  • Ability for global #define statements to take unit values - deltamode_timestep utilizing

  • Addition of global to force complex output format
  • Addition of internal load order for deltamode modules, to make sure things execute in proper order
  • Addition of three-phase or higher-voltage connectivity to the house model
  • Addition of HELICS-interfaceable event field to eventgen object
  • Improvement to house to enable adding the powerflow induction motor to house HVAC models
  • Improvement to evcharger_det to include simple subsecond capabilities and simple SAE J2894 capabilities
  • Addition of powerflow flag to convert models to constant impedance at particular voltage triggers (outside in-rush)
  • Improvements to multi-island powerflow capabilities, including the ability to solve them separately
  • Improvements of wind power capability curve
  • Addition of inverter_dyn object - a new microgrid/dynamics-oriented inverter
  • Addition of DC model to solar object for use with inverter_dyn
  • Addition of sync_check object
  • Addition of ability to export the right-hand-side vector as part of the NR matrix dump

  • Bug Fixes

  • Performance improvements to NR solver

  • Fix to constant current implementations in load objects to be more intuitive and flexible to off-nominal angles (migration of transient mode capabilities)
  • Fixes to compilation process and files to better handle MSYS2 and cross-platform consistency
  • Fix for _err autotest checking so a failure to fail is not considered a success
  • Fixes for HVAC operation with a tripped breaker
  • Fixes to diesel_dg and existing inverter object for transient mode initialization
  • Fixes to frequency calculation methods to better handle transient mode/QSTS transitions
  • Fix so base line objects can take matrix definitions, though not encouraged
  • Fix for normalized schedules
  • General clean-up of generator and powerflow objects and headers for new API and eliminate erroneous inclusions
  • Tickets (tickets relating specifically to the development of this version)

Lugo (Version 4.1)

is a minor upgrade of GridLAB-D™ planned for October 2018. Changes and improvements in Lugo were focused primarily on the transient mode transient analysis (microgrids) and FNCS/HELICS integration, with several minor features and fixes incorporated.

  • New Capabilities

  • FNCS and HELICS interfaces incorporated

    • Several bug fixes and improvements to the interfaces
    • Includes transient mode capabilities with FNCS/HELICS
  • MySQL module
    • Improved writing mechanism to reduce overhead
    • Several usage fixes
  • Generator module
    • Cleaned up several deprecated objects that had no functionality
    • Inverter has had significant improvements to its functionality
    • Deltamode improvements for better transient simulations
      • Ability to operate as a voltage source inverter and be grid forming
      • Operate in either isochronous or droop mode
      • Droop controller for f/P and V/Q in grid following implementations
      • Ramping limits to reflect power electronics slew limitations
    • Improvements to the inverter IEEE 1547 and IEEE 1547a functionality
    • New Volt/Watt mode
    • Diesel generator has had improvements to its functionality
    • Simplified steady state model to remove inaccurate model
    • Simple overload checking incorporated
      • Deltamode improvements for better transient simulations
      • Added convergence limits for voltage to help control transient mode simulation intervals
      • Simplified set point variables for frequency, voltage, real power, and reactive power dispatch outputs
      • Implemented new control modes for resiliency analysis
        • Constant reactive power dispatch mode
        • Constant real power dispatch mode
        • CVR method for transient reduction, per this paper
      • Simplified fuel use and emissions calculations
  • Powerflow module
    • Fixes for tape-shielded cables
    • Multiple islands supported, including the ability for an island to "fail" and not terminate the simulation
    • Tiered-TOU pricing fixed for triplex_meter
    • Induction motor models
    • Single-phase and three-phase implementation
    • Deltamode support
    • Simple protection schemes (thermal trip and under-voltage contactor)
    • AMI-like fields for meter and triplex_meter
    • fault_check incorporated SINGLE_DEBUG to help track down feeder topology problems
    • Deltamode capability improvements
    • Capacitor objects now can update in transient mode
    • Regulator objects now can update in transient mode
    • Separate integration method selections for series vs. shunt impedance and in-rush calculations
    • Improved GFA functionality in node-type objects
  • Tape module
    • Deltamode support for group_recorder
    • New object - metrics_collector
  • Build/Support
    • Migration to MSYS2-based environment for Windows compiling
    • Updated incorporated superLU MT version to 3.1
    • Updates to build numbering to better reflect GitHub hash system
    • Migration of several objects to GLD API
  • Tickets (tickets relating specifically to the development of this version)

Keeler (Version 4.0)

is a major upgrade of GridLAB-D™ planned for some time in 2015.

  • [New capabilities] (these capabilities were first implemented in this version)
  • [Approved capabilities] (these capabilities were approved for implementation in this version)
  • [Proposed capabilities] (these capabilities were proposed for implementation in this version)
  • Tickets (tickets relating specifically to the development of this version)

Jojoba (Version 3.2)

is a minor upgrade of GridLAB-D™ planned for late 2015.

  • [New capabilities] (these capabilities were first implemented in this version)
  • [Approved capabilities] (these capabilities were approved for implementation in this version)
  • [Proposed capabilities] (these capabilities were proposed for implementation in this version)
  • Tickets (tickets relating specifically to the development of this version)

Hatwai (Version 3.1)

is a minor upgrade of GridLAB-D™ released September 30, 2014.

  • [New capabilities] (these capabilities were first implemented in this version)
  • [Approved capabilities] (these capabilities were approved for implementation in this version)
  • [Proposed capabilities] (these capabilities were proposed for implementation in this version)
  • Tickets (tickets relating specifically to the development of this version)

Hassayampa (Version 3.0)

  • Added Features (new features since v2.3):
  • Added "linkage" capability for linking with external software (e.g., MATLAB).
  • Enhanced internal C++ Module API.
  • Enhanced streaming and realtime server modes.
  • Enhanced HTML/GUI support.
  • Added multirun capability.
  • Improved speed performance, both in core functions and at module level.
  • Added simulation connection to Powerworld via SimAuto.
  • Added numerous command line functions (e.g., "--example" and "--pcontrol"). Types can be viewed via "--help".
  • Created internal validation ("--validate") and test ("--test") command line calls.
  • Added job/batch processor support ("--job").
  • Random numbers are seedable and reproducable on different OS.
  • External transforms are supported.
  • Added precommit, finalize, and notify callbacks.
  • Init() is no longer order dependent, but object oriented.
  • Added multi-thread support (some classes are not yet compliant).
  • Added support for mingw 64-bit.
  • Enhanced timezone support for international usage and automatic configuration with location.
  • Overhauled Linux and MacOS make files.
  • Added support for model sanitization.
  • Upgraded to Xerces v3.1.1.
  • Added a general solver library.
  • Created a script directive.
  • Added configuration script for Windows builds.
  • Added parameter expansion of global variables.

  • Added module level classes: pw_model, pw_load, pw_recorder, load_tracker, group_recorder, evcharger_det, and triplex_load (NOTE: some of these may have been simultaneously added to v2.3).

  • Bug Fixes (since trunk branching on 12/6/2011):

  • Ticket 591: Sync time determination restructured
  • Ticket 612: glmjava and module_load load process corrected
  • Ticket 621: Corrected error in solar direct calculation when using quadratic interpolation
  • Ticket 628: loader processes directives before next macro is processed
  • Ticket 629: Corrected line number errors when using macros
  • Ticket 640: Moved climate data to shared directory
  • Ticket 642: Added % progress to --pcontrol screen
  • Ticket 645: Added DST support for CSV reader
  • Ticket 646: Group recorder is now printing units properly
  • Ticket 648: Corrected error in implicit end uses causing simulation to continously run
  • Ticket 658: Corrected "rogue" pointer behavior with models that did not include DST
  • Ticket 660: Harmonized build numbers
  • Ticket 670: Updated and corrected clock block to be "object" oriented
  • Ticket 675: Updated build dependency in Windows
  • Ticket 679: Added "entropy" to random seed in globals and randomvar
  • Ticket 680: Updated troubleshooting documentation to correctly populate online site
  • Ticket 688: Added check for property size during initialization to prevent memory errors
  • Ticket 698: Added a ranking structure to commit or a post commit for recorders and assert objects
  • Ticket 701: Collectors support unit conversions
  • Ticket 707: Upgraded climate module for use in southern hemisphere
  • Ticket 709: COllapsed NR solver to a single pass
  • Ticket 721: Set "better" defaults for starttime and stoptime
  • Ticket 728: Fixed return calls in exec.c used where throws should be used
  • Ticket 729: Corrected memory leaks in Linux
  • Ticket 731: Corrected CC, DL, CCFLAGS environment variables are not set up correctly
  • Ticket 737: Upgraded classes to use deferred init
  • Ticket 739: Upgraded make tools to more current versions
  • Ticket 744: Corrected transforms sometimes cause loader null pointer errors
  • Ticket 747: Enhanced wind turbine functionality
  • Ticket 755: Added error catches to numerous DG models
  • Ticket 756: Added error catches to numerous DG models
  • Ticket 763: Upgraded histogram to use new API functions
  • Ticket 764: Corrected errors in random number generation in Linux
  • Ticket 774: Corrected architecture printing
  • r4094: Out of time step error corrected in water heater

Grizzly (Version 2.3)

(branched November 2011) (released March 2013)

This is an extension of [Four Corners (Version 2.2)] to support microgrid and advanced controls analysis for the US DOE.

  • Development of simulation capabilities within GridLAB-D™ loosely designed around microgrid development concepts.
    • Introduced machine dynamics.
    • Sub-second simulations capabilities were introduced as DELTA-mode.
    • Generator excitor and governor controls (diesel_dg).
  • Updated the PV solar model and validated in cooperation with NREL using SAM model.
    • Updated solar model to SOLPOS.
    • Included fixed axis and multi-point efficiency.
    • Updated inverter model for four-quadrant controls and a volt/var control method.
  • Extended weather and time zone models to southern and eastern hemispheres.
  • Added "load_tracker" object in powerflow to ease calibration to substation SCADA data (AusGrid).
  • Parallelized server mode to allow multiple simultaneous HTTP socket connections (AusGrid).
  • Updated thermostat DR controls and auction models to incorporate "lessons learned" from AEP gridSMART design and specifications for real-time double-auction market.
  • Added a "group_recorder" object to collect a single variable from a group of objects over time (i.e., voltage of every node object every 15 minutes).
  • Added deterministic EV charger model to better represent individual device charging.
  • Added basic optimization functionality (particle swarm optimization, gradient search, etc.).
  • Added generator controller to market module to simulate behavior of generator bidding in the Olympic Peninsula Demonstration Project.
  • Windows 7 and XP 64- and 32-bit, Linux Red Hat v4 and v5, Ubuntu v11, and Mac OS X fully supported.
  • Added basic support for VS2010.
  • Extensive bug fixes from v2.2.

Four Corners (Version 2.2)

(September 2011)

Four Corners was developed to support analysis of the US DOE's ARRA SGIG projects. The following are improvement made in this release.

  • Added generator_controller to market module to allow generators to bid into a wholesale/retail market, including fixed rates, fuel costs, and start up and shut down costs. Tested but not validated.
  • Added a limited emissions support to powerflow module, which attempts to estimate the generated emissions of a feeder by giving it a predefined dispatch order and capacity limit. Limited capabilities are tested but not validated.
  • Added optional parasitic power draws and multiple billing strategies (fixed, tiered, time of use, and real time) to meter and triplex_meter classes. Additionally, a billdump class was added to collect all customer bills into a single file at the end of each simulated month.
  • Diesel distributed generation model was enhanced to include fuel costs/usage, efficiencies, and heat transfer rates. This is in preparation for future CHP models.
  • Added a current and voltage “dump” feature in powerflow that allows the user to specify a time, then all current or voltage measurements are dumped to a single output file.
  • Updated troubleshooting documentation. Now is fully linked on Sourceforge site to internal troubleshooting code.
  • Added a stub bidder object to the market module to allow users to create a “fake” bidder, with enhanced flexibility on the bidding rules.
  • Market module, including auction, controller, and passive controller updated, with major bugs removed. Module is tested and validated to the extent that it is used for SGIG analysis for US DOE ARRA projects.
  • The solar panel and inverter models were “cleaned up” for analysis. Test and partially validation.
  • A thermal energy storage model added to residential module. Similar to Ice Bear technology, it converts electricity to ice, which is then used to cool the house object during peak load periods. Validated against available data.
  • Multiple economic elasticity models were added to the market module, including daily and substitution values. Only linear 2- and 3-tier TOU and TOU/CPP models have been validated. A non-linear version has been included but it is not fully validated.
  • Direct load control and demand response capabilities have been added to the market module. These include controls for HVAC cycling, water heater cycling and shutoff, and pool pump cycling and shutoff. These models have been validated to the extent they were used for analysis, but have not been fully tested.
  • A duty cycle mode was added to the zipload class in the residential module. Originally intended to represent pool pump cycling, it can also be used to represent anything with a simple duty cycle.
  • The Newton-Raphson (NR) powerflow solver method was “cleaned up” to increase performance. Additionally, code was added to assist in replacing the SuperLU solver with external solvers, such as the KLU solver, resulting in additional performance enhancement. However, due the licensing restrictions, only the capability to include KLU is provided, not KLU itself. (The external KLU solver can be downloaded from a separate folder on SourceForge.)
  • Extended the capabilities of the reliability module to support more classes, such as fuses and switches, and provide IEEE 1366 metrics assessment.
  • Initial enhancements were made to include detailed short circuit analysis. These capabilities are still in the testing and development phase.
  • Added scripts compatible with version 2.2 and the taxonomy feeders have been added to the open source repository. These Matlab based scripts were used to convert standard utility feeder models to models fully populated with residential and commercial buildings and loads representative of different regions within the United States in support of the 2011 SGIG analysis of US DOE ARRA projects.

Template:VERSION21

(November 2010)

  • Linux support include (RH/Fedora, Ubuntu)
  • Mac OS X support
  • Windows 64 bit support (w/o runtime classes)
  • Support for schedule skews
  • Improvements to markets and controllers
  • Direct impedance value (as opposed to geometric specification) capability added to powerflow.
  • Overhaul and full specification of market module begins.
  • Overhaul of taxonomy feeders, including population with residential, thermal loads, limited automation, and shunt transformer losses for DOE studies.
  • Multi-object recorder added as a function within recorders (records multiple variables from multiple objects).
  • Secondary power and current calculations finished for all objects in powerflow.
  • Presented paper on voltage regulation devices and time series analysis for the IEEE 8500 Node Test System at the 2010 PES T&D Conference and Exposition.
  • Functionality of scheduled loadshapes significantly increased.
  • Majority of feeder restoration completed and added (by ISU).
  • Volt-Var control object added to control capacitors and regulators in concert for voltage reduction.
  • Presentation on voltage reduction concepts at 2010 Distributech.
  • Major auto-validation is started on residential model.
  • Tree searching structure added to restoration in power flow (for ISU).
  • Visited University of Washington for two days to present and teach applications of GridLAB-D™.
  • Passive controller object added to markets for non-bidding appliance responses.
  • Double controller object added to solve conflicting thermostatic set points (clashes between cooling and heating during low prices).
  • SuperLU-MT (multi-thread) replaced standard SuperLU in build.
  • Bill dump object added to powerflow, which allows user to collect all customer bills into a single file.
  • A number of error checks in powerflow added to prevent singularities in NR method.
  • House_e ETP model numerical instabilities fixed.
  • More flexible support for house_e heating AUX mode.
  • Basic motor models added into HVAC model, including shunt losses important for CVR analysis.
  • Additional controls enabled on some appliances.
  • Measured values for certain ZIP loads applied to defaults.
  • Stub auction object added to create a passive (non-bidding) market signal.
  • Frequency response implemented in powerflow.
  • Initial fault checking object added to powerflow in preparation of ISU additions.
  • Multiple customer billing modes added to triplex meters.
  • A rudimentary restoration object for reconfiguration studies is added to power flow module.
  • Multiple heating and cooling systems added to house_e model, including tighter coupling between powerflow and HVAC loads.
  • Included a mode to incorporate weather data other than tmy2.
  • Release version 2.0 RC of GridLAB-D™ is separated and released.
  • The first phase of house_e development is completed.
  • A series reactor object is added to power flow.
  • A ZIP load object (impedance, current, and power fraction) is added to residential to simplify some of the secondary system loads.
  • The 2009 D.O.E. Use Cases are released to showcase the abilities and uses of GridLAB-D™.

Eldorado (led to Version 2.1)

is the branch that led to Version 2.1, which was release in November 2010. In included the following capabilities:

  • Linux support include (RH/Fedora, Ubuntu)
  • Mac OS X support
  • Windows 64 bit support (w/o runtime classes)
  • Support for schedule skews
  • Improvements to markets and controllers

Diablo (Version 2.0)

(September 2009)

  • Trans-active, market controller added to market module. Major development of Olypen model started.
  • Implicit end use load shapes are implemented for all residential end uses.
    • Analog driven load shapes are completed.
    • Dishwasher, range, hot water heaters, and evcharger completed as demand driven models.
  • Installer gets updates to include TMY2 data, and other options, when installing.
  • Three-phase Newton-Raphson power flow method finished and validated for all objects within the power flow solver.
  • Voltage dump object added to power flow to extract all voltages from the system into a single file.
  • Default house model is switched from house_a (ASHRAE model) to house_e (ETP model).
    • House_a model becomes deprecated.
  • Major components of validation system are added.
  • A short course for GridLAB-D™ users is first taught.
  • Functionality of loader was greatly increased, including larger buffer sizes, ability to “include” multiple input files through a single input, and inclusion of schedules.
  • Schedule and load shape objects added in preparation for implementation of residential end use schedule driven loads.
    • Schedule is later developed to be used for all object inputs and a schedule linear transformation is created.
  • Major work begins on Equivalent Thermal Parameter (ETP) house model.
  • The SuperLU, single-thread, open-source solver added to build for Newton-Raphson solver.
  • Independent, automatic control algorithms for capacitor and regulator objects are added.
  • Commit “timestep” added to sync order for eventual speed-up in calculation time. Allows for final values to be calculated at end of cycles, instead of repeatedly.
  • Macro “minimum_timestep” implemented to force the system to jump ahead a certain amount of time, instead of being driven by the model.
    • While this function is highly useful and seems to work well, it has not been fully tested to see how much it affects simulation results.
  • A validation program, the assert module, and auto-test files created to begin continuously self-validating GridLAB-D™ modules and notify developers of unintended consequences of updates.
  • PQ load is created to represent complex loads without using a state driven model.
  • Gauss-Seidel power flow solver deemed a failed experiment.
    • Implementation of a three-phase Newton-Raphson solver started.
  • Style sheets are opened for user defined xml format style sheets for data output.
  • Overhaul of phase tests in power flow solver in preparation of Newton-Raphson solver implemention.
  • Troubleshooting documentation function added, so that all error messages have a troubleshooting explanation attached to them and are automatically available on the Sourceforge Wiki site.
  • Reliability module overhauled.
  • Histogram plots added to tape module.
  • Completed migration of build to Sourceforge from local PNNL SVN site.
  • “Smart grid” module removed from build.
  • Implementation of a three-phase Gauss-Seidel power flow solver started.
  • Migration to Sourceforge SVN initiated.
  • Initial one-line network solver completed.
  • Matlab was removed from build.
  • HVAC and end use loads separated into different loads on the house panel in preparation for more explicit modeling of residential end use loads.
    • Drier, freezer, and clothes washer state models added to residential module.
  • Electric Vehicle and charger state model added to residential module.
  • Minimal GNU plot and functions for plotting simulation data added to build.

  • Major overhaul of power flow solver in preparation for Gauss-Seidel implementation. [Diablo (Version 2.0)] was begun in August 2008. This version was expected to include preliminary support for

  • Distributed generation

  • Runtime classes (compiling code in models)
  • Support for gdb and msvc debuggers
  • Support for gnuplot output using tape module

  • 3 phase unbalanced power flow solution using Gauss-Seidel method Considered, but not implemented capabilities available:

  • Multispeak

  • Integration with EPRI's OpenDSS (this is a long shot for this version)

Coyote (Version 1.3)

(Never released)

This version was begun in May 2008 and never released. This developer-only version included preliminary support for

  • Distribution reliability metrics calculations
  • Power markets
  • Commercial multi-zone office modeling
  • Distribution automation
  • Control network modeling
  • Java runtime modules
  • KML support (Google Earth data files)
  • XSD, XSL, and CSS support (XML stylesheets)

Coulee (Version 1.2)

(May 2008)

This was a second general release of GridLAB-D™ that included a number of cross-platform enhancements not available in Version 1.1.

Coulee is the branch of GridLAB-D™ that led to Version 1.2. It included a number of cross-platform releases of Version 1.1 ([Buckley]).

Coulee is the branch of GridLAB-D™ that led to Version 1.3, which was never released. This version was begun in May 2008 and never released. This developer-only version included preliminary support for

  • Distribution reliability metrics calculations
  • Power markets
  • Commercial multi-zone office modeling
  • Distribution automation
  • Control network modeling
  • Java runtime modules
  • KML support (Google Earth data files)
  • XSD, XSL, and CSS support (XML stylesheets)

Buckley (Version 1.1)

(April 2008)

This version was the first general release of GridLAB-D™ made available to the public. This version includes additional support for

  • Commercial single-zone office buildings
  • General balanced 3-phase transmission network flow calculations (experimental)

Allston (Version 1.0)

(January 2008)

This version was the first limited release of GridLAB-D™ made available to the partners who expressed interest in collaborating with PNNL during 2008 to assist in getting the tool ready for open source distribution by early 2009. This version includes support for

  • Windows 32bit and 64 bit platforms (XP only tested)
  • Linux 32bit platforms (not all variants tested)
  • Unbalanced 3-phase distribution powerflow calculations
  • Residential single-family home and appliance modeling
  • XML and KML support

Version 0.2

(2004)

This was the last version called PDSS. It was a special build designed to support the market operations of load-serving entities. It was also the last version to require the use of Matlab.

Version 0.1

(2003)

This was the official version of PDSS that was use by PNNL in the early years of the GridWise program. It was developed under LDRD (a special type of DOE research funding that is managed by the Laboratory) during 2002-2003. It required the use of Matlab and was very limited in the capabilities. However, it demonstrated many of the important characteristics that came to be essential to GridLAB-D™.

With Version 1, GridLAB-D™ revealed the potential for a transformation in how complex energy systems are modeled, and garnered a great deal of interest from potential users around the world. The availability of Version 2 has built on that interest and provides a much more appealing and flexible product with a wider potential range of users. The open-source system works well on both proprietary and open-source operating system and is expected to perform strongly in the utility market. GridLAB-D™ is set to transform how we model and study modern energy systems.

David Chassin and Ross Guttromson were commissioned under the Laboratory’s Energy Systems Transformation Initiative to look into a) whether such a software system could be built, b) whether it could model how energy systems might evolve over time, and c) how much value would this evolution bring to consumers and utilities. In 2007, after the US Department of Energy's Office of Electricity committed to getting the results of that work more widely available, the open-source model of development and distribution was used to make sure that as many people as possible could both contribute to it and benefit from what it has to offer. Since then, GridLAB-D™ has grown quickly, mainly because of the hard work and dedication of all the contributors, and of course the early dedication of the GridLAB-D™ team at PNNL.