1. Important Changes
2. Upgrade Compatibility
3. General Changes
   1. Solver updates
4. Major Features
   1. Universal Classes
   2. Electric Modeling Enhancements
      1. Battery Class Updates
      2. Generator Class Updates
      3. Power2X Updates
      4. Inertia Enhancements
      5. Region Marginal Resource Reporting
   3. Water Modeling Updates
      1. Storage Updates
      2. Water Pump Station Updates
      3. Water Plant and Water Zone Enhancements
      4. Water Pump Enhancements
   4. Stochastic Updates
   5. Gas Modeling Updates
      1. General
      2. Gas Units of Measure
      3. Gas Plant Properties
      4. Gas Capacity Release Offer Properties
      5. New Reporting Properties
5. Machine Learning Grid Enhancements
6. New Attributes
7. New Input Properties
8. New Reporting Properties

Released

June 27, 2022

Previous Version

9.0

Next Version

9.2

Important Changes

Upgrade Compatibility

This version will automatically upgrade any previous Version 8.x or 9.0 database. Although versions before 8.x are supported you should consult your support representative before attempting to upgrade older databases. You may need to check the upgrade notes of earlier releases for any compatibility issues.

Note that Version 9 databases will automatically retro-grade back to Version 8.3, but not to earlier versions.

If you experience any problems upgrading or your simulations run differently or slower in this version during upgrade contact Energy Exemplar Support.

General Changes

Solver updates

The current solver versions are shown in Table 1.

Solver	Version	Notes
CPLEX	20.10	Same as latest 9.0
Gurobi	9.5.2	Same as latest 9.0, upgraded from Gurobi 9.1.2 in PLEXOS 9.0 R01
MOSEK	10.0.12	New beta version
GLPK	5.0	Same as latest 9.0
SCIP	7.02	Same as latest 9.0

Major Features

Universal Classes

Flow Storage input properties have been added that can set the Max Cycles allowed in for intervals. Max Cycles can also be set for Day, Hour, Month, Week, and Year periods. Flow Storage expansion outputs have been added that describe Commodity flows and losses.

Do not use directed flow variables if the flow is unidirectional for Transmission. A more accurate conversion value for Joules per barrel of oil (i.e. 6,118,000,000 Joules in barrel of oil) has been implemented for the Process class.

Build Cost Multiplier has been added as an input property for Facility, Commodity, and Flow Storage classes. The Build Cost Multiplier sets the unit for the input build cost. New Facility output properties Outage, Outage Hours, and Outage Rate report the capacity lost to outage, number of hours on outage, and proportion of installed capacity on outage respectively.

Electric Modeling Enhancements

Battery Class Updates

The following features are now available for the Battery class:

• New input properties Charging VO&M Charge and Discharging VO&M Charge have been added for battery modeling.
• From 9.1 onward, Battery Installed Capacity now refers to energy capacity (MWh) instead of power capacity (MW).
• New output properties Charging and Discharging report the MW rate or GWh total energy added and consumed from the battery, respectively.
• Battery Recharge Timeframe has been implemented to model deferred load.

Generator Class Updates

• New input property Generating Units allow users to set an upper limit on the number of units that are generating electricity.
• New input property Outage Coefficient sets the conditional coefficient of capacity on outage.
• New output properties Outage, Outage Hours, and Outage Rate report the capacity lost to outage, number of hours on outage, and proportion of installed capacity on outage respectively.

Power2X Updates

• New input properties Build Non-anticipativity and Retire Non-anticipativity set a price for violating build and retire non-anticipativity constraints in scenario-wise decomposition mode.
• New constraints can be defined using the Acceptable Risk Coefficient, Net Profit Coefficient, and Net Revenue Coefficient for the Power2X class.
• New objectives can be defined using the Acceptable Risk Coefficient, Net Profit Coefficient, and Net Revenue Coefficient for the Power2X class.

Inertia Enhancements

Inertia is a Reserve Type. The Intertia Constant represents how much stored energy a power source has per unit of capacity. The inertia constant is used to calculate the Inertia provided by a generator, and must be defined for a power source to supply inertia reserve. Inertia constants can be defined for Generator, Battery, Power2X, and Vehicle objects.

Region Marginal Resource Reporting

Report Marginal Resources has been added as a new reporting option. When activated with Regional Transmission Detail the solver does an advanced simplex solve after the initial LP is solved to determine which resources would respond to a slight adjustment to the Region Load. Memberships are created dynamically between the Region and all marginal resources (Generator, Battery, and Market, etc.) in the simulation. The solution will report the percentage that each resource is marginal for each period.

Water Modeling Updates

The following enhancements have been made for water modeling.

• Water Pump Max Starts implementation for the Water Pump class.
• Implementation of new output properties for Emission Water Plants for the Water Plant class.
• Reformulation of "Pump Control" constraints.

Storage Updates

The following enhancements have been added for storage to model potential energy flows:

• New output properties Min Potential Energy and Max Potential Energy report the potential energy of storage at minimum and maximum volumes, respectively.
• New output properties Release Energy and Inflow Energy report the energy release and influx, respectively.
• New output property Downstream Efficiency reports the aggregate efficiency of generation down the river chain. Downstream Release Energy reports the potential energy of downstream releases.
• New output properties End Potential Energy and Initial Potential Energy report the final and starting energy levels, respectively.

Additional properties include:

• Generator Release Energy
• Natural Inflow Energy

Water Pump Station Updates

The following new Water Pump Station input properties have been added:

• Max Flow Rate
• Max Head
• Max Power

Water Plant and Water Zone Enhancements

The following input properties have also been added to model Water Zone capacity reserves for planning in the LT:

• Max Capacity Reserve Margin
• Min Capacity Reserve Margin

New output properties associated with Water Plant non-anticipativity constraints. This includes:

• Build Non-anticipativity
• Retire Non-anticipativity

Water Pump Enhancements

The following new Water Pump output properties have been added:

• Flow Rate
• Head
• Operating Cost

Stochastic Updates

The following performance improvements have been made to stochastic modeling with SDDP and rolling horizons.

• The stochastic storage trajectory calculation during rolling horizons incorporates more information from hanging branches.
• For sampled chronology with rolling horizons, there is no need to sample periods of time after the chronology is simplified. Accounting for this reduces the number of LP solves for rescaling substantially.
• The reported Storage Shadow Price and Storage Marginal Value are now the weighted-average across full and hanging branches from the rolling iterations rather than the values from the final deterministic solve.
• Speed improvements for the first forward and backward passes in SDDP, scenario tree generation, and for both rolling horizons and SDDP related to switching between samples during solution recording and problem set up.
• Reduced the number of times input data are marked dirty for SDDP (e.g. when reading solution values is not necessary)

The following additions have been made for stochastic analysis:

• Users can now view a progress message per stage when running a model in Connect.
• There is now an error message for invalid input for historical (PARMA) sampling.
• Using PARMA to generate synthetic hanging branches (with historical full branches) now works with both the Balanced Scenario Tree and Brazil Scenario Tree.
• Tree construction is not required for rolling horizons with no scenario tree.
• Users can now do sampling with user-selected bands for rolling horizons with other variables (e.g. for wind/solar profiles).

Gas Modeling Updates

General

Membership can now be created between Gas Node and Heat Plant objects. Gas Node emission modeling is now disconnected from Gas Demand and gas sources. Minor formulation improvements have been added to modeling of the initial volume in gas storage by reducing the size of Big M coefficients. Membership can be created between a Gas Zone and Emission object to report the Emission Cost for Gas Zones.

Gas Units of Measure

New input attributes Unit and Energy Density have been added to Gas objects. These provide the ability to specify a different Unit of measure than the base settings of Metric or Imperial. This allows the modeling of systems with different units, such as allowing a Gas Field data to be entered in GJ while in an Imperial system. The user-interface will display the selected Unit in the "Units" column of the property grid. See Gas Modelling section 2.2 Units of Data for details.

The attributes have been added for the following classes:

• Fuel
• Gas Basin
• Gas Capacity Release Offer
• Gas Contract
• Gas Demand
• Gas DSM Program
• Gas Field
• Gas Node
• Gas Pipeline
• Gas Plant
• Gas Storage
• Gas Transport

Gas Plant Properties

New input properties Build Non-anticipativity and Retire Non-anticipativity set a price for violating build and retire non-anticipativity constraints in scenario-wise decomposition mode for Gas Plants.

Gas Capacity Release Offer Properties

New input properties have been added that can model the maximum and minimum release capacity for the Gas Capacity Release Offer class over different time-frames. These include:

• Max Released Capacity
• Max Released Capacity Day
• Max Released Capacity Hour
• Max Released Capacity Month
• Max Released Capacity Week
• Max Released Capacity Year
• Min Released Capacity
• Min Released Capacity Day
• Min Released Capacity Hour
• Min Released Capacity Month
• Min Released Capacity Week
• Min Released Capacity Year

New Reporting Properties

Gas Basin Dispatch Price and Price are the price for dispatch and production respectively from gas basin fields. Gas Field Recovered Capital Cost and Recovery Price are associated with the build cost of the project over the economic life.

The revenue from the total gas capacity release can be reported with the Revenue property. Utilization Back and Utilization Forward report the flow back adn flow forward capacity utilization for Gas Pipelines.

Machine Learning Grid Enhancements

PLEXOS can now consume Machine Learning Models generated with Microsoft Visual Studio, or from PLEXOS itself. The Machine Learning Grid (ML Grid) allows you to generate a Machine Learning Model from Solution results.

The Variable class provides features to integrate machine learning into the fundamentals simulation. It supports models built with Microsoft.ML open source machine learning library. More information can be found related to the ML Grid and ML Models in the PLEXOS Documentation.

New Attributes

The new attributes in this release are listed in Table 2.

Table 2: New Attributes

Class	Name	Description
Competition	Start Cost Mark-up Method	Algorithm used to apply start cost mark-ups
Diagnostic	Infeasibility LP Files	Write infeasible and repaired math programs to disk in text format
Diagnostic	Infeasibility MPS Files	Write infeasible and repaired math programs to disk in MPS format
Fuel	Energy Density	Energy per unit of the fuel
Fuel	Unit	Unit the fuel is measured in
Gas Basin	Energy Density	Energy per unit of the gas
Gas Basin	Unit	Unit the gas is measured in
Gas Capacity Release Offer	Energy Density	Energy per unit of the gas
Gas Capacity Release Offer	Unit	Unit the gas is measured in
Gas Contract	Energy Density	Energy per unit of the gas
Gas Contract	Unit	Unit the gas is measured in
Gas Demand	Energy Density	Energy per unit of the gas
Gas Demand	Unit	Unit the gas is measured in
Gas DSM Program	Energy Density	Energy per unit of the gas
Gas DSM Program	Unit	Unit the gas is measured in
Gas Field	Energy Density	Energy per unit of the gas
Gas Field	Unit	Unit the gas is measured in
Gas Node	Energy Density	Energy per unit of the gas
Gas Node	Unit	Unit the gas is measured in
Gas Pipeline	Energy Density	Energy per unit of the gas
Gas Pipeline	Unit	Unit the gas is measured in
Gas Plant	Energy Density	Energy per unit of the gas
Gas Plant	Unit	Unit the gas is measured in
Gas Storage	Energy Density	Energy per unit of the gas
Gas Storage	Unit	Unit the gas is measured in
Gas Transport	Energy Density	Energy per unit of the gas
Gas Transport	Unit	Unit the gas is measured in
Production	Min Heat Rate Tranche Size	Minimum tranche size in fuel function piecewise linear approximation
Stochastic	Deep Branching	For Rolling Horizon this is the level of additional branching after the end of regular branching
Stochastic	SDDP Replace Samples	If the forward pass samples in SDDP should be replaced by user-defined samples
Stochastic	SDDP Resampling	Flag if resampling is performed for each SDDP iteration at the beginning of the forward pass (The Scenario Tree must be created with PARMA model using Brazilian Methodology)
Stochastic	SDDP Warm Start	If the first forward pass of SDDP is replaced by fixed 'warm start' storage levels
Stochastic	SDDP Warm Start Level	The levels to fix the storage in SDDP 'warm start' as a proportion of the distance between minimum and maximum storage levels

New Input Properties

The new input properties in this release are listed in Table 3.

Table 3: New Input Properties

Collection	Name	Description
Battery	Build Cost Multiplier	Sets the unit for the input Build Cost
Battery	Charging VO&M Charge	Variable operation and maintenance charge for charging
Battery	Discharging VO&M Charge	Variable operation and maintenance charge for discharging
Battery	Inertia Constant	Stored energy per unit of power
Battery.Constraints	Inertia Provision Coefficient	Coefficient of inertia provision
Battery.Markets	Offer Price	Price of energy in band for capacity market
Battery.Markets	Offer Quantity	Quantity offered in band for capacity market
Battery.Objectives	Inertia Provision Coefficient	Coefficient of inertia provision
Commodity	Build Cost Multiplier	Sets the unit for the input Build Cost
Facility	Build Cost Multiplier	Sets the unit for the input Build Cost
Flow Storage	Build Cost Multiplier	Sets the unit for the input Build Cost
Flow Storage	Max Cycles	Number of cycles allowed each interval
Flow Storage	Max Cycles Day	Number of cycles allowed each day
Flow Storage	Max Cycles Hour	Number of cycles allowed each hour
Flow Storage	Max Cycles Month	Number of cycles allowed each month
Flow Storage	Max Cycles Week	Number of cycles allowed each week
Flow Storage	Max Cycles Year	Number of cycles allowed each year
Flow Storage.Constraints	Cycles Coefficient	Coefficient of cycles
Flow Storage.Objectives	Cycles Coefficient	Coefficient of cycles
Gas Capacity Release Offer	Max Released Capacity	Maximum capacity that can be released
Gas Capacity Release Offer	Max Released Capacity Day	Maximum capacity that can be released in a day
Gas Capacity Release Offer	Max Released Capacity Hour	Maximum capacity that can be released in a hour
Gas Capacity Release Offer	Max Released Capacity Month	Maximum capacity that can be released in a month
Gas Capacity Release Offer	Max Released Capacity Week	Maximum capacity that can be released in a week
Gas Capacity Release Offer	Max Released Capacity Year	Maximum capacity that can be released in a year
Gas Capacity Release Offer	Min Released Capacity	Minimum capacity that can be released
Gas Capacity Release Offer	Min Released Capacity Day	Minimum capacity that can be released in day
Gas Capacity Release Offer	Min Released Capacity Hour	Minimum capacity that can be released in hour
Gas Capacity Release Offer	Min Released Capacity Month	Minimum capacity that can be released in month
Gas Capacity Release Offer	Min Released Capacity Week	Minimum capacity that can be released in week
Gas Capacity Release Offer	Min Released Capacity Year	Minimum capacity that can be released in year
Gas Plant	Build Non-anticipativity	Price for violating non-anticipativity constraints in scenario-wise decomposition mode
Gas Plant	Retire Non-anticipativity	Price for violating non-anticipativity constraints in scenario-wise decomposition mode
Generator	Generating Units	Number of generating units
Generator	Inertia Constant	Stored energy per unit of capacity
Generator	Max Down Time Penalty	Penalty for violation of max down time
Generator	Max Heat Penalty	Adds a penalty to the max heat constraint to allow for relaxation
Generator	Max Load Penalty	Penalty for violation of [Max Load].
Generator	Max Up Time Penalty	Penalty for violation of max up time
Generator	Min Down Time Penalty	Penalty for violation of min down time
Generator	Min Up Time Penalty	Penalty for violation of min up time
Generator	Pump Load Penalty	Penalty for violation of Pump Load.
Generator.Constraints	Inertia Provision Coefficient	Coefficient of inertia provision
Generator.Objectives	Inertia Provision Coefficient	Coefficient of inertia provision
Generator.Variables	Outage Coefficient	Coefficient of capacity on outage
Global	Tree Stages Position Incr	Scenario Tree: Increment to the position of each stage
Heat Plant	Build Non-anticipativity	Price for violating non-anticipativity constraints in scenario-wise decomposition mode
Heat Plant	Retire Non-anticipativity	Price for violating non-anticipativity constraints in scenario-wise decomposition mode
Power2X	Build Non-anticipativity	Price for violating non-anticipativity constraints in scenario-wise decomposition mode
Power2X	Inertia Constant	Stored energy per unit of power
Power2X	Retire Non-anticipativity	Price for violating non-anticipativity constraints in scenario-wise decomposition mode
Power2X.Constraints	Acceptable Risk Coefficient	Coefficient of entity acceptable risk
Power2X.Constraints	Fixed Costs Coefficient	Coefficient of fixed costs
Power2X.Constraints	Inertia Provision Coefficient	Coefficient of inertia provision
Power2X.Constraints	Net Profit Coefficient	Coefficient of net profit
Power2X.Constraints	Net Revenue Coefficient	Coefficient of net revenue
Power2X.Constraints	Pool Revenue Coefficient	Coefficient of pool revenue
Power2X.Constraints	Start & Shutdown Cost Coefficient	Coefficient of start and shutdown cost
Power2X.Objectives	Acceptable Risk Coefficient	Coefficient of entity acceptable risk
Power2X.Objectives	Fixed Costs Coefficient	Coefficient of fixed costs
Power2X.Objectives	Inertia Provision Coefficient	Coefficient of inertia provision
Power2X.Objectives	Net Profit Coefficient	Coefficient of net profit
Power2X.Objectives	Net Revenue Coefficient	Coefficient of net revenue
Power2X.Objectives	Pool Revenue Coefficient	Coefficient of pool revenue
Power2X.Objectives	Start & Shutdown Cost Coefficient	Coefficient of start and shutdown cost
Region	Report Marginal Resources	If marginal resources are reported for the region in the solution
Storage.Constraints	Initial Volume Coefficient	Coefficient of storage initial volume.
Storage.Variables	End Potential Energy Coefficient	Coefficient of the end potential energy in storage in the condition equation
Storage.Variables	Initial Potential Energy Coefficient	Coefficient of the initial potential energy in storage in the condition equation
Storage.Variables	Initial Volume Coefficient	Coefficient of the initial volume in storage in the condition equation
Variable	Lookup Table	Multi-dimensional lookup table for use in LOOKUP operator in RPN expressions
Vehicle	Inertia Constant	Stored energy per unit of power
Water Plant	Build Non-anticipativity	Price for violating non-anticipativity constraints in scenario-wise decomposition mode
Water Plant	Retire Non-anticipativity	Price for violating non-anticipativity constraints in scenario-wise decomposition mode
Water Pump Station	Max Flow Rate	Maximum flow rate of pump station
Water Pump Station	Max Head	Maximum head of pump station
Water Pump Station	Max Power	Maximum power of pump station
Water Storage	Decomposition Method	Method used to pass the optimal storage trajectory from one simulation phase to the next.
Water Zone	Max Capacity Reserve Margin	Maximum capacity reserve margin for capacity planning
Water Zone	Min Capacity Reserve Margin	Minimum capacity reserve margin for capacity planning

New Reporting Properties

The new reporting properties in this release are listed in Table 4.

Table 4: New Reporting Properties

Collection	Name	Description
Battery	Capacity Built	Battery capacity built
Battery	Charging	Charge rate/energy
Battery	Discharging	Discharge rate/energy
Battery	Firm Generation Capacity	Contribution of the battery generation to capacity reserves
Battery	Generation Capacity	Installed generation capacity
Battery	Generation Capacity Built	Generation capacity built
Battery	Inertia	Provision of inertia
Battery.Markets	Cleared Offer Cost	Cost of cleared offer bands.
Battery.Markets	Cleared Offer Price	Price of marginal offer band
Battery.Markets	Revenue	Revenue from capacity market
Battery.Markets	Sales	Capacity sold to market
Charging Station	Inertia	Provision of inertia
Company	Inertia	Provision of inertia
Contingency.Lines	Shadow Price	Shadow price for contingency constraint
Contingency.Transformers	Shadow Price	Shadow price for contingency constraint
Facility	Outage	Capacity lost to outage
Facility	Outage Hours	Number of hours on outage
Facility	Outage Rate	Proportion of installed capacity on outage
Fleet	Inertia	Provision of inertia
Flow Storage	Age	Number of cycles completed
Flow Storage	Consumption	Gross amount of the Commodity drawn from the Flow Node
Flow Storage	Production	Net amount of the Commodity released to the Flow Node
Gas Basin	Dispatch Price	Average dispatch price from basin fields
Gas Basin	Price	Average price of producing gas from basin fields
Gas Capacity Release Offer	Revenue	Total revenue from capacity released
Gas Field	Recovered Capital Cost	Capital cost recovered by extracting gas from the field
Gas Field	Recovery Price	Capital cost recovery price of gas field expansion
Gas Pipeline	Utilization Back	Flow back capacity utilization
Gas Pipeline	Utilization Forward	Flow forward capacity utilization
Generator	Inertia	Provision of inertia
Generator	Max Down Time Violation	Violation of maximum down time constraint.
Generator	Max Down Time Violation Cost	Cost of violating maximum down time constraint.
Generator	Max Heat Violation	Amount above Generator Max Heat
Generator	Max Heat Violation Cost	Cost of Generator Max Heat violoation
Generator	Max Load Violation	Violation of [Max Load] constraint.
Generator	Max Load Violation Cost	Cost of [Max Load] violations.
Generator	Max Up Time Violation	Violation of maximum up time constraint.
Generator	Max Up Time Violation Cost	Cost of violating maximum up time constraint.
Generator	Min Down Time Violation	Violation of min down time constraint.
Generator	Min Down Time Violation Cost	Cost of violating min up time constraint.
Generator	Min Up Time Violation	Violation of min up time constraint.
Generator	Min Up Time Violation Cost	Cost of violating min up time constraint.
Generator	Outage	Capacity lost to outage
Generator	Outage Hours	Number of hours on outage
Generator	Outage Rate	Proportion of installed capacity on outage
Generator	Pump Load Violation	Violation of maximum pump load constraint.
Generator	Pump Load Violation Cost	Cost of violating maximum pump load constraint.
Generator.Companies	Inertia	Provision of inertia
Power2X	Inertia	Provision of inertia
Region	Inertia	Provision of inertia
Region	Outage	Capacity lost to outage
Storage	Downstream Efficiency	Aggregate efficiency of generation down the river chain
Storage	Downstream Release Energy	Potential energy of downstream releases
Storage	End Potential Energy	Potential energy of end volume
Storage	Generator Release Energy	Potential energy of generator releases
Storage	Inflow Energy	Potential energy of inflows
Storage	Initial Potential Energy	Potential energy of initial volume
Storage	Max Potential Energy	Potential energy of storage at max volume
Storage	Min Potential Energy	Potential energy of storage at min volume
Storage	Natural Inflow Energy	Potential energy of natural inflows
Storage	Release Energy	Potential energy of releases
Storage	Spill Energy	Potential energy of spill to "the sea"
Variable	Activity	Value of the left hand side of the equation defining the conditional Variable
Vehicle	Inertia	Provision of inertia
Water Pump	Flow Rate	Pump flow rate
Water Pump	Head	Pump head
Water Pump	Operating Cost	Electric cost of operating the pump
Water Zone	Available Capacity	Aggregate of Water Availability of Water Plants in the Water Zone
Water Zone	Capacity Reserve Margin	Capacity reserve margin
Water Zone	Capacity Reserves	Capacity reserves (net of Peak Load)
Water Zone	Max Capacity Reserve Margin	Maximum capacity reserve margin for capacity planning
Water Zone	Max Capacity Reserves	Maximum capacity reserves allowed
Water Zone	Min Capacity Reserve Margin	Minimum capacity reserve margin for capacity planning
Water Zone	Min Capacity Reserves	Minimum capacity reserves allowed
Water Zone	Min Load	Minimum load across the current period
Water Zone	Peak Load	Peak load
Zone	Inertia	Provision of inertia