PLEXOS 6.300 Release Notes

  1. Upgrade Compatibility
  2. Changes
    1. Enhanced Decomposition in Stochastic Hydro Modelling
    2. Memory and performance improvement
  3. Features
    1. Gas Model and Gas-electric Cooptimization
    2. Decision Variable Class
    3. Global Class
    4. Multi-stage Stochastic Optimization
    5. Multi-level Interleaved Simulation
    6. Heat Storage
    7. Fuel Stockpiles
    8. AC Line Expansion
    9. Constraints on Risk
    10. Coefficients for Modelling Flexibility
    11. Hour Constraint Types and Reporting
    12. Condition Enhancements and Multiple Forecasts Support
  4. User Interface
  5. New Inputs
  6. New Outputs
Released
July 7, 2013
Previous Version
6.208
Next Version
6.301

1. Upgrade Compatibility

This version will automatically upgrade any previous version 5 or version 6 database. You may need to check the upgrade notes of earlier releases for any compatibility issues.

Databases in 6.300 format will retro-grade without manual changes to 6.208.

2. Changes

The following are the changes to existing functionality between this version and 6.208:

2.1. Enhanced Decomposition in Stochastic Hydro Modelling

A state-of-the-art enhancement has been introduced to the optimization of long-term storage by MT Schedule and ST Schedule. When Storage Decomposition Method = "Shadow Prices" and MT Schedule is run with Stochastic Risk Sample Count > 1 and Stochastic Method ="Scenario-wise Decomposition" or "Independent Samples" the decomposition is done by computing Bender's cuts describing the multi-dimensional water value surface (or "Future Cost Function"). This greatly improves the robustness of ST Schedule storage optimization and is similar to the approach used by traditional stochastic dual dynamic programming.

2.2. Memory and Performance Improvements

The simulation engine code has been improved and now consumes less memory on large databases.

3. Features

3.1. Gas Model and Gas-electric Cooptimization

This version introduces the integrated Gas and Electric model described in the Gas Modelling article. The Gas model is enabled throughout the simulation from capacity planning in LT Plan through to short-term optimization in ST Schedule. The integrated model co-optimizes electric and gas expansion and production decisions simultaneously.

3.2. Decision Variable Class

The new Decision Variable class allows you to create generic variables in the mathematical programming problem in a similar way to Constraint for generic constraints. The feature supports linear and integer decisions and time-lagged coefficients, allowing you to create models of system components that are not part of the 'native' functionality.

3.3. Global Class

The new Global class exposes a number of simulation-wide settings that were previously unavailable. It also implements user-defined Future Cost Function for hydro optimization.

3.4. Multi-stage Stochastic Optimization

Support for multi-stage stochastic optimization has been introduced. The scenario tree parameters are defined on the Global class and currently work with all production simulation related non-anticipativity constraints. See the Variable and Unit Commitment topics for details.

3.5. Multi-level Interleaved Simulation

Model Interleaved simulation now works with any number of nested interleaved processes. For example, you can now run day-ahead, hour-ahead and real-time simulations in one interleaved simulation.

3.6. Heat Storage

The generator class has been enhanced to support storage of heat for CHP plant. See the articles Combined Heat and Power and Heat Storage.

3.7. Fuel Stockpiles

The fuel class now supports modelling of fuel inventory (stockpiles).

3.8. AC Line Expansion

LT Plan now supports expansion of the transmission network with ac and dc lines. See the new property Type for details.

3.9. Constraints on Risk

In portfolio optimization you can now define constraints on the level of 'risk' (variance in Net Profit) from a stochastic optimization. See the property Formulate Risk for details.

3.10. Coefficients for Modelling Flexibility

3.11. Hour Constraint Types and Reporting

To improve decomposition of constraints such as hydro energy in models where ST Schedule is sub-hourly and particularly for very short dispatch intervals like 10 minutes, a new Constraint RHS Hour type has been introduced. You can define constraints of hour type but also, which are useful for sub-hourly modelling and also report summary data by hour, again useful for sub-hourly modelling.

3.12. Condition Enhancements and Multiple Forecasts Support

The new Condition properties Step Hour Active From and Step Hours Active allow a Condition to activate depending on the hour number in a step. Since you can now combine Condition with Variable when defining a property this means that the values read in to a property can change mid-step, which allow you to change for example from an intra-day load forecast to day-ahead forecast. See the Unit Commitment article for details.

4. User Interface

There are no significant changes to the user interface, but performance has been improved especially on large databases.

5. New Inputs

Please refer to the Class Reference for Gas Model inputs.

New inputs for the Electric model are:

Collection Property Relates To
Generator Start Profile Range Maximum range for4 [Start Profile]
Generator Internal Volume Scalar Storage volume scaling factor used internal to the mathematical program
Generator End Effects Method Method used to value or constrain end-or-period gas volumes.
Generator Recycle Penalty Penalty for violating the recycling constraint.
Generator Decomposition Method Method used to pass the optimal storage trajectory from one simulation phase to the next.
Generator Decomposition Penalty a Decomposition storage target penalty function 'a' term
Generator Decomposition Penalty b Decomposition storage target penalty function 'b' term.
Generator Decomposition penalty c Decomposition storage target penalty function 'c' term
Generator Decomposition Penalty x Decomposition storage target penalty function 'x' term.
Generator Decomposition Bound Penalty Penalty applied to violation of storage bounds when the decomposition implies possible violations.
Generator Enforce Bounds If the storage bounds are enforced.
Generator Max Heat Maximum heat allowed in storage
Generator Min Heat Minimum heat allowed in storage
Generator Opening Heat Initial heat in the storage
Generator Heat Withdrawal Charge Incremental cost of withdrawing heat from the storage
Generator Heat Injection Charge Incremental cost of injecting heat into the storage
Generator Max Heat Withdrawal Maximum amount of heat that can be withdrawn from the storage in a hour
Generator Max Heat Withdrawal Hour Maximum amount of heat that can be withdrawn from the storage in a hour
Generator Max Heat Withdrawal Day Maximum amount of heat that can be withdrawn from the storage in a day
Generator Max Heat Withdrawal Week Maximum amount of heat that can be withdrawn from the storage in a week.
Generator Max Heat Withdrawal Month Maximum amount of heat that can be withdrawn from the storage in a month
Generator Max Heat Withdrawal Year Maximum amount of heat that can be withdrawn from the storage in a year
Generator Max Heat Injection Hour Maximum amount of heat that can be injected into the storage in a hour
Generator Max Heat Withdrawal Amount of heat that must be withdrawn from storage
Generator Min Heat Withdrawal Amount of heat that must be withdrawn from storage
Generator Min Heat Withdrawal Hour Amount of heat that must be withdrawn
Generator Min Heat Withdrawal Day Amount of heat that must be withdrawn from storage each day
Generator Min Heat Withdrawal Week Amount of heat that must be withdrawn from storage each week
Generator Min Heat Withdrawal Month Amount of heat that must be withdrawn from the storage each month
Generator Min Heat Withdrawal Year Amount of heat that must be withdrawn from storage each year
Generator Min Heat Injection Amount of heat that must be injected into the storage
Generator Min Heat Injection Hour Amount of heat that must be injected into the storage each hour
Generator Min Heat Injection Day Amount of heat that must be injected into the storage each day
Generator Min Heat Injection Week Amount of heat that must be injected into the storage each week
Generator Min Heat Injection Month Amount of heat that must be injected into the storage each month
Generator Min Heat Injection Year Amount of heat that must be injected into the storage each year
Generator Heat Loss Rate at which heat is lost from storage
Generator Generation Non-anticipativity Price for violating non-anticipativity constraints in scenario-wise decomposition mode.
Generator Generation Non-anticipativity Time Window of time over which to enforce non-anticipativity constraints in scenario-wise decomposition
Generator Pump Load Non-anticipativity Price for Violating non-anticipativity constraints in scenario-wise decomposition mode
Generator Pump Load Non-anticipativity Time Window of time over which to enforce non-anticipativity constraints in scenario-wise decomposition
Fuel Units Flag if fuel exists
Fuel Max Inventory Maximum fuel allowed in stockpile
Fuel Min Inventory Minimum fuel required in stockpile
Fuel Opening Inventory Initial fuel in the stockpile
Fuel Delivery Fuel delivered to the stockpile
Fuel Delivery Charge Cost of delivering fuel to the stockpile
Fuel Inventory Charge Cost applied to closing inventory in the stockpile.
Fuel Reservation Charge Cost applied to unused inventory capacity in the stockpile
Fuel Withdrawal Charge Incremental cost of taking fuel from stockpile
Fuel Max Withdrawal Maximum amount of fuel that can be taken from stockpile
Fuel Max Withdrawal Hour Maximum amount of fuel that can be taken from stockpile in a hour
Fuel Max Withdrawal Day Maximum amount of fuel that can be taken from stockpile in a day
Fuel Max Withdrawal Week Maximum amount of fuel that can be taken from stockpile in a week
Fuel Max Withdrawal Month Maximum amount of fuel that can be taken from stockpile in a month
Fuel Max Withdrawal Year Maximum amount of fuel that can be taken from stockpile in a year
Fuel Min Withdrawal Amount of fuel that must be taken from stockpile
Fuel Min Withdrawal Hour Amount of fuel that must be taken from stockpile each hour
Fuel Min Withdrawal Day Amount of fuel that must be taken from stockpile each day
Fuel Min Withdrawal Week Amount of fuel that must be take from stockpile each week
Fuel Min Withdrawal Month Amount of fuel that must be taken from stockpile each month
Fuel Min Withdrawal year Amount of fuel that must be taken from stockpile each year
Storage Units Flag if Storage is in service
Storage Loss Rate Rate of loss due to evaporation, leakage, etc
Line Repair Time Distribution Distribution used to generate repair times (Auto, Constant, Uniform, Triangular, Exponential, Weibull, Lognormal, SEV, LEV)
Line Repair Time Shape Repair time function shape parameter (for Weibull, lognormal)
Line Repair Time Shape Repair time function scale parameter (for exponential, Weibull Lognormal, SEV, LEV
Line Repair Time Scale Repair time function scale parameter (for exponential, Weibull, lognormal ,SEV, LEV)
Company Type Line Expansion type
Company Formulate Risk If constraint should be formulated to bound company net profit risk
Company Target Profit Target net profit for risk constraints
Company Acceptable Risk Acceptable risk around target net profit
Decision Variable Include in LT Plan If the generic decision variable is modelled in the LT Plan phase.
Decision Variable Include in PASA If the generic decision variable is modelled in the PASA phase.
Decision Variable Include in MT Schedule If the generic decision variable is modelled in the MT Schedule phase.
Decision Variable Include in ST Schedule If the generic decision variable is modelled in the ST Schedule phase.
Decision Variable Objective Function Coefficient Objective function value of the generic decision variable
Decision Variable Lower Bound Lower bound of the generic decision variable
Decision Variable Upper Bound Upper bound of the generic decision variable
Variable Sampling Flag if random sampling should occur in the period
Global FCF Constant Future Cost Function: objective function constant term
Global Sample Weight Sampling: Weight applied to samples
Global Tree Stage Count Scenario Tree: Number of stages in the tree
Global Tree Position Exp Factor Scenario Tree: Controls the end positions of each stage
Global Tree Leaves Exp Factor Scenario Tree: Controls the number of samples in each stage
Global Tree Stages Position Scenario Tree: Position of each stage
Global Tree Stages Leaves Scenario Tree: Number of leaves in each stage
Fuel Companies Share Percentage share of ownership
Constraint Generators Hours Down Coefficient Coefficient of number of hours the generating unit has been off
Constraint Generators Flexibility Up Coefficient Coefficient of flexibility up
Constraint Generators Flexibility Up Coefficient Coefficient of flexibility up
Constraint Generators Flexibility Down Coefficient Coefficient of flexibility down
Constraint Generators Ramp Flexibility Up Coefficient Ramp Flexibility Down Coefficient
Constraint Generators Ramp Flexibility Down Coefficient Coefficient of ramp flexibility down
Constraint Generators Withdrawal Coefficient Coefficient of generator heat withdrawal
Constraint Generators Injection Coefficient Coefficient of generator heat injection
Constraint Generators Net Profit Coefficient Coefficient of net profit
Constraint Generators Pool Revenue Coefficient Coefficient of pool revenue
Constraint Generators Net Revenue Coefficient Coefficient of net revenue
Constraint Generators Start & Shutdown Cost Coefficient Coefficient of start and shutdown cost
Constraint Generators Fixed Costs Coefficient Coefficient of fixed costs
Constraint Fuels Closing Inventory Coefficient Coefficient of fuel stockpile closing inventory.
Constraint Fuels Inventory Change Coefficient Coefficient of change in fuel stockpile level.
Constraint Fuels Delivery Coefficient Coefficient of delivery to fuel stockpile.
Constraint Fuels Withdrawal Coefficient Coefficient of withdrawal from fuel stockpile.
Constraint Decision Variables Value Coefficient Coefficient of the variable sample value
Constraint Variables Expected Value Coefficient Coefficient of the variable expected value
Constraint Variables Value Coefficient Coefficient of the variable sample value
Constraint Variables Error Coefficient Coefficient of the variable sample error
Constraint Variables Positive Error Coefficient Coefficient of the positive sample error
Constraint Variables Negative Error Coefficient Coefficient of the negative sample error
Condition Zones Load Coefficient Coefficient of zone demand in condition
Condition Zones Capacity Reserves Coefficient Coefficient of zone capacity reserves in condition
Decision Variable Nodes Net Injection Definition Coefficient Coefficient of Decision Variable in Node net injection definition equation
Global Storages FCF Shadow Price Shadow price of water in storage in future cost function

6. New Outputs

Please refer to the class reference for Gas Model outputs
New outputs for the Electric model are:

Collection Property Relates To
Generator Flexibility Up Amount of additional generation that could be provided
Generator Flexibility Down Amount of generation that could be unloaded
Generator Ramp Flexibility Up Amount of unused ramp up capability
Generator Ramp Flexibility Down Amount of unused ramp down capability
Generator VO&M Charge Variable operation and maintenance charge
Generator Heat Rate Heat Rate at [Max Capacity]
Generator Max Heat Maximum heat allowed in storage
Generator Min Heat Minimum heat required in storage
Generator Opening Heat Heat in storage at the start of the period
Generator Closing Heat Heat in storage at the end of the period
Generator Heat Withdrawal Heat withdrawn from storage
Generator Heat Injection Heat injected into storage
Generator Net Heat Withdrawal Net of withdrawal and injection
Generator Heat Loss Heat loss from storage
Generator Heat Withdrawal Cost Cost of withdrawing heat from storage
Generator Heat Injection Cost Cost of injecting heat into storage
Generator Heat Shadow Price Shadow price of heat in storage
Generator Fuels Transport Charge Cost of transporting the fuel to the generator
Fuel Max Inventory Maximum fuel allowed in stockpile
Fuel Min Inventory Minimum fuel required in stockpile
Fuel Opening Inventory Initial fuel in the stockpile
Fuel Closing Inventory Final fuel in stockpile
Fuel Delivery Fuel delivered to the stockpile
Fuel Withdrawal Fuel withdrawn from the stockpile
Fuel Net Withdrawal Net of withdrawal and delivery
Fuel Delivery Cost Cost of deliveries to the stockpile
Fuel Inventory Cost Cost applied to closing inventory in the stockpile
Fuel Reservation Cost Cost applied to unused inventory capacity in the stockpile
Fuel Withdrawal Cost Cost of withdrawing fuel from stockpile
Fuel Installed Capacity Installed generation capacity
Emission Generators Generation Production Net production of the emission from generation
Emission Generators Unit Start Production Net production of the emission from unit start up
Storage Working Volume Working storage volume at the end of the period
Storage Utilization Storage utilization based on end volume
Storage Working Utilization Storage utilization based on working volume
Storage Average Utilization Average storage utilization based on end volume
Storage Average Working Utilization Average storage utilization based on working volume
Storage Loss Loss due to evaporation, leakage, etc
Reserve Time-weighted Price Time weighted average price of reserve
Gas Field Initial Volume Storage volume at the start of the period
Gas Field End Volume Storage volume at the end of the period
Gas Field Production Quantity of gas produced by the gas field
Gas Field Production Cost Cost of extracting gas from the field
Gas Field FO&M Cost Fixed operation and maintenance cost
Gas Field Fixed Costs Total fixed costs including amortized build costs
Gas Field Shadow Price Shadow price of gas in the field
Gas Field Units Flag if the gas field is in existence
Gas Field Units Built Flag if the gas field is built in this year
Gas Field Build Cost Cost of building the gas field
Gas Field x Pass-through value (summed in summary)
Gas Field y Pass-through value (summed in summary)
Gas Field z Pass-through value (averaged in summary
Gas Storage Max Volume Maximum volume of gas allowed in storage
Gas Storage Min Volume Minimum volume of gas allowed in storage
Gas Storage Initial Volume Storage volume at the start of the period
Gas Storage End Volume Storage volume at the end of the period
Gas Storage Working Volume Working storage volume at the end of the period
Gas Storage Utilization Storage utilization based on end volume
Gas Storage Working Utilization Storage utilization based on working volume
Gas Storage Average Utilization Average storage utilization based on working volume
Gas Storage Average Working Utilization Average storage utilization based on working volume
Gas Storage Withdrawal Quantity of gas withdrawn from the storage
Gas Storage Injection Quantity of gas injected into the gas storage
Gas Storage Net Withdrawal Net of withdrawal and injection
Gas Storage Withdrawal Cost Cost of withdrawing gas from the storage
Gas Storage Injection Cost Cost of injecting gas into the storage
Gas Storage Production Cost Total cost of injections and withdrawals
Gas Storage Shadow Price Shadow price of gas in the storage
Gas Storage FO&M Cost Fixed operation and maintenance cost
Gas Storage Fixed Costs Total fixed costs including amortized build costs
Gas Storage Units Flag if the gas storage is in existence
gas Storage Units Built Flag if the gas storage is built in this year
Gas Storage Build Cost Cost of building the gas storage
Gas Storage Units Retired Flag if the gas storage is retired in this year
Gas Storage Retirement Cost Cost of retiring the gas storage
Gas Storage x Pass-through value (summed in summary)
Gas Storage y Pass-through value (summed in summary)
Gas Storage z Pass-through value (averaged in summary)
Gas Pipeline Flow Quantity of gas extracted from the pipeline
Gas Pipeline Max Volume Maximum volume of gas allowed in the pipeline
Gas Pipeline Min Volume Minimum volume of gas allowed in the pipeline
Gas Pipeline Initial Volume Volume of gas stored in the pipeline at the start of the period
Gas Pipeline End Volume Volume of gas stored in the pipeline at the end of the period
Gas Pipeline Production Cost Cost of extracting gas from the pipeline
Gas Pipeline FO&M Cost Fixed operation and maintenance cost
Gas Pipeline Fixed Costs Total fixed costs including amortized build costs
Gas Pipeline Units Out Number out of units out of service
Gas Pipeline Hours of Maintenance Number of hours the pipeline is on maintenance
Gas Pipeline Hours of Forced Outage Number of hours the pipeline is on forced outage
Gas Pipeline Service Factor Proportion of pipeline capacity available
Gas Pipeline Units Flag if the gas pipeline is in existence
Gas Pipeline Units Built Flag if the gas pipeline is built in this year
Gas Pipeline Build Cost Cost of building the gas pipeline
Gas Pipeline Units Retired Flag if the gas pipeline is retired in this year
Gas Pipeline Retirement Cost Cost of retiring the gas pipeline
Gas Pipeline x Pass-through value (summed in summary)
Gas Pipeline y Pass-through value (summed in summary)
Gas Pipeline z Pass-through value (averaged in summary)
Gas Node Demand Demand at the gas node
Gas Node Flow Flow of gas through the node
Gas Node Production Cost Cost of flowing gas through the node
Gas Node Hours of Shortage Number of hours of shortage in supply of gas at the node
Gas Node Shortage Shortage of gas supply
Gas Node Shortage Cost Cost of gas supply shortages
Gas Node Hours of Excess Number of hours of excess supply of gas at the node
Gas Node Excess Number of hours of excess supply of gas at the node
Gas Node Excess Cost Cost of gas excesses
Gas Node Shadow Price Shadow price of gas at the gas node
Gas Node FO&M Cost Fixed operation and maintenance cost
Gas Node Fixed Costs Total fixed costs including amortized build costs
Gas Node Units Flag if the gas node is in existence
Gas Node Units Built Flag if the gas node is built in this year
Gas Node Build Cost Cost of building the gas node
Gas Node Units Retired Flag if the gas node is retired in this year
Gas Node Retirement Cost Cost of retiring the gas node
Gas Node x Pass-through value (summed in summary)
Gas Node y Pass-through value (summed in summary)
Gas Node z Pass-through value (averaged in summary)
Gas Demand Demand Gas demand
Gas Demand Hours of Shortage Number of hours of shortage in gas supply
Gas Demand Shortage Shortage of gas supply
Gas Demand Shortage Cost Cost of gas supply shortages
Gas Demand Hours of Excess Number of hours of excess supply of gas
Gas Demand Excess Excess of gas supply
Gas Demand Excess Cost Cost of gas excesses
Gas Demand Net Demand Gas demand net of shortages and excesses
Gas Demand Cost Cost of gas demand
Gas Demand Price Paid Price paid for gas demand
Gas Demand x Pass-through value (summed in summary)
Gas Demand y Pass-through value (summed in summary
Gas Demand z Pass-through value (averaged in summary)
Gas Zone Production Quantity of gas produced by the gas fields
Gas Zone Demand Gas demand
Gas Zone Imports Imports on gas pipelines
Gas Zone Exports Exports on gas pipelines
Gas Zone Net Intercharge Net exports on gas pipelines
Gas Zone Initial Volume Initial volume in gas storage
Gas Zone End Volume End volume in gas storage
Gas Zone Hours of Shortage Number of hours of shortage in gas supply
Gas Zone Shortage Shortage of gas supply
Gas Zone Shortage Cost Cost of gas supply shortages
Gas Zone Hours of Excess Number of hours of excess supply of gas
Gas Zone Excess Excess of gas supply
Gas Zone Excess Cost Cost of gas excesses
Gas Zone Net Demand Gas demand net of shortages and excesses
Gas Zone Cost Cost of gas demand
Gas Zone Price Paid Price paid for gas demand
Gas Zone x Pass-through value (summed in summary)
Gas Zone y Pass-through value (summed in summary)
Gas Zone z Pass-through value (averaged in summary)
Region SRMC Highest short-run marginal cost of running generators
Region Annualized Build Cost Annualized cost of generating units built
Region Total Cost Total of fixed and variable generation costs
Region Levelized Cost Levelized cost of electricity
Region Fuel Inventory Cost Cost of fuel stockpile.
Zone SRMC Highest short-run marginal cost of running generators
Zone Annualized Build Cost Annualized cost of generating units built
Zone Total Cost Total of fixed and variable generation costs
Zone Levelized Cost Levelized cost of electricity
Company Fuel Inventory Cost Cost of fuel stockpile
Company Annualized Build Cost Annualized cost of generating units built
Company Total Cost Total of fixed and variable generation costs
Company Levelized Cost Levelized cost of electricity
Company Fuels Inventory Cost Costs associated with fuel stockpile
Decision Variable Value Value of generic decision variable
Decision Variable Reduced Cost Reduced cost of the generic decision variable
Decision Variable Cost Total objective function contribution of generic decision variable
Decision Variable Objective Function Coefficient Objective function value of the generic decision variable
Decision Variable Lower Bound Lower bound of the generic decision variable
Decision Variable Upper Bound Upper bound of the generic decision variable
Decision Variable Min Value Minimum value of generic decision variable
Variable Expected Value Expected Vaue