Electricity Supply Policies

Purpose

This section provides guidance for developers to create and maintain policy files that change electric generation inputs in ENERGY 2100. Covers file placement, coding pattern, common datasets to modify, examples, testing, and troubleshooting.

Types of Electric Utility Generation Policies

Modify renewable generation goals
Specify fixed amounts of energy transfers between areas through contracts
Limit or increase flows and/or costs across transmission lines
Activate offset requirements for generating units
Modify characteristics of generating units (retirement year, outage rate, generating costs, etc.)
Modify capacity expansion/build rules
Modify characteristics of plant types as a whole (differentiated from individual units)
Establish GHG performance goals

Where to put a policy file

Folder: C:\2100ModelName\Policy
Naming convention: Electric_<PolicyName>_<Region>.jl
Add the file to a policy aggregator file (e.g. Ref25.jl) when ready

High‑level pattern (read → modify → write)

Read sets/variables using ReadDisk (or Select helpers).
Modify values in memory.
Write changes back with WriteDisk.

Minimal policy file template

Key points:

Import only required helpers: ReadDisk, WriteDisk, Select, etc.
Create function to make changes to desired policy variables
Create PolicyControl() function that calls policy changes

div class="html-code-box">

#
# Electric_[PolicyName]_[Region].jl
#
# Brief description of policy objectives and data sources
#

using EnergyModel

module [Policy_Electric_Template]

import ...EnergyModel: ReadDisk,WriteDisk,Select,Zero
import ...EnergyModel: HisTime,ITime,MaxTime,First,Future,Final,Yr
import ...EnergyModel: @finite_math
import ...EnergyModel: DB

const VariableArray{N} = Array{Float32,N} where {N}
const SetArray = Vector{String}

Base.@kwdef struct [Control]
  db::String
  
  #
  # Define dimension sets
  #  
  Area::SetArray = ReadDisk(db,"MainDB/AreaKey")
  Areas::Vector{Int} = collect(Select(Area))
  Unit::SetArray = ReadDisk(db,"MainDB/UnitKey")
  Units::Vector{Int} = collect(Select(Unit))
  Year::SetArray = ReadDisk(db,"MainDB/YearKey")
  Years::Vector{Int} = collect(Select(Year))
  # ... other dimensions
  
  # Load data variables:
  UnCode::Array{String} = ReadDisk(db,"EGInput/UnCode") # [Unit] Unit Code
  UnNode::Array{String} = ReadDisk(db,"EGInput/UnNode") # [Unit] Transmission Node
  UnOnLine::VariableArray{1} = ReadDisk(db,"EGInput/UnOnLine") # [Unit] On-Line Date (Year)
  # ... other data as needed

end

function [PolicyName](db)
  data = [Control](; db)
  (; Unit,Units) = data
  (; UnOnLine) = data
 
  # TODO: apply transformations to policy variables using explicit indexing

end
 
end # module Policy_Electric_Template
unction PolicyControl(db)
  @info("[PolicyName] PolicyControl function called")
  
  [PolicyName](db)  # Call to function that modifies the policy variable(s)
  
  @info("Policy executed successfully")
end

if abspath(PROGRAM_FILE) == @__FILE__
  PolicyControl(DB)
end

Common policy types & typical policy variables to modify

Modify renewable generation goals

EGInput/xGCPot, EGInput/PjMax (plant potentials / costs)

Specify fixed energy transfers (contracts)

EGInput/HDXLoad, EGInput/LLMax (contracted transfers / line capacity)

Limit / increase flows or costs across transmission lines

EGInput/LLMax (capacity)
ECalDB/LineCost or ECalDB/PEDC if line costs are modeled there

Activate offset requirements for generating units

EGInput/OffRq, unit offset trackers

Modify generating unit characteristics (retirement, outage, costs)

EGInput/UnOnLine, EGInput/UnRetire, EGInput/UnEAF (availability/outage)

Modify capacity expansion / build rules

EGInput/xGCPot, EGInput/PjMax, plant potential

Modify plant‑type characteristics (affect all units of a plant type)

GCCCN, UOMC, UFOMC — map to Unit

Establish GHG performance goals

EGInput/UnPCFMax, EGInput/PCF (per‑unit or per‑plant carbon intensity)
possibly set UnRetire where non‑compliant

Concrete examples (short)

Set retirement year for a list of units

# \Policy\Electric_SetRetireYears.jl

using EnergyModel

module SetRetireYear

import ...EnergyModel: ReadDisk,WriteDisk,Select,Zero

import ...EnergyModel: HisTime,ITime,MaxTime,First,Future,Final,Yr

import ...EnergyModel: @finite_math

import ...EnergyModel: DB

Base.@kwdef struct EControl

db::String

Unit::SetArray = ReadDisk(db,"MainDB/UnitKey")

Units::Vector{Int} = collect(Select(Unit))

Year::SetArray = ReadDisk(db,"MainDB/YearKey")

Years::Vector{Int} = collect(Select(Year))

UnArea::Array{String} = ReadDisk(db,"EGInput/UnArea") # [Unit] Area Pointer

UnCode::Array{String} = ReadDisk(db,"EGInput/UnCode") # [Unit] Unit Code

UnRetire::VariableArray{2} = ReadDisk(db,"EGInput/UnRetire") # [Unit,Year] Retirement Date (Year)

end

function ElectricPolicy(db)

data = EControl(; db)

(; Units,Years) = data

(; UnCode,UnRetire) = data

for unit in Units

if UnCode[unit] == "AB00002000101"

for year in Years

UnRetire[unit,year] = 2050

end

if UnCode[unit] == "AB00002000300"

for year in Years

UnRetire[unit,year] = 2050

end

WriteDisk(DB, "EGInput/UnRetire",UnRetire)

end

function PolicyControl(db)

@info "Electric_SetRetirementYears.jl - PolicyControl"

ElectricPolicy(db)

end

if abspath(PROGRAM_FILE) == @__FILE__

PolicyControl(DB)

end

end # module

Modify a transmission line capacity example (pseudo)

# \Policy\Electric_ModifyLineCapacity.jl

using EnergyModel

module ModifyLineCapacity

import ...EnergyModel: ReadDisk,WriteDisk,Select,Zero

import ...EnergyModel: HisTime,ITime,MaxTime,First,Future,Final,Yr

import ...EnergyModel: @finite_math

import ...EnergyModel: DB

Base.@kwdef struct EControl

db::String

Node::SetArray = ReadDisk(db,"MainDB/NodeKey")

Nodes::Vector{Int} = collect(Select(Node))

NodeX::SetArray = ReadDisk(db,"MainDB/NodeXKey")

NodeXs::Vector{Int} = collect(Select(NodeX))

TimeP::SetArray = ReadDisk(db,"MainDB/TimePKey")

TimePs::Vector{Int} = collect(Select(TimeP))

Year::SetArray = ReadDisk(db,"MainDB/YearKey")

Years::Vector{Int} = collect(Select(Year))

LLMax::VariableArray{5} = ReadDisk(db,"EGInput/LLMax") # [Node,NodeX,TimeP,Month,Year] Maximum Loading on Transmission Lines (MW)

end

function ElectricPolicy(db)

data = EControl(; db)

(; Units,Years) = data

(; UnCode,UnRetire) = data

# New line capacity to Ontario (ON) from Pennsylvania (PJME)

node = Select(Node,"ON") # To Node

nodex = Select(NodeX,"PJME") # From NodeX

years = collect(Yr(2030):Final)

for year in years, month in Months, timep in TimePs

LLMax[node,nodex,timep,month,year] = 1000

end

# New line capacity from Ontario (ON) to Pennsylvania (PJME)

node = Select(Node,"PJME") # To Node

nodex = Select(NodeX,"ON") # From NodeX

years = collect(Yr(2030):Final)

for year in years, month in Months, timep in TimePs

LLMax[node,nodex,timep,month,year] = 1000

end

# Write LLMax to database

WriteDisk(db,"EGInput/LLMax",LLMax)

end

function PolicyControl(db)

@info "Electric_SetRetirementYears.jl - PolicyControl"

ElectricPolicy(db)

end

if abspath(PROGRAM_FILE) == @__FILE__

PolicyControl(DB)

end

end # module

Testing policy files

From Julia REPL:

julia> import EnergyModel: DB

julia> include("\Policy\Electric_SetRetireYears.jl")

julia> Electric_SetRetireYears.PolicyControl(DB)

What happens when a policy changes DB variables

Policies modify EGInput (and possibly ECalDB/EGOutput) datasets in the HDF5.
Model initialization and engine modules (dispatch, capacity expansion, flows) read these datasets at run start and use modified values during simulation.

Documentation & header conventions

Top of file should include:

Purpose and description
Inputs: list of required datasets (exact HDF5 paths)
Outputs: datasets modified
External dependencies (e.g., NextGrid files)
Author, date, scenario tag

Checklist before committing

[ ] Test running individual policy and verify policy variables changed as intended
[ ] Add header documentation and usage instructions in the file
[ ] Add to Ref25.jl or policy aggregator only when ready