diff --git a/src/PowerSystems.jl b/src/PowerSystems.jl
index 32f8a6d23e..9d61947807 100644
--- a/src/PowerSystems.jl
+++ b/src/PowerSystems.jl
@@ -18,6 +18,8 @@ export AggregationTopology
 export Area
 export LoadZone
 export get_aggregation_topology_accessor
+export SupplementalAttribute
+export GeographicInfo
 
 export Component
 export Device
@@ -204,6 +206,11 @@ export PriorityCurrentLimiter
 export Source
 export PeriodicVariableSource
 
+# Outages
+export Outage
+export ForcedOutage
+export PlannedOutage
+
 export Service
 export AbstractReserve
 export Reserve
@@ -241,6 +248,7 @@ export ForecastCache
 export StaticTimeSeriesCache
 export NormalizationFactor
 export NormalizationTypes
+export TimeSeriesCounts
 
 export get_dynamic_components
 
@@ -282,6 +290,13 @@ export get_forecast_horizon
 export get_forecast_initial_timestamp
 export get_forecast_interval
 export get_forecast_window_count
+export add_supplemental_attribute!
+export remove_supplemental_attribute!
+export remove_supplemental_attributes!
+export get_supplemental_attribute
+export get_supplemental_attributes
+export has_supplemental_attributes
+export iterate_supplemental_attributes
 export get_time_series
 export get_time_series_array
 export get_time_series_resolution
@@ -318,6 +333,8 @@ export CompressionTypes
 export get_bus_numbers
 export get_name
 export set_name!
+export get_component_uuids
+export get_supplemental_attributes_container
 export get_description
 export set_description!
 export get_base_power
@@ -420,15 +437,18 @@ import InfrastructureSystems:
     Scenarios,
     ForecastCache,
     StaticTimeSeriesCache,
+    TimeSeriesCounts,
     InfrastructureSystemsComponent,
     InfrastructureSystemsType,
     InfrastructureSystemsInternal,
+    SupplementalAttribute,
     DeviceParameter,
     FlattenIteratorWrapper,
     LazyDictFromIterator,
     DataFormatError,
     InvalidRange,
     InvalidValue,
+    GeographicInfo,
     copy_time_series!,
     get_count,
     get_data,
@@ -436,6 +456,10 @@ import InfrastructureSystems:
     get_resolution,
     get_window,
     get_name,
+    get_component_uuids,
+    get_supplemental_attribute,
+    get_supplemental_attributes,
+    get_supplemental_attributes_container,
     set_name!,
     get_internal,
     set_internal!,
@@ -451,6 +475,7 @@ import InfrastructureSystems:
     get_percentiles, # Probabilistic Forecast Exports
     get_next_time_series_array!,
     get_next_time,
+    has_supplemental_attributes,
     get_units_info,
     set_units_info!,
     to_json,
@@ -548,6 +573,9 @@ include("models/dynamic_branch.jl")
 include("models/supplemental_constructors.jl")
 include("models/supplemental_accessors.jl")
 
+# Supplemental attributes
+include("outages.jl")
+
 # Definitions of PowerSystem
 include("base.jl")
 include("data_format_conversions.jl")
diff --git a/src/base.jl b/src/base.jl
index 67f428295d..85fac43f8f 100644
--- a/src/base.jl
+++ b/src/base.jl
@@ -210,13 +210,13 @@ function System(file_path::AbstractString; assign_new_uuids = false, kwargs...)
         )
         runchecks && check(sys)
         if assign_new_uuids
-            IS.assign_new_uuid!(sys)
+            IS.assign_new_uuid_internal!(sys)
             for component in get_components(Component, sys)
-                IS.assign_new_uuid!(component)
+                assign_new_uuid!(sys, component)
             end
             for component in
                 IS.get_masked_components(InfrastructureSystemsComponent, sys.data)
-                IS.assign_new_uuid!(component)
+                assign_new_uuid!(sys, component)
             end
             # Note: this does not change UUIDs for time series data because they are
             # shared with components.
@@ -914,11 +914,24 @@ function get_components(
     return IS.get_components(T, sys.data, filter_func)
 end
 
-# These are helper functions for debugging problems.
-# Searches components linearly, and so is slow compared to the other get_component functions
+"""
+Return a vector of components that are attached to the supplemental attribute.
+"""
+function get_components(sys::System, attribute::SupplementalAttribute)
+    return IS.get_components(sys.data, attribute)
+end
+
+"""
+Get the component by UUID.
+"""
 get_component(sys::System, uuid::Base.UUID) = IS.get_component(sys.data, uuid)
 get_component(sys::System, uuid::String) = IS.get_component(sys.data, Base.UUID(uuid))
 
+"""
+Change the UUID of a component.
+"""
+assign_new_uuid!(sys::System, x::Component) = IS.assign_new_uuid!(sys.data, x)
+
 function _get_components_by_name(abstract_types, data::IS.SystemData, name::AbstractString)
     _components = []
     for subtype in abstract_types
@@ -1258,6 +1271,104 @@ function transform_single_time_series!(sys::System, horizon::Int, interval::Date
     return
 end
 
+"""
+Add a supplemental attribute to the component. The attribute may already be attached to a
+different component.
+"""
+function add_supplemental_attribute!(
+    sys::System,
+    component::Component,
+    attribute::IS.SupplementalAttribute,
+)
+    return IS.add_supplemental_attribute!(sys.data, component, attribute)
+end
+
+"""
+Remove the supplemental attribute from the component. The attribute will be removed from the
+system if it is not attached to any other component.
+"""
+function remove_supplemental_attribute!(
+    sys::System,
+    component::Component,
+    attribute::IS.SupplementalAttribute,
+)
+    return IS.remove_supplemental_attribute!(sys.data, component, attribute)
+end
+
+"""
+Remove the supplemental attribute from the system and all attached components.
+"""
+function remove_supplemental_attribute!(sys::System, attribute::IS.SupplementalAttribute)
+    return IS.remove_supplemental_attribute!(sys.data, attribute)
+end
+
+"""
+Remove all supplemental attributes with the given type from the system.
+"""
+function remove_supplemental_attributes!(
+    ::Type{T},
+    sys::System,
+) where {T <: IS.SupplementalAttribute}
+    return IS.remove_supplemental_attributes!(T, sys.data)
+end
+
+"""
+Returns an iterator of supplemental attributes. T can be concrete or abstract.
+Call collect on the result if an array is desired.
+
+# Examples
+```julia
+iter = get_supplemental_attributes(ForcedOutage, sys)
+iter = get_supplemental_attributes(Outage, sys)
+iter = get_supplemental_attributes(x -> x.forced_outage_rate >= 0.5, ForcedOutage, sys)
+outages = get_supplemental_attributes(ForcedOutage, sys) do outage
+    x.forced_outage_rate >= 0.5
+end
+outages = collect(get_supplemental_attributes(ForcedOutage, sys))
+```
+
+See also: [`iterate_supplemental_attributes`](@ref)
+"""
+function get_supplemental_attributes(
+    filter_func::Function,
+    ::Type{T},
+    sys::System,
+) where {T <: IS.SupplementalAttribute}
+    return IS.get_supplemental_attributes(filter_func, T, sys.data)
+end
+
+function get_supplemental_attributes(
+    ::Type{T},
+    sys::System,
+) where {T <: IS.SupplementalAttribute}
+    return IS.get_supplemental_attributes(T, sys.data)
+end
+
+"""
+Return the supplemental attribute with the given uuid.
+
+Throws ArgumentError if the attribute is not stored.
+"""
+function get_supplemental_attribute(sys::System, uuid::Base.UUID)
+    return IS.get_supplemental_attribute(sys.data, uuid)
+end
+
+"""
+Iterates over all supplemental_attributes.
+
+# Examples
+```julia
+for supplemental_attribute in iterate_supplemental_attributes(sys)
+    @show supplemental_attribute
+end
+```
+
+See also: [`get_supplemental_attributes`](@ref)
+"""
+function iterate_supplemental_attributes(sys::System)
+    return IS.iterate_supplemental_attributes(sys.data)
+end
+
 """
 Sanitize component values.
 """
@@ -1507,6 +1618,11 @@ function deserialize_components!(sys::System, raw)
     end
 
     # Run in order based on type composition.
+    # Bus and AGC instances can have areas and LoadZones.
+    # Most components have buses.
+    # Static injection devices can contain dynamic injection devices.
+    # StaticInjectionSubsystem instances have StaticInjection subcomponents.
+    # RegulationDevice instances have one StaticInjection subcomponent.
     deserialize_and_add!(; include_types = [Area, LoadZone])
     deserialize_and_add!(; include_types = [AGC])
     deserialize_and_add!(; include_types = [Bus])
@@ -1514,12 +1630,10 @@ function deserialize_components!(sys::System, raw)
         include_types = [Arc, Service],
         skip_types = [StaticReserveGroup],
     )
-    deserialize_and_add!(; include_types = [Branch], skip_types = [DynamicBranch])
+    deserialize_and_add!(; include_types = [Branch])
     deserialize_and_add!(; include_types = [DynamicBranch])
-    # Static injection devices can contain dynamic injection devices.
     deserialize_and_add!(; include_types = [StaticReserveGroup, DynamicInjection])
-    # StaticInjectionSubsystem instances have StaticInjection subcomponents.
-    deserialize_and_add!(; skip_types = [StaticInjectionSubsystem])
+    deserialize_and_add!(; skip_types = [StaticInjectionSubsystem, RegulationDevice])
     deserialize_and_add!()
 
     for subsystem in get_components(StaticInjectionSubsystem, sys)
@@ -1529,6 +1643,10 @@ function deserialize_components!(sys::System, raw)
             IS.mask_component!(sys.data, subcomponent)
         end
     end
+
+    for component in get_components(RegulationDevice, sys)
+        IS.mask_component!(sys.data, component.device)
+    end
 end
 
 """
@@ -1731,9 +1849,7 @@ function handle_component_addition!(sys::System, component::RegulationDevice; kw
     copy_time_series!(component, component.device)
     if !isnothing(get_component(typeof(component.device), sys, get_name(component.device)))
         # This will not be true during deserialization, and so won't run then.
-        remove_component!(sys, component.device)
-        # The line above removed the component setting so needs to be added back
-        set_units_setting!(component.device, component.internal.units_info)
+        IS.mask_component!(sys.data, component.device; remove_time_series = true)
     end
     return
 end
@@ -1942,7 +2058,7 @@ function convert_component!(
         InfrastructureSystems.TimeSeriesContainer(),
         deepcopy(line.internal),
     )
-    IS.assign_new_uuid!(line)
+    assign_new_uuid!(sys, line)
     add_component!(sys, new_line)
     copy_time_series!(new_line, line)
     remove_component!(sys, line)
@@ -1951,7 +2067,7 @@ end
 
 """
 Converts a MonitoredLine component to a Line component and replaces the original in the
-system
+system.
 """
 function convert_component!(
     sys::System,
@@ -1984,7 +2100,7 @@ function convert_component!(
         InfrastructureSystems.TimeSeriesContainer(),
         deepcopy(line.internal),
     )
-    IS.assign_new_uuid!(line)
+    assign_new_uuid!(sys, line)
     add_component!(sys, new_line)
     copy_time_series!(new_line, line)
     remove_component!(sys, line)
@@ -1993,7 +2109,7 @@ end
 
 """
 Converts a PowerLoad component to a StandardLoad component and replaces the original in the
-system. Does not set any fields in StandardLoad that lack a PowerLoad equivalent
+system. Does not set any fields in StandardLoad that lack a PowerLoad equivalent.
 """
 function convert_component!(
     sys::System,
@@ -2015,7 +2131,7 @@ function convert_component!(
         services = Device[],
         time_series_container = InfrastructureSystems.TimeSeriesContainer(),
     )
-    IS.assign_new_uuid!(new_load)
+    assign_new_uuid!(sys, old_load)
     add_component!(sys, new_load)
     copy_time_series!(new_load, old_load)
     for service in get_services(old_load)
@@ -2048,7 +2164,9 @@ function _validate_or_skip!(sys, component, skip_validation)
 end
 
 """
-Return a tuple of counts of components with time series and total time series and forecasts.
+Return an instance of TimeSeriesCounts.
+
+See also: [`TimeSeriesCounts`](@ref)
 """
 get_time_series_counts(sys::System) = IS.get_time_series_counts(sys.data)
 
diff --git a/src/descriptors/power_system_structs.json b/src/descriptors/power_system_structs.json
index c9bd1765fd..1641da6ad0 100644
--- a/src/descriptors/power_system_structs.json
+++ b/src/descriptors/power_system_structs.json
@@ -438,6 +438,13 @@
                     "null_value": "Dict{String, Any}()",
                     "default": "Dict{String, Any}()"
                 },
+                {
+                    "name": "supplemental_attributes_container",
+                    "comment": "container for supplemental attributes",
+                    "null_value": "InfrastructureSystems.SupplementalAttributesContainer()",
+                    "data_type": "InfrastructureSystems.SupplementalAttributesContainer",
+                    "default": "InfrastructureSystems.SupplementalAttributesContainer()"
+                },
                 {
                     "name": "internal",
                     "comment": "power system internal reference, do not modify",
@@ -510,6 +517,13 @@
                 "null_value": "Dict{String, Any}()",
                 "default": "Dict{String, Any}()"
               },
+              {
+                  "name": "supplemental_attributes_container",
+                  "comment": "container for supplemental attributes",
+                  "null_value": "InfrastructureSystems.SupplementalAttributesContainer()",
+                  "data_type": "InfrastructureSystems.SupplementalAttributesContainer",
+                  "default": "InfrastructureSystems.SupplementalAttributesContainer()"
+              },
               {
                 "name": "internal",
                 "comment": "power system internal reference, do not modify",
@@ -3913,6 +3927,13 @@
                     "data_type": "InfrastructureSystems.TimeSeriesContainer",
                     "default": "InfrastructureSystems.TimeSeriesContainer()"
                 },
+                {
+                    "name": "supplemental_attributes_container",
+                    "comment": "container for supplemental attributes",
+                    "null_value": "InfrastructureSystems.SupplementalAttributesContainer()",
+                    "data_type": "InfrastructureSystems.SupplementalAttributesContainer",
+                    "default": "InfrastructureSystems.SupplementalAttributesContainer()"
+                },
                 {
                     "name": "internal",
                     "comment": "power system internal reference, do not modify",
diff --git a/src/models/generated/ACBus.jl b/src/models/generated/ACBus.jl
index 087086aa95..fc0aa8961c 100644
--- a/src/models/generated/ACBus.jl
+++ b/src/models/generated/ACBus.jl
@@ -16,6 +16,7 @@ This file is auto-generated. Do not edit.
         area::Union{Nothing, Area}
         load_zone::Union{Nothing, LoadZone}
         ext::Dict{String, Any}
+        supplemental_attributes_container::InfrastructureSystems.SupplementalAttributesContainer
         internal::InfrastructureSystemsInternal
     end
 
@@ -32,6 +33,7 @@ A power-system bus.
 - `area::Union{Nothing, Area}`: the area containing the bus
 - `load_zone::Union{Nothing, LoadZone}`: the load zone containing the bus
 - `ext::Dict{String, Any}`
+- `supplemental_attributes_container::InfrastructureSystems.SupplementalAttributesContainer`: container for supplemental attributes
 - `internal::InfrastructureSystemsInternal`: power system internal reference, do not modify
 """
 mutable struct ACBus <: Bus
@@ -54,11 +56,13 @@ mutable struct ACBus <: Bus
     "the load zone containing the bus"
     load_zone::Union{Nothing, LoadZone}
     ext::Dict{String, Any}
+    "container for supplemental attributes"
+    supplemental_attributes_container::InfrastructureSystems.SupplementalAttributesContainer
     "power system internal reference, do not modify"
     internal::InfrastructureSystemsInternal
 
-    function ACBus(number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area, load_zone, ext, internal, )
-        (number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area, load_zone, ext, internal, ) = check_bus_params(
+    function ACBus(number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area, load_zone, ext, supplemental_attributes_container, internal, )
+        (number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area, load_zone, ext, supplemental_attributes_container, internal, ) = check_bus_params(
             number,
             name,
             bustype,
@@ -69,18 +73,19 @@ mutable struct ACBus <: Bus
             area,
             load_zone,
             ext,
+            supplemental_attributes_container,
             internal,
         )
-        new(number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area, load_zone, ext, internal, )
+        new(number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area, load_zone, ext, supplemental_attributes_container, internal, )
     end
 end
 
-function ACBus(number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area=nothing, load_zone=nothing, ext=Dict{String, Any}(), )
-    ACBus(number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area, load_zone, ext, InfrastructureSystemsInternal(), )
+function ACBus(number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area=nothing, load_zone=nothing, ext=Dict{String, Any}(), supplemental_attributes_container=InfrastructureSystems.SupplementalAttributesContainer(), )
+    ACBus(number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area, load_zone, ext, supplemental_attributes_container, InfrastructureSystemsInternal(), )
 end
 
-function ACBus(; number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area=nothing, load_zone=nothing, ext=Dict{String, Any}(), internal=InfrastructureSystemsInternal(), )
-    ACBus(number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area, load_zone, ext, internal, )
+function ACBus(; number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area=nothing, load_zone=nothing, ext=Dict{String, Any}(), supplemental_attributes_container=InfrastructureSystems.SupplementalAttributesContainer(), internal=InfrastructureSystemsInternal(), )
+    ACBus(number, name, bustype, angle, magnitude, voltage_limits, base_voltage, area, load_zone, ext, supplemental_attributes_container, internal, )
 end
 
 # Constructor for demo purposes; non-functional.
@@ -96,6 +101,7 @@ function ACBus(::Nothing)
         area=nothing,
         load_zone=nothing,
         ext=Dict{String, Any}(),
+        supplemental_attributes_container=InfrastructureSystems.SupplementalAttributesContainer(),
     )
 end
 
@@ -119,6 +125,8 @@ get_area(value::ACBus) = value.area
 get_load_zone(value::ACBus) = value.load_zone
 """Get [`ACBus`](@ref) `ext`."""
 get_ext(value::ACBus) = value.ext
+"""Get [`ACBus`](@ref) `supplemental_attributes_container`."""
+get_supplemental_attributes_container(value::ACBus) = value.supplemental_attributes_container
 """Get [`ACBus`](@ref) `internal`."""
 get_internal(value::ACBus) = value.internal
 
@@ -140,3 +148,5 @@ set_area!(value::ACBus, val) = value.area = val
 set_load_zone!(value::ACBus, val) = value.load_zone = val
 """Set [`ACBus`](@ref) `ext`."""
 set_ext!(value::ACBus, val) = value.ext = val
+"""Set [`ACBus`](@ref) `supplemental_attributes_container`."""
+set_supplemental_attributes_container!(value::ACBus, val) = value.supplemental_attributes_container = val
diff --git a/src/models/generated/DCBus.jl b/src/models/generated/DCBus.jl
index 7b260bdd5e..929306b442 100644
--- a/src/models/generated/DCBus.jl
+++ b/src/models/generated/DCBus.jl
@@ -14,6 +14,7 @@ This file is auto-generated. Do not edit.
         area::Union{Nothing, Area}
         load_zone::Union{Nothing, LoadZone}
         ext::Dict{String, Any}
+        supplemental_attributes_container::InfrastructureSystems.SupplementalAttributesContainer
         internal::InfrastructureSystemsInternal
     end
 
@@ -28,6 +29,7 @@ A power-system DC bus.
 - `area::Union{Nothing, Area}`: the area containing the DC bus
 - `load_zone::Union{Nothing, LoadZone}`: the load zone containing the DC bus
 - `ext::Dict{String, Any}`
+- `supplemental_attributes_container::InfrastructureSystems.SupplementalAttributesContainer`: container for supplemental attributes
 - `internal::InfrastructureSystemsInternal`: power system internal reference, do not modify
 """
 mutable struct DCBus <: Bus
@@ -46,16 +48,18 @@ mutable struct DCBus <: Bus
     "the load zone containing the DC bus"
     load_zone::Union{Nothing, LoadZone}
     ext::Dict{String, Any}
+    "container for supplemental attributes"
+    supplemental_attributes_container::InfrastructureSystems.SupplementalAttributesContainer
     "power system internal reference, do not modify"
     internal::InfrastructureSystemsInternal
 end
 
-function DCBus(number, name, magnitude, voltage_limits, base_voltage, area=nothing, load_zone=nothing, ext=Dict{String, Any}(), )
-    DCBus(number, name, magnitude, voltage_limits, base_voltage, area, load_zone, ext, InfrastructureSystemsInternal(), )
+function DCBus(number, name, magnitude, voltage_limits, base_voltage, area=nothing, load_zone=nothing, ext=Dict{String, Any}(), supplemental_attributes_container=InfrastructureSystems.SupplementalAttributesContainer(), )
+    DCBus(number, name, magnitude, voltage_limits, base_voltage, area, load_zone, ext, supplemental_attributes_container, InfrastructureSystemsInternal(), )
 end
 
-function DCBus(; number, name, magnitude, voltage_limits, base_voltage, area=nothing, load_zone=nothing, ext=Dict{String, Any}(), internal=InfrastructureSystemsInternal(), )
-    DCBus(number, name, magnitude, voltage_limits, base_voltage, area, load_zone, ext, internal, )
+function DCBus(; number, name, magnitude, voltage_limits, base_voltage, area=nothing, load_zone=nothing, ext=Dict{String, Any}(), supplemental_attributes_container=InfrastructureSystems.SupplementalAttributesContainer(), internal=InfrastructureSystemsInternal(), )
+    DCBus(number, name, magnitude, voltage_limits, base_voltage, area, load_zone, ext, supplemental_attributes_container, internal, )
 end
 
 # Constructor for demo purposes; non-functional.
@@ -69,6 +73,7 @@ function DCBus(::Nothing)
         area=nothing,
         load_zone=nothing,
         ext=Dict{String, Any}(),
+        supplemental_attributes_container=InfrastructureSystems.SupplementalAttributesContainer(),
     )
 end
 
@@ -88,6 +93,8 @@ get_area(value::DCBus) = value.area
 get_load_zone(value::DCBus) = value.load_zone
 """Get [`DCBus`](@ref) `ext`."""
 get_ext(value::DCBus) = value.ext
+"""Get [`DCBus`](@ref) `supplemental_attributes_container`."""
+get_supplemental_attributes_container(value::DCBus) = value.supplemental_attributes_container
 """Get [`DCBus`](@ref) `internal`."""
 get_internal(value::DCBus) = value.internal
 
@@ -105,3 +112,5 @@ set_area!(value::DCBus, val) = value.area = val
 set_load_zone!(value::DCBus, val) = value.load_zone = val
 """Set [`DCBus`](@ref) `ext`."""
 set_ext!(value::DCBus, val) = value.ext = val
+"""Set [`DCBus`](@ref) `supplemental_attributes_container`."""
+set_supplemental_attributes_container!(value::DCBus, val) = value.supplemental_attributes_container = val
diff --git a/src/models/generated/ThermalStandard.jl b/src/models/generated/ThermalStandard.jl
index d6f99d7baa..9aefa17b33 100644
--- a/src/models/generated/ThermalStandard.jl
+++ b/src/models/generated/ThermalStandard.jl
@@ -27,6 +27,7 @@ This file is auto-generated. Do not edit.
         dynamic_injector::Union{Nothing, DynamicInjection}
         ext::Dict{String, Any}
         time_series_container::InfrastructureSystems.TimeSeriesContainer
+        supplemental_attributes_container::InfrastructureSystems.SupplementalAttributesContainer
         internal::InfrastructureSystemsInternal
     end
 
@@ -54,6 +55,7 @@ Data Structure for thermal generation technologies.
 - `dynamic_injector::Union{Nothing, DynamicInjection}`: corresponding dynamic injection device
 - `ext::Dict{String, Any}`
 - `time_series_container::InfrastructureSystems.TimeSeriesContainer`: internal time_series storage
+- `supplemental_attributes_container::InfrastructureSystems.SupplementalAttributesContainer`: container for supplemental attributes
 - `internal::InfrastructureSystemsInternal`: power system internal reference, do not modify
 """
 mutable struct ThermalStandard <: ThermalGen
@@ -87,16 +89,18 @@ mutable struct ThermalStandard <: ThermalGen
     ext::Dict{String, Any}
     "internal time_series storage"
     time_series_container::InfrastructureSystems.TimeSeriesContainer
+    "container for supplemental attributes"
+    supplemental_attributes_container::InfrastructureSystems.SupplementalAttributesContainer
     "power system internal reference, do not modify"
     internal::InfrastructureSystemsInternal
 end
 
-function ThermalStandard(name, available, status, bus, active_power, reactive_power, rating, active_power_limits, reactive_power_limits, ramp_limits, operation_cost, base_power, time_limits=nothing, must_run=false, prime_mover_type=PrimeMovers.OT, fuel=ThermalFuels.OTHER, services=Device[], time_at_status=INFINITE_TIME, dynamic_injector=nothing, ext=Dict{String, Any}(), time_series_container=InfrastructureSystems.TimeSeriesContainer(), )
-    ThermalStandard(name, available, status, bus, active_power, reactive_power, rating, active_power_limits, reactive_power_limits, ramp_limits, operation_cost, base_power, time_limits, must_run, prime_mover_type, fuel, services, time_at_status, dynamic_injector, ext, time_series_container, InfrastructureSystemsInternal(), )
+function ThermalStandard(name, available, status, bus, active_power, reactive_power, rating, active_power_limits, reactive_power_limits, ramp_limits, operation_cost, base_power, time_limits=nothing, must_run=false, prime_mover_type=PrimeMovers.OT, fuel=ThermalFuels.OTHER, services=Device[], time_at_status=INFINITE_TIME, dynamic_injector=nothing, ext=Dict{String, Any}(), time_series_container=InfrastructureSystems.TimeSeriesContainer(), supplemental_attributes_container=InfrastructureSystems.SupplementalAttributesContainer(), )
+    ThermalStandard(name, available, status, bus, active_power, reactive_power, rating, active_power_limits, reactive_power_limits, ramp_limits, operation_cost, base_power, time_limits, must_run, prime_mover_type, fuel, services, time_at_status, dynamic_injector, ext, time_series_container, supplemental_attributes_container, InfrastructureSystemsInternal(), )
 end
 
-function ThermalStandard(; name, available, status, bus, active_power, reactive_power, rating, active_power_limits, reactive_power_limits, ramp_limits, operation_cost, base_power, time_limits=nothing, must_run=false, prime_mover_type=PrimeMovers.OT, fuel=ThermalFuels.OTHER, services=Device[], time_at_status=INFINITE_TIME, dynamic_injector=nothing, ext=Dict{String, Any}(), time_series_container=InfrastructureSystems.TimeSeriesContainer(), internal=InfrastructureSystemsInternal(), )
-    ThermalStandard(name, available, status, bus, active_power, reactive_power, rating, active_power_limits, reactive_power_limits, ramp_limits, operation_cost, base_power, time_limits, must_run, prime_mover_type, fuel, services, time_at_status, dynamic_injector, ext, time_series_container, internal, )
+function ThermalStandard(; name, available, status, bus, active_power, reactive_power, rating, active_power_limits, reactive_power_limits, ramp_limits, operation_cost, base_power, time_limits=nothing, must_run=false, prime_mover_type=PrimeMovers.OT, fuel=ThermalFuels.OTHER, services=Device[], time_at_status=INFINITE_TIME, dynamic_injector=nothing, ext=Dict{String, Any}(), time_series_container=InfrastructureSystems.TimeSeriesContainer(), supplemental_attributes_container=InfrastructureSystems.SupplementalAttributesContainer(), internal=InfrastructureSystemsInternal(), )
+    ThermalStandard(name, available, status, bus, active_power, reactive_power, rating, active_power_limits, reactive_power_limits, ramp_limits, operation_cost, base_power, time_limits, must_run, prime_mover_type, fuel, services, time_at_status, dynamic_injector, ext, time_series_container, supplemental_attributes_container, internal, )
 end
 
 # Constructor for demo purposes; non-functional.
@@ -123,6 +127,7 @@ function ThermalStandard(::Nothing)
         dynamic_injector=nothing,
         ext=Dict{String, Any}(),
         time_series_container=InfrastructureSystems.TimeSeriesContainer(),
+        supplemental_attributes_container=InfrastructureSystems.SupplementalAttributesContainer(),
     )
 end
 
@@ -168,6 +173,8 @@ get_dynamic_injector(value::ThermalStandard) = value.dynamic_injector
 get_ext(value::ThermalStandard) = value.ext
 """Get [`ThermalStandard`](@ref) `time_series_container`."""
 get_time_series_container(value::ThermalStandard) = value.time_series_container
+"""Get [`ThermalStandard`](@ref) `supplemental_attributes_container`."""
+get_supplemental_attributes_container(value::ThermalStandard) = value.supplemental_attributes_container
 """Get [`ThermalStandard`](@ref) `internal`."""
 get_internal(value::ThermalStandard) = value.internal
 
@@ -209,3 +216,5 @@ set_time_at_status!(value::ThermalStandard, val) = value.time_at_status = val
 set_ext!(value::ThermalStandard, val) = value.ext = val
 """Set [`ThermalStandard`](@ref) `time_series_container`."""
 set_time_series_container!(value::ThermalStandard, val) = value.time_series_container = val
+"""Set [`ThermalStandard`](@ref) `supplemental_attributes_container`."""
+set_supplemental_attributes_container!(value::ThermalStandard, val) = value.supplemental_attributes_container = val
diff --git a/src/models/generated/includes.jl b/src/models/generated/includes.jl
index 6e9a600074..3e674fa6a7 100644
--- a/src/models/generated/includes.jl
+++ b/src/models/generated/includes.jl
@@ -619,6 +619,7 @@ export get_states_types
 export get_status
 export get_storage_capacity
 export get_storage_target
+export get_supplemental_attributes_container
 export get_sustained_time
 export get_switch
 export get_tF_delay
@@ -1155,6 +1156,7 @@ export set_states_types!
 export set_status!
 export set_storage_capacity!
 export set_storage_target!
+export set_supplemental_attributes_container!
 export set_sustained_time!
 export set_switch!
 export set_tF_delay!
diff --git a/src/models/serialization.jl b/src/models/serialization.jl
index b19f9e8f97..f961e5e124 100644
--- a/src/models/serialization.jl
+++ b/src/models/serialization.jl
@@ -4,11 +4,12 @@ const _ENCODE_AS_UUID_A = (
     Union{Nothing, Bus},
     Union{Nothing, LoadZone},
     Union{Nothing, DynamicInjection},
+    Union{Nothing, StaticInjection},
     Vector{Service},
 )
 
 const _ENCODE_AS_UUID_B =
-    (Arc, Area, Bus, LoadZone, DynamicInjection, Vector{Service})
+    (Arc, Area, Bus, LoadZone, DynamicInjection, StaticInjection, Vector{Service})
 @assert length(_ENCODE_AS_UUID_A) == length(_ENCODE_AS_UUID_B)
 
 should_encode_as_uuid(val) = any(x -> val isa x, _ENCODE_AS_UUID_B)
diff --git a/src/models/supplemental_constructors.jl b/src/models/supplemental_constructors.jl
index bba1268350..e355bfc8bb 100644
--- a/src/models/supplemental_constructors.jl
+++ b/src/models/supplemental_constructors.jl
@@ -76,6 +76,7 @@ function ACBus(
         area,
         load_zone,
         ext,
+        IS.SupplementalAttributesContainer(),
         InfrastructureSystemsInternal(),
     )
 end
diff --git a/src/models/topological_elements.jl b/src/models/topological_elements.jl
index 8b9a1c3b22..fed1bd592f 100644
--- a/src/models/topological_elements.jl
+++ b/src/models/topological_elements.jl
@@ -34,6 +34,7 @@ function check_bus_params(
     area,
     load_zone,
     ext,
+    attributes,
     internal,
 )
     if !isnothing(bustype)
@@ -55,5 +56,6 @@ function check_bus_params(
     area,
     load_zone,
     ext,
+    attributes,
     internal
 end
diff --git a/src/outages.jl b/src/outages.jl
new file mode 100644
index 0000000000..302c98fcd4
--- /dev/null
+++ b/src/outages.jl
@@ -0,0 +1,63 @@
+abstract type Outage <: SupplementalAttribute end
+
+struct ForcedOutage <: Outage
+    forced_outage_rate::Float64
+    mean_time_to_recovery::Int
+    outage_probability::Float64
+    recovery_probability::Float64
+    time_series_container::InfrastructureSystems.TimeSeriesContainer
+    component_uuids::InfrastructureSystems.ComponentUUIDs
+    internal::InfrastructureSystemsInternal
+end
+
+function ForcedOutage(;
+    forced_outage_rate = 0.0,
+    mean_time_to_recovery = 0,
+    outage_probability = 0.0,
+    recovery_probability = 0.0,
+    time_series_container = InfrastructureSystems.TimeSeriesContainer(),
+    component_uuids = InfrastructureSystems.ComponentUUIDs(),
+    internal = InfrastructureSystemsInternal(),
+)
+    return ForcedOutage(
+        forced_outage_rate,
+        mean_time_to_recovery,
+        outage_probability,
+        recovery_probability,
+        time_series_container,
+        component_uuids,
+        internal,
+    )
+end
+
+get_component_uuids(x::ForcedOutage) = x.component_uuids
+get_internal(x::ForcedOutage) = x.internal
+get_time_series_container(x::ForcedOutage) = x.time_series_container
+
+struct PlannedOutage <: Outage
+    time_to_recovery::Int
+    outage_schedule::Int
+    time_series_container::InfrastructureSystems.TimeSeriesContainer
+    component_uuids::InfrastructureSystems.ComponentUUIDs
+    internal::InfrastructureSystemsInternal
+end
+
+function PlannedOutage(;
+    time_to_recovery = 0,
+    outage_schedule = 0.0,
+    time_series_container = InfrastructureSystems.TimeSeriesContainer(),
+    component_uuids = InfrastructureSystems.ComponentUUIDs(),
+    internal = InfrastructureSystemsInternal(),
+)
+    return PlannedOutage(
+        time_to_recovery,
+        outage_schedule,
+        time_series_container,
+        component_uuids,
+        internal,
+    )
+end
+
+get_component_uuids(x::PlannedOutage) = x.component_uuids
+get_internal(x::PlannedOutage) = x.internal
+get_time_series_container(x::PlannedOutage) = x.time_series_container
diff --git a/test/common.jl b/test/common.jl
index 7ff431b963..037635f167 100644
--- a/test/common.jl
+++ b/test/common.jl
@@ -156,6 +156,50 @@ function create_system_with_dynamic_inverter()
     return sys
 end
 
+"""
+Create a system with supplemental attributes with the criteria below.
+
+- Two GeographicInfo instances each assigned to multiple components.
+- Two ThermalStandards each with two ForcedOutage instances and two PlannedOutage instances.
+- Each outage has time series.
+"""
+function create_system_with_outages()
+    sys = PSB.build_system(
+        PSITestSystems,
+        "c_sys5_uc";
+        add_forecasts = true,
+    )
+    gens = collect(get_components(ThermalStandard, sys))
+    gen1 = gens[1]
+    gen2 = gens[2]
+    geo1 = GeographicInfo(; geo_json = Dict("x" => 1.0, "y" => 2.0))
+    geo2 = GeographicInfo(; geo_json = Dict("x" => 3.0, "y" => 4.0))
+    add_supplemental_attribute!(sys, gen1, geo1)
+    add_supplemental_attribute!(sys, gen1.bus, geo1)
+    add_supplemental_attribute!(sys, gen2, geo2)
+    add_supplemental_attribute!(sys, gen2.bus, geo2)
+    initial_time = Dates.DateTime("2020-01-01T00:00:00")
+    end_time = Dates.DateTime("2020-01-01T23:00:00")
+    dates = collect(initial_time:Dates.Hour(1):end_time)
+    fo1 = ForcedOutage(; forced_outage_rate = 1.0)
+    fo2 = ForcedOutage(; forced_outage_rate = 2.0)
+    po1 = PlannedOutage(; outage_schedule = 3.0)
+    po2 = PlannedOutage(; outage_schedule = 4.0)
+    add_supplemental_attribute!(sys, gen1, fo1)
+    add_supplemental_attribute!(sys, gen1, po1)
+    add_supplemental_attribute!(sys, gen2, fo2)
+    add_supplemental_attribute!(sys, gen2, po2)
+    for (i, outage) in enumerate((fo1, fo2, po1, po2))
+        data = collect(i:(i + 23))
+        ta = TimeSeries.TimeArray(dates, data, ["1"])
+        name = "ts_$(i)"
+        ts = SingleTimeSeries(; name = name, data = ta)
+        add_time_series!(sys, outage, ts)
+    end
+
+    return sys
+end
+
 function test_accessors(component)
     ps_type = typeof(component)
 
diff --git a/test/runtests.jl b/test/runtests.jl
index 329d2640bd..02ac00a124 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -98,8 +98,8 @@ function run_tests()
     else
         config = IS.LoggingConfiguration(;
             filename = LOG_FILE,
-            file_level = Logging.Info,
-            console_level = Logging.Error,
+            file_level = get_logging_level_from_env("SIIP_FILE_LOG_LEVEL", "Info"),
+            console_level = get_logging_level_from_env("SIIP_CONSOLE_LOG_LEVEL", "Error"),
         )
     end
     console_logger = ConsoleLogger(config.console_stream, config.console_level)
diff --git a/test/test_outages.jl b/test/test_outages.jl
new file mode 100644
index 0000000000..d25f115294
--- /dev/null
+++ b/test/test_outages.jl
@@ -0,0 +1,51 @@
+@testset "Test outages" begin
+    sys = create_system_with_outages()
+    gens = collect(get_components(ThermalStandard, sys))
+    gen1 = gens[1]
+    gen2 = gens[2]
+    @test length(get_supplemental_attributes(Outage, sys)) == 4
+    forced_outages = collect(get_supplemental_attributes(ForcedOutage, sys))
+    @test length(forced_outages) == 2
+    @test get_supplemental_attribute(sys, IS.get_uuid(forced_outages[1])) ==
+          forced_outages[1]
+    planned_outages = collect(get_supplemental_attributes(PlannedOutage, sys))
+    @test length(planned_outages) == 2
+    @test get_supplemental_attribute(sys, IS.get_uuid(planned_outages[1])) ==
+          planned_outages[1]
+
+    geos = get_supplemental_attributes(GeographicInfo, sys)
+    for geo in geos
+        @test length(get_components(sys, geo)) == 2
+    end
+
+    for gen in (gen1, gen2)
+        for type in (ForcedOutage, PlannedOutage, GeographicInfo)
+            attributes = collect(get_supplemental_attributes(type, gen))
+            @test length(attributes) == 1
+            uuid = IS.get_uuid(attributes[1])
+            get_supplemental_attribute(sys, uuid)
+            get_supplemental_attribute(gen, uuid)
+            @test get_supplemental_attribute(gen, uuid) ==
+                  get_supplemental_attribute(sys, uuid)
+        end
+    end
+
+    @test length(
+        get_supplemental_attributes(x -> x.forced_outage_rate == 2.0, ForcedOutage, sys),
+    ) == 1
+    @test length(
+        get_supplemental_attributes(x -> x.forced_outage_rate == 2.0, ForcedOutage, gen1),
+    ) == 0
+    @test length(
+        get_supplemental_attributes(x -> x.forced_outage_rate == 2.0, ForcedOutage, gen2),
+    ) == 1
+    @test length(
+        get_supplemental_attributes(x -> x.outage_schedule == 4.0, PlannedOutage, sys),
+    ) == 1
+    @test length(
+        get_supplemental_attributes(x -> x.outage_schedule == 4.0, PlannedOutage, gen1),
+    ) == 0
+    @test length(
+        get_supplemental_attributes(x -> x.outage_schedule == 4.0, PlannedOutage, gen2),
+    ) == 1
+end
diff --git a/test/test_serialization.jl b/test/test_serialization.jl
index 30e0166c95..baaa62b484 100644
--- a/test/test_serialization.jl
+++ b/test/test_serialization.jl
@@ -1,4 +1,4 @@
-@testset "Test JSON serialization of RTS data with mutable time series" begin
+@testset "Test JSON serialization of RTS data with RegulationDevice" begin
     sys = PSB.build_system(PSITestSystems, "test_RTS_GMLC_sys"; add_forecasts = false)
     # Add an AGC service to cover its special serialization.
     control_area = get_component(Area, sys, "1")
@@ -222,6 +222,12 @@ end
     end
 end
 
+@testset "Test serialization of supplemental attributes" begin
+    sys = create_system_with_outages()
+    sys2, result = validate_serialization(sys; assign_new_uuids = true)
+    @test result
+end
+
 @testset "Test verification of invalid ext fields" begin
     sys = PSB.build_system(PSITestSystems, "test_RTS_GMLC_sys"; add_forecasts = false)
     gen = first(get_components(ThermalStandard, sys))
diff --git a/test/test_system.jl b/test/test_system.jl
index 3bd02dd4a7..30256329eb 100644
--- a/test/test_system.jl
+++ b/test/test_system.jl
@@ -325,11 +325,10 @@ end
         PSITestSystems,
         "c_sys5_uc";
         add_forecasts = true,
-        force_build = true,
     )
-    _, ts_count, forecast_count = get_time_series_counts(c_sys5)
-    @test ts_count == 0
-    @test forecast_count == 3
+    counts = get_time_series_counts(c_sys5)
+    @test counts.static_time_series_count == 0
+    @test counts.forecast_count == 3
 end
 
 @testset "Test deepcopy with time series options" begin