ReEDS translation reference for Sienna and PLEXOS

This reference provides a side-by-side view of how R2X translates ReEDS concepts and technologies into Sienna and PLEXOS. It summarizes their physical roles, target component types, timeseries treatment and important modeling assumptions and limitations.

System structure and demand

ReEDS model element	Model role	Sienna representation	PLEXOS representation
Model zone (ReEDSRegion)	Electrical region	Area and ACBus	PLEXOSRegion and PLEXOSNode
Electricity demand (ReEDSDemand)	Inflexible electricity demand	PowerLoad	Load timeseries on PLEXOSRegion
Transmission region (transreg)	Aggregation of ReEDS model zones	No separate component; used for reserve grouping	PLEXOSZone

Electricity-consuming technologies

ReEDS technology or demand type	Model role	Sienna representation	PLEXOS representation
electrolyzer	Electricity consumption for hydrogen production	StandardLoad	PLEXOSPurchaser
smr	Electricity consumption associated with steam methane reforming	StandardLoad	PLEXOSPurchaser
smr_ccs	Electricity consumption associated with steam methane reforming with carbon capture	StandardLoad	PLEXOSPurchaser
Optimally sited data-center load (data-center)	Electricity demand	StandardLoad	PLEXOSPurchaser
Other technology in the CONSUME subset (ReEDSConsumingTechnology)	Technology-specific electricity consumption	StandardLoad	PLEXOSGenerator

Thermal and hydrogen generation

ReEDS technology or technology subset	Model role	Sienna representation	PLEXOS representation
Conventional thermal generation	Dispatchable electricity generation	ThermalStandard	PLEXOSGenerator
h2-cc family, such as gas-cc_h2-cc	Hydrogen-fueled combined-cycle electricity generation	ThermalStandard	PLEXOSGenerator
h2-ct family, such as gas-ct_h2-ct	Hydrogen-fueled combustion-turbine electricity generation	ThermalStandard	PLEXOSGenerator
nuclear-smr	Small modular nuclear electricity generation	ThermalStandard	PLEXOSGenerator

Variable and distributed generation

ReEDS technology or technology subset	Model role	Sienna representation	PLEXOS representation
Utility-scale PV in the UPV subset	Curtailable variable generation	RenewableDispatch	PLEXOSGenerator
Onshore wind in the ONSWIND subset	Curtailable variable generation	RenewableDispatch	PLEXOSGenerator
Offshore wind in the OFSWIND subset	Curtailable variable generation	RenewableDispatch	PLEXOSGenerator
Distributed PV in the distpv subset	Nondispatchable distributed generation	RenewableNonDispatch	PLEXOSGenerator with an availability profile

Conventional hydro

ReEDS technology subset	Model role	Sienna representation	PLEXOS representation
Dispatchable conventional hydro in HYDRO_D	Dispatchable generation with a water-energy budget	HydroDispatch	PLEXOSGenerator with energy and hourly power limits
Nondispatchable conventional hydro in HYDRO_ND	Fixed hydro generation derived from water availability	RenewableNonDispatch	PLEXOSGenerator with Fixed Load

The ReEDS technology subset membership is the authoritative distinction between dispatchable and nondispatchable conventional hydro. Technology-name prefixes alone are not sufficient for classification.

Dispatchable hydro retains an hourly generation decision. Its power limit is derived from installed capacity and the applicable hydro capacity adjustment. Its energy budget is derived from installed capacity, hydro capacity factor and the duration of the budget interval.

Nondispatchable hydro does not receive a flexible energy budget. Its hourly output is installed capacity multiplied by the applicable hydro capacity factor.

The target budget interval is separate from the simulation timestep. An hourly simulation can enforce a daily, weekly or monthly energy budget.

Note

Nondispatchable hydro could be serialized as a PowerSystems.jl hydro component. However PowerSimulations.jl assigns one DeviceModel formulation to each component type in a simulation template. If both hydro categories used HydroDispatch, a single simulation template could not assign HydroDispatchRunOfRiverBudget to dispatchable hydro and FixedOutput to nondispatchable hydro at the same time. The translator therefore uses HydroDispatch for dispatchable hydro and RenewableNonDispatch for nondispatchable hydro.

Note

HydroDispatch can represent the ReEDS generation VOM as a hydro generation cost. RenewableNonDispatch does not provide the same operating-cost representation. The translator preserves the original nondispatchable hydro VOM as ext["reeds_vom_cost"].

Pumped hydro

ReEDS technology	Model role	Sienna representation	PLEXOS representation
pumped-hydro technology in the PSH subset	Storage with pumping and turbine generation	HydroPumpTurbine with linked head and tail HydroReservoir components	PLEXOSGenerator with linked head and tail PLEXOSStorage objects

ReEDS classifies pumped hydro through its storage framework rather than the conventional-hydro framework. The target representation preserves pumping, turbine generation, stored energy and the relationship between the head and tail reservoirs.

The Sienna translator uses explicit ReEDS energy_capacity in MWh when available, falling back to capacity × storage_duration. The PLEXOS translator calculates reservoir Max Volume as capacity × storage_duration / 1000 in GWh and does not use explicit energy_capacity. For example, 100 MW with a four-hour duration and an explicit 600 MWh capacity produces 600 MWh in Sienna and 0.4 GWh (400 MWh) in PLEXOS. The ReEDS storage efficiency is applied during pumping while turbine efficiency remains one.

Initial head and tail levels use translator assumptions because ReEDS does not provide a fixed initial state.

Note

PLEXOS can apply ReEDS VOM to turbine generation. HydroPowerSimulations.jl uses the HydroPumpTurbine operation cost for both generation and pumping, while ReEDS applies this VOM only to generation. The Sienna translator therefore sets the pumped-hydro operation cost to zero to avoid applying a generation-only cost during pumping. It preserves the original value as ext["reeds_vom_cost"].

Note

ReEDS does not provide external water inflow for this pumped-hydro representation. Sienna therefore requires explicit zero inflow profiles on both reservoirs to satisfy the HydroPowerSimulations formulation.

Storage

ReEDS technology or technology subset	Model role	Sienna representation	PLEXOS representation
Battery technologies in the BATTERY subset	Electrochemical storage	EnergyReservoirStorage	PLEXOSBattery
Other non-pumped technologies in the STORAGE subset	Generic energy storage	EnergyReservoirStorage	No generic target rule

Transmission and interfaces

ReEDS transmission capacity type or interface	Model role	Sienna representation	PLEXOS representation
AC transmission capacity type	Directional AC transfer capability	MonitoredLine	PLEXOSLine
VSC transmission capacity type	Directional HVDC transfer capability	TwoTerminalGenericHVDCLine	PLEXOSLine
LCC transmission capacity type	Directional HVDC transfer capability	TwoTerminalGenericHVDCLine	PLEXOSLine
B2B transmission capacity type	Directional back-to-back transfer capability	TwoTerminalGenericHVDCLine	PLEXOSLine
Interzonal interface (ReEDSInterface)	Aggregate transfer interface	AreaInterchange	PLEXOSInterface

Reserves

ReEDS operating reserve concept	Sienna representation	PLEXOS representation
Spinning, regulation and flexibility reserve products	VariableReserve	PLEXOSReserve
NON_SPINNING reserve product	VariableReserveNonSpinning	PLEXOSReserve
Reserve direction	Reserve direction	Encoded in the reserve Type property
Translated reserve eligibility	Service membership	Reserve membership
Hourly requirement	Requirement timeseries	Min Provision timeseries

Related references and implementation

For pipeline setup and component diagrams, see ReEDS to Sienna and ReEDS to PLEXOS. For individual properties, see the Sienna mappings and PLEXOS mappings.

The following implementation links refer to the verified code at commit 39be9d19a1833b3e736e9039b29292a4e6819778:

• Sienna component-selection rules.
• Sienna property getters, including storage capacity and hydro costs.
• Sienna time-series post-processing, including pumped-hydro inflow.
• PLEXOS component-selection and property rules.
• PLEXOS property getters, including reservoir maximum volume.
• PLEXOS time-series handling, including hydro budgets.