Pumped Storage Reservoir
The Pumped Storage Reservoir object models a level reservoir where there are facilities that can release water to generate power but can also be pump water into the reservoir to increase storage.
General Slots
Canal Flow
Type: Agg Series
Units: Flow
Description: Flow into (out of) the reservoir from (to) a canal
Information:
Defined by: Explicit Optimization variable in the mass balance constraint
Diversion
Type: Series Slot
Units: Flow
Description: Flow from the reservoir to a diverting object
Information:
Defined by: Explicit Optimization variable in the mass balance constraint
Elevation Volume Table
Type: Table
Units: Length vs Volume
Description: Table relating elevation of the reservoir to volume stored in the reservoir
Information:
I/O: Input only
Defined by: Input only
Energy
Type: Agg Series Slot
Units: Energy
Description: Product of the power generated by flow through the turbines and the length of the timestep.
Information:
Defined by: Replaced by Power * Timestep Length
Description:
Flow FROM Pumped Storage
Type: Agg Series Slot
Units: Flow
Description: Flow into the reservoir from a pumped storage reservoir
Information:
Defined by: Explicit Optimization variable in the mass balance constraint. This slot should be linked to Outflow on a Pumped Storage object. The Pumped Storage object constrains its Outflow.
Flow TO Pumped Storage
Type: Agg Series Slot
Units: Flow
Description: Flow out of the reservoir into a pumped storage reservoir
Information:
Defined by: Explicit Optimization variable in the mass balance constraint. This slot should be linked to Pumped Flow on a Pumped Storage object.
Inflow
Type: MultiSlot
Units: Flow
Description: Inflow into the reservoir from upstream
Information:
Defined by: Explicit Optimization variable in the mass balance constraint
Information:
Operating Head
Type: Agg Series Slot
Units: Length
Description: Elevation difference between the average Pool Elevation and the average Tailwater Elevation during a timestep
Information:
Defined by: Replacement by (Pool Elevation(t) + Pool Elevation(t-1)) / 2 - Tailwater Elevation
Outflow
Type: Agg Series Slot
Units: Flow
Description: Outflow from the reservoir
Information:
Defined by: Explicit Optimization variable as Outflow = Turbine Release + Spill
Information:
Pool Elevation
Type: Agg Series Slot
Units: Length
Description: Elevation of the water surface of the Reservoir
Information: When Pool Elevation is a part of the optimization problem, as it is in all conceivable RiverWare Optimization applications, this slot is numerically approximated as a function of Storage (Numerical 2-D Approximation). The relationship between Pool Elevation and Storage will come from the user-input Elevation Volume Table. The table will be queried either using user-input points defined in the Pool Elevation LP Param table.
Defined by: Numerical 2-D Approximation in terms of Storage, based upon the Elevation Volume Table. The Pool Elevation LP Param table values are used as approximation points indexing the Elevation Volume Table. The Elevation Volume Table should have increasing values of Pool Elevation and Storage. Storage is required to be a concave function of Pool Elevation. The preferred order of approximation is substitution, piece-wise, tangent, two-point line.
Pool Elevation LP Param
Type: Table Slot
Units: Volume
Description: Specifies the Storage points used to take the tangent, line and piecewise approximations for Pool Elevation linearization
Information: This table is used for linearization unless Pool Elevation Linearization Automation category has selected Plant Automation. The best Storage point to choose for tangent approximation would be the expected storage expected during the run; for the line approximation, the expected maximum and minimum Storage; for piecewise approximation, use points that cover the full range of expected Storage during the run with intermediate points such that a piecewise linear curve reasonably approximates the actual curve.
Defined by: User input
Pool elevation storage relationship. Not drawn to scale.
Power
Type: Agg Series Slot
Units: Power
Description: Power generated by flow through the turbines
Information:
Defined by: Numerical 3-D Approximation in terms of Operating Head and Turbine Release. Approximation is based on the Plant Power Table. The Power LP Param table contains a value for Operating Head used to index the Operating Head column of the Plant Power Table. This approximated value, therefore, reduces the Power to a function of Turbine Release at the given Operating Head.
The flow values in the Power LP Param table are then used as approximation points indexing the Turbine Release column of the Plant Power Table. The Plant Power Table should have increasing values of Operating Head and Turbine Release. Power should be a concave function of Operating Head, but concavity is not strictly enforced; mild non-concave regions are permissible to allow for round-off error, and so on. The preferred order of approximation is substitution, piece-wise, two-point line, tangent.
Return Flow
Type: MultiSlot
Units: Flow
Description: Flow returning from a diversion object
Information:
Defined by: Explicit Optimization variable in the mass balance constraint (see Storage)
Spill
Type: Agg Series Slot
Units: Flow
Description: Sum of the Bypass, Regulated Spill and Unregulated Spill
Information:
Defined by: Explicit Optimization variable as Spill = Bypass + Regulated Spill + Unregulated Spill
Storage
Type: Series Slot
Units: Volume
Description: Volume of water stored in the reservoir
Information:
Defined by: Explicit Optimization variable as Storage = Storage(t-1) + Precipitation Volume - Evaporation - Change in Bank Storage + timestep * ( Inflow + Canal Flow + Flow TO Pumped Storage + Hydrologic Inflow Net + Return Flow - (Outflow + Diversion + Flow FROM Pumped Storage))
Tailwater Base Value
Type: Series Slot
Units: Length
Description: Elevation of tailwater or base elevation used to compute elevation of tailwater
Information:
Defined by: Explicit Optimization variable should be input or linked. See Pump Power Numerical Approximation in Optimization for descriptions of related constraints and other objects to which the slot is linked.
Tailwater Elevation
Type: Agg Series Slot
Units: Length
Description: Water surface elevation on the downstream side of the dam
Information:
Defined by: Various approaches dependent on the method selected in the Optimization Tailwater category.
Turbine Capacity LP Param
Type: Table
Units: Length, Length, Length
Description: LP Param table for turbine capacity
Information: See power methods for details
Turbine Capacity
Type: Agg Series Slot
Units: Flow
Description: Flow capacity of the entire power plant’s turbines
Information:
Defined by: Numerical 2-D Approximation in terms of Operating Head, based upon a maximum turbine capacity table. This capacity table is determined in various ways according to the Power method.
Turbine Release
Type: Agg Series Slot
Units: Flow
Description: Flow through the turbines of a power reservoir
Information:
Defined by: Explicit Optimization variable as Turbine Release <= Power Plant Cap Fraction * Turbine Capacity
Revised: 07/09/2023