Hydro power¶

The hydropower variants in LtmApi are:

Detailed hydro modules
Aggregated hydropower
Batteries (modelled as aggregated hydropower)
Pumps in the LtmApi

Detailed hydro modules¶

Detailed description of detailed hydro modules in the LTM-API. The LTM hydropower modelling use the standard hydro modules which contains both a reservoir and a hydropower plant.

In the LTM-API reservoirs and hydropower plants are two separate objects, as described in Reservoir and Plant. They can be connected to each other by the Connections object to form a LTM standard hydro module.

The definition of a minimal hydropower module specifying the energy equivalent and maximum discharge (omitting the tailrace elevation, pq-curve and volume curve) is not possible in the LtmApi. A minimal (synthetic) example in the LtmApi is provided below.

The gross head is set to 100 m

The tailrace elevation is set to 1000 m (100 m below the reservoir)

Two-point linear pq-curve from 0 MW production at 0 m3/s discharge to 10 MW production at 25 m3/s discharge

Minimal example

"reservoirs": [
  {
      "name": "upper_main",
      "average_spill_energy_equivalent": 0.7,
      "regulated_inflow_name": "ten",
      "average_regulated_inflow": 50.0,
      "max_discharge": 25.0,
      "reference_curve": {
          "timestamps": [
              "2023-W17",
              "2023-W40"
          ],
          "scenarios": [
              [
                  200,
                  450
              ]
          ]
      },
      "initial_volume": 400,
      "max_volume": 500
  }
],
"plants": [
    {
        "name": "plant",
        "discharge_energy_equivalent": {
            "scenarios": [
                [
                    0.113
                ]
            ]
        },
        "pq_curves": {
            "2024-01-01T00:00:00Z": {
                "y": [
                    0.0,
                    10.0
                ],
                "x": [
                    0.0,
                    25.0
                ]
            }
        },
        "unregulated_inflow_name": "one",
        "average_unregulated_inflow": 1.0,
        "tailrace_elevation": 1000.0,
        "gross_head": 100.0,
    }
],
"connections": [
    {
        "from": "upper_main",
        "to": "plant"
    }
]

Reservoir¶

See the discription of the LTM Reservoir.

The table below shows Required Reservoir Parameters. The parameters in italics means that one of the two must be specified, where the user choose the appropriate one.

Required Reservoir Parameters¶
Parameter	Datatype	Description
name	string	Object name
average_spill_energy_equivalent	double	Local average energy equivalent for spills [kWh/m3]. See Energy equivalents and the importance for Pump object.
average_regulated_inflow	double	Average yearly regulated Inflow [m3/s].
max_discharge	double	Global maximum discharge from the reservoir [m^3/sec]. If the pq-curve on Plant is defined for a higher discharge, the whole pq-curve is not used.
reference_curve	Txy	Reservoir reference curve [Mm^3] See reservoir curve here Reservoir.
max_volume	double	Mm3
volume_curve	xy	The volume curve show the functional relationship between the elevation above sea level and the reservoir volume [m - Mm3]. See Reservoir.

Below is a reservoir example:

"reservoirs": [
    {
        "name": "Example reservoir",
        "average_spill_energy_equivalent": 0.12,
        "average_regulated_inflow": 0.79492267,
        "initial_volume": 60,
        "max_discharge": 30,
        "reference_curve": {
            "timestamps": [
                "2024-04-22T00:00:00Z",
                "2024-06-03T00:00:00Z",
                "2025-01-01T00:00:00Z"
            ],
            "scenarios": [
                [
                    0.0,
                    75.0,
                    85.0
                ]
            ]
        },
        "regulated_inflow": {
            "#comment": "Refers to unregulated inflow label",
            "external_reference": {
                "type": "csv",
                "filename": "constant_inflow.csv"
            }
        },
        "volume_curve": {
            "x": [
                1050,
                1100
            ],
            "y": [
                0,
                100
            ]
        }
    }
]

The optional reservoir parameters are listed in the table below Optional Reservoir Parameters.

Optional Reservoir Parameters¶
Parameter	Datatype	Description
degree_of_regulation	double	Reservoir regulation degree [years]. Factor describes how many years it takes to fill the reservoir.
reservoir_type	reservoir_type	Regulation or buffer reservoir. See Reservoir types.
regulated_inflow	Txy	Regulated inflow [m3/sec]. See Inflow.
regulated_inflow_name	string	Reference to a regulated inflow time series [m3/sec]. inflow_series
initial_volume	double	Reservoir volume at simulation start. [Mm3]
gross_head	double	Nominal gross head [m]. See Production discharge curve
tailrace_elevation	double	Tailrace elevation (utløpskote) [m]. See Production discharge curve
max_volume_curve	Txy	Maximal allowed volume for given points in time [Mm3]
max_volume_curve_hard_limit	bool	Reservoir has hard upper volume limit
min_volume_curve	Txy	Minimum allowed volume for given points in time [Mm3]
min_volume_curve_hard_limit	bool	Reservoir has hard lower volume limit
max_discharge_curve	Txy	Maximum allowed discharge for given points in time [m3/sec]
max_discharge_name	string	Reference to a time series for maximum discharge
max_discharge_scale	double	Scaling factor for the maximum discharge time series
min_discharge_curve	Txy	Minimum allowed discharge for given points in time [m3/sec]
min_discharge_name	string	Reference to a time series for minimum discharge
min_discharge_scale	double	Scaling factor for the minimum discharge time series
min_bypass_curve	Txy	Minimum allowed bypass for given points in time [m3/sec]
min_bypass_name	string	Reference to a time series for minimum bypass
min_bypass_scale	double	Scaling factor for the minimum bypass time series
max_bypass_curve	Txy	Maximum allowed bypass for given points in time [m3/sec]
max_bypass_name	string	Reference to a time series for maximum bypass
max_bypass_scale	double	Scaling factor for the maximum bypass time series
hc_max_flow	int	Maximum flow on hydraulic couplings [m3/s]
hc_has_gate	int	Hydraulic coupling has gate/hatch [m3/s]
#comment	string
metadata	json	output
module_number	int	output

Plant¶

See description of LTM Plant. The required plant parameters are listed in the table below.

Required Plant Parameters Overview¶
Parameter	Datatype	Description
name	string	Object name
discharge_energy_equivalent	Txy	Local discharge energy equivalent time series, given together with turbine PQ-curves. [kWh/m^3]. Plant and Energy equivalents.
pq_curves	xyt	PQ efficiency curves [MW - m3/s]. Production discharge curve. The highest discharge on the pq-curve restricts the discharge through the station even though the maximum discharge from the reservoir may be larger (Reservoir).
average_unregulated_inflow	double	Average yearly unregulated inflow [m^3/s]. Inflow.
gross_head	double	Nominal gross head (brutto fallhoyde) [m]. Gross head Hnom in Production discharge curve. Value must be >0.0.
tailrace_elevation*	double	Plant tailrace elevation (utlopskote stasjon) [m] Production discharge curve.

Below is a minimal plant example. The “yearly_inflow_profile” is a reference to the name of a defined inflow_series.

"plants": [
  {
      "name": "plant",
      "discharge_energy_equivalent": {
          "scenarios": [
              [
                  0.12
              ]
          ]
      },
      "pq_curves": {
          "2024-01-01T00:00:00Z": {
              "y": [
                  0.0,
                  9.89
              ],
              "x": [
                  0.0,
                  24.6
              ]
          }
      },
      "average_unregulated_inflow": 0.6,
      "gross_head": 40.0,
      "tailrace_elevation": 1030,
      "unregulated_inflow_name": "yearly_inflow_profile"
  }
]

The optional plant parameters are listed in the table below. The parameters in italics means that one of the two must be specified, where the user choose the appropriate one.

Optional Plant Parameters Overview¶
Parameter	Datatype	Description
unregulated_inflow	Txy	Unregulated inflow time series [m3/sec]. Inflow.
unregulated_inflow_name	string	reference to the name of an inflow time series. inflow_series
ownership	double	%
max_discharge_curve	Txy	Maximum discharge constraint [m3/sec]. Time dependent constraints.
max_discharge_name	string	Name of time series
max_discharge_scale	double	Scaling factor of the input series
min_discharge_curve	Txy	Minimum discharge constraint [m3/sec]. Time dependent constraints.
min_discharge_name	string	Name of time series
min_discharge_scale	double	Scaling factor of the input series
min_bypass_curve	Txy	Minimum bypass constraint [m3/sec]. Time dependent constraints.
min_bypass_name	string	Name of time series
min_bypass_scale	double	Scaling factor of the input series
gross_head_max_discharge	xy	Maximum discharge as function of gross head [m3/s].
max_bypass_curve	Txy	Maximum bypass constraint [m3/sec]. Time dependent constraints.
max_bypass_name	string	Name of time series
max_bypass_scale	double	Scaling factor of the input series
unavailable_capacity	Txy	MW
#comment	string
metadata	json	User meta data: Output

Aggregated hydropower¶

Input¶

The API expects input data to be given as a list of “aggregated_hydro_modules” objects. The aggregated hydro modules include the following input where the Parameters in bold are required and the others are optional:

Input¶
Parameter	Type	Description
name	string	Object name
reservoir_energy	double	Maximum reservoir energy [MWh]
station_power	double	Max station production [MW]
unregulated_power_inflow	Txy	Unregulated power inflow [MW], see Inflow
regulated_power_inflow	Txy	Regulated power inflow [MW], see Inflow
start_reservoir_energy	double	Initial aggregated reservoir energy [MWh]
upper_reservoir_limits	Txy	Upper reservoir limits [MWh]
lower_reservoir_limits	Txy	Lower reservoir limits [MWh]
upper_production_limits	Txy	Upper production limits [MW]
lower_production_limits	Txy	Lower production limits [MW]
metadata	json	User metadata: output

Hydro power¶

Detailed hydro modules¶

Reservoir¶

Plant¶

Aggregated hydropower¶

Input¶

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