Note

You can download this example as a Jupyter notebook or start it in interactive mode.

Two chained reservoirs

Two disconnected electrical loads are fed from two reservoirs linked by a river; the first reservoir has inflow from rain onto a water basin.

Note that the two reservoirs are tightly coupled, meaning there is no time delay between the first one emptying and the second one filling, as there would be if there were a long stretch of river between the reservoirs. The reservoirs are essentially assumed to be close to each other. A time delay would require a “Link” element between different snapshots, which is not yet supported by PyPSA (but could be enabled by passing network.lopf() an extra_functionality function).

[1]:
import pypsa
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt

from pyomo.environ import Constraint
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Cell In [1], line 1
----> 1 import pypsa
      2 import pandas as pd
      3 import numpy as np

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/site-packages/pypsa/__init__.py:10
      1 # -*- coding: utf-8 -*-
      4 """
      5 Python for Power Systems Analysis (PyPSA)
      6
      7 Grid calculation library.
      8 """
---> 10 from pypsa import (
     11     components,
     12     contingency,
     13     descriptors,
     14     examples,
     15     geo,
     16     io,
     17     linopf,
     18     linopt,
     19     networkclustering,
     20     opf,
     21     opt,
     22     optimization,
     23     pf,
     24     plot,
     25 )
     26 from pypsa.components import Network, SubNetwork
     28 __version__ = "0.21.2"

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/site-packages/pypsa/components.py:50
     37 from pypsa.io import (
     38     export_to_csv_folder,
     39     export_to_hdf5,
   (...)
     47     import_series_from_dataframe,
     48 )
     49 from pypsa.opf import network_lopf, network_opf
---> 50 from pypsa.optimization.optimize import OptimizationAccessor
     51 from pypsa.pf import (
     52     calculate_B_H,
     53     calculate_dependent_values,
   (...)
     62     sub_network_pf,
     63 )
     64 from pypsa.plot import iplot, plot

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/site-packages/pypsa/optimization/__init__.py:7
      1 #!/usr/bin/env python3
      2 # -*- coding: utf-8 -*-
      3 """
      4 Build optimisation problems from PyPSA networks with Linopy.
      5 """
----> 7 from pypsa.optimization import abstract, constraints, optimize, variables
      8 from pypsa.optimization.optimize import create_model

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/site-packages/pypsa/optimization/constraints.py:9
      6 import logging
      8 import pandas as pd
----> 9 from linopy.expressions import LinearExpression, merge
     10 from numpy import arange, cumsum, inf, nan, roll
     11 from scipy import sparse

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/site-packages/linopy/__init__.py:9
      1 #!/usr/bin/env python3
      2 # -*- coding: utf-8 -*-
      3 """
      4 Created on Wed Mar 10 11:03:06 2021.
      5
      6 @author: fabulous
      7 """
----> 9 from linopy import model, remote
     10 from linopy.expressions import merge
     11 from linopy.io import read_netcdf

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/site-packages/linopy/model.py:22
     20 from linopy import solvers
     21 from linopy.common import best_int, replace_by_map
---> 22 from linopy.constraints import (
     23     AnonymousConstraint,
     24     AnonymousScalarConstraint,
     25     Constraints,
     26 )
     27 from linopy.eval import Expr
     28 from linopy.expressions import LinearExpression, ScalarLinearExpression

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/site-packages/linopy/constraints.py:21
     18 from scipy.sparse import coo_matrix
     19 from xarray import DataArray, Dataset
---> 21 from linopy import expressions, variables
     22 from linopy.common import (
     23     _merge_inplace,
     24     has_assigned_model,
   (...)
     27     replace_by_map,
     28 )
     31 class Constraint(DataArray):

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/site-packages/linopy/expressions.py:23
     20 from xarray.core.dataarray import DataArrayCoordinates
     21 from xarray.core.groupby import _maybe_reorder, peek_at
---> 23 from linopy import constraints, variables
     24 from linopy.common import as_dataarray
     27 def exprwrap(method, *default_args, **new_default_kwargs):

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/site-packages/linopy/variables.py:398
    393     roll = varwrap(DataArray.roll)
    395     rolling = varwrap(DataArray.rolling)
--> 398 @dataclass(repr=False)
    399 class Variables:
    400     """
    401     A variables container used for storing multiple variable arrays.
    402     """
    404     labels: Dataset = Dataset()

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/dataclasses.py:1211, in dataclass.<locals>.wrap(cls)
   1210 def wrap(cls):
-> 1211     return _process_class(cls, init, repr, eq, order, unsafe_hash,
   1212                           frozen, match_args, kw_only, slots,
   1213                           weakref_slot)

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/dataclasses.py:959, in _process_class(cls, init, repr, eq, order, unsafe_hash, frozen, match_args, kw_only, slots, weakref_slot)
    956         kw_only = True
    957     else:
    958         # Otherwise it's a field of some type.
--> 959         cls_fields.append(_get_field(cls, name, type, kw_only))
    961 for f in cls_fields:
    962     fields[f.name] = f

File ~/checkouts/readthedocs.org/user_builds/pypsa/conda/v0.21.2/lib/python3.11/dataclasses.py:816, in _get_field(cls, a_name, a_type, default_kw_only)
    812 # For real fields, disallow mutable defaults.  Use unhashable as a proxy
    813 # indicator for mutability.  Read the __hash__ attribute from the class,
    814 # not the instance.
    815 if f._field_type is _FIELD and f.default.__class__.__hash__ is None:
--> 816     raise ValueError(f'mutable default {type(f.default)} for field '
    817                      f'{f.name} is not allowed: use default_factory')
    819 return f

ValueError: mutable default <class 'xarray.core.dataset.Dataset'> for field labels is not allowed: use default_factory

First tell PyPSA that links will have a 2nd bus by overriding the component_attrs. This is needed so that water can both go through a turbine AND feed the next reservoir

[2]:
override_component_attrs = pypsa.descriptors.Dict(
    {k: v.copy() for k, v in pypsa.components.component_attrs.items()}
)
override_component_attrs["Link"].loc["bus2"] = [
    "string",
    np.nan,
    np.nan,
    "2nd bus",
    "Input (optional)",
]
override_component_attrs["Link"].loc["efficiency2"] = [
    "static or series",
    "per unit",
    1.0,
    "2nd bus efficiency",
    "Input (optional)",
]
override_component_attrs["Link"].loc["p2"] = [
    "series",
    "MW",
    0.0,
    "2nd bus output",
    "Output",
]
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [2], line 1
----> 1 override_component_attrs = pypsa.descriptors.Dict(
      2     {k: v.copy() for k, v in pypsa.components.component_attrs.items()}
      3 )
      4 override_component_attrs["Link"].loc["bus2"] = [
      5     "string",
      6     np.nan,
   (...)
      9     "Input (optional)",
     10 ]
     11 override_component_attrs["Link"].loc["efficiency2"] = [
     12     "static or series",
     13     "per unit",
   (...)
     16     "Input (optional)",
     17 ]

NameError: name 'pypsa' is not defined
[3]:
network = pypsa.Network(override_component_attrs=override_component_attrs)
network.set_snapshots(pd.date_range("2016-01-01 00:00", "2016-01-01 03:00", freq="H"))
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [3], line 1
----> 1 network = pypsa.Network(override_component_attrs=override_component_attrs)
      2 network.set_snapshots(pd.date_range("2016-01-01 00:00", "2016-01-01 03:00", freq="H"))

NameError: name 'pypsa' is not defined

Add assets to the network.

[4]:
network.add("Carrier", "reservoir")
network.add("Carrier", "rain")

network.add("Bus", "0", carrier="AC")
network.add("Bus", "1", carrier="AC")

network.add("Bus", "0 reservoir", carrier="reservoir")
network.add("Bus", "1 reservoir", carrier="reservoir")


network.add(
    "Generator",
    "rain",
    bus="0 reservoir",
    carrier="rain",
    p_nom=1000,
    p_max_pu=[0.0, 0.2, 0.7, 0.4],
)


network.add("Load", "0 load", bus="0", p_set=20.0)

network.add("Load", "1 load", bus="1", p_set=30.0)
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [4], line 1
----> 1 network.add("Carrier", "reservoir")
      2 network.add("Carrier", "rain")
      4 network.add("Bus", "0", carrier="AC")

NameError: name 'network' is not defined

The efficiency of a river is the relation between the gravitational potential energy of 1 m^3 of water in reservoir 0 relative to its turbine versus the potential energy of 1 m^3 of water in reservoir 1 relative to its turbine

[5]:
network.add(
    "Link",
    "spillage",
    bus0="0 reservoir",
    bus1="1 reservoir",
    efficiency=0.5,
    p_nom_extendable=True,
)


# water from turbine also goes into next reservoir
network.add(
    "Link",
    "0 turbine",
    bus0="0 reservoir",
    bus1="0",
    bus2="1 reservoir",
    efficiency=0.9,
    efficiency2=0.5,
    capital_cost=1000,
    p_nom_extendable=True,
)

network.add(
    "Link",
    "1 turbine",
    bus0="1 reservoir",
    bus1="1",
    efficiency=0.9,
    capital_cost=1000,
    p_nom_extendable=True,
)


network.add(
    "Store", "0 reservoir", bus="0 reservoir", e_cyclic=True, e_nom_extendable=True
)

network.add(
    "Store", "1 reservoir", bus="1 reservoir", e_cyclic=True, e_nom_extendable=True
)
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [5], line 1
----> 1 network.add(
      2     "Link",
      3     "spillage",
      4     bus0="0 reservoir",
      5     bus1="1 reservoir",
      6     efficiency=0.5,
      7     p_nom_extendable=True,
      8 )
     11 # water from turbine also goes into next reservoir
     12 network.add(
     13     "Link",
     14     "0 turbine",
   (...)
     21     p_nom_extendable=True,
     22 )

NameError: name 'network' is not defined
[6]:
network.lopf(network.snapshots)
print("Objective:", network.objective)
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [6], line 1
----> 1 network.lopf(network.snapshots)
      2 print("Objective:", network.objective)

NameError: name 'network' is not defined
[7]:
network.generators_t.p.plot.area(figsize=(9, 4))
plt.tight_layout()
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [7], line 1
----> 1 network.generators_t.p.plot.area(figsize=(9, 4))
      2 plt.tight_layout()

NameError: name 'network' is not defined

Now, let’s have look at the different outputs of the links.

[8]:
network.links_t.p0.plot(figsize=(9, 4), lw=3)
plt.tight_layout()
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [8], line 1
----> 1 network.links_t.p0.plot(figsize=(9, 4), lw=3)
      2 plt.tight_layout()

NameError: name 'network' is not defined
[9]:
network.links_t.p1.plot(figsize=(9, 4), lw=3)
plt.tight_layout()
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [9], line 1
----> 1 network.links_t.p1.plot(figsize=(9, 4), lw=3)
      2 plt.tight_layout()

NameError: name 'network' is not defined
[10]:
network.links_t.p2.plot(figsize=(9, 4), lw=3)
plt.tight_layout()
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [10], line 1
----> 1 network.links_t.p2.plot(figsize=(9, 4), lw=3)
      2 plt.tight_layout()

NameError: name 'network' is not defined

What are the energy outputs and energy levels at the reservoirs?

[11]:
pd.DataFrame({attr: network.stores_t[attr]["0 reservoir"] for attr in ["p", "e"]})
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [11], line 1
----> 1 pd.DataFrame({attr: network.stores_t[attr]["0 reservoir"] for attr in ["p", "e"]})

NameError: name 'pd' is not defined
[12]:
pd.DataFrame({attr: network.stores_t[attr]["1 reservoir"] for attr in ["p", "e"]})
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In [12], line 1
----> 1 pd.DataFrame({attr: network.stores_t[attr]["1 reservoir"] for attr in ["p", "e"]})

NameError: name 'pd' is not defined