Note

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

Multi-Link usage: CHP with fixed heat-power ratio#

This notebook if a demonstration of Link with multiple outputs: Combined-Heat-and-Power (CHP) with fixed heat-power ratio

For a CHP with a more complicated heat-power feasible operational area, see the power-to-gas example

This example demonstrates a Link component with more than one bus output (“bus2” in this case). In general links can have many output buses.

In this example a CHP must be heat-following because there is no other supply of heat to the bus “Frankfurt heat”.

[1]:

import pypsa

[2]:

network = pypsa.Network()

network.add("Bus", "Frankfurt", carrier="AC")
network.add("Load", "Frankfurt", bus="Frankfurt", p_set=5)


network.add("Bus", "Frankfurt heat", carrier="heat")
network.add("Load", "Frankfurt heat", bus="Frankfurt heat", p_set=3)


network.add("Bus", "Frankfurt gas", carrier="gas")
network.add("Store", "Frankfurt gas", e_initial=1e6, e_nom=1e6, bus="Frankfurt gas")

network.add(
    "Link",
    "OCGT",
    bus0="Frankfurt gas",
    bus1="Frankfurt",
    p_nom_extendable=True,
    capital_cost=600,
    efficiency=0.4,
)


network.add(
    "Link",
    "CHP",
    bus0="Frankfurt gas",
    bus1="Frankfurt",
    bus2="Frankfurt heat",
    p_nom_extendable=True,
    capital_cost=1400,
    efficiency=0.3,
    efficiency2=0.3,
)

[2]:

Index(['CHP'], dtype='object')

[3]:

network.optimize();

WARNING:pypsa.consistency:The following buses have carriers which are not defined:
Index(['Frankfurt', 'Frankfurt heat', 'Frankfurt gas'], dtype='object', name='Bus')
WARNING:pypsa.consistency:The following links have carriers which are not defined:
Index(['OCGT', 'CHP'], dtype='object', name='Link')
WARNING:pypsa.consistency:Encountered nan's in static data for columns ['efficiency2'] of component 'Link'.
WARNING:pypsa.consistency:The following stores have carriers which are not defined:
Index(['Frankfurt gas'], dtype='object', name='Store')
WARNING:pypsa.consistency:The following buses have carriers which are not defined:
Index(['Frankfurt', 'Frankfurt heat', 'Frankfurt gas'], dtype='object', name='Bus')
WARNING:pypsa.consistency:The following links have carriers which are not defined:
Index(['OCGT', 'CHP'], dtype='object', name='Link')
WARNING:pypsa.consistency:Encountered nan's in static data for columns ['efficiency2'] of component 'Link'.
WARNING:pypsa.consistency:The following stores have carriers which are not defined:
Index(['Frankfurt gas'], dtype='object', name='Store')
INFO:linopy.model: Solve problem using Highs solver
INFO:linopy.io: Writing time: 0.04s
INFO:linopy.solvers:Log file at /tmp/highs.log
INFO:linopy.constants: Optimization successful:
Status: ok
Termination condition: optimal
Solution: 6 primals, 12 duals
Objective: 1.70e+04
Solver model: available
Solver message: optimal

INFO:pypsa.optimization.optimize:The shadow-prices of the constraints Link-ext-p-lower, Link-ext-p-upper, Store-fix-e-lower, Store-fix-e-upper, Store-energy_balance were not assigned to the network.

Running HiGHS 1.7.2 (git hash: 184e327): Copyright (c) 2024 HiGHS under MIT licence terms
Coefficient ranges:
  Matrix [3e-01, 1e+00]
  Cost   [6e+02, 1e+03]
  Bound  [0e+00, 0e+00]
  RHS    [3e+00, 1e+06]
Presolving model
0 rows, 0 cols, 0 nonzeros  0s
0 rows, 0 cols, 0 nonzeros  0s
Presolve : Reductions: rows 0(-12); columns 0(-6); elements 0(-18) - Reduced to empty
Solving the original LP from the solution after postsolve
Model   status      : Optimal
Objective value     :  1.7000000000e+04
HiGHS run time      :          0.00
Writing the solution to /tmp/linopy-solve-f6ybo1il.sol

[4]:

network.loads_t.p

[4]:

Load	Frankfurt	Frankfurt heat
snapshot
now	5.0	3.0

[5]:

network.links_t.p0

[5]:

Link	OCGT	CHP
snapshot
now	5.0	10.0

[6]:

network.links_t.p1

[6]:

Link	OCGT	CHP
snapshot
now	-2.0	-3.0

[7]:

network.links_t.p2

[7]:

Link	OCGT	CHP
snapshot
now	0.0	-3.0