test_lopf_multilink.py

# -*- coding: utf-8 -*-
import numpy as np
import pytest
from conftest import SUPPORTED_APIS, optimize

import pypsa


@pytest.fixture
def network():
    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["bus3"] = [
        "string",
        np.nan,
        np.nan,
        "3rd 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["efficiency3"] = [
        "static or series",
        "per unit",
        1.0,
        "3rd bus efficiency",
        "Input (optional)",
    ]
    override_component_attrs["Link"].loc["p2"] = [
        "series",
        "MW",
        0.0,
        "2nd bus output",
        "Output",
    ]
    override_component_attrs["Link"].loc["p3"] = [
        "series",
        "MW",
        0.0,
        "3rd bus output",
        "Output",
    ]

    n = pypsa.Network(override_component_attrs=override_component_attrs)
    n.set_snapshots(range(10))

    n.add("Bus", "bus")
    n.add("Load", "load", bus="bus", p_set=1.0)

    n.add("Bus", "transport")
    n.add("Load", "transport", bus="transport", p_set=1.0)

    n.add("Bus", "diesel")

    n.add("Store", "diesel", bus="diesel", e_cyclic=True, e_nom=1000.0)

    n.add("Bus", "hydrogen")

    n.add("Store", "hydrogen", bus="hydrogen", e_cyclic=True, e_nom=1000.0)

    n.add(
        "Link", "electrolysis", p_nom=2.0, efficiency=0.8, bus0="bus", bus1="hydrogen"
    )

    n.add(
        "Link",
        "FT",
        p_nom=4,
        bus0="hydrogen",
        bus1="diesel",
        bus2="co2 stored",
        efficiency=1.0,
        efficiency2=-1,
    )

    # minus sign because opposite to how fossil fuels used:
    # CH4 burning puts CH4 down, atmosphere up
    n.add("Carrier", "co2", co2_emissions=-1.0)

    # this tracks CO2 in the atmosphere
    n.add("Bus", "co2 atmosphere", carrier="co2")

    # NB: can also be negative
    n.add("Store", "co2 atmosphere", e_nom=1000, e_min_pu=-1, bus="co2 atmosphere")

    # this tracks CO2 stored, e.g. underground
    n.add("Bus", "co2 stored")

    # NB: can also be negative
    n.add("Store", "co2 stored", e_nom=1000, e_min_pu=-1, bus="co2 stored")

    n.add(
        "Link",
        "DAC",
        bus0="bus",
        bus1="co2 stored",
        bus2="co2 atmosphere",
        efficiency=1,
        efficiency2=-1,
        p_nom=5.0,
    )

    n.add(
        "Link",
        "diesel car",
        bus0="diesel",
        bus1="transport",
        bus2="co2 atmosphere",
        efficiency=1.0,
        efficiency2=1.0,
        p_nom=2.0,
    )

    n.add("Bus", "gas")

    n.add("Store", "gas", e_initial=50, e_nom=50, marginal_cost=20, bus="gas")

    n.add(
        "Link",
        "OCGT",
        bus0="gas",
        bus1="bus",
        bus2="co2 atmosphere",
        p_nom_extendable=True,
        efficiency=0.5,
        efficiency2=1,
    )

    n.add(
        "Link",
        "OCGT+CCS",
        bus0="gas",
        bus1="bus",
        bus2="co2 stored",
        bus3="co2 atmosphere",
        p_nom_extendable=True,
        efficiency=0.4,
        efficiency2=0.9,
        efficiency3=0.1,
    )

    # Add a cheap and a expensive biomass generator.
    biomass_marginal_cost = [20.0, 50.0]
    biomass_stored = [40.0, 15.0]

    for i in range(2):
        n.add("Bus", "biomass" + str(i))

        n.add(
            "Store",
            "biomass" + str(i),
            bus="biomass" + str(i),
            e_nom_extendable=True,
            marginal_cost=biomass_marginal_cost[i],
            e_nom=biomass_stored[i],
            e_initial=biomass_stored[i],
        )

        # simultaneously empties and refills co2 atmosphere
        n.add(
            "Link",
            "biomass" + str(i),
            bus0="biomass" + str(i),
            bus1="bus",
            p_nom_extendable=True,
            efficiency=0.5,
        )

        n.add(
            "Link",
            "biomass+CCS" + str(i),
            bus0="biomass" + str(i),
            bus1="bus",
            bus2="co2 stored",
            bus3="co2 atmosphere",
            p_nom_extendable=True,
            efficiency=0.4,
            efficiency2=1.0,
            efficiency3=-1,
        )

    # can go to -50, but at some point can't generate enough electricity for DAC and demand
    target = -50
    n.add(
        "GlobalConstraint",
        "co2_limit",
        sense="<=",
        carrier_attribute="co2_emissions",
        constant=target,
    )
    return n


@pytest.mark.parametrize("api", SUPPORTED_APIS)
def test_lopf(network, api):
    status, condition = optimize(network, api)
    assert status == "ok"