Natural Gas Updates

workflow/repo_data/config/config.sector.yaml

@@ -3,11 +3,12 @@ sector:
     sequestration_potential: 0
     policy: "config/policy_constraints/sector_co2_limits.csv"
   natural_gas:
-    allow_imports_exports: true # false to be implemented
-    cyclic_storage: false
+    force_imports_exports: true 
+    cyclic_storage: true
+    standing_loss: 0
   methane:
-    leakage_rate: 2 # percent # to be implemented 
-    gwp: 18 # to be implemented 
+    leakage_rate: 0.02 # per unit 
+    gwp: 18 
   heating:
     heat_pump_sink_T: 55.
   service_sector:

workflow/scripts/add_sectors.py

@@ -18,7 +18,7 @@
 
 from _helpers import configure_logging, get_snapshots, load_costs
 from add_electricity import sanitize_carriers
-from build_co2_tracking import build_co2_tracking
+from build_emission_tracking import build_ch4_tracking, build_co2_tracking
 from build_heat import build_heat
 from build_natural_gas import StateGeometry, build_natural_gas
 from build_stock_data import (
@@ -385,6 +385,8 @@ def get_pwr_co2_intensity(carrier: str, costs: pd.DataFrame) -> float:
         co2_intensity = get_pwr_co2_intensity(carrier, costs)
         convert_generators_2_links(n, carrier, f" gas", co2_intensity)
 
+    ng_options = snakemake.params.sector["natural_gas"]
+
     # add natural gas infrastructure and data
     build_natural_gas(
         n=n,
@@ -394,8 +396,17 @@ def get_pwr_co2_intensity(carrier: str, costs: pd.DataFrame) -> float:
         county_path=snakemake.input.county,
         pipelines_path=snakemake.input.pipeline_capacity,
         pipeline_shape_path=snakemake.input.pipeline_shape,
+        options=ng_options,
     )
 
+    # add methane tracking - if leakage rate is included
+    # this must happen after natural gas system is built
+    methane_options = snakemake.params.sector["methane"]
+    leakage_rate = methane_options.get("leakage_rate", 0)
+    if leakage_rate > 0.000001:
+        gwp = methane_options.get("gwp", 1)
+        build_ch4_tracking(n, gwp, leakage_rate)
+
     pop_layout_path = snakemake.input.clustered_pop_layout
     cop_ashp_path = snakemake.input.cop_air_total
     cop_gshp_path = snakemake.input.cop_soil_total

workflow/scripts/build_emission_tracking.py

@@ -0,0 +1,179 @@
+"""
+Module for building state and sector level co2 tracking.
+"""
+
+import itertools
+import logging
+from typing import Any, Optional
+
+import numpy as np
+import pandas as pd
+import pypsa
+
+logger = logging.getLogger(__name__)
+
+
+def build_co2_tracking(
+    n: pypsa.Network,
+    config: Optional[dict[str, Any]] = None,
+) -> None:
+    """
+    Main funtion to interface with.
+    """
+
+    states = n.buses.STATE.unique()
+
+    sectors = ["pwr", "trn", "res", "com", "ind"]
+
+    if not config:
+        config = {}
+
+    if "co2" not in n.carriers:
+        _add_co2_carrier(n, config)
+
+    _build_co2_bus(n, states, sectors)
+    _build_co2_store(n, states, sectors)
+
+
+def build_ch4_tracking(
+    n: pypsa.Network,
+    gwp: float,
+    leakage_rate: float,
+    config: Optional[dict[str, Any]] = None,
+) -> None:
+    """
+    Builds CH4 tracking.
+
+    Natural gas network must already be constructed
+    """
+
+    states = [x for x in n.buses.STATE.dropna().unique() if x != np.nan]
+
+    if not config:
+        config = {}
+
+    if "ch4" not in n.carriers:
+        _add_ch4_carrier(n, config)
+
+    _build_ch4_bus(n, states)
+    _build_ch4_store(n, states)
+    _build_ch4_links(n, states, gwp, leakage_rate)
+
+
+def _add_co2_carrier(n, config: dict[Any]):
+    try:
+        nice_name = config["plotting"]["nice_names"]["co2"]
+    except KeyError:
+        nice_name = "CO2"
+    try:
+        color = config["plotting"]["tech_colors"]["co2"]
+    except KeyError:
+        color = "#000000"  # black
+
+    n.add("Carrier", "co2", nice_name=nice_name, color=color)
+
+
+def _build_co2_bus(n: pypsa.Network, states: list[str], sectors: list[str]):
+    """
+    Builds state level co2 bus per sector.
+    """
+
+    df = pd.DataFrame(itertools.product(states, sectors), columns=["state", "sector"])
+    df.index = df.state + " " + df.sector
+
+    n.madd("Bus", df.index, suffix="-co2", carrier="co2", STATE=df.state)
+
+
+def _build_co2_store(n: pypsa.Network, states: list[str], sectors: list[str]):
+    """
+    Builds state level co2 stores per sector.
+    """
+
+    df = pd.DataFrame(itertools.product(states, sectors), columns=["state", "sector"])
+    df.index = df.state + " " + df.sector
+
+    n.madd(
+        "Store",
+        df.index,
+        suffix="-co2",
+        bus=df.index + "-co2",
+        e_nom_extendable=False,
+        marginal_cost=0,
+        e_nom=np.inf,
+        e_initial=0,
+        e_cyclic=False,
+        e_cyclic_per_period=False,
+        standing_loss=0,
+        e_min_pu=0,
+        e_max_pu=1,
+        carrier="co2",
+    )
+
+
+def _add_ch4_carrier(n, config: dict[Any]):
+    try:
+        nice_name = config["plotting"]["nice_names"]["ch4"]
+    except KeyError:
+        nice_name = "CH4"
+    try:
+        color = config["plotting"]["tech_colors"]["co2"]
+    except KeyError:
+        color = "#000000"  # black
+
+    n.add("Carrier", "ch4", nice_name=nice_name, color=color)
+
+
+def _build_ch4_bus(n: pypsa.Network, states: list[str]):
+    """
+    Builds state level co2 bus per sector.
+    """
+
+    df = pd.DataFrame(states, columns=["state"])
+    df.index = df.state
+
+    n.madd("Bus", df.index, suffix=" gas-ch4", carrier="ch4", STATE=df.state)
+
+
+def _build_ch4_store(n: pypsa.Network, states: list[str]):
+    """
+    Builds state level co2 stores per sector.
+    """
+
+    df = pd.DataFrame(states, columns=["state"])
+    df.index = df.state
+
+    n.madd(
+        "Store",
+        df.index,
+        suffix=" gas-ch4",
+        bus=df.index + " gas-ch4",
+        e_nom_extendable=False,
+        marginal_cost=0,
+        e_nom=np.inf,
+        e_initial=0,
+        e_cyclic=False,
+        e_cyclic_per_period=False,
+        standing_loss=0,
+        e_min_pu=0,
+        e_max_pu=1,
+        carrier="ch4",
+    )
+
+
+def _build_ch4_links(n, states: list[str], gwp: float, leakage_rate: float):
+    """
+    Modifies existing gas production links.
+    """
+
+    # first extract out exising gas production links
+
+    gas_production = [f"{x} gas production" for x in states]
+    links = n.links[n.links.index.isin(gas_production)].index
+
+    # calculate co2e value per unit injected to the ng system
+    emissions = gwp * leakage_rate
+
+    # append the connection to methane stores
+
+    n.links.loc[links, "bus2"] = n.links.loc[links,].bus1 + "-ch4"  # 'CA gas-ch4'
+    n.links.loc[links, "efficency2"] = emissions