diff --git a/scripts/_helpers.py b/scripts/_helpers.py
index 67b20877..d84f025b 100644
--- a/scripts/_helpers.py
+++ b/scripts/_helpers.py
@@ -360,8 +360,24 @@ def generate_periodic_profiles(dt_index, nodes, weekly_profile, localize=None):
     return week_df
 
 
-def parse(l):
-    return yaml.safe_load(l[0]) if len(l) == 1 else {l.pop(0): parse(l)}
+def parse(infix):
+    """
+    Recursively parse a list into a dictionary or a YAML object.
+
+    Parameters
+    ----------
+    list_to_parse : list
+        The list to parse.
+
+    Returns
+    -------
+    dict or YAML object
+        The parsed list.
+    """
+    if len(infix) == 1:
+        return yaml.safe_load(infix[0])
+    else:
+        return {infix[0]: parse(infix[1:])}
 
 
 def update_config_with_sector_opts(config, sector_opts):
@@ -369,8 +385,8 @@ def update_config_with_sector_opts(config, sector_opts):
 
     for o in sector_opts.split("-"):
         if o.startswith("CF+"):
-            l = o.split("+")[1:]
-            update_config(config, parse(l))
+            infix = o.split("+")[1:]
+            update_config(config, parse(infix))
 
 
 def get_checksum_from_zenodo(file_url):
diff --git a/scripts/add_electricity.py b/scripts/add_electricity.py
index e626f456..c9e5abca 100755
--- a/scripts/add_electricity.py
+++ b/scripts/add_electricity.py
@@ -294,10 +294,10 @@ def attach_load(n, regions, load, nuts3_shapes, ua_md_gdp, countries, scaling=1.
     nuts3 = gpd.read_file(nuts3_shapes).set_index("index")
 
     def upsample(cntry, group):
-        l = opsd_load[cntry]
+        load = opsd_load[cntry]
 
         if len(group) == 1:
-            return pd.DataFrame({group.index[0]: l})
+            return pd.DataFrame({group.index[0]: load})
         nuts3_cntry = nuts3.loc[nuts3.country == cntry]
         transfer = shapes_to_shapes(group, nuts3_cntry.geometry).T.tocsr()
         gdp_n = pd.Series(
@@ -314,8 +314,8 @@ def attach_load(n, regions, load, nuts3_shapes, ua_md_gdp, countries, scaling=1.
             # overwrite factor because nuts3 provides no data for UA+MD
             factors = normed(ua_md_gdp.loc[group.index, "GDP_PPP"].squeeze())
         return pd.DataFrame(
-            factors.values * l.values[:, np.newaxis],
-            index=l.index,
+            factors.values * load.values[:, np.newaxis],
+            index=load.index,
             columns=factors.index,
         )
 
@@ -622,7 +622,7 @@ def attach_hydro(n, costs, ppl, profile_hydro, hydro_capacities, carriers, **par
             hydro.max_hours > 0, hydro.country.map(max_hours_country)
         ).fillna(6)
 
-        if flatten_dispatch := params.get("flatten_dispatch", False):
+        if params.get("flatten_dispatch", False):
             buffer = params.get("flatten_dispatch_buffer", 0.2)
             average_capacity_factor = inflow_t[hydro.index].mean() / hydro["p_nom"]
             p_max_pu = (average_capacity_factor + buffer).clip(upper=1)
diff --git a/scripts/build_biomass_transport_costs.py b/scripts/build_biomass_transport_costs.py
index 9271b600..05b64519 100644
--- a/scripts/build_biomass_transport_costs.py
+++ b/scripts/build_biomass_transport_costs.py
@@ -80,4 +80,9 @@ def build_biomass_transport_costs():
 
 
 if __name__ == "__main__":
+    if "snakemake" not in globals():
+        from _helpers import mock_snakemake
+
+        snakemake = mock_snakemake("build_biomass_transport_costs")
+
     build_biomass_transport_costs()
diff --git a/scripts/build_clustered_population_layouts.py b/scripts/build_clustered_population_layouts.py
index 2f237656..f1d386bd 100644
--- a/scripts/build_clustered_population_layouts.py
+++ b/scripts/build_clustered_population_layouts.py
@@ -28,7 +28,7 @@ if __name__ == "__main__":
         gpd.read_file(snakemake.input.regions_onshore).set_index("name").buffer(0)
     )
 
-    I = cutout.indicatormatrix(clustered_regions)
+    I = cutout.indicatormatrix(clustered_regions)  # noqa: E741
 
     pop = {}
     for item in ["total", "urban", "rural"]:
diff --git a/scripts/build_gas_input_locations.py b/scripts/build_gas_input_locations.py
index 0c9e4c4b..d8727063 100644
--- a/scripts/build_gas_input_locations.py
+++ b/scripts/build_gas_input_locations.py
@@ -27,8 +27,11 @@ def build_gem_lng_data(fn):
     df = pd.read_excel(fn[0], sheet_name="LNG terminals - data")
     df = df.set_index("ComboID")
 
-    remove_country = ["Cyprus", "Turkey"]
-    remove_terminal = ["Puerto de la Luz LNG Terminal", "Gran Canaria LNG Terminal"]
+    remove_country = ["Cyprus", "Turkey"]  # noqa: F841
+    remove_terminal = [
+        "Puerto de la Luz LNG Terminal",
+        "Gran Canaria LNG Terminal",
+    ]  # noqa: F841
 
     df = df.query(
         "Status != 'Cancelled' \
@@ -45,8 +48,8 @@ def build_gem_prod_data(fn):
     df = pd.read_excel(fn[0], sheet_name="Gas extraction - main")
     df = df.set_index("GEM Unit ID")
 
-    remove_country = ["Cyprus", "Türkiye"]
-    remove_fuel_type = ["oil"]
+    remove_country = ["Cyprus", "Türkiye"]  # noqa: F841
+    remove_fuel_type = ["oil"]  # noqa: F841
 
     df = df.query(
         "Status != 'shut in' \
@@ -96,8 +99,8 @@ def build_gas_input_locations(gem_fn, entry_fn, sto_fn, countries):
     ]
 
     sto = read_scigrid_gas(sto_fn)
-    remove_country = ["RU", "UA", "TR", "BY"]
-    sto = sto.query("country_code != @remove_country")
+    remove_country = ["RU", "UA", "TR", "BY"]  # noqa: F841
+    sto = sto.query("country_code not in @remove_country")
 
     # production sites inside the model scope
     prod = build_gem_prod_data(gem_fn)
diff --git a/scripts/build_heat_demand.py b/scripts/build_heat_demand.py
index 77768404..b983f125 100644
--- a/scripts/build_heat_demand.py
+++ b/scripts/build_heat_demand.py
@@ -34,7 +34,7 @@ if __name__ == "__main__":
         gpd.read_file(snakemake.input.regions_onshore).set_index("name").buffer(0)
     )
 
-    I = cutout.indicatormatrix(clustered_regions)
+    I = cutout.indicatormatrix(clustered_regions)  # noqa: E741
 
     pop_layout = xr.open_dataarray(snakemake.input.pop_layout)
 
diff --git a/scripts/build_industrial_distribution_key.py b/scripts/build_industrial_distribution_key.py
index 08de3bae..fe7cf0c1 100644
--- a/scripts/build_industrial_distribution_key.py
+++ b/scripts/build_industrial_distribution_key.py
@@ -30,7 +30,7 @@ def locate_missing_industrial_sites(df):
     try:
         from geopy.extra.rate_limiter import RateLimiter
         from geopy.geocoders import Nominatim
-    except:
+    except ImportError:
         raise ModuleNotFoundError(
             "Optional dependency 'geopy' not found."
             "Install via 'conda install -c conda-forge geopy'"
@@ -99,7 +99,7 @@ def prepare_hotmaps_database(regions):
         # get all duplicated entries
         duplicated_i = gdf.index[gdf.index.duplicated()]
         # convert from raw data country name to iso-2-code
-        code = cc.convert(gdf.loc[duplicated_i, "Country"], to="iso2")
+        code = cc.convert(gdf.loc[duplicated_i, "Country"], to="iso2")  # noqa: F841
         # screen out malformed country allocation
         gdf_filtered = gdf.loc[duplicated_i].query("country == @code")
         # concat not duplicated and filtered gdf
diff --git a/scripts/build_line_rating.py b/scripts/build_line_rating.py
index 4d45b910..5b4cd6b3 100755
--- a/scripts/build_line_rating.py
+++ b/scripts/build_line_rating.py
@@ -98,7 +98,7 @@ def calculate_line_rating(n, cutout):
     -------
     xarray DataArray object with maximal power.
     """
-    relevant_lines = n.lines[(n.lines["underground"] == False)]
+    relevant_lines = n.lines[~n.lines["underground"]]
     buses = relevant_lines[["bus0", "bus1"]].values
     x = n.buses.x
     y = n.buses.y
diff --git a/scripts/build_population_layouts.py b/scripts/build_population_layouts.py
index 3e2b77d4..e215e6c0 100644
--- a/scripts/build_population_layouts.py
+++ b/scripts/build_population_layouts.py
@@ -33,7 +33,7 @@ if __name__ == "__main__":
     nuts3 = gpd.read_file(snakemake.input.nuts3_shapes).set_index("index")
 
     # Indicator matrix NUTS3 -> grid cells
-    I = atlite.cutout.compute_indicatormatrix(nuts3.geometry, grid_cells)
+    I = atlite.cutout.compute_indicatormatrix(nuts3.geometry, grid_cells)  # noqa: E741
 
     # Indicator matrix grid_cells -> NUTS3; inprinciple Iinv*I is identity
     # but imprecisions mean not perfect
diff --git a/scripts/build_retro_cost.py b/scripts/build_retro_cost.py
index d2aae140..67440263 100755
--- a/scripts/build_retro_cost.py
+++ b/scripts/build_retro_cost.py
@@ -554,7 +554,7 @@ def prepare_temperature_data():
 
 
 # windows ---------------------------------------------------------------
-def window_limit(l, window_assumptions):
+def window_limit(l, window_assumptions):  # noqa: E741
     """
     Define limit u value from which on window is retrofitted.
     """
@@ -567,7 +567,7 @@ def window_limit(l, window_assumptions):
     return m * l + a
 
 
-def u_retro_window(l, window_assumptions):
+def u_retro_window(l, window_assumptions):  # noqa: E741
     """
     Define retrofitting value depending on renovation strength.
     """
@@ -580,7 +580,7 @@ def u_retro_window(l, window_assumptions):
     return max(m * l + a, 0.8)
 
 
-def window_cost(u, cost_retro, window_assumptions):
+def window_cost(u, cost_retro, window_assumptions):  # noqa: E741
     """
     Get costs for new windows depending on u value.
     """
@@ -600,7 +600,7 @@ def window_cost(u, cost_retro, window_assumptions):
     return window_cost
 
 
-def calculate_costs(u_values, l, cost_retro, window_assumptions):
+def calculate_costs(u_values, l, cost_retro, window_assumptions):  # noqa: E741
     """
     Returns costs for a given retrofitting strength weighted by the average
     surface/volume ratio of the component for each building type.
@@ -626,7 +626,7 @@ def calculate_costs(u_values, l, cost_retro, window_assumptions):
     )
 
 
-def calculate_new_u(u_values, l, l_weight, window_assumptions, k=0.035):
+def calculate_new_u(u_values, l, l_weight, window_assumptions, k=0.035):  # noqa: E741
     """
     Calculate U-values after building retrofitting, depending on the old
     U-values (u_values). This is for simple insulation measuers, adding an
@@ -746,7 +746,7 @@ def calculate_heat_losses(u_values, data_tabula, l_strength, temperature_factor)
     """
     #  (1) by transmission
     # calculate new U values of building elements due to additional insulation
-    for l in l_strength:
+    for l in l_strength:  # noqa: E741
         u_values[f"new_U_{l}"] = calculate_new_u(
             u_values, l, l_weight, window_assumptions
         )
diff --git a/scripts/build_temperature_profiles.py b/scripts/build_temperature_profiles.py
index a13ec3c2..02fa4a71 100644
--- a/scripts/build_temperature_profiles.py
+++ b/scripts/build_temperature_profiles.py
@@ -34,7 +34,7 @@ if __name__ == "__main__":
         gpd.read_file(snakemake.input.regions_onshore).set_index("name").buffer(0)
     )
 
-    I = cutout.indicatormatrix(clustered_regions)
+    I = cutout.indicatormatrix(clustered_regions)  # noqa: E741
 
     pop_layout = xr.open_dataarray(snakemake.input.pop_layout)
 
diff --git a/scripts/cluster_network.py b/scripts/cluster_network.py
index 28f08396..01af29aa 100644
--- a/scripts/cluster_network.py
+++ b/scripts/cluster_network.py
@@ -133,6 +133,7 @@ import pyomo.environ as po
 import pypsa
 import seaborn as sns
 from _helpers import configure_logging, update_p_nom_max
+from add_electricity import load_costs
 from pypsa.clustering.spatial import (
     busmap_by_greedy_modularity,
     busmap_by_hac,
@@ -141,11 +142,7 @@ from pypsa.clustering.spatial import (
 )
 
 warnings.filterwarnings(action="ignore", category=UserWarning)
-
-from add_electricity import load_costs
-
 idx = pd.IndexSlice
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/scripts/make_summary.py b/scripts/make_summary.py
index 7f08b678..0fab5367 100644
--- a/scripts/make_summary.py
+++ b/scripts/make_summary.py
@@ -506,10 +506,6 @@ def calculate_weighted_prices(n, label, weighted_prices):
 
         if carrier in ["H2", "gas"]:
             load = pd.DataFrame(index=n.snapshots, columns=buses, data=0.0)
-        elif carrier[:5] == "space":
-            load = heat_demand_df[buses.str[:2]].rename(
-                columns=lambda i: str(i) + suffix
-            )
         else:
             load = n.loads_t.p_set[buses]
 
diff --git a/scripts/plot_network.py b/scripts/plot_network.py
index d8c17587..6a3783e7 100644
--- a/scripts/plot_network.py
+++ b/scripts/plot_network.py
@@ -895,8 +895,7 @@ def plot_series(network, carrier="AC", name="test"):
     fig.tight_layout()
 
     fig.savefig(
-        "{}/{RDIR}maps/series-{}-{}-{}-{}-{}.pdf".format(
-            "results",
+        "results/{}maps/series-{}-{}-{}-{}.pdf".format(
             snakemake.params.RDIR,
             snakemake.wildcards["ll"],
             carrier,
diff --git a/scripts/plot_summary.py b/scripts/plot_summary.py
index 7e2c955d..b2ec0892 100644
--- a/scripts/plot_summary.py
+++ b/scripts/plot_summary.py
@@ -11,12 +11,11 @@ import logging
 import matplotlib.gridspec as gridspec
 import matplotlib.pyplot as plt
 import pandas as pd
+from prepare_sector_network import co2_emissions_year
 
 logger = logging.getLogger(__name__)
 plt.style.use("ggplot")
 
-from prepare_sector_network import co2_emissions_year
-
 
 # consolidate and rename
 def rename_techs(label):
diff --git a/scripts/prepare_network.py b/scripts/prepare_network.py
index 75e5daba..5652dc6e 100755
--- a/scripts/prepare_network.py
+++ b/scripts/prepare_network.py
@@ -194,7 +194,7 @@ def apply_time_segmentation(n, segments, solver_name="cbc"):
     logger.info(f"Aggregating time series to {segments} segments.")
     try:
         import tsam.timeseriesaggregation as tsam
-    except:
+    except ImportError:
         raise ModuleNotFoundError(
             "Optional dependency 'tsam' not found." "Install via 'pip install tsam'"
         )
diff --git a/scripts/prepare_perfect_foresight.py b/scripts/prepare_perfect_foresight.py
index 00f23fab..1c3a0ebe 100644
--- a/scripts/prepare_perfect_foresight.py
+++ b/scripts/prepare_perfect_foresight.py
@@ -305,7 +305,7 @@ def set_carbon_constraints(n, opts):
         m = re.match(r"^\d+p\d$", o, re.IGNORECASE)
         if m is not None:
             budget = snakemake.config["co2_budget"][m.group(0)] * 1e9
-    if budget != None:
+    if budget is not None:
         logger.info(f"add carbon budget of {budget}")
         n.add(
             "GlobalConstraint",
@@ -428,7 +428,7 @@ def apply_time_segmentation_perfect(
     """
     try:
         import tsam.timeseriesaggregation as tsam
-    except:
+    except ImportError:
         raise ModuleNotFoundError(
             "Optional dependency 'tsam' not found." "Install via 'pip install tsam'"
         )
diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index 21291d7e..4d36e7d4 100755
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -183,8 +183,6 @@ def define_spatial(nodes, options):
     return spatial
 
 
-from types import SimpleNamespace
-
 spatial = SimpleNamespace()
 
 
@@ -1472,7 +1470,6 @@ def add_land_transport(n, costs):
     # TODO options?
 
     logger.info("Add land transport")
-    nhours = n.snapshot_weightings.generators.sum()
 
     transport = pd.read_csv(
         snakemake.input.transport_demand, index_col=0, parse_dates=True
@@ -3120,6 +3117,7 @@ def add_waste_heat(n):
     # TODO options?
 
     logger.info("Add possibility to use industrial waste heat in district heating")
+    cf_industry = snakemake.params.industry
 
     # AC buses with district heating
     urban_central = n.buses.index[n.buses.carrier == "urban central heat"]
@@ -3480,7 +3478,7 @@ def apply_time_segmentation(
     """
     try:
         import tsam.timeseriesaggregation as tsam
-    except:
+    except ImportError:
         raise ModuleNotFoundError(
             "Optional dependency 'tsam' not found." "Install via 'pip install tsam'"
         )
diff --git a/scripts/retrieve_monthly_fuel_prices.py b/scripts/retrieve_monthly_fuel_prices.py
index 11e351ce..e64066cb 100644
--- a/scripts/retrieve_monthly_fuel_prices.py
+++ b/scripts/retrieve_monthly_fuel_prices.py
@@ -7,13 +7,12 @@ Retrieve monthly fuel prices from Destatis.
 """
 
 import logging
-
-logger = logging.getLogger(__name__)
-
 from pathlib import Path
 
 from _helpers import configure_logging, progress_retrieve
 
+logger = logging.getLogger(__name__)
+
 if __name__ == "__main__":
     if "snakemake" not in globals():
         from _helpers import mock_snakemake
diff --git a/scripts/solve_network.py b/scripts/solve_network.py
index 4a1e27f9..1c37bfd2 100644
--- a/scripts/solve_network.py
+++ b/scripts/solve_network.py
@@ -572,7 +572,7 @@ def add_SAFE_constraints(n, config):
     peakdemand = n.loads_t.p_set.sum(axis=1).max()
     margin = 1.0 + config["electricity"]["SAFE_reservemargin"]
     reserve_margin = peakdemand * margin
-    conventional_carriers = config["electricity"]["conventional_carriers"]
+    conventional_carriers = config["electricity"]["conventional_carriers"]  # noqa: F841
     ext_gens_i = n.generators.query(
         "carrier in @conventional_carriers & p_nom_extendable"
     ).index
@@ -694,7 +694,7 @@ def add_lossy_bidirectional_link_constraints(n):
         return
 
     n.links["reversed"] = n.links.reversed.fillna(0).astype(bool)
-    carriers = n.links.loc[n.links.reversed, "carrier"].unique()
+    carriers = n.links.loc[n.links.reversed, "carrier"].unique()  # noqa: F841
 
     forward_i = n.links.query(
         "carrier in @carriers and ~reversed and p_nom_extendable"