aggregate curtailment into single curtailment generator per bus (#1177)

* add curtailment generator mode

* add documentation

config/config.default.yaml

@@ -786,6 +786,7 @@ solving:
   options:
     clip_p_max_pu: 1.e-2
     load_shedding: false
+    curtailment_mode: false
     noisy_costs: true
     skip_iterations: true
     rolling_horizon: false
@@ -830,7 +831,7 @@ solving:
   solver_options:
     highs-default:
       # refer to https://ergo-code.github.io/HiGHS/dev/options/definitions/
-      threads: 4
+      threads: 1
       solver: "ipm"
       run_crossover: "off"
       small_matrix_value: 1e-6
@@ -841,7 +842,7 @@ solving:
       parallel: "on"
       random_seed: 123
     gurobi-default:
-      threads: 4
+      threads: 8
       method: 2 # barrier
       crossover: 0
       BarConvTol: 1.e-6

doc/configtables/solving.csv

@@ -2,6 +2,7 @@
 options,,,
 -- clip_p_max_pu,p.u.,float,To avoid too small values in the renewables` per-unit availability time series values below this threshold are set to zero.
 -- load_shedding,bool/float,"{'true','false', float}","Add generators with very high marginal cost to simulate load shedding and avoid problem infeasibilities. If load shedding is a float, it denotes the marginal cost in EUR/kWh."
+-- curtailment_mode,bool/float,"{'true','false'}","Fixes the dispatch profiles of generators with time-varying p_max_pu by setting ``p_min_pu = p_max_pu`` and adds an auxiliary curtailment generator (with negative sign to absorb excess power) at every AC bus. This can speed up the solving process as the curtailment decision is aggregated into a single generator per region. Defaults to ``false``."
 -- noisy_costs,bool,"{'true','false'}","Add random noise to marginal cost of generators by :math:`\mathcal{U}(0.009,0,011)` and capital cost of lines and links by :math:`\mathcal{U}(0.09,0,11)`."
 -- skip_iterations,bool,"{'true','false'}","Skip iterating, do not update impedances of branches. Defaults to true."
 -- rolling_horizon,bool,"{'true','false'}","Switch for rule :mod:`solve_operations_network` whether to optimize the network in a rolling horizon manner, where the snapshot range is split into slices of size `horizon` which are solved consecutively. This setting has currently no effect on sector-coupled networks."

doc/release_notes.rst

@@ -41,6 +41,12 @@ Upcoming Release
 
 * Enable parallelism in :mod:`determine_availability_matrix_MD_UA.py` and remove plots. This requires the use of temporary files.
 
+* Added option ``solving: curtailment_mode``` which fixes the dispatch profiles
+  of generators with time-varying p_max_pu by setting ``p_min_pu = p_max_pu``
+  and adds an auxiliary curtailment generator with negative sign (to absorb
+  excess power) at every AC bus. This can speed up the solving process as the
+  curtailment decision is aggregated into a single generator per region.
+
 PyPSA-Eur 0.11.0 (25th May 2024)
 =====================================
 

scripts/solve_network.py

@@ -471,6 +471,22 @@ def prepare_network(
             p_nom=1e9,  # kW
         )
 
+    if solve_opts.get("curtailment_mode"):
+        n.add("Carrier", "curtailment", color="#fedfed", nice_name="Curtailment")
+        n.generators_t.p_min_pu = n.generators_t.p_max_pu
+        buses_i = n.buses.query("carrier == 'AC'").index
+        n.madd(
+            "Generator",
+            buses_i,
+            suffix=" curtailment",
+            bus=buses_i,
+            p_min_pu=-1,
+            p_max_pu=0,
+            marginal_cost=-0.1,
+            carrier="curtailment",
+            p_nom=1e6,
+        )
+
     if solve_opts.get("noisy_costs"):
         for t in n.iterate_components():
             # if 'capital_cost' in t.df: