add biomass constraint for biomass spatial enabled

scripts/prepare_sector_network.py

@@ -2330,6 +2330,14 @@ def add_biomass(n, costs):
             marginal_cost=costs.at["solid biomass", "fuel"]
             + bus_transport_costs * average_distance,
         )
+        n.add(
+            "GlobalConstraint",
+            "biomass limit",
+            carrier_attribute="solid biomass",
+            sense="<=",
+            constant=biomass_potentials["solid biomass"].sum(),
+            type="operational_limit",
+        )
 
     # AC buses with district heating
     urban_central = n.buses.index[n.buses.carrier == "urban central heat"]