diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index 9c1a85d7..ae5d12df 100644
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -2333,6 +2333,7 @@ def add_biomass(n, costs):
                 efficiency=costs.at["biomass boiler", "efficiency"],
                 capital_cost=costs.at["biomass boiler", "efficiency"]
                 * costs.at["biomass boiler", "fixed"],
+                marginal_cost=costs.at["biomass boiler", "pelletizing cost"],
                 lifetime=costs.at["biomass boiler", "lifetime"],
             )