diff --git a/scripts/prepare_sector_network.py b/scripts/prepare_sector_network.py
index 53b811aa..b86f9557 100644
--- a/scripts/prepare_sector_network.py
+++ b/scripts/prepare_sector_network.py
@@ -688,7 +688,7 @@ def add_co2_tracking(n, costs, options):
         e_nom_extendable=True,
         e_nom_max=e_nom_max,
         capital_cost=options["co2_sequestration_cost"],
-        marginal_cost=0.1,
+        marginal_cost=-0.1,
         bus=sequestration_buses,
         lifetime=options["co2_sequestration_lifetime"],
         carrier="co2 sequestered",