diff --git a/etrago/execute/__init__.py b/etrago/execute/__init__.py
index 32f41001..9985dc8e 100644
--- a/etrago/execute/__init__.py
+++ b/etrago/execute/__init__.py
@@ -359,6 +359,7 @@ def iterate_lopf(
 
     else:
         run_lopf(etrago, extra_functionality, method)
+        etrago.export_to_csv(path)
 
     if args["lpfile"]:
         network.model.write(lp_path)
diff --git a/etrago/tools/constraints.py b/etrago/tools/constraints.py
index 311e7c23..c5fec3f7 100755
--- a/etrago/tools/constraints.py
+++ b/etrago/tools/constraints.py
@@ -2931,7 +2931,7 @@ def add_chp_constraints_nmp(n):
             for e_chp in elec_chp
         )
 
-        lhs = linexpr((1, lhs_1), (1, lhs_2))
+        lhs = linexpr((1, lhs_1), (-1, lhs_2))
 
         define_constraints(
             n, lhs, "<=", 0, "chplink_" + str(i), "backpressure"