diff --git a/scripts/add_electricity.py b/scripts/add_electricity.py
index f2dfdfef..9a99d314 100755
--- a/scripts/add_electricity.py
+++ b/scripts/add_electricity.py
@@ -337,7 +337,7 @@ def attach_conventional_generators(n, costs, ppl, conventional_carriers, extenda
             # Single value affecting all generators of technology k indiscriminantely of country
             n.generators.loc[idx, "p_max_pu"] = factors
         elif isinstance(factors, str):
-            factors = pd.read_file(factors, index_col=0)
+            factors = pd.read_csv(factors, index_col=0)['factor']
             # Values affecting generators of technology k country-specific
             # First map generator buses to countries; then map countries to p_max_pu
             bus_factors = n.buses.country.map(factors)