Update preprocessing.py

preprocessing.py

@@ -93,7 +93,7 @@ def prepare_miner_features(
     if electricity_rate is not None:
         df["electricity_rate"] = float(electricity_rate)
     else:
-        df["efficiency"] = specs["electricity_rate"]
+        df["electricity_rate"] = specs["electricity_rate"]
         
         # # fallback: keep old behaviour if not provided
         # df["electricity_rate"] = df["date"].dt.date.apply(