Update app.py

app.py

@@ -242,7 +242,7 @@ if st.button('Calculate Optimal Energy Mix'):
         st.markdown("### Heatmap of Renewable Energy and Demand Characteristics")
         hourly_data = numeric_energy_data_df.copy()
         hourly_data['Time'] = pd.to_datetime(energy_data_df['Time'], errors='coerce')
-        hourly_data['Date'] = hourly_data['Time'].dt.date
+        hourly_data['Date'] = hourly_data['Time'].dt.strftime('%j').astype(int)  # Convert to day of year (1-365)
         hourly_data['Hour'] = hourly_data['Time'].dt.hour
         
         for column in hourly_data.columns[2:]: