| Year | Electrical | Fossil fuel | ||
| Energy efficiency | Exergy efficiency | Energy efficiency | Exergy efficiency | |
| 2001 | 49.50 | 36.56 | 65 | 13.20 |
| 2002 | 49.50 | 36.56 | 65 | 13.20 |
| 2003 | 49.50 | 36.56 | 65 | 13.20 |
| 2004 | 49.50 | 36.56 | 65 | 13.20 |
| 2005 | 49.50 | 36.56 | 65 | 13.20 |
| 2006 | 49.50 | 36.56 | 65 | 13.20 |
| 2007 | 49.50 | 36.56 | 65 | 13.20 |
| 2008 | 49.50 | 36.56 | 65 | 13.20 |
| 2009 | 49.50 | 36.56 | 65 | 13.20 |
| 2010 | 49.50 | 36.56 | 65 | 13.20 |
