| Nicor Gas Company                                                                                                                                                                                                                                                                                                                                                                                     |   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
| Computation of Consolidated Ratio of Earnings to Fixed Charges                                                                                                                                                                                                                                                                                                                                        |   |
| (thousands)                                                                                                                                                                                                                                                                                                                                                                                           |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   | Year Ended December 31 |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   | 2010 |   |   | 2009 |   |   | 2008 |   |   | 2007 |   |   | 2006 |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Earnings available to cover fixed charges:                                                                                                                                                                                                                                                                                                                                                            |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|       Net income                                                                                                                                                                                                                                                                                                                                                             |   |   | $ | 100,871 |   |   | $ | 74,960 |   |   | $ | 59,569 |   |   | $ | 66,277 |   |   | $ | 58,656 |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|      Add:  Income Tax Expense                                                                                                                                                                                                                                                                                                                                                |   |   |   | 59,264 |   |   |   | 40,316 |   |   |   | 30,991 |   |   |   | 34,197 |   |   |   | 27,814 |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                 Fixed charges                                                                                                                                                                                                                                                                                              |   |   | 36,585 |   |   |   | 34,933 |   |   |   | 38,246 |   |   |   | 41,000 |   |   |   | 45,041 |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                Allowance for funds used                                                                                                                                                                                                                                                                                              |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                during construction and other                                                                                                                                                                                                                                                                                         |   |   | - |   |   |   | (51 | ) |   |   | (62 | ) |   |   | (182 | ) |   |   | (614 | ) |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   | $ | 196,720 |   |   | $ | 150,158 |   |   | $ | 128,744 |   |   | $ | 141,292 |   |   | $ | 130,897 |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Fixed charges:                                                                                                                                                                                                                                                                                                                                                                                        |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|       Interest on debt                                                                                                                                                                                                                                                                                                                                                       |   | $ | 34,855 |   |   | $ | 32,991 |   |   | $ | 35,204 |   |   | $ | 37,515 |   |   | $ | 37,665 |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|       Other interest charges and                                                                                                                                                                                                                                                                                                                                        |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|           amortization of debt discount,                                                                                                                                                                                                                                                                                                                      |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|           premium, and expense, net                                                                                                                                                                                                                                                                                                                                |   |   | 1,730 | * |   |   | 1,942 | * |   |   | 3,042 | * |   |   | 3,485 | * |   |   | 7,376 |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   | $ | 36,585 |   |   | $ | 34,933 |   |   | $ | 38,246 |   |   | $ | 41,000 |   |   | $ | 45,041 |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Ratio of earnings to fixed charges                                                                                                                                                                                                                                                                                                                                                                    |   |   | 5.38 |   |   |   | 4.30 |   |   |   | 3.37 |   |   |   | 3.45 |   |   |   | 2.91 |   |
|                                                                                                                                                                                                                                                                                                                                                                                                  |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| * The Company began accruing interest expense for uncertain tax positions on January 1, 2007. Accordingly, for 2007 and going forward, the interest included in Fixed charges is only the interest on third party indebtedness. Any interest expense accrued on uncertain tax positions is excluded from the calculation of Earnings. Prior years' calculations were not changed. |   |