** **

**Exhibit 31.01**

 

**Certification**

 

I, Tim E. Taylor, certifythat:

 

1.               I have reviewed this reporton Form 10-Q/A of Public Service Co. of Colorado;

 

2.               Based on my knowledge, thisreport does not contain any untrue statement of a material fact or omit to statea material fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading withrespect to the period covered by this report;

 

3.               Based on my knowledge, thefinancial statements, and other financial information included in this report,fairly present in all material respects the financial condition, results ofoperations and cash flows of the registrant as of, and for, the periodspresented in this report;

 

4.               The registrant’s othercertifying officer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) for the registrant and have:

 

a)              Designed suchdisclosure controls and procedures, or caused such disclosure controls andprocedures to be designed under our supervision to ensure that materialinformation relating to the registrant, including its consolidatedsubsidiaries, is made known to us by others within those entities, particularlyduring the period in which this report is being prepared;

 

b)             Evaluated the effectivenessof the registrant’s disclosure controls and procedures and presented in thisreport our conclusions about the effectiveness of the disclosure controls andprocedures, as of the end of the period covered by this report based on suchevaluation; and

 

c)              Disclosed in this report anychange in the registrant’s internal control over financial reporting thatoccurred during the registrant’s most recent fiscal quarter (the registrant’s fourthfiscal quarter in the case of an annual report) that has materially affected,or is reasonably likely to materially affect, the registrant’s internal controlover financial reporting;

 

5.                 The registrant’s othercertifying officer and I have disclosed, based on our most recent evaluation ofinternal control over financial reporting, to the registrant’s auditors and theaudit committee of registrant’s board of directors (or persons performing theequivalent functions):

 

a)              All significant deficienciesand material weaknesses in the design or operation of internal control overfinancial reporting which are reasonably likely to adversely affect theregistrant’s ability to record, process, summarize and report financialinformation; and

 

b)             Any fraud, whether or notmaterial, that involves management or other employees who have a significantrole in the registrant’s internal control over financial reporting.

 

Date: Dec. 17, 2007

 
| /s/ TIM E. TAYLOR                      |   |
|----------------------------------------|--------|
| Tim E. Taylor                          |
| President  and Chief Executive Officer |

 

1

----

 

I,Benjamin G.S. Fowke III, certify that:

 

1.               I have reviewed this reporton Form 10-Q/A of Public Service Co. of Colorado;

 

2.               Based on my knowledge, thisreport does not contain any untrue statement of a material fact or omit tostate a material fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading withrespect to the period covered by this report;

 

3.               Based on my knowledge, thefinancial statements, and other financial information included in this report,fairly present in all material respects the financial condition, results ofoperations and cash flows of the registrant as of, and for, the periodspresented in this report;

 

4.               The registrant’s othercertifying officer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) for the registrant and have:

 

a)              Designed suchdisclosure controls and procedures, or caused such disclosure controls andprocedures to be designed under our supervision to ensure that materialinformation relating to the registrant, including its consolidatedsubsidiaries, is made known to us by others within those entities, particularlyduring the period in which this report is being prepared;

 

b)             Evaluated the effectivenessof the registrant’s disclosure controls and procedures and presented in thisreport our conclusions about the effectiveness of the disclosure controls andprocedures, as of the end of the period covered by this report based on suchevaluation; and

 

c)              Disclosed in this report anychange in the registrant’s internal control over financial reporting thatoccurred during the registrant’s most recent fiscal quarter (the registrant’sfourth fiscal quarter in the case of an annual report) that has materiallyaffected or is reasonably likely to materially affect, the registrant’sinternal control over financial reporting;

 

5.               The registrant’s othercertifying officer and I have disclosed, based on our most recent evaluation ofinternal control over financial reporting, to the registrant’s auditors and theaudit committee of registrant’s board of directors (or persons performing theequivalent functions):

 

a)              All significant deficienciesand material weaknesses in the design or operation of internal control overfinancial reporting which are reasonably likely to adversely affect theregistrant’s ability to record, process, summarize and report financialinformation; and

 

b)             Any fraud, whether or notmaterial, that involves management or other employees who have a significantrole in the registrant’s internal control over financial reporting.

 

 Date: Dec. 17, 2007

 
| /s/ BENJAMIN G.S. FOWKE  III                |   |
|---------------------------------------------|--------|
| Benjamin G.S. Fowke III                     |
| Vice  President and Chief Financial Officer |

 

2

----