**Exhibit      31(a)**

**TXU      CORP.**

**Certificate      Pursuant to Section 302 **

**of      Sarbanes - Oxley Act of 2002**

**CERTIFICATION      OF CEO**

| 1.   | I                have reviewed this quarterly report on Form 10-Q of TXU Corp.; |
|----------------|---------------------------------------------------------------------------------|

| 2.   | Based                on my knowledge, this report does not contain any untrue statement                of a                material fact or omit to state a material fact necessary to make                the                statements made, in light of the circumstances under which such statements                were made, not misleading with respect to the period covered by this                report; |
|----------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 3.   | Based                on my knowledge, the financial statements, and other financial information                included in this report, fairly present in all material respects                the                financial condition, results of operations and cash flows of the                registrant as of, and for, the periods presented in this                report; |
|----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 4.   | The                registrant’s other certifying officer(s) and I are responsible for                establishing and maintaining disclosure controls and procedures (as                defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal                control over financial reporting (as defined in Exchange Act Rules                13a-15(f) and 15d-15(f)) for                the registrant and have: |
|----------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | a. | Designed such disclosure controls and              procedures, or caused such disclosure controls and procedures to be              designed under our supervision, to ensure that material information              relating to the registrant, including its consolidated subsidiaries,              is              made known to us by others within those entities, particularly during              the              period in which this report is being              prepared;  |
|--------|----|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | b. | Designed              such internal control over financial reporting, or caused such internal              control over financial reporting to be designed under our supervision,              to              provide reasonable assurance regarding the reliability of financial              reporting and the preparation of financial statements for external              purposes in accordance with generally accepted accounting              principles; |
|--------|----|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | c. | Evaluated              the effectiveness of the registrant’s disclosure controls and procedures              and presented in this report our conclusions about the effectiveness              of              the disclosure controls and procedures, as of the end of the period              covered by this report based on such evaluation; and |
|--------|----|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | d. | Disclosed              in this report any change in the registrant’s internal control over              financial reporting that occurred during the registrant’s most recent              fiscal quarter (the registrant’s fourth fiscal quarter in the case of an              annual report) that has materially affected, or is reasonably likely              to              materially affect, the registrant’s internal control over financial              reporting; and |
|--------|----|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 5.   | The                registrant’s other certifying officer(s) and I have disclosed, based on                our most recent evaluation of internal control over financial reporting,                to the registrant’s auditors and the audit committee of the registrant’s                board of directors (or persons performing the equivalent                functions): |
|----------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | a.  | All              significant deficiencies and material weaknesses in the design or              operation of internal control over financial reporting which are              reasonably likely to adversely affect the registrant’s ability to record,              process, summarize and report financial information; and |
|--------|----------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | b. | Any              fraud, whether or not material, that involves management or other              employees who have a significant role in registrant's internal control              over financial reporting. |
|--------|----|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|                                               |                                                                                                                                                                                            |                                                                                                                                                                                                                                          |
|----------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                                               |                                                                                                                                                                                            |
|                                          |                                                                                                                                                                                       |                                                                                                                                                                                                                                     |
| Date: August              4, 2006   |                                                                                                                                                                                            |                                                /s/  C. John Wilder  |
|                                               | Signature:                C.              John Wilder                                                           |
|                                               | Title:                                      Chairman, President and CEO |