Exhibit 31.1

 

**Certifications**

 

 
|   | I, Dawn L. Farrell, certify that:                                                                                                                                                                                                                                                                                                                                       |
|--------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |                                                                                                                                                                                                                                                                                                                                                                    |
| 1.     | I have reviewed this annual report on Form 40-F of   TransAlta Corporation;                                                                                                                                                                                                                                                                                        |
|   |                                                                                                                                                                                                                                                                                                                                                                    |
| 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   issuer as of, and for, the periods presented in this report;                                                                               |
|   |                                                                                                                                                                                                                                                                                                                                                                    |
| 4.     | The issuer’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 issuer 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 issuer, 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 issuer’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 issuer’s internal   control over financial reporting that occurred during the period covered by   the annual report that has materially affected, or is reasonably likely to   materially affect, the issuer’s internal control over financial reporting;   and |
|   |                                                                                                                                                                                                                                                                                                                                                                    |
| 5.     | The issuer’s   other certifying officer(s) and I have disclosed, based on our most   recent evaluation of internal control over financial reporting, to the   issuer’s auditors and the audit committee of the issuer’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 issuer’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 the issuer’s internal control   over financial reporting. |

 

 
| March 3, 2017 |                                    |
|--------------------|-----------------------------------------|
|               | /s/   Dawn L. Farrell                   |
|               | Dawn L. Farrell                         |
|               | President and Chief   Executive Officer |

 

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