EXHIBIT 31a

Certification Pursuant to Rules13a-14 and 15d-14
of the 1934 Securities Exchange Act

|                                     |                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                             
|------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|I, Thomas M. OFlynn,
 certify that:
|                                     |                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                             
|1.                                   | I have reviewed this
 Annual Report on Form 10-K of Public Service Enterprise Group Incorporated;                                                                                                                                                                                                                                           
|                                     |                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                             
|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 the registrants internal control over financial reporting.                                                                                                                                                                                                                

|      |                    |  |                                              
|----- | ------------------ |  | ---------------------------------------------
|Date: | February 26,
 2009 |  | /s/ Thomas
 M. OFlynn                       
|      |                    |  |                                              
|      |                    |  | Thomas M. OFlynn                            
|      |                    |  | Public
 Service Enterprise Group Incorporated
|      |                    |  | Chief
 Financial Officer                     

---