Exhibit 21(a)

ENERGY FUTURE HOLDINGS CORP.

SUBSIDIARY HIERARCHY

Effective February 28, 2009



|                                           |  |             
|------------------------------------------ |  | ------------
|                                           |  | Jurisdiction
|Energy Future Holdings Corp.               |  | Texas       
|Energy Future Competitive Holdings Company |  | Texas       
|Texas Competitive Electric Holdings LLC    |  | Delaware    
|TCEH Finance, Inc.                         |  | Delaware    
|Generation MT Company LLC                  |  | Delaware    
|EFH CG Holdings Company LP1                |  | Texas       
|DFW Midstream Services LLC                 |  | Texas       
|Luminant Holding Company LLC               |  | Delaware    
|Luminant Energy Company LLC                |  | Texas       
|Luminant ET Services Company               |  | Texas       
|Luminant Energy Trading California Company |  | Texas       
|Luminant Energy Trading Canada Limited     |  | Canada      
|EFH CG Holdings Company LP2                |  | Texas       
|Luminant Energy Services Company           |  | Texas       
|Luminant Generation Company LLC            |  | Texas       
|Nuclear Energy Future Holdings LLC         |  | Delaware    
|Nuclear Energy Future Holdings II LLC      |  | Delaware    
|Comanche Peak Nuclear Power Company LLC3   |  | Delaware    
|Valley NG Power Company LLC                |  | Texas       
|Luminant Renewables Company LLC            |  | Texas       
|Fuelco LLC4                                |  | Delaware    
|EFH CG Holdings Company LP5                |  | Texas       
|Generation SVC Company                     |  | Texas       
|Luminant Power Services Company            |  | Delaware    
|Big Brown 3 Power Company LLC              |  | Texas       
|Big Brown Power Company LLC                |  | Texas       
|Collin Power Company LLC                   |  | Delaware    
|DeCordova Power Company LLC                |  | Texas       
|Lake Creek 3 Power Company LLC             |  | Texas       
|Martin Lake 4 Power Company LLC            |  | Texas       
|Monticello 4 Power Company LLC             |  | Texas       
|Morgan Creek 7 Power Company LLC           |  | Texas       
|Oak Grove Management Company LLC           |  | Delaware    
|Oak Grove Power Company LLC                |  | Texas       
|Sandow Power Company LLC                   |  | Texas       
|Tradinghouse 3 & 4 Power Company LLC       |  | Texas       
|Tradinghouse Power Company LLC             |  | Texas       
|Valley Power Company LLC                   |  | Texas       
|Luminant Mining Services Company           |  | Delaware    
|Big Brown Lignite Company LLC              |  | Texas       
|Luminant Big Brown Mining Company LLC      |  | Texas       
|Luminant Mining Company LLC                |  | Texas       
|Oak Grove Mining Company LLC               |  | Texas       
|Luminant Mineral Development Company LLC   |  | Texas       
|NCA Resources Development Company LLC      |  | Texas       
|Wichita/Victory Avenue LLC                 |  | Texas       



---

|                                                    |  |                     
|--------------------------------------------------- |  | --------------------
|                                                    |  | Jurisdiction        
|TXU Energy Retail Company LLC                       |  | Texas               
|TXU Retail Services Company                         |  | Delaware            
|EFH CG Holdings Company LP6                         |  | Texas               
|TXU SESCO Company LLC                               |  | Texas               
|TXU SESCO Energy Services Company                   |  | Texas               
|TXU Energy Solutions Company LLC                    |  | Texas               
|TXU Chilled Water Solutions Company                 |  | Texas               
|TXU SEM Company                                     |  | Delaware            
|TXU Energy Retail Management Company LLC            |  | Delaware            
|Energy Future Intermediate Holding Company LLC      |  | Delaware            
|Oncor Electric Delivery Holdings Company LLC        |  | Delaware            
|Oncor Electric Delivery Company LLC7                |  | Delaware            
|Oncor Management Investment LLC8                    |  | Delaware            
|Oncor Electric Delivery Transition Bond Company LLC |  | Delaware            
|EFH CG Holdings Company LP9                         |  | Texas               
|Oncor License Holdings Company LLC                  |  | Texas               
|Oncor Communications Holdings Company LLC           |  | Delaware            
|EFH Corporate Services Company                      |  | Texas               
|EFH CG Management Company LLC                       |  | Texas               
|EFH CG Holdings Company LP10                        |  | Texas               
|EFH Communications Holdings Company LLC             |  | Delaware            
|Generation Development Company LLC                  |  | Delaware            
|NCA Development Company LLC                         |  | Texas               
|EFH Industries Company LLC                          |  | Delaware            
|EFH Properties Company                              |  | Texas               
|Communications License Holdings I Inc.              |  | Texas               
|EFH Investment Company                              |  | Texas               
|Basic Resources Inc.                                |  | Texas               
|TXU Receivables Company                             |  | Delaware            
|EFH CC Holdings Company LLC                         |  | Texas               
|EFH Vermont Insurance Company                       |  | Vermont             
|LSGT Gas Company LLC                                |  | Texas               
|LSGT Processing Company                             |  | Texas               
|Lone Star Energy Services, Inc                      |  | Texas               
|ENS Holdings I, Inc.                                |  | Texas               
|ENS Holdings II, Inc.                               |  | Texas               
|ENS Holdings Limited Partnership11                  |  | Texas               
|LSGT SACROC, Inc.12                                 |  | Texas               
|LSGT Finance (II), Inc.                             |  | Texas               
|LSGT House Inc.                                     |  | Texas               
|Enserch Finance N.V.                                |  | Netherlands Antilles
|LSGT International Investments Limited              |  | Delaware            
|Humphreys & Glasgow Limited                         |  | United Kingdom      
|EEC Holdings, Inc                                   |  | Nevada              
|EECI, Inc.                                          |  | Nevada              
|Ebasco Services of Canada, Ltd                      |  | Canada              
|EFH CG Holdings Company LP13                        |  | Texas               
|EFH Australia (No. 2) Holdings Company              |  | Delaware            
|EFH FS Holdings Company                             |  | Delaware            
|TXU Europe Limited                                  |  | United Kingdom      
|TXU Europe CP Inc                                   |  | Delaware            
|TXU Eastern Finance (A) Ltd                         |  | United Kingdom      
|TXU Eastern Finance (B) Ltd                         |  | United Kingdom      
|TXU Eastern Funding Company14                       |  | United Kingdom      
|EFH Finance (No. 2) Holdings Company                |  | Delaware            
|TXU Finance (No. 2) Limited15                       |  | United Kingdom      



---



|1 | 0.3% ownership interest
|- | -----------------------

|2 | 22% ownership interest
|- | ----------------------

|3 | 88% ownership interest
|- | ----------------------

|4 | 33% ownership interest
|- | ----------------------

|5 | 2.4% ownership interest
|- | -----------------------

|6 | 28.4% ownership interest
|- | ------------------------

|7 | 80.0417% ownership interest
|- | ---------------------------

|8 | Oncor Management Investment LLC owns 0.2083% of Oncor Electric Delivery Company LLC. Regarding the ownership of Oncor
Management Investment LLC, Oncor Electric Delivery Company LLC owns 100% of the Class A membership interests. Certain management employees of Oncor Electric Delivery Company LLC own 100% of the Class B membership interests.
|- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|9 | 19.5% ownership interest
|- | ------------------------

|10 | 21.5% ownership interest
|-- | ------------------------

|11 | 99% owned by ENS Holdings II, Inc. and 1% owned by ENS Holdings
I, Inc.
|-- | -----------------------------------------------------------------------

|12 | 0.35% owned by ENS Holdings Limited Partnership and 99.65% owned by LSGT Finance (II), Inc.
|-- | -------------------------------------------------------------------------------------------

|13 | 5.9% ownership interest
|-- | -----------------------

|14 | 50% owned by TXU Eastern Finance (A) Ltd and 50% owned by TXU Eastern Finance (B) Ltd
|-- | -------------------------------------------------------------------------------------

|15 | 10% owned by EFH Finance (No. 2) Holdings Company and 90% owned by TXU Europe Limited
|-- | -------------------------------------------------------------------------------------