EXHIBIT 21

ENERGY FUTURE HOLDINGS CORP.

SUBSIDIARY HIERARCHY

Effective December 31, 2010



|                                               |  |             
|---------------------------------------------- |  | ------------
|                                               |  | 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    
|Luminant Holding Company LLC                   |  | Delaware    
|Luminant Energy Company LLC                    |  | Texas       
|Luminant ET Services Company                   |  | Texas       
|Luminant Energy Trading California Company     |  | 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 LLC1       |  | Delaware    
|Valley NG Power Company LLC                    |  | Texas       
|Luminant Renewables Company LLC                |  | Texas       
|                                               |  | 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       
|TXU Energy Retail Company LLC                  |  | Texas       
|TXU Retail Services Company                    |  | Delaware    
|TXU SESCO Company LLC                          |  | Texas       
|TXU SESCO Energy Services Company              |  | Texas       
|TXU Energy Solutions Company LLC               |  | Texas       
|TXU SEM Company                                |  | Delaware    
|Brighten Holdings LLC                          |  | Delaware    
|Brighten Energy LLC                            |  | Delaware    
|Energy Future Intermediate Holding Company LLC |  | Delaware    
|EFIH Finance Inc.                              |  | Delaware    
|Oncor Electric Delivery Holdings Company LLC   |  | Delaware    
|Oncor Electric Delivery Company LLC2           |  | Delaware    
|Oncor Management Investment LLC3               |  | Delaware    



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|                                                    |  |               
|--------------------------------------------------- |  | --------------
|                                                    |  | Jurisdiction  
|Oncor Electric Delivery Transition Bond Company LLC |  | Delaware      
|Oncor Electric Delivery Administration Corp.        |  | Texas         
|Oncor License Holdings Company LLC                  |  | Texas         
|Oncor Communications Holdings Company LLC           |  | Delaware      
|EFH Renewables Company LLC                          |  | Delaware      
|EFH Corporate Services Company                      |  | Texas         
|EFH CG Management Company LLC                       |  | Texas         
|Generation Development Company LLC                  |  | Delaware      
|NCA Development Company LLC                         |  | Texas         
|EFH Properties Company                              |  | Texas         
|Basic Resources Inc.                                |  | Texas         
|TXU Receivables Company                             |  | Delaware      
|EFH Vermont Insurance Company                       |  | Vermont       
|LSGT Gas Company LLC                                |  | Texas         
|LSGT SACROC, Inc.                                   |  | Texas         
|Humphreys & Glasgow Limited                         |  | United Kingdom
|EEC Holdings, Inc                                   |  | Nevada        
|EECI, Inc.                                          |  | Nevada        
|Ebasco Services of Canada, Ltd                      |  | Canada        
|                                                    |  | United Kingdom



|1 | 88% ownership interest
|- | ----------------------

|2 | 80.033% ownership interest
|- | --------------------------

|3 | Oncor Management Investment LLC owns 0.217% 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.
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