EarlyBirdCapital, Inc. 600 Third Avenue 33rd Floor New York, New York 10016 April 19, 2004 Tremisis Energy Acquisition Corporation 1775 Broadway Suite 604 New York, New York 10019 Lawrence S. Coben Isaac Kier David A. Preiser Jon Schotz Gentlemen:...

                             EarlyBirdCapital, Inc.
                                000 Xxxxx Xxxxxx
                                   00xx Xxxxx
                            Xxx Xxxx, Xxx Xxxx 00000


                                                              April 19, 2004



Tremisis Energy Acquisition Corporation
0000 Xxxxxxxx
Xxxxx 000
Xxx Xxxx, Xxx Xxxx 00000

Xxxxxxxx X. Xxxxx
Xxxxx Xxxx
Xxxxx X. Xxxxxxx
Xxx Xxxxxx


Gentlemen:

         Reference is made to each of your respective letter agreements with
EarlyBirdCapital, Inc. and Tremisis Energy Acquisition Corporation, dated March
3, 2004. The undersigned hereby waives its rights under Section 8 of each of
your letter agreements relating to your restrictions on being involved with
future "Acquisition Funds." Except as indicated above, each of the letter
agreements shall remain in full force and effect.



                                                      EARLYBIRDCAPITAL, INC.



                                                  By: /s/ Xxxxxx Xxxxxx
                                                      -----------------
                                                      Name: Xxxxxx Xxxxxx
                                                      Title: Managing Director