March 13, 2009

Tremisis Energy Acquisition Corporation II
2925 Briarpark, Suite 150-A
Houston, TX 77042

Gentlemen:

The undersigned, as a condition to the consummation of the transactions
contemplated by that certain agreement (the “Put/Call Agreement”), dated the
date hereof, by and among Tremisis Energy Acquisition Corporation II
(“Company”), Lawrence S. Coben, Ronald D. Ormand, Jon Schotz, Charles A. Norris,
Stephen N. Casati, Bill Goldstein, Dean Vanech, Olympus Capital Investment, LLC,
Jerry Doren, Owen Coleman, Bill Armstrong, Trevor Wilson, Brian McInerney,
Richard Kassar, David Levine, Jim Land, David A. Preiser, Gary C. Evans,
Jonathan Jacobs (collectively, the “Sellers”), the undersigned and SoftForum
Co., Ltd., hereby agrees as follows (certain capitalized terms used herein are
defined in paragraph 12 hereof):

1.           In the event that the Company fails to consummate a Business
Combination within 24 months from the effective date (“Effective Date”) of the
registration statement relating to the Company’s initial public offering of
securities (“IPO”), the undersigned will (i) cause the trust fund established in
connection with the Company’s IPO (the “Trust Fund”) to be liquidated and
distributed to the holders of IPO Shares and (ii) take all reasonable actions
within his power to cause the Company to liquidate as soon as reasonably
practicable. The undersigned hereby waives any and all right, title, interest or
claim of any kind in or to any distribution of the Trust Fund and any remaining
net assets of the Company as a result of such liquidation (“Claim”) and hereby
waives any Claim the undersigned may have in the future as a result of, or
arising out of, any contracts or agreements with the Company and will not seek
recourse against the Trust Fund for any reason whatsoever. In the event of the
liquidation of the Trust Fund, the undersigned agrees to indemnify and hold
harmless the Company against any and all loss, liability, claims, damage and
expense whatsoever (including, but not limited to, any and all legal or other
expenses reasonably incurred in investigating, preparing or defending against
any litigation, whether pending or threatened, or any claim whatsoever) that the
Company may become subject as a result of any claim by any vendor or other
person who is owed money by the Company for services rendered or products sold
or contracted for, or by any target business, but only to the extent necessary
to ensure that such loss, liability, claim, damage or expense does not reduce
the amount in the Trust Fund.

2.           In order to minimize potential conflicts of interest that may arise
from multiple affiliations, the undersigned agrees to present to the Company for
its consideration, prior to presentation to any other person or entity, any
suitable opportunity to acquire an operating business, until the earlier of the
consummation by the Company of a Business Combination, the liquidation of the
Company or until such time as the undersigned ceases to be an officer or
director of the Company, subject to any pre-existing fiduciary and contractual
obligations the undersigned might have.

3.           The undersigned acknowledges and agrees that the Company will not
consummate any Business Combination that involves a company that is affiliated
with any of the Insiders unless the Company obtains an opinion from an
independent investment banking firm reasonably acceptable to Merrill Lynch,
Pierce, Fenner & Smith Incorporated, as representative of the underwriters of
the Company’s IPO, that the Business Combination is fair to the Company’s
stockholders from a financial perspective.
 

--------------------------------------------------------------------------------

4.           Neither the undersigned, any member of the family of the
undersigned, nor any affiliate (“Affiliate”) of the undersigned will be entitled
to receive and will not accept any compensation for services rendered to the
Company prior to or in connection with the consummation of the Business
Combination; provided that the undersigned shall be entitled to reimbursement
from the Company for his out-of-pocket expenses incurred in connection with
seeking and consummating a Business Combination.

5.           Neither the undersigned, any member of the family of the
undersigned, nor any Affiliate of the undersigned will be entitled to receive or
accept a finder’s fee or any other compensation in the event the undersigned,
any member of the family of the undersigned or any Affiliate of the undersigned
originates a Business Combination.

6.           The undersigned acknowledges and agrees that any Insider Shares
that may be transferred to him upon consummation of a Business Combination
pursuant to the Put/Call Agreement will continue to be held in escrow until one
year after the consummation by the Company of such Business Combination, subject
to the terms of that certain Stock Escrow Agreement, dated as of December 6,
2007 by and among the Company, the Sellers and Continental Stock Transfer &
Trust Company.

7.           The undersigned agrees to be a Director and Co-Chief Executive
Officer of the Company until the earlier of the consummation by the Company of a
Business Combination or the liquidation of the Company. The undersigned’s
biographical information furnished to the Company and the Underwriters and
attached hereto as Exhibit A is true and accurate in all respects, does not omit
any material information with respect to the undersigned’s background and
contains all of the information required to be disclosed pursuant to Item 401 of
Regulation S-K, promulgated under the Securities Act of 1933. The undersigned
represents and warrants that:

(a)           he is not subject to, or a respondent in, any legal action for,
any injunction, cease-and-desist order or order or stipulation to desist or
refrain from any act or practice relating to the offering of securities in any
jurisdiction;

(b)           he has never been convicted of or pleaded guilty to any crime (i)
involving any fraud or (ii) relating to any financial transaction or handling of
funds of another person, or (iii) pertaining to any dealings in any securities
and he is not currently a defendant in any such criminal proceeding; and

(c)           he has never been suspended or expelled from membership in any
securities or commodities exchange or association or had a securities or
commodities license or registration denied, suspended or revoked.

8.           The undersigned has full right and power, without violating any
agreement by which he is bound, to enter into this letter agreement and to serve
as a Director and as Co-Chief Executive Officer of the Company.

9.           The undersigned hereby waives his right to exercise conversion
rights with respect to any shares of the Company’s common stock owned or to be
owned by the undersigned, directly or indirectly, and agrees that he will not
seek conversion with respect to such shares in connection with any vote to
approve a Business Combination.
 

--------------------------------------------------------------------------------

10.           In the event that the Company does not consummate a Business
Combination and must liquidate, and its remaining net assets are insufficient to
complete such liquidation, the undersigned agrees to advance such funds
necessary to complete such liquidation and agrees not to seek repayment for such
expenses.

11.           This letter agreement may not be amended or modified without the
prior consent of Ronald D. Ormand, as representative of the Sellers. This letter
agreement shall be governed by and construed and enforced in accordance with the
laws of the State of New York, without giving effect to conflicts of law
principles that would result in the application of the substantive laws of
another jurisdiction. The undersigned hereby (i) agrees that any action,
proceeding or claim against him arising out of or relating in any way to this
letter agreement (a “Proceeding”) shall be brought and enforced in the courts of
the State of New York of the United States of America for the Southern District
of New York, and irrevocably submits to such jurisdiction, which jurisdiction
shall be exclusive, (ii) waives any objection to such exclusive jurisdiction and
that such courts represent an inconvenient forum and (iii) irrevocably agrees to
appoint Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. as agent for the
service of process in the State of New York to receive, for the undersigned and
on his behalf, service of process in any Proceeding. If for any reason such
agent is unable to act as such, the undersigned will promptly notify the Company
and the Underwriters and appoint a substitute agent acceptable to the Company
within 30 days and nothing in this letter agreement will affect the right of
either party to serve process in any other manner permitted by law.

12.           As used herein, (i) a “Business Combination” shall mean an
acquisition by merger, capital stock exchange, asset or stock acquisition,
reorganization or otherwise, of an operating business; (ii) “Insiders” shall
mean all former and current officers and directors of the Company and all
stockholders of the Company that acquired shares of Common Stock of the Company
prior to the IPO, or, if after the IPO, in a private transfer from another
former or current officer or director of the Company, or from a stockholder that
purchased such shares of Common Stock prior to the IPO; (iii) “Insider Shares”
shall mean all of the shares of Common Stock of the Company acquired by an
Insider prior to the IPO or, if acquired after the IPO, in a private transfer
from another Insider; and (iv) “IPO Shares” shall mean the shares of Common
Stock issued in the Company’s IPO.

  /s/ Sang-Chul Kim  
Sang-Chul Kim

 

--------------------------------------------------------------------------------