NUCO Nuco2 (MM)

CUSIP No. 629428103 13G Page 2 of 5 Pages



1. NAME OF REPORTING PERSONS
 I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

 Avenir Corporation

 I.R.S. Identification Nos. of above persons (entities only).

 54-1146619
_______________________________________________________________________________
2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
 (a) [_]
 (b) [X]

_______________________________________________________________________________
3. SEC USE ONLY



_______________________________________________________________________________
4. CITIZENSHIP OR PLACE OF ORGANIZATION

 State of Virginia, USA
_______________________________________________________________________________
 NUMBER OF 5. SOLE VOTING POWER

 SHARES 1,938,393
 ________________________________________________________________
BENEFICIALLY 6. SHARED VOTING POWER

 OWNED BY 0
 ________________________________________________________________
 EACH 7. SOLE DISPOSITIVE POWER
 REPORTING
 1,938,393
 ________________________________________________________________
 PERSON 8. SHARED DISPOSITIVE POWER

 WITH 0
_______________________________________________________________________________
9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

 1,938,393

_______________________________________________________________________________
10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

 NA [_]

_______________________________________________________________________________
11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

 13.1%

_______________________________________________________________________________
12. TYPE OF REPORTING PERSON*

 IA



_______________________________________________________________________________
 *SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 629428103 13G Page 3 of 5 Pages

_______________________________________________________________________________
Item 1(a). Name of Issuer:

 NUCO2

_______________________________________________________________________________
Item 1(b). Address of Issuer's Principal Executive Offices:

 2800 SE MARKET PLACE
 STUART, FL 34997


_______________________________________________________________________________
Item 2(a). Name of Person Filing:

 Avenir Corporation
_______________________________________________________________________________
Item 2(b). Address of Principal Business Office, or if None, Residence:

 1919 Pennsylvania Ave NW, 4th Floor
 Washington, DC 20006

_______________________________________________________________________________
Item 2(c). Citizenship:

 State of Virginia, USA
_______________________________________________________________________________
Item 2(d). Title of Class of Securities:

 Common Stock
_______________________________________________________________________________
Item 2(e). CUSIP Number:

 629428103
_______________________________________________________________________________
Item 3. If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b)
 or (c), Check Whether the Person Filing is a:

 (a) [_] Broker or dealer registered under Section 15 of the Exchange Act.

 (b) [_] Bank as defined in Section 3(a)(6) of the Exchange Act.

 (c) [_] Insurance company as defined in Section 3(a)(19) of the Exchange
 Act.

 (d) [_] Investment company registered under Section 8 of the Investment
 Company Act.

 (e) [X] An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

 (f) [_] An employee benefit plan or endowment fund in accordance with
 Rule 13d-1(b)(1)(ii)(F);

 (g) [ ] A parent holding company or control person in accordance with
 Rule 13d-1(b)(1)(ii)(G);

 (h) [_] A savings association as defined in Section 3(b) of the Federal
 Deposit Insurance Act;

 (i) [_] A church plan that is excluded from the definition of an
 investment company under Section 3(c)(14) of the Investment
 Company Act;

 (j) [_] Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

 If this statement is filed pursuant to Rule 13d-1(c), check this box. [_]

CUSIP No. 629428103 13G Page 4 of 5 Pages

Item 4. Ownership.

 Provide the following information regarding the aggregate number and
percentage of the class of securities of the issuer identified in Item 1.

 (a) Amount beneficially owned:

 1,938,393

 (b) Percent of class:

 13.1%

 (c) Number of shares as to which such person has:

 (i) Sole power to vote or to direct the vote

 1,938,393

 (ii) Shared power to vote or to direct the vote

 0

 (iii) Sole power to dispose or to direct the disposition of

 1,938,393

 (iv) Shared power to dispose or to direct the disposition of

 0
_______________________________________________________________________________
Item 5. Ownership of Five Percent or Less of a Class.

 NA
_______________________________________________________________________________
Item 6. Ownership of More Than Five Percent on Behalf of Another Person.

 NA
_______________________________________________________________________________
Item 7. Identification and Classification of the Subsidiary Which Acquired the
 Security Being Reported on by the Parent Holding Company.

 NA
_______________________________________________________________________________
Item 8. Identification and Classification of Members of the Group.

 NA
_______________________________________________________________________________
Item 9. Notice of Dissolution of Group.

 NA
_______________________________________________________________________________
Item 10. Certifications.

 (a) The following certification shall be included if the statement is
 filed pursuant to Rule 13d-1(b):

 "By signing below I certify that, to the best of my knowledge and
 belief, the securities referred to above were acquired and are held in
 the ordinary course of business and were not acquired and not held for
 the purpose of or with the effect of changing or influencing the
 control of the issuer of the securities and were not acquired and are
 not held in connection with or as a participant in any transaction
 having such purpose or effect."

CUSIP No. 629428103 13G Page 5 of 5 Pages

 SIGNATURE

 After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.


 February 14, 2008
 -----------------------------------
 Date

 /s/ Peter C. Keefe
 -----------------------------------
 Signature

 Peter C. Keefe, President
 -----------------------------------
 Name/Title