UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

o

Rule 13d-1(b)

o

Rule 13d-1(c)

x

Rule 13d-1(d)

1.

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

Metalmark Capital LLC

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

(a)              T
(b)              £

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

20,494,938

6.

SHARED VOTING POWER

0

7.

SOLE DISPOSITIVE POWER

20,494,938

8.

SHARED DISPOSITIVE POWER

0

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

20,494,938

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)

£

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

43.7%

12.

TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

CO

1.

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

Morgan Stanley

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

(a)              £
(b)              T

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

2,463,302

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

2,463,302

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

2,463,302

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)

£

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

5.3%

12.

TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

CO

1.

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

MSDW Capital Partners IV, Inc.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

(a)              T
(b)              £

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

515,697

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

515,697

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

515,697

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)

£

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

1.1%

12.

TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

CO, IA

1.

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

MSDW Capital Partners IV, LLC

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

(a)              T
(b)              £

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

515,697

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

515,697

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

515,697

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)

£

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

1.1%

12.

TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

CO, IA

1.

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

Morgan Stanley Dean Witter Capital Investors IV, L.P.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

(a)              T
(b)              £

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

515,697

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

515,697

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

515,697

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)

£

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

1.1%

12.

TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

PN

1.

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

Morgan Stanley Global Emerging Markets, Inc.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

(a)              T
(b)              £

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

1,947,605

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

1,947,605

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,947,605

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)

£

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

4.2%

12.

TYPE OF REPORTING PERSON (See Instructions)

CO, IA

1.

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

MSGEM, LLC

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

(a)              T
(b)              £

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

1,947,605

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

1,947,605

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,947,605

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)

£

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

4.2%

12.

TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

CO

1.

NAMES OF REPORTING PERSON
I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

Morgan Stanley Global Emerging Markets Private Investment Fund, L.P.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

(a)              T
(b)              £

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

1,835,861

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

1,835,861

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,835,861

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)

£

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

3.9%

12.

TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

PN

1.

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

Morgan Stanley Global Emerging Markets Private Investors, L.P.

2.

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

(a)              T
(b)              £

3.

SEC USE ONLY

4.

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

SHARES

BENEFICIALLY

OWNED BY

EACH

REPORTING

PERSON

WITH

5.

SOLE VOTING POWER

0

6.

SHARED VOTING POWER

111,744

7.

SOLE DISPOSITIVE POWER

0

8.

SHARED DISPOSITIVE POWER

111,744

9.

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

111,744

10.

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)

£

11.

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

0.2%

12.

TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

PN

Item 1

(a).

Name of Issuer:

EnerSys

Item 1

(b).

Address of Issuer’s Principal Executive Offices:

2366 Bernville Road
Reading, PA  19605

Item 2

(a).

Name of Person Filing:

This statement is filed on behalf of the persons identified below. In accordance with Rule 13d-1(k)(1) under the Act, each person filing this statement acknowledges that it is responsible for the completeness and accuracy of the information concerning that person but is not responsible for the completeness or accuracy of the information concerning the other persons making the filing, unless such person knows or has reason to believe that such information is inaccurate.

Metalmark Capital LLC (“Metalmark”)

Morgan Stanley (“MS”)

MSDW Capital Partners IV, Inc. (“MSCP IV, Inc.”)

MSDW Capital Partners IV, LLC (“MSCP IV, LLC”)

Morgan Stanley Dean Witter Capital Investors IV, L.P. (“MSCI IV, L.P.” and, together with MSCP IV, Inc. and MSCP IV, LLC, the “MSCP Funds”)

Morgan Stanley Global Emerging Markets, Inc. (“MSGEM, Inc.”)

MSGEM, LLC (“MSGEM, LLC”)

Morgan Stanley Global Emerging Markets Private Investment Fund, L.P. (“MSGEM PIF”)

Morgan Stanley Global Emerging Markets Private Investors, L.P. (“MSGEM PI” and, together with MSGEM, Inc., MSGEM, LLC and MSGEM PIF, the “MSGEM Funds”)

Item 2

(b).

Address of Principal Business Office or, if none, Residence:

The address of the principal business office of Metalmark is:
1177 Avenue of the Americas
New York, NY 10036

The address of the principal business office of MS, MSCP IV, Inc., MSCP IV, LLC, MSCI IV, L.P., MSGEM, Inc., MSGEM, LLC, MSGEM PIF and MSGEM PI is:
1585 Broadway
New York, NY 10036

Item 2

(c).

Citizenship:

The place of organization of Metalmark, MS, MSCP IV, Inc., MSCP IV, LLC, MSCI IV, L.P., MSGEM, Inc., MSGEM, LLC, MSGEM PIF and MSGEM PI is Delaware.

Item 2

(d).

Title of Class of Securities:

This statement relates to the Company’s Common Stock, par value $0.01 per share.

Item 2

(e).

CUSIP Number:

29275Y 10 2

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)

£   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).

Item 4.

Ownership.

The filing of this statement should not be construed as an admission by any person that such person is, for purposes of Section 13(d) or 13(g) of the Exchange Act, the beneficial owner of any securities covered by this statement, other than the securities set forth opposite such person’s name in the table in Item 4(c) below.

(a) Amount beneficially owned:

As of December 31, 2006, Morgan Stanley Dean Witter Capital Partners IV, L.P. (“MSCP IV, L.P.”) owned directly 18,869,605 shares and MSDW IV 892 Investors, L.P. (“MSCP IV 892, L.P.”) owned directly 1,607,833 shares.  An affiliate of Metalmark is the subadvisor to MSCP IV, L.P. and MSCP IV 892, L.P. and, as such, has the sole power to vote or direct the vote and to dispose or direct the disposition of all shares held by MSCP IV, L.P. and MSCP IV 892, L.P.

As of December 31, 2006, MSCI IV, L.P. owned directly 515,697 shares.  MSCP IV, LLC is the general partner of MSCI IV, L.P. and, as such, has the power to vote or direct the vote and to dispose or direct the disposition of all shares held by MSCI IV, L.P.  MSCP IV, Inc. is the managing member of MSCP IV, LLC and, as such, shares the power to direct the actions of MSCI IV, LLC.  MS, as sole shareholder of MSCP IV, Inc., controls the actions of MSCP IV, Inc.  Therefore, MSCP IV, LLC and MSCP IV, Inc. each may be deemed to have beneficial ownership of the 515,697 shares held by MSCI IV, L.P.

As of December 31, 2006, MSGEM PIF owned directly 1,835,861 shares and MSGEM PI owned directly 111,744 shares.  MSGEM, LLC is the general partner of MSGEM PIF and MSGEM PI and, as such, has the power to vote or direct the vote and to dispose or direct the disposition of all shares held by MSGEM PIF and MSGEM PI.  MSGEM, Inc. is the managing member of MSGEM, LLC and, as such, shares the power to direct the actions of MSGEM, LLC.  MS, as sole shareholder of MSGEM, Inc., controls the actions of MSGEM, Inc.  Therefore, MSGEM, Inc. and MSGEM, LLC each may be deemed to have beneficial ownership of the 1,947,605 shares held by MSGEM PIF and MSGEM PI.

Therefore, MS may be deemed to have beneficial ownership of the 2,463,302 shares held by MSCI IV, LP, MSGEM PIF and MSGEM PI.

MS is filing solely in its capacity as parent company of, and indirect beneficial owner of securities held by, one of its business units.

By virtue of a subadvisory arrangement, Metalmark may be deemed to have sole power to vote or direct the vote and to dispose or direct the disposition of the shares held by MSCP IV, L.P. and MSCP IV 892, L.P.  In addition, under the subadvisory arrangement, MSCI IV, L.P. is effectively obligated to vote or direct the vote and to dispose or direct the disposition of any shares owned directly by it on the same terms and conditions as MSCP IV, L.P. and MSCP IV 892, L.P. Metalmark also beneficially owns 17,500 shares issuable upon exercise of fully vested options.

(b)  Percent of class: (1)

Metalmark Capital LLC

43.7% of the Common Stock

Morgan Stanley

5.3% of the Common Stock

MSDW Capital Partners IV, Inc.

1.1% of the Common Stock

MSDW Capital Partners IV, LLC

1.1% of the Common Stock

Morgan Stanley Dean Witter Capital Investors IV, L.P.

1.1% of the Common Stock

Morgan Stanley Global Emerging Markets, Inc.

4.2% of the Common Stock

MSGEM, LLC

4.2% of the Common Stock

Morgan Stanley Global Emerging Markets Private Investment Fund, L.P.

3.9% of the Common Stock

Morgan Stanley Global Emerging Markets Private Investors, L.P.

0.2% of the Common Stock

(1) Based on the Common Stock outstanding on December 31, 2006.

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

(i)
Sole power to

vote or to direct the  vote

(ii)
Shared power to

vote or to direct the  vote

(iii)
Sole power to

dispose or to direct the disposition of

(iv)
Shared power to

dispose or to direct the disposition of

Metalmark Capital LLC

20,494,938

- 0 -

20,494,938

- 0 -

Morgan Stanley

2,463,302

2,463,302

MSDW Capital Partners IV, Inc.

- 0 -

515,697

- 0 -

515,697

MSDW Capital Partners IV, LLC

- 0 -

515,697

- 0 -

515,697

Morgan Stanley Dean Witter Capital Investors IV, L.P.

- 0 -

515,697

- 0 -

515,697

Morgan Stanley Global Emerging Markets, Inc.

- 0 -

1,947,605

- 0 -

1,947,605

MSGEM, LLC

- 0 -

1,947,605

- 0 -

1,947,605

Morgan Stanley Global Emerging Markets Private Investment Fund, L.P.

- 0 -

1,835,861

- 0 -

1,835,861

Morgan Stanley Global Emerging Markets Private Investors, L.P.

- 0 -

111,744

- 0 -

111,744

Item 5.

Ownership of Five Percent or Less of a Class.

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following  £

Item 6.

Ownership of More than Five Percent on Behalf of Another Person.

N/A

Item 7.

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

N/A

Item 8.

Identification and Classification of Members of the Group.

Metalmark, the MSCP Funds, the MSGEM Funds, J.P. Morgan Direct Corporate Finance Institutional Investors LLC (“J.P. Morgan Institutional”), J.P. Morgan Direct Corporate Finance Private Investors LLC (“J.P. Morgan Private”), 522 Fifth Avenue Fund, L.P. (together with J.P. Morgan Institutional and J.P. Morgan Private, the “J.P. Morgan Funds”), First Plaza Group Trust (“First Plaza”) and Performance Direct Investments I, L.P. (together with First Plaza, the “GM Stockholders”) have entered into a 2004 Securityholder Agreement dated as of July 26, 2004, which governs certain relationships among such parties as stockholders.

Metalmark, the MSCP Funds, the MSGEM Funds, the J.P. Morgan Funds and the GM Stockholders may be deemed to be a “group” for purposes of Section 13(d)(3) or Section 13(g)(3) of the Act and Rule 13d-5(b)(1) thereunder.

Metalmark, the MSCP Funds and the MSGEM Funds believe that, as of December 31, 2006, the J.P. Morgan Funds held 2,272,215 shares, or 4.8%, of the Common Stock, and the GM Stockholders held 1,947,606 shares, or 4.2%, of the Common Stock.

Item 9.

Notice of Dissolution of Group.

N/A

Item 10.

Certifications.

Not Applicable to filings pursuant to Rule 13d-1(d).