UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549



FORM 10-Q/A

Amendment No.1



QUARTERLY REPORT PURSUANT TO SECTION 13
OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934



For the quarterly period ended March
31, 2013



Commission file number: 0-19771



ACORN ENERGY, INC.

(Exact name of registrant as specified in
charter)



|Delaware
        (State or other jurisdiction of incorporation
        or organization)      |  | 22-2786081
        (I.R.S. Employer Identification No.)
|-------------------------------------------------------------------------------------------- |  | -------------------------------------------------------
|                                                                                             |  |                                                        
|3903 Centerville Road, Wilmington, Delaware
        (Address of principal executive offices) |  | 19807
        (Zip Code)                               



302-656-1707

(Registrant’s telephone number,
including area code)



Indicate
by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange
Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports),
and (2) has been subject to such filing requirements for the past 90 days. YesxNo ̈



Indicate
by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive
Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such
shorter period that the registrant was required to submit and post such files).  YesxNo ̈



Indicate by check mark whether the registrant is a large accelerated
filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated
filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check
one):



Large
accelerated filer ̈Accelerated
filerxNon-accelerated
filer ̈Smaller
reporting company ̈



Indicate by check mark whether the registrant
is a shell company (as defined in Rule 12b-2 of the Exchange Act).

Yes ̈Nox



Indicate the number of shares outstanding
of each of the issuer's classes of common stock, as of the latest practicable date.

|Class                                   |  | Outstanding at May 2, 2013
|--------------------------------------- |  | --------------------------
|Common Stock, $0.01 par value per share |  | 18,090,536 shares         











Explanatory Note



The purpose of this Amendment No. 1 to the Quarterly Report
on Form 10-Q of Acorn Energy, Inc. for the quarterly period ended March 31, 2013, filed with the Securities and Exchange Commission
on May 9, 2013 (the “Form 10-Q”), is solely to file certifications of the Chief Executive Officer and Chief Financial
Officer as Exhibits 31.1, 31.2, 32.1 and 32.2 to the Form 10-Q which were inadvertently omitted in the initial filing of the Form
10-Q.



No other changes have been made to the Form 10-Q. This Amendment
No. 1 to the Form 10-Q speaks as of the original filing date of the Form 10-Q, does not reflect events that may have occurred subsequent
to the original filing date, and does not modify or update in any way disclosures made in the original Form 10-Q.











PART II



ITEM 6. EXHIBITS.





|##10.1* | GridSense Employee Incentive Plan.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|##10.2* | Form of award for GridSense Employee Incentive Plan.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|#31.1   | Certification of Chief Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|#31.2   | Certification of Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|#32.1   | Certification of Chief Executive Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|#32.2   | Certification of Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|##101.1 | The following financial statements from Acorn Energy's Form 10-Q for the quarter ended March 31, 2013, filed on May 9, 2013, formatted in XBRL (eXtensible Business Reporting Language): (i) Condensed Consolidated Balance Sheets, (ii) Condensed Consolidated Statements of Operations, (iii) Condensed Consolidated Statements of Comprehensive Loss, (iv) Condensed Consolidated Statements of Changes in Equity, (v) Condensed Consolidated Statements of Cash Flows and (vi) Notes to Condensed Consolidated Financial Statements, tagged as blocks of text.



* This exhibit includes a management contract, compensatory
plan or arrangement in which one or more directors or executive officers of the Registrant participate.



# This exhibit is filed or furnished herewith.

## This exhibit has been previously filed or furnished.











SIGNATURES



Pursuant to the requirements
of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by its principal
financial officer thereunto duly authorized.



|                    | ACORN ENERGY, INC.
|------------------- | ------------------
|                    |                   
|Dated: May 14, 2013 | By:               
|                    |                   
|                    |