Eilenberg & Krause llp

11 East 44th Street

New York, New York 10017

Telephone: (212) 986-9700

Facsimile: (212) 986-2399

August 28, 2012

Acorn Energy, Inc.

3903 Centerville Road

Wilmington, DE 19807

Ladies and Gentlemen:

We are acting as counsel to Acorn Energy, Inc., a Delaware corporation (the “Company”), in connection with its registration statement on Form S-3, File No. 333-169434 (the “Registration Statement”), filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the “Act”) relating to the proposed public offering (the “Offering”) of up to 600,000 shares of the common stock, par value $0.01 per share (the “Common Stock”) of the Company (the “Shares”) under the Company’s Dividend Reinvestment Plan (the “DRIP”). The Offering is being made pursuant to the Prospectus dated October 27, 2010, which forms a part of the Registration Statement, as supplemented by a Prospectus Supplement filed on August 15, 2012 (together with the Prospectus, the “Prospectus Supplement”) which sets forth the terms of the DRIP. 

For purposes of this opinion letter, we have examined copies of such agreements, instruments and documents as we have deemed an appropriate basis on which to render the opinions hereinafter expressed, including the DRIP.   In our examination of the aforesaid documents, we have assumed the genuineness of all signatures, the legal capacity of all natural persons, the accuracy and completeness of all documents submitted to us, the authenticity of all original documents, and the conformity to authentic original documents of all documents submitted to us as copies (including telecopies).  As to all matters of fact, we have relied on the representations and statements of fact made in the documents so reviewed, and we have not independently established the facts so relied on.  This opinion letter is given, and all statements herein are made, in the context of the foregoing.

Based upon, subject to and limited by the foregoing, we are of the opinion that, as of the date hereof:

1. The Shares have been duly authorized by all necessary corporate action on the part of the Company.

2. When sold in the manner contemplated by the DRIP, and upon receipt by the Company of payment therefor as provided therein, the Shares will be validly issued, fully paid and nonassessable.

Acorn Energy, Inc.

August 28, 2012

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Please be advised that we are qualified to practice law in the State of New York, and we do not purport to be experts on, nor do we express any opinion as to, the laws of any jurisdiction other than the laws of the State of New York, the Delaware General Corporation Law and the federal laws of the United States.

We hereby consent to the filing of this opinion letter as Exhibit 5.1 to the Company’s Current Report on Form 8-K expected to be filed on August 28, 2012, and to the reference to this firm under the caption “Legal Matters” in the Prospectus Supplement.  In giving this consent, we do not thereby admit that we are an “expert” within the meaning of the Securities Act of 1933, as amended.