Exhibit 32.1

CERTIFICATION PURSUANT TO SECTION 1350 OF CHAPTER 63

OF TITLE 18 OF THE UNITED STATES CODE

I, C. Adam Procell, Chief Executive Officer of Lime Energy Co. (the “Company”), certify pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge and belief:

1.The Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2015 (the “Report”) fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2.The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ C. Adam Procell

C. Adam Procell

President and Chief Executive Officer

March 30, 2016