Green Plains (GPRE) 10-Q 2008 Q3 Quarterly report

Exhibit 32.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER PURSUANT TO 18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Green Plains Renewable Energy, Inc. (the “Company”) on Form 10-Q for the fiscal quarter ended August 31, 2008 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Wayne B. Hoovestol, Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

1)

The Report fully complies with the requirements of Sections 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.

Date: October 10, 2008	/s/ Wayne B. Hoovestol
	Wayne B. Hoovestol
	Chief Executive Officer and Director