As previously disclosed, Beacon Power Corporation (the "Company") has entered into a Common Stock Purchase Agreement dated as of February 19, 2009 between the Company and Seaside 88, LP and a first amendment to such agreement dated as of June 19, 2009 (as so amended, the "Agreement"). Under the Agreement, the Company is required to issue and Seaside to buy 1,500,000 shares of the Company's common stock twice each month at closings on the 5th day and 20th day of each month during the term of the Agreement (or if that day is not a business day, then on the next business day) at a purchase price equal to 86% of the volume weighted average trading price of the Company's common stock over the ten trading day period immediately preceding each closing, but in no event below $0.20 per share, and in each case subject to the terms and conditions of the Agreement.

Pursuant to the Agreement, the Company will issue, and Seaside will purchase, 1,500,000 shares of common stock on October 20, 2009 at a price per share of $0.62797, for gross proceeds of $941,955. The price per share is equal to the daily volume weighted average trading price for the ten consecutive trading days immediately preceding the closing date, multiplied by 86%. In addition, the Company will pay Seaside $9,000 in non-accountable expenses. This represents the thirteenth closing under the Agreement.

(d) Exhibits

5.1                 Opinion of Edwards Angell Palmer & Dodge LLP



23.2              Consent of Edwards Angell Palmer & Dodge LLP (contained in
Exhibit 5.1)