Energy-focused private equity firm First Reserve Partners is buying Utility Services Associates Inc.

Utility Services consists of C.W. Wright Construction Co. Inc., Booth & Associates Inc. and Coastal Power & Electric Inc. The target provides utility services, including maintenance, repair and construction services for power transmission and distribution infrastructure. The company also designs storm-related restoration systems. Terms of the deal were not disclosed.

First Reserve says the company will be able to capitalize on utilities seeking to outsource maintenance as investments in the electrical grid increase.

Greenwich, Conn.-based First Reserve focuses on investing in energy companies. In June, the firm invested $500 million to form Century Midstream LLC. And in December, the firm closed a deal for Ameriforge Group. First Reserve won Mergers & Acquisitions Private Equity of the Year Award for 2011.

Other recent electricity deals include Emera Inc.’s (TSX: EMA) purchase of three electricity facilities for $541 million, and Atwell LLC’s deal for Peak Power Engineering Inc.