Goldman Sachs Group Inc. executive Ken Pontarelli, who helped lead the firm's private-equity investments in the energy sector, is retiring, according to an internal memo.

Pontarelli spent 22 years at Goldman Sachs, and most recently served as chief investment officer of West Street Energy Partners, the bank's fund focused on renewable energy and natural resources.

Scott Lebovitz will replace Pontarelli.

A bank spokesman confirmed the contents of the memo on Jan. 11.

Pontarelli joined Goldman Sachs in 1992 as an investment banking analyst. After working in various roles in debt capital markets and banking, he joined the firm's private-equity division in 1999 to build its energy and natural resources investing unit. He became managing director in 2004 and partner in 2006.

Most recently, Pontarelli's group helped to establish a bond facilty to target $1 billion in investment within the next few years for clean energy projects in Japan. It also backed India's clean energy company ReNew Power Venture Pvt.

Pontarelli is the latest senior departure at Goldman Sach's merchant bank, which is led by longtime partner Richard Friedman. Last year, Thomas Carella, who led healthcare investment, joined private-equity firm Warburg Pincus LLC. Jack Daly, who ran industrials investments at Goldman, also resigned to join TPG Capital.