Jonathan Darnell is a Managing Director with responsibility for business development and impact measurement and management. Jon joined Lime Rock in 2025, bringing over 30 years of New Energy experience across the public policy and commercial arenas. From 2016 to 2025, he served as a Managing Director at AltEnergy, LLC, a cleantech private equity firm, and Chief Financial Officer of AltEnergy Acquisition Corp. In 2012, Jon founded capital advisor Patolan Partners, securing equity commitments for clients including a leading US renewables developer and Eos Energy Storage. Previously, he was a Vice President at Morgan Stanley & Co. and CEO of Telefund, Inc., supporting the nation’s top environmental groups while growing profit for 10 years.
Jon serves as a Trustee and Investment Committee Member for Green Century Funds, the nation’s first environmentally screened and fossil-free family of mutual funds. He is a former nationally ranked squash player and avid musician who trained at The Juilliard School. Jon is a graduate of Princeton University (A.B.) and the Wharton School of the University of Pennsylvania (M.B.A.)