William Lemmons

William R. ("Billy") Lemmons Jr. is a co-founder and Managing Partner of EnCap Flatrock Midstream, a San Antonio–based investment firm he helped establish in 2008 as a partnership between Flatrock Energy Advisors and EnCap Investments L.P. He is one of the firm's founding leaders alongside Bill Waldrip and Dennis Jaggi, a group that has worked together across much of the past three decades in the midstream sector. From 2002 to 2008, Lemmons served as Executive Vice President and Senior Partner of Flatrock Energy Advisors, the predecessor advisory firm.

Earlier in his career, Lemmons spent a decade at Enron Corp. (1992–2002), where he served as a Vice President and held a range of energy-finance and commercial-origination positions. Before Enron, he worked as an engineer at Texas Oil & Gas Corporation from 1984 to 1992, giving him a technical foundation in the oil-and-gas business that predates his move into energy finance.

Lemmons holds a B.S. in Petroleum Engineering from Texas A&M University and an M.B.A. (Phi Kappa Phi) from the Mays Graduate School of Business at Texas A&M. He is a (currently inactive) Registered Professional Engineer in Texas and a member of the Society of Petroleum Engineers and the Society of Petroleum Evaluation Engineers.

Beyond investing, Lemmons is active in board and philanthropic work. He serves as Chair of the Board of Trustees of the Texas A&M Foundation (and previously chaired its Investment Committee) and was appointed to the Board of Trustees of the George & Barbara Bush Foundation in July 2017. He also sits on the boards of EFM portfolio companies including Cardinal Midstream Partners and M6 Midstream, and supports community organizations such as Hill Country Daily Bread, Hill Country Family Services, and Family Legacy Ministries.

• Growth capital for proven teams, not seed bets: EFM provides "value-added growth capital to proven management teams focused on midstream infrastructure opportunities across North America." The firm backs experienced operators rather than unproven early-stage founders.
• Large, structured commitments: Targeted capital commitments typically run $200M–$300M per management team, with the ability to go larger in conjunction with EnCap's investment partners.
• Deep midstream sector specialization: Investments span natural gas gathering/treating/compression/processing/storage, crude oil gathering and transportation, NGL fractionation/storage/transportation, produced-water handling and disposal, and CO2 gathering/transportation/sequestration.
• Scale: EFM manages Funds I–V with roughly $9–10 billion in aggregate capital commitments from institutional investors, and is currently deploying its flagship EFM Fund V.
• What makes them say yes: A management team with a demonstrated midstream operating track record and a clearly scoped North American infrastructure buildout plan — the firm repeatedly re-backs teams it knows (e.g., forming "II" vehicles with existing partners).