Onyx Announces Appointment of Mary Beth Mandanas as Chief Executive Officer

New York, New York - January 23, 2022

Onyx Renewable Partners L.P. (“Onyx”), a leading renewable energy development and solutions company headquartered in New York, today announced it has hired Mary Beth Mandanas to become its new Chief Executive Officer and member of the Advisory Board.

Mandanas succeeds Buck Fletcher and Dan Swayze, who will step down as interim Co-CEOs and resume as Chief Financial Officer and Chief Operating Officer, respectively.

“Following a comprehensive search process, we identified Mary Beth as the clear choice to bring Onyx into its next phase of growth as we aim to enhance its position as a premier renewable and distributed energy company. With more than 25 years of energy and finance experience and her proven track record building profitable platforms, Mary Beth will be a terrific leader of our team,” said Jonathan Maxwell, Chairman of the Onyx board and CEO and Founder of Sustainable Development Capital LLP (“SDCL”). “We are thrilled that Mary Beth has joined the company at this exciting time.”

“Mary Beth’s record of success in investing, corporate strategy, and investment banking will be vital in enhancing Onyx’s position as the leading North American renewable and distributed energy platform, while also developing vanguard solutions for clients to push towards a sustainable clean energy future. We are excited to have her aboard and look forward to her contributions. We also thank Buck and Dan who have guided Onyx effectively as interim Co-CEOs during the leadership transition,” said Bilal Khan, an Onyx board director and Senior Managing Director at Blackstone.

Mandanas previously served as the Chief Investment Officer of Sol Systems, where she played a pivotal role in the repositioning of the company’s growth strategy. Prior to Sol Systems, Mandanas served as Executive Vice President and Chief Strategy Officer at CleanChoice Energy, a retail electricity company specializing in the procurement and delivery of renewable electricity. Her previous experience includes Head of the Power and Utilities Corporate Banking group at the Royal Bank of Canada, where she covered renewable, power, and utility clients. She also spent an aggregate of fifteen years working with power and utility clients at Citigroup and Credit Suisse First Boston. She currently serves as an independent director for TortoiseEcofin Acquisition Corp. III (NYSE: TRTL) and has been named as an independent director for Energy Vault, Inc.

“It will be a privilege to lead Onyx, and I am excited to partner with SDCL and Blackstone to support Onyx’s growth trajectory and strategic plan. Onyx is one of the largest sustainable energy platforms of its kind in the United States, and this is an extraordinary opportunity to position Onyx at the forefront of the national dialogue on energy transition and as one of the leading participants in this rapidly-evolving sector,” said Mandanas.