Executive Leadership

Thad Hill President and Chief Executive Officer

Thad Hill became Calpine’s President and Chief Executive Officer and a member of its Board of Directors in May 2014. Mr. Hill joined the company in September 2008 as Executive Vice President and Chief Commercial Officer. He became Chief Operating Officer in November 2010 and was named President in December 2012. Prior to Calpine, Mr. Hill was with NRG Energy from 2006 to 2008, serving as President of NRG Texas in 2007- 2008. Prior to NRG, Mr. Hill was Executive Vice President of Strategy and Business Development at Texas Genco LP from 2005 to 2006. From 1995 to 2005, he was with Boston Consulting Group Inc., where he rose to Partner and Managing Director and led the North American energy practice, serving companies in the power and gas sector with a focus on commercial and strategic issues. Mr. Hill received his Bachelor of Arts degree from Vanderbilt University magna cum laude and a Master of Business Administration degree from the Amos Tuck School of Dartmouth College, where he was elected an Edward Tuck Scholar.

Thad Miller Executive Vice Chairman and Chief Legal Officer

W. Thaddeus Miller joined Calpine Corporation in August 2008 as Executive Vice President, Chief Legal Officer and Secretary. In March 2018, he was named Executive Vice Chairman of Calpine’s Board of Directors. Mr. Miller brings decades of legal and energy industry experience to Calpine. He previously served as Executive Vice President and Chief Legal Officer of Texas Genco Inc. until 2006. From 2002 to 2004, Mr. Miller was a consultant to Texas Pacific Group, a private equity firm. From 1998 to 2002, he served as Executive Vice President and Chief Legal Officer of Orion Power, an independent power producer. From 1994 to 1998, Mr. Miller was Vice President of Goldman Sachs & Co., where he focused on wholesale electric and other energy commodity trading. Before joining Goldman Sachs & Co., Mr. Miller was a partner in a New York law firm. Mr. Miller currently serves on the board of RMG Acquisition Corp. since December 2019. Mr. Miller earned his Bachelor of Science degree from the United States Merchant Marine Academy and his Juris Doctor from St. John's School of Law. In addition, he was an officer in the United States Coast Guard.

Zamir Rauf Executive Vice President and Chief Financial Officer

Zamir Rauf has served as Executive Vice President and Chief Financial Officer since December 2008. Mr. Rauf previously was interim Chief Financial Officer and Treasurer from June 2008 to December 2008. Prior to his role as Interim CFO, Mr. Rauf was Senior Vice President, Finance and Treasurer at Calpine. In that position, he had responsibility for Calpine's corporate and project finance, treasury and debt compliance functions and managed the corporate banking, investment banking and rating agency relationships. Prior to Calpine, Mr. Rauf held various accounting and finance roles with Enron North America and Dynegy Inc., as well as Comerica Bank in both credit and lending roles. He earned his Bachelor of Arts degree in business and commerce and master's degree in business administration-finance from the University of Houston.

Charlie Gates Executive Vice President of Power Operations

Charlie Gates joined Calpine as Executive Vice President of Power Operations in April 2016. Previously, Mr. Gates had served as Senior Vice President and Chief Fossil/Hydro Officer for Duke Energy Corporation since August 2014. He had been Duke’s SVP of Power Generation Operations since July 2012, when Progress Energy merged with Duke. Mr. Gates had served in a similar capacity for Progress since January 2012 after being promoted from Vice President of Fossil Generation for Progress Energy for the Carolinas and Florida. He was previously General Manager of Progress Energy Florida from the time the company merged with Carolina Power & Light Company in 2001 to 2006. Mr. Gates began his power industry career with Carolina Power & Light in 1982 as an associate engineer and moved up through increasingly responsible positions to become General Manager of five fossil-fuel plants in 2000. Mr. Gates’ other industry leadership roles include serving as Chairman of the Generation Council for the Electric Power Research Institute. He earned bachelor’s degrees in chemical engineering from North Carolina State University and in political science from the University of North Carolina.

ANDREW NOVOTNY Chief Operating Officer

Andrew Novotny has served as Chief Operating Officer since January 2021. In this role, Mr. Novotny is responsible for Calpine’s Commercial and Power Operations. Prior to his current role, he served as Executive Vice President of Commercial Operations, co-leading the company’s wholesale commercial operations and analytics functions while also providing oversight to Calpine's ISO and RTO advocacy across North America. Mr. Novotny joined Calpine in April 2012 as Vice President of Power Trading, holding a variety of trading leadership roles since that time. Before joining Calpine, Mr. Novotny served as Vice President of Financial Gas and Power Trading for the BG Group beginning in 2007. Prior to his time at the BG Group, Mr. Novotny was a Vice President with Duke Energy. Mr. Novotny received a Bachelor of Arts from Vanderbilt University, graduating magna cum laude with high honors in Economics. He also received a Master of Business Administration from Rice University, where he was named a Jones Scholar.

CALEB STEPHENSON Executive Vice President, Commercial Operations

Caleb Stephenson has served as an Executive Vice President of Commercial Operations since March 2018. In this role, he leads the wholesale commercial and analytics function. He is responsible for the teams who develop wholesale customer relationships and new power projects, as well as those who support the company with information technology applications and infrastructure. Mr. Stephenson joined Calpine in October 2008 as Vice President of Commercial Analytics. He became Senior Vice President of Commercial Analytics in May 2014 and added wholesale origination to his responsibilities in February 2017.He came to Calpine from PA Consulting Group’s Global Energy Practice, where he advised merchant power industry participants on energy market outlook and risk management issues. He holds a Master of Business Administration in finance from Washington University.

Hether Benjamin Brown Senior Vice President and Chief Administrative Officer

Hether Benjamin Brown has served as Calpine’s Senior Vice President and Chief Administrative Officer since May 2014. In this role, she oversees the company’s Corporate Communications, Facilities, Human Resources, Information Technology, and Supply Chain Services functions. Ms. Benjamin Brown previously served as Calpine’s Senior Vice President of Human Resources beginning in February 2012. In this role, she led staffing and talent acquisition, organizational development, and compensation and benefits. She joined Calpine in May 2009 as Vice President of Supply Chain Services, and in that position she transformed and centralized Calpine’s supply chain function to improve efficiency, lower costs and leverage the company’s size and scale nationally. Prior to joining Calpine, she was Director of Supply Chain Management for the University of Texas M.D. Anderson Cancer Center. Previously, Ms. Benjamin Brown served in leadership roles of increasing responsibility at other public- and private-sector organizations in the aerospace/defense, environmental/waste and information technology industries. She holds a Bachelor of Arts in political science from the University of Texas at Arlington and a Master of Business Administration from Texas Women’s University.

RICK COLGAN Senior Vice President of Services

As Calpine’s Senior Vice President of Services, Rick Colgan oversees the company’s Turbine Maintenance, Outage Services and Engineering groups. Previously, he served as Calpine’s Vice President of Outage Services from October 2014 until moving into his current role in October 2017. Mr. Colgan joined Calpine in 1996 serving in a variety of plant management roles before becoming Director of Asset Management for Calpine’s West Region in 2010. He was Vice President of Regional Operations for the company’s former Southeast Region from October 2012 until October 2014. Earlier in his career, he worked with Bechtel Power’s start-up and operations group. Mr. Colgan studied industrial engineering at the University of Wyoming and served in the U.S. Navy.

MIKE DEL CASALE Senior Vice President of Power Operations

Mike Del Casale has served as Calpine’s Senior Vice President of Power Operations since October 2017. In January 2021, his role was expanded to include Asset Performance Management. Previously, Mr. Del Casale had served as Vice President of Regional Operations and Construction since October 2016 and as Vice President of Engineering and Construction beginning in February 2015. Mr. Del Casale joined Calpine as a part of the Conectiv Energy acquisition in 2010 and earlier served as Calpine’s East Region Asset Manager and Plant Manager at the York Energy Center. Before the acquisition, he was involved with a number of plant construction and commissioning projects along with other operations and engineering positions throughout his career. Mr. Del Casale worked at the Philadelphia Naval Shipyard for several years before joining Delmarva Power and Light, which later become Conectiv Energy. He has a bachelor’s degree in mechanical engineering from Villanova University.

Bryan Kimzey Senior Vice President, Finance and Treasurer

Bryan Kimzey has served as Calpine’s Senior Vice President of Finance and Treasurer since March 2018. In this role, he is responsible for Calpine’s treasury function, credit, financial planning and analysis, and relationships with Calpine’s debt investors. Previously, Mr. Kimzey had served as Vice President of Investor Relations and Financial Planning since January 2015. He joined the company as Vice President of Investor Relations at Calpine in September 2011. Prior to Calpine, Mr. Kimzey was with Progress Energy, Inc., from 2004 to 2011, serving in various roles in Investor Relations, Treasury and Strategic Planning. Prior to Progress Energy, Inc., Mr. Kimzey was with Credit Suisse First Boston from 1998 to 2004, where he rose to Vice President in the firm’s investment banking group in New York, serving companies in the power and gas sectors with a focus on mergers, acquisitions and underwriting. He began his career in 1996 with Arthur Andersen, where he audited energy marketing and trading businesses in Houston. Mr. Kimzey received his Bachelor of Science degree in business administration and his Master of Accounting degree from the University of North Carolina at Chapel Hill.

JEFF KOSHKIN Senior Vice President, Chief Accounting Officer and Chief Risk Officer

Jeff Koshkin has served as Calpine’s Senior Vice President and Chief Accounting Officer since August 1, 2015, and gained additional responsibility as Chief Risk Officer in March 2018. He joined Calpine in December 2008 and has served in a number of leadership roles including the Controller of Commercial Operations and Controller of Corporate and Plant Accounting, as well as in interim roles heading Financial Planning and Analysis and as Chief Risk Officer. Prior to Calpine, Mr. Koshkin was a Senior Manager in the Regulatory and Capital Markets practice for Deloitte and Touche, LLP. He holds a master’s degree in Professional Accounting from the University of Texas at Austin. Mr. Koshkin is a Certified Public Accountant and a member of the American Institute of Certified Public Accountants and the Texas Society of Certified Public Accountants.

TOM LONG Senior Vice President, Asset Performance Management

Tom Long was named Calpine’s Senior Vice President of Asset Performance Management in October 2016. In this role, he leads the company’s asset management, operational analytics, project development and strategic procurement functions. Previously, Mr. Long served as Vice President of Development and Optimization Engineering since October 2011. He joined Calpine in 2000 through Calpine’s acquisition of SkyGen Energy, which he joined in 1994 and served in a number of roles in development, engineering, procurement and construction. Mr. Long holds a Bachelor of Science in Mechanical Engineering from Iowa State University and an MBA from the University of Illinois at Chicago.

ALEX MAKLER Senior Vice President, West Region

Alex Makler has served as Senior Vice President of Calpine’s West Region since May 2014. In this role, he leads the company’s commercial team in California and the West, and he collaborates with the Government & Regulatory Affairs team on policy and advocacy efforts in the region. Previously, Mr. Makler served as Calpine’s Vice President of Strategic Origination and Development for the West Region from January 2009 to May 2014. He joined Calpine’s legal department in 1999, where he served as the company’s lead attorney for California energy crisis matters and became Vice President and Assistant General Counsel. He has a background in commercial transactions, project financing, federal and state regulatory activities, legislative issues, mergers and acquisitions, and all aspects of electric generation development. Prior to Calpine, Mr. Makler practiced commercial law with major law firms in New York, Houston and San Francisco. He earned both a Bachelor of Arts degree in Political Economy and a law degree from the University of California, Berkeley.

KEVIN G. MCMAHON Senior Vice President, Internal Audit and Chief Compliance Officer

Kevin G. McMahon serves as Senior Vice President, Internal Audit and Chief Compliance Officer. He joined Calpine in May 2006 to lead the Internal Audit function and took on the added role of Chief Compliance Officer in August 2009. Mr. McMahon is responsible for managing and conducting all internal audit activities, supporting operations and the functional departments as requested, managing the Sarbanes Oxley (SOX) compliance oversight program, leading records management activities and reporting audit findings with the appropriate recommendations to senior management and the Audit Committee. In addition, he oversees the company’s regulatory compliance efforts with particular emphasis on ensuring that proper procedures are in place to help the company meet all FERC and NERC regulatory requirements. Prior to joining Calpine, he was Vice President and General Auditor for Exide Technologies, a global manufacturer of stored electrical energy products and services for industrial and transportation applications. He previously served as Vice President-Internal Audit Services and in other senior auditing positions for HCA, Inc., the largest hospital provider in the United States, and served in senior management and auditing positions for Ernst & Young LLP, Southern Company Services, FPL Group and HSBC/Marine Midland Bank N.A. Mr. McMahon has a Master of Business Administration degree from Palm Beach Atlantic University and a Bachelor of Science degree in accounting from the State University of New York. He is both a Certified Internal Auditor (CIA) and Certified in Risk Management Assurance (CRMA).

SARAH NOVOSEL Senior Vice President, Government Affairs

Sarah Novosel is Senior Vice President of Government Affairs and Managing Counsel for Calpine. She manages Calpine's Washington, D.C., office and directs its federal regulatory practice. Ms. Novosel has been practicing energy law for more than 25 years. She began her career in 1991 with the law firm of Bracewell & Patterson in Washington, D.C., where she represented natural gas and power marketing clients. After leaving Bracewell & Patterson in 1997, Ms. Novosel joined Enron Corp. and later worked for American Electric Power. She joined Calpine in 2004 as Senior Regulatory Counsel and was promoted in 2007 to her present position. A graduate of the University of Maryland with a bachelor's degree in Government and Politics, Ms. Novosel earned her law degree from Georgetown University Law Center. She is a member of the Maryland State Bar, the District of Columbia Bar and the Energy Bar Association.

RICK PEÑA Senior Vice President, Mergers, Acquisitions and Integration

Rick Peña leads Calpine’s merger and acquisition activities as well as the integration of acquired businesses. His accomplishments at Calpine have included negotiating acquisitions and divestitures of power plants that advanced the company’s strategic priorities of building scale in key competitive markets, as well as the acquisition of retail platforms that provide more direct channels to our power customers. Mr. Peña joined Calpine in June 2007 as a Director of Strategic Origination, serving our Southeast, ERCOT and North regions over the years. He was named Vice President of Corporate Development in January 2013. Prior to joining Calpine, Mr. Peña served as Manager of Mergers and Acquisitions for Direct Energy and as a Senior Analyst, Commercial Services, at Duke Energy North America. He earned his bachelor’s degree in Finance from Texas A&M University.

STEVEN SCHLEIMER Senior Vice President, Government and Regulatory Affairs

Steven Schleimer has been Calpine’s Senior Vice President for Government and Regulatory Affairs since January 1, 2014. He had previously served as Vice President of Government and Regulatory Affairs for Calpine’s North Region since 2010. From 2006 to 2010, Mr. Schleimer was Vice President at Barclays Capital in New York and was responsible for market design and regulatory issues. Prior to that, he had served as Calpine’s Vice President of Market and Regulatory Affairs in the West Region from 2000 to 2006. Mr. Schleimer spent the first 12 years of his career at Pacific Gas and Electric Company. He earned a master’s degree and a bachelor’s degree, with highest honors, in Economics from the University of California at Santa Cruz.

Will Stokes Senior Vice President – Power Trading

Will Stokes is responsible for all regional power trading in the strategic wholesale markets where Calpine operates. He joined the company in October 2009 as Vice President of Strategy. In June 2010, he went on to lead the East Trading Desk and more recently the West Trading Desk. Mr. Stokes came to Calpine from NRG, where he served in various leadership positions. He was Director of Business Development and Strategic Planning at Texas Genco, LLC, prior to its acquisition by NRG in 2006 and previously gained power industry experience through leadership positions at Merrill Lynch Commodities, Energy-Koch and the Boston Consulting Group. He holds a Bachelor of Science in Accounting and Spanish from Trinity University and a Master of Business Administration from Northwestern University.

MICHAEL SULLIVAN President & CEO, Champion Energy

Michael Sullivan has led Calpine’s retail business, Champion Energy, as President and Chief Executive Officer since March 2016 and North American Power since January 2017. He joined Champion Energy as Senior Vice President of Operations in 2008 and was promoted to Chief Operating Officer in 2010. In that role, he was responsible for all aspects of the company’s day-to-day operations, including commercial and residential sales, wholesale supply and customer operations. Prior to joining Champion Energy, Mr. Sullivan was a founding partner of Ambridge Energy, LLC, which merged with Champion Energy in June 2008. Prior to founding Ambridge, he held several roles at Reliant Energy. Mr. Sullivan’s career began at Anderson Consulting. He earned a Bachelor of Science in finance from the University of South Alabama and a Master of Business Administration from Baylor University. Click here to learn more about Champion’s leadership team.

TODD THORNTON Senior Vice President, Origination and Development

Todd Thornton has served as Calpine’s Senior Vice President of Origination and Development since May 2014. In this role, he leads development and origination activities throughout our central and eastern regions. Previously, Mr. Thornton was appointed to the position of Vice President of Commercial Development in January 2013, responsible for greenfield and brownfield development efforts. From 2009-2013, he served as Vice President, Finance and Treasurer, responsible for corporate and project finance, treasury operations, investment analytics, debt compliance and commercial credit. Mr. Thornton joined Calpine in 2000 through Calpine’s acquisition of SkyGen Energy, where he served in various financial roles. Mr. Thornton earned a Bachelor of Science degree in Finance from Northern Illinois University and holds the Chartered Financial Analyst (CFA) designation.

JIM WOOD President, Calpine Energy Solutions

Jim Wood serves as president of Calpine’s commercial and industrial retail subsidiary, Calpine Energy Solutions. As one of America’s top retail energy marketers, Calpine Energy Solutions supplies electricity and natural gas to companies and helps them manage their energy risk. Mr. Wood was President of Noble Americas Energy Solutions (Noble Solutions) before Calpine purchased that company in December 2016. He joined Noble Solutions’ predecessor company, Sempra Energy Solutions LLC, as Vice President in 2002 and was responsible for its growth strategy before becoming president in 2006. Previously, he served in progressively responsible roles at Enron and its subsidiaries from 1990-2002, finishing as Senior Director-Product and Market Management/Development. Mr. Wood earned a bachelor’s degree in marketing from Miami University in Oxford, Ohio.