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Corporate Leadership

Corporate oversight at UniSource Energy Services.

UES' record of performance and reputation for service are testaments to our employees' skill and dedication — starting with UES leadership.

UES Leadership

Bill De Julio
General Manager of UNS Electric Operations, Mohave

Nathan Shelley
General Manager of UNS Gas Operations



  • Paul J. Bonavia Chairman and CEO
  • Paul J. Bonavia Paul J. Bonavia is Chairman and Chief Executive Officer of UniSource Energy and its principal subsidiaries, Tucson Electric Power and UniSource Energy Services.

    Mr. Bonavia assumed that role Jan. 1, 2009, after his appointment by UniSource Energy's Board of Directors. Since then, he has worked to expand the company's leadership role in renewable energy and energy efficiency while maintaining safe, affordable, and reliable service to nearly 640,000 utility customers across Arizona.

    Mr. Bonavia was recently named by Governor Jan Brewer to the Board of Directors of the Arizona Commerce Authority and currently serves as Chair of the Board of Directors of Tucson Regional Economic Opportunities, Vice Chairman of the Board of Directors of the United Way of Tucson and Southern Arizona and as a member of the Tucson Airport Authority. He is a former Director of the American Wind Energy Association.

    Before joining UniSource Energy, Mr. Bonavia was President of the Utilities Group of Xcel Energy. He earned degrees from Drake University and the University of Miami School of Law and completed Harvard Business School's Advanced Management Program.


  • David G. Hutchens President and Chief Operating Officer
  • David Hutchens Mr. Hutchens is President of UniSource Energy, TEP and UES. Since joining UniSource Energy in 1995, Mr. Hutchens has held various management positions, including Vice President of Energy Efficiency and Resource Planning, Vice President of Wholesale Energy and Vice President of UNS Gas.

    Mr. Hutchens graduated from the University of Arizona with a bachelor's degree in aerospace engineering and an MBA with an emphasis in finance.


  • Kevin P. Larson Senior Vice President, Chief Financial Officer and Treasurer
  • Kevin Larson Mr. Larson is Senior Vice President and Chief Financial Officer. A 26-year veteran of UniSource Energy, Mr. Larson served in a variety of capacities in the treasury and finance areas before being named CFO in 2000. Mr. Larson also serves as Treasurer of UniSource Energy.

    Mr. Larson is a Chartered Financial Analyst and has a bachelor's degree in economics from the University of Minnesota.


  • Philip J. Dion Senior Vice President of Public Policy and Customer Solutions
  • Philip Dion Phil Dion is Vice President of Public Policy. In this capacity, he is responsible for the direction and execution of regulatory and legislative strategy at the federal and state levels for UNS Energy and its affiliates. He also oversees the customer experience through customer service and engagement, marketing, corporate communications and community relations. Mr. Dion joined UNS Energy in 2008 as Vice President of Legal and Environmental Services and was promoted to Vice President of Public Policy in 2010.

    Prior to joining UNS Energy, Mr. Dion was chief of staff and chief legal advisor to Commissioner Marc Spitzer of the Federal Energy Regulatory Commission. Mr. Dion previously worked in various roles at the Arizona Corporation Commission, including as the advisor to then-Commissioner Spitzer and as an administrative law judge. Mr. Dion's career began in litigation, including serving as a white collar crime prosecutor for Maricopa County, Arizona.

    Mr. Dion has been active on many professional and community-based boards during his career. He currently serves on the Edison Electric Institute’s Retail Energy Services Executive Advisory Committee and the Energy Delivery Public Policy Executive Advisory Committee. He also serves on the Phoenix Suns Charities’ Board of Directors.

    Mr. Dion received his bachelor's degree in finance from the University of Arizona and earned his Juris Doctorate and an MBA in finance from Santa Clara University.


  • Kentton C. Grant Vice President, Finance and Rates
  • Kentton Grant Mr. Grant is Vice President of Finance and Rates. Mr. Grant joined the company in 1995 and has held management positions in financial planning, capital resources and treasury services. Mr. Grant also serves as Treasurer of TEP and UES. Prior to joining UniSource Energy, Mr. Grant worked as a staff member at the Public Utility Commission of Texas.

    Mr. Grant is a Chartered Financial Analyst who earned a bachelor's degree in civil engineering from Purdue University and an MBA from the University of Texas at Austin.


  • Todd C. Hixon Vice President and General Counsel
  • Hixon Mr. Hixon is Vice President and General Counsel of UniSource Energy, TEP and UES. A 13-year veteran of UniSource Energy, Mr. Hixon served in a variety of capacities in the company's legal department, most recently serving as Associate General Counsel. Mr. Hixon practiced law for three years prior to joining UniSource Energy.

    Mr. Hixon has a bachelor's degree in Architecture and a Juris Doctorate from the University of Arizona.


  • Mark Mansfield Vice President, Generation
  • Mr. Mansfield is Vice President of Generation. He joined the company in 2008 most recently serving as Senior Director of Generation. Prior to joining TEP, Mr. Mansfield held various leadership positions at PacifiCorp Energy.

    Mr. Mansfield holds a Bachelor of Science in Mechanical Engineering from Brigham Young University and a Master of Business Administration from the University of Utah.


  • Herlinda H. Kennedy Corporate Secretary
  • Herlinda Kennedy Ms. Kennedy is Corporate Secretary. She has held a variety of positions during three decades at Tucson Electric Power and UniSource Energy, including assistant Corporate Secretary. Ms. Kennedy was elected to her current position in 2006.

    Ms. Kennedy is a Certified Legal Assistant and earned an associate's degree of applied science - paralegal from Pima Community College.


  • Karen G. Kissinger Vice President, Controller and Chief Compliance Officer
  • David Hutchens Ms. Kissinger is Vice President, Controller and Principal Accounting Officer. Ms. Kissinger, who has been with UniSource Energy for 20 years, is also the company's Chief Compliance Officer. Prior to joining TEP, she was a senior manager at the accounting firm of Deloitte & Touche.

    Ms. Kissinger is a Certified Public Accountant and has a bachelor's degree in Spanish from the University of Virginia and an MBA from the University of Arizona.


  • Thomas A. McKenna Vice President, Energy Delivery
  • Thomas McKenna Mr. McKenna is Vice President of Engineering and also serves as Vice President of UNS Gas and UNS Electric. Mr. McKenna has accumulated more than four decades of experience in the utility industry. Before joining UniSource Energy in 1998, Mr. McKenna was a Vice President of Sargent & Lundy, an engineering services company.

    Mr. McKenna earned a bachelor's degree in engineering from the University of Illinois-Chicago.


  • Catherine E. Ries Vice President, Human Resources and Information Technology
  • Catherine Ries Ms. Ries is Vice President of Human Resources and Information Services and also oversees the company's information services functions. Before joining UniSource Energy in 2007, Ms. Ries was Vice President of Human Resources for Clopay Building Products Company, a division of Griffon Corporation. Ms. Ries also spent more than a dozen years in the airline industry, where she specialized in development and training.

    Ms. Ries earned both a bachelor's degree in fine arts and an MBA from Arizona State University.