CESER Leadership
Alex Fitzsimmons
Director
Alex Fitzsimmons is the Director of the Office of Cybersecurity, Energy Security, and Emergency Response (CESER) at U.S. Department of Energy (DOE). Appointed in May 2025, he leads the Department's efforts to safeguard the nation's energy infrastructure against evolving cyber and physical threats, ensuring resilience and security across critical energy systems.
With more than a decade of experience in energy policy and government leadership, Fitzsimmons has held several key positions within DOE. Most recently, he served as DOE’s Chief of Staff, guiding the Department through its initial 100 days under the Trump Administration. Prior to that, he was Deputy Assistant Secretary in the Office of Energy Efficiency and Renewable Energy (EERE), where he also served as Chief of Staff to the Assistant Secretary. In these roles, Fitzsimmons advanced initiatives related to energy efficiency, advanced manufacturing, and cybersecurity, including the development of EERE’s Cybersecurity Multiyear Program Plan, published in November 2020.
Before rejoining DOE, Fitzsimmons led government affairs at Sila Nanotechnologies, a next-generation energy storage company, and served as Senior Director at ClearPath, focusing on energy storage and critical mineral supply chains. Earlier in his career, he managed policy and public affairs at the Institute for Energy Research and its advocacy arm, the American Energy Alliance.
Fitzsimmons holds a Bachelor of Arts in Political Science from The George Washington University and a Master of Science in Cybersecurity from the Georgia Institute of Technology.
Lili Colon
Principal Deputy Director
With more than 20 years of experience, Lili Colon has a deep understanding of how quickly the threat landscape changes and what is needed to best secure and protect the U.S. energy supply from all threats. She helps drive the U.S. Department of Energy’s Office of Cybersecurity, Energy Security, and Emergency Response (CESER) mission to strengthen the security and resilience of U.S. energy infrastructure from cyber, physical, and natural hazard risks and disruptions by leveraging critical expertise across both public and private sectors.
Lili guides the department and its programs towards success with an emphasis on multi-disciplinary collaboration among agency partners, industry, academia, and education. Her background in operations and cyber, physical, and communications domains is rooted in her commitment to excellence and ensures a critical eye is kept on the horizon.
Most recently, Lili served as the Deputy Associate Director for the Integrated Operations Division within the Cybersecurity Infrastructure Security Agency (CISA). In this role, she worked to minimize the impact to our Nation’s Critical Infrastructure by establishing operational and leadership support within the Agency’s 24/7 Operation Center. Lili also served as the deputy co-chair to the COMM-ISAC and supported CISA’s operational processes in response to Emergency Support Functions #2: “Communication” and #14: “Cross-sector Business and Infrastructure” responsibilities under the National Response Framework.
Previously, Lili served as the Chief for Strategic Planning and Resource Management for the Cybersecurity Division within CISA. Ther work was integral in managing strategy, policy coordination, integrating program planning, and performance of a $1.2B annual budget. Furthermore, she was responsible for maturing the Division’s annual operating plans and long-term strategy to achieve national cybersecurity objectives. This required Lili to establish multiple agency strategic policy development planning efforts and coordinate engagements to support the Department of Homeland Security’s broader mission to increase resilience in our Nation’s Critical Infrastructure and reduce exposure to cyber risks.
Throughout her career, Lili has honed her expertise through various Information Technology/Cybersecurity Positions in the government and private sectors relating to the Certification and Accreditation Process, Cybersecurity Curriculum Manager, Information Assurance, Cyber Strategic Planning, and Security Policy Development.
Her role at CESER clarifies the Office’s vison for how our Nation can secure its energy infrastructure now and in the future.
Mara Winn
Deputy Director, Preparedness, Policy, and Risk Analysis
Mara Winn is the Deputy Director for the Preparedness, Policy, and Risk Analysis (PPRA) division of the Office of Cybersecurity, Energy Security, and Emergency Response (CESER). In this role, Winn leads the division in supporting energy sector security and resilience through strong, two-way coordination and communication with the Department of Energy‘s (DOE) government and industry partners.
Prior to joining the DOE, Winn was the Associate Director for Planning and Coordination at the Cybersecurity and Infrastructure Security Agency’s (CISA) National Risk Management Center. She oversaw planning and collaboration activities focused on addressing the Nation's highest priority critical infrastructure risks, originating from cyber-attacks and other hazards. Winn has more than twenty years of experience in all stages of acquisition management, systems engineering, project management, and product development life cycles from analysis through implementation and closeout. She has led teams across the Department of Homeland Security (DHS) in the areas of risk management, radiological and nuclear detection, transportation security, and immigration, as well as in medical device development in the private sector.
Winn received a Bachelor of Arts in Physics from Smith College and a Bachelor of Engineering from Dartmouth College, and is a graduate of the DHS Senior Executive Services Candidate Development Program. Winn also holds a Certificate in Project Management from Boston University, is a certified Project Management Institute (PMI) Project Management Professional (PMP), and holds several technical certifications.
Thomas McGarry
Acting Deputy Director, Office of Petroleum Reserves
Thomas McGarry is currently employed at the U.S. Department of Energy, holding the position of (Acting) Deputy Director for the Office of Petroleum Reserves. Throughout his career at the Department of Energy, Tom has fulfilled various roles, including Director of Operations and Readiness for the Office of Petroleum Reserves as well as General Engineer for the Office of Planning and Engineering. With a rich background spanning 40 years, Tom has amassed extensive expertise in petroleum management, encompassing diverse areas such as bulk terminal management, engineering design of bulk fuel terminals, and logistical support for the U.S. Navy’s global petroleum needs. Tom obtained a Bachelor of Science degree in Chemistry from North Georgia College, a Bachelor of Science degree in Chemical Engineering from the Georgia Institute of Technology, and an MBA from Virginia Tech, where his studies focused on Derivatives Management.