Management Team

Mr. Sakellaris is the President and Chief Executive Officer, as well as the Chairman of the Board of Directors of Ameresco, Inc. (NYSE:AMRC), a leading energy efficiency and renewable energy company headquartered in Framingham, MA.

A visionary and entrepreneur, Mr. Sakellaris founded Ameresco in April 2000. He aspired to build an entirely product-neutral and supplier-independent energy company that had the skills, capabilities and foresight to create independent energy solutions that went beyond just conservation; one that addressed a customer’s entire energy stream including supply and demand, energy efficiency and renewable energy.

Early in his career, Mr. Sakellaris worked at the utility New England Electric System (NEES), where he welcomed the challenge to establish NEES Energy, a company that would promote energy efficiency, thereby avoiding the need to build new power generation plants. Mr. Sakellaris then purchased the business known as NEES Energy in 1991 and renamed it NORESCO. He built NORESCO into a an industry-leading independent energy services company before selling it to Equitable Resources in 1997, where he continued to lead NORESCO and was also appointed as a Senior Vice President of Equitable Resources (NYSE:EQT), a Fortune 500 Energy Company.

Today, Mr. Sakellaris leads Ameresco, a public company, employing over 1,000. Ameresco continues to grow and thrive, and currently supports more than 70 local offices throughout North America and the United Kingdom.

With more than 30 years of experience in the energy industry, Mr. Sakellaris has worked to create budget-neutral business models for energy efficiency and renewable energy projects. Mr. Sakellaris’ dedication and influence in promoting energy efficiency dates back to his involvement with the Electrical Power Research Institute (EPRI) where he championed the development of demand side management (DSM) programs that were widely implemented across the country. Additionally, he was a founding member of the National Association of Energy Service Companies (NAESCO) where he served as the first president and advocated for the new industry. He remains an active NAESCO member today.

Mr. Sakellaris earned both M.B.A and M.S.E.E. degrees from Northeastern University and a B.S.E.E. degree from the University of Maine – Orono. In May 2012, the University of Maine granted him an Honorary Doctorate for his lifetime of achievements, recognizing his dedication and exemplary leadership in the field of energy efficiency and renewable energy.

Mr. Sakellaris was the recipient of the 2015 Finance Monthly CEO Award, Ernst & Young Entrepreneur of the Year 2011 New England, Energy, Cleantech & Natural Resources Award. In 2012, he was named the Worcester Business Journal’s Business Leader of the Year for large businesses and also honored by The Boston Globe for Ameresco’s Globe-100 Top-performing Public Companies #29 ranking. The Boston Business Journal ranked Ameresco #31 in the Area’s Fastest Growing Public Companies and #49 in Massachusetts’ 150 Top Public Companies. In 2011, Ameresco was honored on the Forbes 100 list as one of America’s Best Small Companies and in 2010, as the New England Clean Energy Council Employer of the Year.

Mr. Bakas is an Executive Vice President, at Ameresco, a leading energy efficiency and renewable energy company. He is a member of the founding management team of the 20-year old public company (NYSE:AMRC).

Mr. Bakas has nearly 30 years of experience in the energy industry and has been at the forefront of the strategic development of renewable energy assets while being instrumental in Ameresco’s corporate strategic planning and growth.

As a pioneer in the renewable energy industry, he drove and completed some of the earliest agreements that helped shape the markets in those states that first implemented renewable portfolio standards. Ever since, he has championed the growth of Ameresco’s renewable energy asset portfolio to become one of the leading energy services providers in North America.

Mr. Bakas directs Ameresco’s Distributed Energy Systems Group, which is primarily responsible for the development and operation of energy generation assets. This group has successfully developed in excess of 400 MWe of small infrastructure energy supply assets (primarily baseload/dispatchable generation) that have won numerous awards from the U.S. EPA, the Department of Energy, the Climate Change Business Journal, state agencies, and other leading industry organizations.

He has been key in fostering and supporting legislation that promotes the use of renewable resources. Mr. Bakas is an active member of the U.S. EPA’s Landfill Methane Outreach Program, National Association of Energy Engineers, and the Greater Boston Chamber of Commerce Energy Committee. Mr. Bakas sits on the Advisory Board for Microgrid Knowledge, the Coalition for Renewable Natural Gas (where he is Chair of the Sustainability Advisory Board), and the Advanced Energy Group.

As an industry expert, Mr. Bakas is often invited to speak at innovative industry and customer forums where he addresses topics such as Energy Efficiency, Distributed Energy Systems, Microgrids, Energy Storage, Renewable Energy, and Public Private Partnerships. He is regularly sought out for expertise and opinion, and has been involved in numerous national media outlets. Over his career he has been tapped to provide his expertise and guidance regarding energy issues in states from California to Massachusetts, as well as to participate in discussions setting direction for Federal, state and local energy policy. In June 2017, Mr. Bakas was invited to provide expert testimony before the Clean Air Congressional Roundtable session hosted by U.S. Senator Tom Carper at the U.S. Capitol. Mr. Bakas is frequently quoted in industry and business publications, most recently by Forbes and Fortune Magazine. Over the course of his career, he has written a number of articles and is most recently published in Distributed Energy Magazine.

Mr. Bakas earned a B.S. in Mechanical Engineering from the University of Massachusetts Amherst and an M.B.A. from Boston College, The Carroll Graduate School of Management.

Ms. Bulgarino is an Executive Vice President for Ameresco, supporting the company’s mission to energize a more sustainable world by helping customers decarbonize to net zero and build energy resiliency while leveraging smart, connected technologies.

With a focus on the cleantech strategy for the company, Ms. Bulgarino develops innovative solutions focused on both energy efficiency and resilient renewable energy infrastructure.  She is responsible for the overall management of Ameresco’s leading business unit serving the critical Federal government agencies as well as leading large-scale projects for Utility customers.  In addition, she manages the Hawaii regional business unit, focusing primarily on customers in the public sector, education, and hospitality markets.

Ms. Bulgarino has over 25 years of experience in developing and executing innovative clean technology and distributed energy solutions through diverse contract structures. Ms. Bulgarino has overseen the development and implementation of over $3 billion of sustainable solutions in federal, government, and utility energy projects – including deep energy retrofits integrating Smart Building controls, advanced microgrids and energy storage solutions, and multiple clean behind-the-meter and front-of-meter generation systems.

As the general manager for Ameresco’s Federal and Utility Solutions groups, Ms. Bulgarino oversees 320 professionals specializing business development, engineering, commissioning, construction, operations and maintenance, and performance assurance for turnkey solutions. Under her leadership, Ameresco’s Federal and Utility Solutions groups have developed and delivered projects featuring efficiency, generation, and resiliency solutions to the Department of Defense, Department of Energy, General Services Administration, the Veterans Administration, the Department of Justice, the Department of Interior, the Environmental Protection Agency, the Department of Commerce, and other civilian agencies, and to several Utilities including Eversource, PG&E, SDGE, Southwest Gas, Duke, and Hawaiian Electric Company.

Ms. Bulgarino is a seasoned industry executive with strong leadership, communications, and strategic execution talents.  A recognized leader within the industry, she has presented on technical and business panels at major conferences and has skillfully developed solutions for some of the most highly regarded Federal agencies across North America.  As a leading woman in technology, she demonstrates the unique balance of developing and managing complex technical projects, while promoting strategic, long-term corporate success.  Ms. Bulgarino has been highlighted for numerous industry awards and accolades, including being named to the 2021 Environment + Energy Leader 100 list and 2022 Energy Storage Report’s Top 40 Women Leaders in Energy Storage, as well as being listed as a finalist for the S&P Global Platts Rising Star Individual award.

Ms. Bulgarino is a licensed professional engineer and earned a Bachelor of Science degree in chemical engineering from the University of Tennessee and an Executive Management and Leadership Certificate from the Massachusetts Institute of Technology.

Mr. Mark Chiplock is Executive Vice President, Chief Financial Officer, and Chief Accounting Officer of Ameresco (NYSE:AMRC), a leading independent clean technology integrator.

He is responsible for the company’s financial strategy and capital management, investor relations, corporate finance, accounting and treasury functions, financial and operations analysis, business planning, internal and external financial reporting, and information technology infrastructure and security. Focused on accountability to our stakeholders and Ameresco’s relentless pursuit of a sustainable future, Mr. Chiplock also serves as the Executive Chair of Ameresco’s Impact Ambassadors – the company’s ESG program.

Mark has more than 30 years of progressive business management and strategic financial expertise. He is a proactive leader with extensive experience managing teams to oversee and control systems and operational improvement projects in a multi-site environment. Mr. Chiplock has strong knowledge of, and experience in GAAP revenue recognition, SOX 404 requirements, and SEC Regulations, with a proven track record of assessing and implementing financial controls and reporting.

Mr. Chiplock served as Corporate Controller (2014 to 2016), Vice President of Finance and Corporate Controller (2016 to 2018), held the role of interim CFO from (2018 to 2019), and Senior Vice President and Chief Accounting Officer (2019 to 2024).

Prior to Ameresco, he served as Vice President, Finance of GlassHouse Technologies, a data center infrastructure consulting firm.

Mr. Chiplock is a Certified Public Accountant. He is a member of the New York State Society of Certified Public Accountants (NYSSCPA). Mr. Chiplock earned a Bachelor of Business Administration in Accounting from The State University of New York at Buffalo.

Mr. Corrsin is Executive Vice President and General Counsel of Ameresco. He is also the Corporate Secretary and is a member of the Board of Directors. Mr. Corrsin has extensive experience with energy regulations, federal, state and local regulatory authorities, and complex energy construction and financing projects, gained through more than 23 years of energy-related legal practice. Mr. Corrsin oversees financial and regulatory issues of independent power, utility and energy conservation projects for Ameresco.

Mr. Corrsin was formerly an executive vice president of Public Power International, Inc., an independent developer of power projects in south Asia and Europe. Prior to joining PPI, Mr. Corrsin held various positions at Palmer & Dodge, LLP, where he co-founded the Palmer & Dodge Energy Group and represented independent power and energy conservation developers in the U.S. and overseas. Mr. Corrsin has also held positions at Chadbourne & Parke, Hudson Research, and the National Wildlife Federation; each position having a focus on energy.

Mr. Corrsin earned a J.D. degree from the University of Chicago and an A.B. degree in biology from Brown University.

Ms. Leila Dillon is Senior Vice President – Corporate Marketing and Communications at Ameresco, a leading cleantech integrator focusing on energy efficiency and renewable energy solutions. Ms. Dillon has more than 20 years of experience in leading corporate marketing and communications, investor relations, partner strategy, lead generation and business development initiatives for industry leading global technology companies.

In her role, Ms. Dillon is responsible for strategic initiatives that amplify Ameresco’s market leadership position, driving external communications programs including media and public relations and shaping internal corporate communications and training programs. She guides the development of corporate lead and demand generation programs to drive business opportunities across the organization. Ms. Dillon is a key strategist on the executive team and is actively involved in the company’s investor relations.

Recognizing the prominence of ESG initiatives within Ameresco’s core mission, vision, and values, Ms. Dillon worked to launch Ameresco’s ESG Ambassadors in 2020. This group spearheaded the company’s first ESG report, “Doing Well by Doing Good” and continues to serve as the driving force behind Ameresco’s ESG initiatives. Serving as an ESG Ambassador herself, Ms. Dillon is responsible for identifying, communicating, and reporting on the many ways ESG is embedded in Ameresco’s culture.

Additionally, Ms. Dillon participates in strategic industry initiatives and technology conferences. She has chaired global buildings & infrastructure programs, and led international plenary sessions on women leadership in IoT, Smart City, SaaS, PaaS, EaaS, and multi-purposed smart infrastructure platforms.

Prior to joining Ameresco, Ms. Dillon served as Vice President Marketing and North American Distribution for Bigbelly, Inc., a leading provider of Smart City, Internet of Things (IoT), and smart waste management solutions.

With a core focus in Clean Technology, Energy Solutions, Renewables, Distributed Energy Generation, IoT, Smart City, Cloud, Mobile and Telecommunications, Ms. Dillon is a recognized leader for women in technology.

Mr. Maltezos is an Executive Vice President of Ameresco, supporting the company’s mission to energize a more sustainable world by helping customers decarbonize to net zero and build energy resiliency while leveraging smart, connected technologies. He is responsible for our West Region in the U.S.A. and our wholly owned subsidiary, Ameresco Canada Inc. Within these regions, Mr. Maltezos provides senior management oversight to all sales and operations activities and is responsible for developing and executing the company’s growth strategies.

Mr. Maltezos has been a senior executive with Ameresco since 2004, having joined us through our acquisition of Exelon’s energy savings performance contracting business, where he served as vice president and general manager. He has more than 35 years of industry experience in a variety of engineering, management, and executive roles spanning energy savings performance contracting, energy services, distributed generation, mechanical contracting, and utility businesses.

Mr. Maltezos earned an M.B.A. degree from Northwestern University’s Kellogg Graduate School of Management and a B.S. degree in Electrical Engineering from the University of Illinois Urbana-Champaign.

Mr. Christakis is Executive Vice President and General Manager, East Region for Ameresco, supporting the company’s mission to energize a more sustainable world by helping customers decarbonize to net zero and build energy resiliency while leveraging smart, connected technologies. He oversees the East Region, ensuring all aspects of engineering, construction and operations meet and exceed customer expectations.

With more than 28 years of experience in the energy industry, Mr. Christakis is responsible for project material purchasing, sub- contractor selection, contract negotiations and overseeing operational aspects of each project including energy conservation measure selection, project implementation costs, and energy savings analyses.

In his long-standing leadership at Ameresco, Mr. Christakis has managed nearly $1 billion in revenue generating projects that comprised complex energy performance contracts, solar installations, large scale infrastructure, and multi-discipline turnkey installations.

Mr. Christakis earned a Bachelor of Science degree in electrical engineering from Northeastern University. He is a Certified Energy Manager, and holds the following licenses in multiple states: Master Electrician, Journeyman Electrician, Unlimited General Contractor, and Construction Supervisor.

Ms. Lenka Patten is Senior Vice President and Chief Human Resources Officer for Ameresco, a leading cleantech integrator focusing on energy efficiency and renewable energy solutions. Ms. Patten boasts over 20 years of forward-thinking human capital experience, bringing a proven track record of implementing integrated human resource strategies that put people first and support the overall mission and vision of organizations.

In her role, Ms. Patten is responsible for leading the human resources team while supporting the company’s strategic business goals across talent acquisition, professional development, and employee engagement. Joining the company in November 2022, she serves on the executive management team to provide guidance as a personnel advisor to each business unit while cultivating a strong companywide talent strategy and rewarding employee experience.

Prior to joining Ameresco, Ms. Patten served as the head of human resources for Reebok International, where she was responsible for developing and executing global human resource strategy, specifically in the areas of talent management; diversity, equity and inclusion; organization design; performance management; training and development; social purpose and community impact, among others. She’s also held human resources leadership roles at other organizations, including Fidelity Investments and publicly traded State Street Corporation.

Ms. Patten graduated from the University of Economics in Prague, Czech Republic with a bachelor’s degree in economics and comparative politics and a master’s degree in economics. She also holds a master’s degree in organizational development from American University in Washington, D.C. and is a Society for Human Resource Management Senior Certified Professional, a nationally lauded recognition.