Our History
Building on a Legacy of Practical Innovation
Forging lasting partnerships with our clients to solve their toughest energy and infrastructure challenges isn’t just something we do.
It's what we've always done.
From our earliest days as an energy service company (ESCO), we’ve been helping our clients build a brighter tomorrow.
Our roots in collaborative consulting run deep.
We were founded in 1994 with a vision to help our clients achieve their energy efficiency, resiliency, infrastructure, and sustainability goals. From the start, we set ourselves apart in our approach as a partner and advocate for our clients.
We’ve grown substantially since then in terms of capabilities, projects, and people.
400+
Employees
48
States we're licensed to work in
Plus Washington D.C. and the U.S. Virgin Islands
But through it all, our commitment
to create a more energy-sustainable
future has remained true.
We are a leader in the industry because we are and have always been passionate about helping our clients make their communities safer, more efficient, and more resilient.
A Timeline of Growth
1994
Energy Systems Group, LLC is formed as a non-regulated, wholly-owned subsidiary of Southern Indiana Gas & Electric Company (SIGECO) in April 1994.
ESG becomes profitable within the first five months of operation.
1996
Ownership is transferred to SIGCORP, a holding company that helps facilitate company growth.
1997
ESG begins discussions with two Indiana-based utility companies.
On June 18, SIGCORP sells two thirds of their ownership to Indiana Energy and Citizens Gas & Coke Utility.
2000
SIGCORP and Indiana Energy merge, forming Vectren Corporation. ESG is now owned by Vectren Corporation and Citizens Gas & Coke Utility.
2003
Vectren Corporation buys the remaining one third ownership from Citizens Gas & Coke Utility, making it the sole owner.
2019
ESG becomes a subsidiary of CenterPoint Energy, Inc. (NYSE: CNP), an energy delivery company, totaling approximately $35 billion in assets.
2023
Oaktree Capital Management acquires ESG, establishing it as a standalone company and supporting its strategic growth in sustainable energy services.
2024
Energy Systems Group has expanded its presence across the Southwestern and California United States by acquiring Yearout Energy Services Company and PacificWest Energy.