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.





States our employees live in


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.

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A Timeline of Growth

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ESG Corporate Office - Night_web


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.


Ownership is transferred to SIGCORP, a holding company that helps facilitate company growth.


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.


SIGCORP and Indiana Energy merge, forming Vectren Corporation. ESG is now owned by Vectren Corporation and Citizens Gas & Coke Utility.


Vectren Corporation buys the remaining one third ownership from Citizens Gas & Coke Utility, making it the sole owner.


ESG becomes a subsidiary of CenterPoint Energy, Inc. (NYSE: CNP), an energy delivery company, totaling approximately $35 billion in assets.


Oaktree Capital Management’s Power Opportunities group acquires ESG, establishing ESG as a standalone company.


Oaktree’s investment will support ESG’s strategic growth plans by leveraging our national platform and expertise in developing and implementing sustainable energy services for public- and private-sector customers.