September 1997 – Sheri Tackett begins building the team and serving industrial natural gas customers as Ashland Energy Services

December 1999 – Acquisition of H&N Gas Marketing

April 2000 – Acquired the assets of EMS (Energy Marketing Services)

May 2000 – Expands energy management services with the signing of first electric energy management contract

October 2001 – Expands the energy management client list through the acquisition of Clinton Energy

December 2003 – The purchase of the assets of Ashland Energy Services is complete. The team officially begins doing business as Delta Energy

August 2004 – Delta is certified as a Women’s Business Enterprise (WBE)

November 2007 – Delta Energy debuts on Business First’s Best Places to Work in Central Ohio (also named to the list in 2008, ‘09, ‘10, ‘11 and ‘12)

July 2008 – Delta Green is introduced, a service devoted to sustainable energy issues and projects

July 2009 – Completed the acquisition of Compass Energy Consulting, LLC

December 2010 – Delta forms a strategic alliance with Bergen Energi (Norway) and Comerc Energia (Brazil) known as the Energy Experts Alliance, allowing us to provide energy management services globally

May 2012 – The Energy Experts Alliance announces their expansion to Australia by welcoming EnergyAdvice to the alliance.

March 2013 – Delta acquires the energy management consulting services division of Energy Advantage in Quebec and Ontario.