In 2003, following a 20-year career working for Grainger and Wesco, Mike Doran recognized the opportunity to help businesses upgrade their lighting using a new utility rebate offered by Platte River Power Authority in Northern Colorado. Establishing Energy Solutions Unlimited, LLC, Mike has cultivated ESU to become one of the premier lighting retrofit distributors in Colorado.

In 2014, Tae Yim of YN Energy acquired Energy Solutions Unlimited. As an electrical engineer and business enthusiast, he keeps the same values the company was built on.