The Energy Department always tries to conserve energy and save money. And that includes employee Tien Nguyen, who recently retired after 30 years of federal service.
Nguyen, an analyst for the agency's fuel cell technologies office, has helped save Americans millions of dollars with his work and he also picked up another money-saving side gig.
Every night for the past 16 years, Nguyen has walked through his building and turned off every light left on. The simple act has saved 1,500 megawatts of energy, which translates into $200,000 saved.
To learn more, check out the video below from the Energy Department: