Fletcher joined the U.S. Department of Energy in February 2013. As an economist in the Office of Energy Policy and Systems Analysis, Fletcher's role is to deliver unbiased analysis to the Department's leadership on existing and prospective energy-related policies, focusing in part on integrative analysis of energy systems.

Much of Fletcher's recent work has been focused on the water-energy nexus. As a lead contributing author of the Department's June 2014 report on the topic, he wrote and performed the analysis behind the chapter covering the potential effects of climate change and other future trends on the nexus. Since then, Fletcher has had the opportunity to directly apply skills he learned at the Nicholas School to examine a myriad of issues including drivers behind adoption of low-water technologies at power plants and of low-energy technologies at waste water treatment plants.