Leveraging recent investments in AMI, Ameren Illinois began aggregating hourly service point load forecast data by voltage (loss) class vs. the hourly system load to determine the loss factors per voltage class for every hour of the day. Not only does this innovative approach reduce the time it takes to perform a loss study from more than a year to seconds, but it more accurately accounts for real losses across the system. This innovative approach to system loss studies will be essential to utility planning efforts, particularly in the siting and integrating DER on the distribution grid. Ameren has filed new tariffs for calculating distribution system losses by voltage class with the Illinois Commerce Commission (ICC). This innovative approach will virtually eliminate the need to perform traditional loss studies, and the ICC Staff view the methodology as a more equitable approach to socializing the cost of technical losses and related distribution system unaccounted for energy (DUFE).