By Paul De Martini ©ISTOCKPHOTO.COM/RASTUDIOW Operational Coordination Architecture New Models and Approaches Digital Object Identifier 10.1109/MPE.2019.2921740 Date of publication: 19 August 2019 september/october 2019 T THE GROWING USE OF DISTRIBUTED ENERGY REsource (DER) services from distributed generation, storage, flexible loads, energy efficiency, and electric vehicles is driving a need for increased coordination among transmission and distribution operators (DOs), customers, aggregators, and a variety of emerging participants. To ensure a reliable and resilient power grid today and into the future, it is essential to consider the architectural implications, particularly in regard to industry structural considerations. These include new transmission-distribution-customer 1540-7977/19©2019IEEE ieee power & energy magazine 29http://www.ISTOCKPHOTO.COM/RASTUDIOW