Fast demand response (fast DR) to provide frequency regulation involves precise, short duration adjustments in energy consumption that follow instruction signals received from the grid operator every 2 to 6 seconds. OpenADR 2.0b facilitates fast DR through a common interface and two way communications. Tests of the ability to aggregate responses by several sites are included in this project, supported by the Center for Electricity Reliability Technology Solutions (CERTS). This multi-phase project examines and compares the value of ancillary services that could be provided by DR throughout US wholesale markets. Communication requirements (transport mechanisms, latencies, and security requirements for communication and control) to support fast DR resource integration into the ancillary services markets are examined from a technical point of view. Methodologies for accurately forecasting DR resource availability for market participation are examined. The ability of commercial building loads to provide regulation service via fast DR is demonstrated using an OpenADR 2.0 enabled signaling architecture to quantify architectural and control system latencies as well as response accuracy.