Proliferation of active grid-edge devices and systems is changing the utility operational and business model. The owners and operators of these systems, generally referred to as prosumers (consumers with Distributed Energy resources, microgrids, smart buildings, etc.) are demanding that regulators allow for, and utilities accommodate, transactive market-based transactions. These include peer-to-peer transactions among prosumers, as well as their voluntary participation in retail and wholesale markets. The volume, frequency, variety, and variability of these transactions call for new methods for tracking, bookkeeping, settlement, and dispute resolution associated with such transactions. A major concern is also security threats in both financial and operational domains. The Blockchain technology provides some features that can be used to advantage to mitigate some of these concerns, but it also entails potential drawbacks in terms of processing efficiency and computational burden. This panel session will address the following topics: emerging industry landscape and peer-to-peer Transactive Energy Systems, generic blockchain elements, attributes, and functions, potential use of blockchain in Transactive Energy Systems, and use cases and examples.