This panel presents a number of selected papers submitted to the forthcoming special section on Transactive Energy in the Transactions on Power Systems. This panel will bring together researchers and practitioners from industry, research laboratories and academia to present and discuss challenges and opportunities related to market-based and transactive approaches to the integration of flexible demand and distributed generation and storage. In the future grid, demand response and response from distributed generation and storage is expected to be used on a large scale to perform active management of distribution grids and to balance the fluctuating power generation of renewable power generation. Key elements of the smart grid vision are the coordination mechanisms. Through these, vast numbers of devices, currently just passively connected to the grid, will become actively involved in system-wide and local coordination tasks. In this light, market-based, transactive approaches are emerging as strong contenders for orchestrating the coordinated operation of so many devices. In a transactive energy system, one is using value as a key operational parameter, i.e. operational decisions are made through an exchange of value-based information captured in transactions between participants. Whereas transactive or market-based coordination mechanisms are already used on the level of bulk power production, trade and transmission across the globe, the use of these mechanisms at the distribution level, integrating numerous flexible devices into the power system, is still a topic needing scientific advancement. Research into transactive energy is strongly interdisciplinary, involving the state of the art in power engineering, computer science, (micro-) economics and control engineering.