Transactive energy is an evolving concept, as initial pilots are testing the capacities of existing technologies, policies, processes, and business models. Transactive energy proponents envision an organized marketplace where prosumers can buy or sell electricity with confidence that transactions are managed through enforceable rules that apply to all. Transactive energy requires a convergence of technologies, policies, and financial drivers in an active prosumer market—where prosumers are buildings, electric vehicles, microgrids, or distributed energy resources, assets like solar panels, wind generators, or energy storage. This chapter examines the different main drivers before exploring the privacy considerations in the evolution from today’s grid to a Smart Grid that includes transactive energy. Regulatory policy is a revolutionary driver for transactive energy. Finance drivers are often closely intertwined with policy drivers, and those synergies are quite apparent. The chapter briefly discusses private enterprise activity in innovative financial mechanisms that have ramifications for the Smart Grid and transactive energy.