The evolution of energy markets is accelerating in the direction of a greater reliance upon distributed energy resources (DER), whether those resources generate, consume, or store electricity. The technologies and new frameworks necessary to manage this increasing two-way complexity remain unclear. Nevertheless, successful strategies to harvest more value from smaller, cleaner, and smarter energy resources are being deployed today. One such strategy is a virtual power plant (VPP), the concept that intelligent aggregation and optimization of DER can provide the same essential services as a traditional 24/7 centralized power plant. VPPs can be viewed as a manifestation of transactive energy, whereby new technologies such as demand response (DR), solar PV systems, advanced batteries, and EVs are transforming formerly passive consumers into active prosumers. The primary goal of a VPP is to achieve the greatest possible profit for asset owners while maintaining the proper balance of the electricity grid?at the lowest possible economic and environmental cost. Without any large-scale fundamental infrastructure upgrades, VPPs can stretch supplies from existing generators and utility demand reduction programs (and other forms of DER). According to Navigant Research, global VPP implementation spending (excluding energy storage) is expected to reach $2.1 billion annually by 2025. This Navigant Research report analyzes the global market for VPPs and enabling technologies in three primary segments: DR, supply-side, and mixed asset. The study provides an analysis of the market issues, including drivers, barriers, and business cases associated with VPPs. Global market forecasts for capacity and implementation spending, broken out by segment, region, and technology, extend through 2025. Along with the three technology categories (metering and telemetry, device controls, and software), this report sizes the capacity growth of energy storage devices in emerging markets for mixed asset VPPs. The report also examines technology issues related to VPPs, as well as the competitive landscape.