VPPs can provide many of the same core services as traditional power plants, namely “capacity, energy, and ancillary services.” They can be called on—"dispatched”—by a grid operator to increase the power supplied to the grid if needed, or to lower demand for power requested from the grid. This allows VPPs to reduce peak demand during high-stress periods, balancing supply and demand in real time and improving grid reliability, especially during extreme weather events. This avoids the costly and polluting impacts of running emergency (“peaker”) fossil fuel plants.
Because VPPs make use of many distributed energy resources, they can help defer or avoid entirely costly grid upgrades, which lowers system costs for utilities and for customers. They also provide reliability services to the grid, which take many different forms. For example, VPPs can control reactive power to ensure voltage remains within safe operating ranges by managing how electrical components oscillate relative to one another. They can also provide power quality services, making rapid, fine-grained adjustments to the shape of the electrical waveform to mitigate distortions and protect grid equipment. These are two examples of grid reliability services, but there are many more.