Tapping into and harnessing small-scale flexibility is a major but rewarding challenge in the energy system transformation. The flexibility of a single battery electric vehicle is limited, but a commercial fleet can make a significant contribution, and multiple fleets – pooled together into a virtual flexibility pool – open up opportunities to participate in markets and stabilize grids. We develop cascaded operational management concepts that enable optimization at various levels. Our research focuses primarily on energy communities as local flexibility hubs, but also includes simulation studies of large battery electric vehicle or heat pump pools operated to benefit the grid or the market.