The Ener-geyser (or Schoonschip Geyser) is a data-driven (floating) fountain that visualises peak times: times when there is a high demand for energy on the communal energy smart-grid of an Amsterdam-based resource community called Schoonschip. By visualising energy levels in real-time, the Geyser helps the community make decisions about when to turn on appliances, in order to achieve their agreed sustainability goals.