[en] The concept of distributed, dispatchable power generation is essentially the reverse of interruptible service. It can be understood by regarding both power and money as vectors: when the direction of the power flow switches, so does the direction of the money flow. At a signal given by the utility, a factory activates its emergency generating system and briefly becomes an independent power producer (IPP), feeding power into a local region of the grid. Upon receipt of another signal, it retires from that role. It may, however, continue to generate power for its own use