A method of controlling energy supply in an energy distribution network comprising an energy generation facility adapted to supply energy to the energy distribution network and an energy consumer coupled to the energy generation facility and adapted to consume energy from the energy distribution network, the method comprising, at the energy generation facility: detecting a curtailment condition, the curtailment condition indicating that the energy generation facility should curtail its supply of energy to the energy distribution network, wherein detecting the curtailment condition comprises one of: receiving a curtailment request message from a control system associated with the energy distribution network; and determining a time at which curtailment should be implemented based on a curtailment schedule; in response to the curtailment condition, transmitting, via a communications link , a request to increase energy consumption to the coupled energy consumer; receiving a reply message from the coupled energy consumer via the communications link; and controlling energy output from the generation facility to the energy distribution network in dependence on the reply message, wherein controlling energy output comprises continuing energy output without curtailment in response to one of: the reply message indicating that the energy consumer has increased its energy consumption; the reply message indicating that the energy consumer has increased its energy consumption by at least a predetermined amount or an amount specified in the request. detecting a curtailment condition, the curtailment condition indicating that the energy generation facility should curtail its supply of energy to the energy distribution network, wherein detecting the curtailment condition comprises one of: receiving a curtailment request message from a control system associated with the energy distribution network; and determining a time at which curtailment should be implemented based on a curtailment schedule; receiving a curtailment request message from a control system associated with the energy distribution network; and determining a time at which curtailment should be implemented based on a curtailment schedule; in response to the curtailment condition, transmitting, via a communications link , a request to increase energy consumption to the coupled energy consumer; receiving a reply message from the coupled energy consumer via the communications link; and controlling energy output from the generation facility to the energy distribution network in dependence on the reply message, wherein controlling energy output comprises continuing energy output without curtailment in response to one of: the reply message indicating that the energy consumer has increased its energy consumption; the reply message indicating that the energy consumer has increased its energy consumption by at least a predetermined amount or an amount specified in the request. the reply message indicating that the energy consumer has increased its energy consumption; the reply message indicating that the energy consumer has increased its energy consumption by at least a predetermined amount or an amount specified in the request. <EOS>