Method implemented by computer, for determining a sequence of operation of at least one set of generator units of an electrical network, the generator units of the set being identical, the sequence of operation allocating for each time interval (Δt) of a given period, an off state or an on state to each generator unit and an operating power (Pf) comprised between a minimum power P min g of the generator unit and a maximum power P max g of the generator unit to each generator unit to which is allocated the on state for the time interval (Δt), the method being characterised in that it comprises the following steps: - Assigning a rank to each generator unit (201, 101); - From a projected load curve, determining a minimum number of generator units N min destined to be allocated the on state over the period (T, 102); - For each generator unit having a rank less than or equal to the minimum number of generator units N min, allocating in the sequence of operation the on state to the generator unit for each time interval (Δt, 103); - For each generator unit having a rank greater than the minimum number of generator units N min, allocating, by increasing rank, for each time interval (Δt) of the sequence of operation the on state or the off state to the generator unit, and for each generator unit to which is assigned the on state at a given time interval (Δt) of the sequence of operation, allocating an operating power (Pf), by optimisation of a cost function over the period with: ∘ a constraint according to which the number of time intervals (Δt) over the whole of the period for which the on state is allocated to the generator unit is greater than or equal to the number of time intervals (Δt) over the whole of the period for which the on state is allocated to each generator unit having a rank greater than the generator unit; or ∘ a constraint according to which, for each time interval (Δt) of the period, the on state can only be allocated to a generator unit if the on state has been allocated to each generator unit having a rank less than the generator unit; the minimum number N min of generator units being chosen such that: ⌊ P min c P max g ⌋ + 1 ≤ N min ≤ ⌊ P max c P min g ⌋ With: P min c the minimum power of the projected load curve, P max c the maximum power of the projected load curve, P min g the minimum power of the generator unit, P max g the maximum power of the generator unit and [. J the integer part. - Assigning a rank to each generator unit (201, 101); - From a projected load curve, determining a minimum number of generator units N min destined to be allocated the on state over the period (T, 102); - For each generator unit having a rank less than or equal to the minimum number of generator units N min, allocating in the sequence of operation the on state to the generator unit for each time interval (Δt, 103); - For each generator unit having a rank greater than the minimum number of generator units N min, allocating, by increasing rank, for each time interval (Δt) of the sequence of operation the on state or the off state to the generator unit, and for each generator unit to which is assigned the on state at a given time interval (Δt) of the sequence of operation, allocating an operating power (Pf), by optimisation of a cost function over the period with: ∘ a constraint according to which the number of time intervals (Δt) over the whole of the period for which the on state is allocated to the generator unit is greater than or equal to the number of time intervals (Δt) over the whole of the period for which the on state is allocated to each generator unit having a rank greater than the generator unit; or ∘ a constraint according to which, for each time interval (Δt) of the period, the on state can only be allocated to a generator unit if the on state has been allocated to each generator unit having a rank less than the generator unit; the minimum number N min of generator units being chosen such that: ⌊ P min c P max g ⌋ + 1 ≤ N min ≤ ⌊ P max c P min g ⌋ With: P min c the minimum power of the projected load curve, P max c the maximum power of the projected load curve, P min g the minimum power of the generator unit, P max g the maximum power of the generator unit and [. J the integer part. ∘ a constraint according to which the number of time intervals (Δt) over the whole of the period for which the on state is allocated to the generator unit is greater than or equal to the number of time intervals (Δt) over the whole of the period for which the on state is allocated to each generator unit having a rank greater than the generator unit; or ∘ a constraint according to which, for each time interval (Δt) of the period, the on state can only be allocated to a generator unit if the on state has been allocated to each generator unit having a rank less than the generator unit; the minimum number N min of generator units being chosen such that: ⌊ P min c P max g ⌋ + 1 ≤ N min ≤ ⌊ P max c P min g ⌋ With: P min c the minimum power of the projected load curve, P max c the maximum power of the projected load curve, P min g the minimum power of the generator unit, P max g the maximum power of the generator unit and [. J the integer part.