1. A method of controlling a power generating unit, the method comprising: receiving, at a computing device, a signal indicative of a first load demand set point, the first load demand set point indicative of a first desired output of the power generating unit; determining, via the computing device, a control signal to be used to drive the power generating unit to operate to generate power according to an initial load ramp process, the initial load ramp process based on a particular model and the first load demand set point; periodically or continuously performing a state estimation while the power generating unit is ramping, according to the initial load ramp process, towards the first load demand set point to obtain a current state estimation of the power generating unit; and while the power generating unit is ramping, according to the initial load ramp process, towards the first load demand set point: receiving a signal indicative of a second load demand set point, the second load demand set point indicative of a second desired output of the power generating unit; using the current state estimation to calculate, via the computing device, a modified control signal for use in driving the power generating unit to operate to generate power according to a modified load ramp process, the modified load ramp process based on the particular model and the second load demand set point; and using the modified control signal to modify operation of the power generating unit to operate according to the modified load ramp process to drive the power generating unit towards the second desired output specified by the second load demand set point signal.