This paper presents analysis on the benefit of Governor Response service by generators and of the Frequency Keeping ancillary service. The benefit is the value of the services to the System Operator and ultimately New Zealand by maintaining secure operation of the grid. Governor Response and Frequency Keeping manage normal variations in demand and intermittent generation, to keep the frequency in the normal band. This ensures secure operation of the grid, and thereby minimises frequency deviations when a contingent event occurs. Ultimately this reduces the likelihood of black-outs, indicating the importance of these services. This is of interest to the GREEN Grid project, which is investigating ways of managing increasing amounts of intermittent renewable generation. Knowing the benefits of these services, and how intermittent generation changes that value, enables GREEN Grid to assess the cost of increased intermittent renewable generation, how those costs should best be recovered, and to assess new ancillary service markets for them. These markets may include demand response. An analysis of the value of Governor Response and Frequency Keeping is considered from the perspective of avoiding lost load due to sub-optimal management of contingent events. Value is also considered from the perspective of how normal frequency is managed