Nowadays, with the structural modification of the electric energy industry around the world, including in Brazil, services characterised as ancillary, that always were offered bundled with energy supply, without specific remuneration, should be dealt with independently. The need for cost optimisation, caused by the new commercial environment, sometimes competitive, has made the generating agents to understand operating reserves and frequency regulation as a new opportunity of providing services. Furthermore, new costs and obligations have been created, thus reinforcing the need for these ancillary services to be remunerated. It is necessary to recognise the benefits aggregated to the electric system by ancillary services, represented by improvement of reliability and energy quality. In this way, issues that deserve to be carefully treated are i) the prices to be paid by consumers, ii) the participation of each agent that really provided the service, and iii) the fairness of the mechanism for distribution of the financial resources among the providers. In this work it is developed a structure for the remuneration of operating reserves and frequency regulation, based on the benefit of this services, awarding efficiency and allowing the recuperation of incurred costs. Through study-cases with actual data, it is verified the consistency of the proposal, by comparing its results with values in practice, and by analysing its impact over current electric energy tariffs.