Due to the strong development of generation from Non-Programmable Renewable Sources (NPRS), the network manager (Terna in Italy) needs new Auxiliary Services (ASs) suppliers, more stringent performance for existing ASs and new ASs. We analyze the technical and remuneration specifications and Terna’s need for the main ASs in recent years, as well as the Pilot Projects launched to increase the number of participants in the Market for Dispatching Services (MDS). The use of ASs is then evaluated at the market zone and ‘Grid Supply Point’ (GSP) level, in terms of quantity and total economic volumes and average prices of the offers accepted on the MDS, and the probability of acceptance of the offers based on price is estimated.

Battery-based Storage Systems (SS) could usefully supply ASs, thanks to management flexibility and speed of response, but still feature high investment costs. A stochastic version of a tool developed in the GAMS environment is implemented for the optimization of the size (energy and power) and management of an SS to provide multiple ASs together (primary, secondary and tertiary frequency control, participation in the Day-Ahead Market or DAM, reduction of imbalances of a coupled NPRS system) in the presence of uncertainties. The application to a SS associated with a GSP in the Northern area quite active in 2019 for tertiary and balancing services shows that the uncertainty of acceptance of the relevant offers reduces the economic convenience of tertiary regulation on the ex-ante MDS, which is potentially more interesting than that of the other services considered.

The charging of an Electric Vehicle (EV) is then optimized in a deterministic way via a balancing service on the ex-post MDS (BM) instead of just purchasing energy on the DAM. As more energy is sold on BM, the savings are greater with bidirectional charging than with unidirectional charging; in the first case they are even more dependent on the daily mileage of the vehicle than in the second. However, further evaluations are needed as far as the choice and acceptance of the service offer prices are concerned. Finally, with a view to simulating the participation of resource aggregates – including stationary SSs and Evs – in electricity markets, a literature review on related modeling problems and optimization approaches is carried out.