After a brief analysis of the historical outcomes of the Dispatching Services Market (MSD) (annual energy movements and their economic value), the possible profitability for Electric Vehicles (EVs) providing reserves for tertiary frequency regulation in the form of Balancing Services (SB) on the Balancing Market (MB), which is the real-time phase of MSD, is analyzed. A simulation is conducted for unidirectional (V1G) or bidirectional (V2G) EV charging, where part of the charging process involves providing SB, meaning energy is exchanged at the offered price when the EV’s offers for the service are accepted. The formulation and acceptance of offers are modeled according to heuristic criteria discussed in previous studies. The “reference” charging mechanism used for comparison involves purchasing all energy for charging from the Day-Ahead Market (MGP) at the National Single Price, without providing services. Total energy exchanges for charging, battery charge-discharge cycles, and the electric bill for the EV owner (calculated according to current regulations) are also evaluated on an annual basis.

Nighttime charging during weekdays is considered for the annual period from August 1, 2016, to July 31, 2017, for an EV in the Northern market zone. The case studies, also covered in previous work, concern a domestic and a non-domestic user, with 2.06 MWh/year or 3.59 MWh/year to recharge and a maximum charging power of 2 kW or 12 kW, respectively. For each case study, the sensitivity of the results is evaluated with respect to the offer prices for SB, assumed constant throughout the year. The maximum savings compared to the reference bill, ranging between approximately 7% and 113% in different cases, are always obtained for offer prices of around €10/MWh for downward regulation and €80/MWh or €350/MWh for upward regulation. In the offer price space, profitability regions expand, and maximum savings compared to the reference bill increase if partial exemptions from bill charges are assumed (they reach around 153% if exemptions apply only to energy consumed for downward regulation and 168% if they also apply to energy injected into the grid for upward regulation) and/or if additional compensation is provided for the capacity made available for SB. The offer prices yielding the highest savings do not vary significantly with or without exemptions.