Electric vehicles (EVs) are a promising source of power system services. This paper looks at the ability of EVs to provide power system reserve by studying the potential driving and charging profiles of EVs. The Irish power system is considered as a case study. The results show that the potential for EVs to provide contingency reserve is strongly dependent on the time of day, day of week and the seasonal effect of climate control on EV energy consumption. The driving and charging patterns are more variable on the weekends than weekdays, which adds uncertainty to the availability of contingency reserve. There is significant daily variation in EV charging however there may be potential to fill these troughs in reserve availability through aggregation with other household loads through demand side management.