  The primary aim of this paper is to illuminate potential
Vehicle-to-Everything (V2X) flexibility services that can be activated at the
three levels of home, community, and grid. To do this, the potential practical
services that can be provided by EVs, flexibility requesters, and the required
exchange mechanisms at these three levels are identified. At the home level,
the two main services that EVs can provide to households are explored. The
initial service focuses on cost reduction for homes by employing smart charging
and discharging methods, and the second service underscores the capability of
an EV equipped with bidirectional chargers to function as a backup resource
during grid outages. At the community level, three flexibility services are
introduced and outlined: community cost reduction, energy sharing, and backup
resources. There is more than one flexibility requester, including the
community manager, EV owners, and other end users. Accordingly, at this level,
having a fair and transparent market mechanism can optimise the activation of
different V2X flexibility services. At the grid level, flexibility providers
can offer two main flexibility services, namely load profile adjustment and
real-time voltage and frequency control, to a wide range of flexibility
requesters, including distribution network/systems operators (DNOs/DSOs) to
overcome technical challenges of the distribution network, energy suppliers to
manage their energy portfolio, and TSOs to support transmission network. In
addition, a review of trial V2X projects and V2X supporting regulations is
presented to contextualize the feasibility and regulatory framework for
implementing these services. This analysis offers insights into the challenges
and opportunities that need to be addressed for the effective integration of
V2X flexibility services across the three identified levels.
