  Large deployment of distribute energy resources and the increasing awareness
of end-users towards their energy procurement are challenging current practices
of electricity markets. A change of paradigm, from a top-down hierarchical
approach to a more decentralized framework, has been recently researched, with
market structures relying on multi-bilateral trades among market participants.
In order to guarantee feasibility in power system operation, it is crucial to
rethink the interaction with system operators and the way operational costs are
shared in such decentralized markets. We propose here to include system
operators, both at transmission and distribution level, as active actors of the
market, accounting for power grid constraints and line losses. Moreover, to
avoid market outcomes that discriminate agents for their geographical location,
we analyze loss allocation policies and their impact on market outcomes and
prices.
