  Power systems are subject to fundamental changes due to the increasing infeed
of decentralised renewable energy sources and storage. The decentralised nature
of the new actors in the system requires new concepts for structuring the power
grid, and achieving a wide range of control tasks ranging from seconds to days.
Here we introduce a multiplex dynamical network model covering all control
timescales. Crucially, we combine a decentralised, self-organised low-level
control and a smart grid layer of devices that can aggregate information from
remote sources. The safety-critical task of frequency control is performed by
the former, the economic objective of demand matching dispatch by the latter.
Having both aspects present in the same model allows us to study the
interaction between the layers. Remarkably, we find that adding communication
in the form of aggregation does not improve the performance in the cases
considered. Instead, the self-organised state of the system already contains
the information required to learn the demand structure in the entire grid. The
model introduced here is highly flexible, and can accommodate a wide range of
scenarios relevant to future power grids. We expect that it is especially
useful in the context of low-energy microgrids with distributed generation.
