  The analysis of load curves collected from smart meters is a key step for
many energy management tasks ranging from consumption forecasting to customers
characterization and load monitoring. In this contribution, we propose a model
based on a functional formulation of nonnegative tensor factorization and
derive updates for the corresponding optimization problem. We show on the
concrete example of multi-sites load curves disaggregation how this formulation
is helpful for 1) exhibiting smooth intraday consumption patterns and 2) taking
into account external variables such as the outside temperature. The benefits
are demonstrated on simulated and real data by exhibiting a meaningful
clustering of the observed sites based on the obtained decomposition.
