  Adopting a zonal structure of electricity market requires specification of
zones' borders. One of the approaches to identify zones is based on clustering
of Locational Marginal Prices (LMP). The purpose of the paper is twofold: (i)
we extend the LMP methodology by taking into account variable weather
conditions and (ii) we point out some weaknesses of the method and suggest
their potential solutions. The offered extension comprises simulations based on
the Optimal Power Flow (OPF) algorithm and twofold clustering method. First,
LMP are calculated by OPF for each of scenario representing different weather
conditions. Second, hierarchical clustering based on Ward's criterion is used
on each realization of the prices separately. Then, another clustering method,
i.e. consensus clustering, is used to aggregate the results from all
simulations and to find the global division into zones. The offered method of
aggregation is not limited only to LMP methodology and is universal.
