  A new microeconomic model is presented that aims at a description of the
long-term unit sales and price evolution of homogeneous non-durable goods in
polypoly markets. It merges the product lifecycle approach with the price
dispersion dynamics of homogeneous goods. The model predicts a minimum critical
lifetime of non-durables in order to survive. Under the condition that the
supply side of the market evolves much faster than the demand side the theory
suggests that unsatisfied demands are present in the first stages of the
lifecycle. With the growth of production capacities these demands disappear
accompanied with a logistic decrease of the mean price of the good. The model
is applied to electricity as a non-durable satisfying the model condition. The
presented theory allows a deeper understanding of the sales and price dynamics
of non-durables.
